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Every time a star forms, it represents an explosion of possibilities. Not for the star itself; its fate is governed by its mass. The possibilities it signifies are in the planets that form around it. Will some be rocky? Will they be in the habitable zone? Will there be life on any of the planets one day?

There’s a point in every solar system’s development when it can no longer form planets. No more planets can form because there’s no more gas and dust available, and the expanding planetary possibilities are truncated. But the total mass of a solar system’s planets never adds up to the total mass of gas and dust available around the young star.

What happens to the mass, and why can’t more planets form?

When a protostar forms in a cloud of molecular hydrogen, it’s accompanied by a rotating disk of gas and dust called a circumstellar disk. As material gathers into larger and larger bodies, planetesimals form, and eventually, planets. At that point, the disk is referred to as a protoplanetary disk. But whatever we call it, the rotating disk is the reservoir of material out of which planets form.

In our Solar System, there are more rocky objects than gaseous ones. Not by mass but by number. Scientists think that systems similar to ours form similar numbers of rocky and gaseous objects.

But in the Solar System’s early days, there was way more gas than there was solids. This contradicts the fact that the disks around young stars contain 100 times more gas than they do solids. Where does all the gas go?

New research based on JWST observations provides an answer. The study is “JWST MIRI MRS Observations of T Cha: Discovery of a Spatially Resolved Disk Wind.” It’s published in The Astronomical Journal, and the lead author is Naman S. Bajaj, a doctoral student at the University of Arizona’s Lunar and Planetary Laboratory.

T Chamaelontis (T Cha) is a young T Tauri star located about 335 light-years away. T Tauri stars are less than about ten million years old and haven’t entered the main sequence yet. At this point in their development, the disks around T Tauri stars are dissipating. The gas in the disk is being actively dispersed into space.

“Knowing when the gas disperses is important as it gives us a better idea of how much time gaseous planets have to consume the gas from their surroundings,” said lead author Bajaj. “With unprecedented glimpses into these disks surrounding young stars, the birthplaces of planets, JWST helps us uncover how planets form.”

Artistic rendition of a protoplanet forming within a protostar’s disk. Image Credit: ESO/L. Calçada http://www.eso.org/public/images/eso1310a/

Since the type and number of planets formed in a disk around a star depends on how much gas and dust are available, knowing how and when it disperses is foundational to understanding the eventual solar system.

“So, in short, the outcome of planet formation depends on the evolution and dispersal of the disk,” Bajaj said.

T Cha is noteworthy for another reason beyond its young age. Its eroding circumstellar disk has a vast dust gap in it about 30 astronomical units wide. On the inside of the gap is a narrow ring of material close to the star, and on the outside of the gap is the remainder of the disk material. A planetary candidate is in the gap but isn’t part of this research.

This schematic from the research shows T Cha, the dust gap, the planetary candidate, and the EUV and X-rays that ionize the noble gases, creating the disk wind. Image Credit: Bajaj et al. 2024.

The force that disperses gas is called the disk wind. In this research, the scientists involved used the JWST to probe the disk and discover what drives the wind. This is the first time that scientists have imaged the disk wind.

Ionization plays a large role in disk dispersion. Ionization happens when energetic photons from a star strike an atom and remove one or more electrons. Ionization of different types of atoms releases particular light that the JWST can see and that scientists can use to trace the activity in the disk. In this research, the JWST detected two noble gases being ionized: argon and neon. The JWST also detected double-ionized argon, the first time it’s ever been detected in a disk.

This figure from the research shows some of the JWST’s observations. The upper panel is the JWST MIRI MRS spectrum of T Cha plotted between showing PAH (polycyclic aromatic hydrocarbon) features and other data, including the forbidden noble gas emissions in green. The lower four panels further highlight the four forbidden line emissions, [Ar ii], [Ar iii], [Ne ii], and [Ne iii], which are especially important in this study. The presence of doubly ionized Argon (Ar iii) has never been observed before. Image Credit: Bajaj et al. 2024.

Astronomers have known for a decade that Ne ii traces disk winds. Scientists working with NASA’s Spitzer Space Telescope discovered that. At T Cha, the Ne ii traces emission away from the disk, which is compatible with a disk wind.

“The neon signature in our images tells us that the disk wind is coming from an extended region away from the disk,” Bajaj said. “These winds could be driven either by high-energy photons – essentially the light streaming from the star – or by the magnetic field that weaves through the planet-forming disk.”

It’s critical to understand the source of the ionization. To dig into it, the researchers relied on simulations. The researchers simulated the intense radiation coming from the young star and compared it to the JWST observations. There was a good match showing that the energetic stellar photons can drive the disk dispersal.

“Our discovery of spatially resolved neon emission – and the first detection of double ionized argon – using the James Webb Space Telescope could become the next step towards transforming our understanding of how gas clears out of a planet-forming disk,” said Ilaria Pascucci, a professor at LPL who helped discover that neon traces disk winds. “These insights will help us get a better idea of the history and impact on our own solar system.”

This is the sharpest image ever taken by ALMA. It shows the protoplanetary disc surrounding the young star HL Tauri, another young T Tauri star. These new ALMA observations reveal substructures within the disc and even show the possible positions of planets forming in the dark patches within the system. Image Credit: ESO/ALMA

As a young T Tauri star, T Cha is changing rapidly. Previous observations about 17 years ago with Spitzer revealed a different spectrum than these observations with the JWST. The differences can be explained by a small inner disk of material near T Cha that has lost noticeable mass in the intervening 17 years. In specific scientific terms, the MIRI [Ne ii] flux is 50% higher than the Spitzer flux obtained in 2006. Future studies can help shed even more light on these wind diagnostic lines.

Chengyan Xie, a second-year doctoral student at LPL who’s involved in the research, thinks that we’re watching disk dispersal in real time and that things will continue to change rapidly.

“Along with the other studies, this also hints that the disk of T Cha is at the end of its evolution,” Xie said. “We might be able to witness the dispersal of all the dust mass in T Cha’s inner disk within our lifetime.”

Planet formation could be about to stall at T Cha, and the JWST is helping us see it happen.

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Saturn’s moon, Enceladus, is a gleaming beacon that captivates our intellectual curiosity. Its clean, icy surface makes it one of the most reflective objects in the entire Solar System. But it’s what’s below that ice that really gets scientists excited.

Under its icy shell is an ocean of warm, salty water, and the ESA says investigating the moon should be a top priority.

Enceladus is Saturn’s sixth-largest moon. It’s only about 500 km (300 miles) in diameter. But despite its small size, it may harbour a buried ocean containing 15 million cubic km of water. (Earth has about 1.4 billion cubic kilometres of water.)

The Cassini spacecraft spotted plumes of water coming from under the ice, and ever since then, scientists have hungered for a closer look at the moon. The European Space Agency (ESA) aims to give them one.

“The mission concepts that we have recommended would provide tremendous scientific return, driving forward our knowledge, and would be fundamental for the successful detection of biosignatures on icy moons.”

Dr. Zita Martins, astrobiologist at Instituto Superior Técnico.

The ESA’s long-term plan for exploring the Solar System is called Voyage 2050. In 2021, the ESA settled on an overarching theme for their Voyage 2050 activities called “Moons of the Giant Solar System Planets.” The ESA struck a committee of top planetary scientists to flesh out their ideas, and that committee laid out the priorities. According to them, the ESA should focus on one of the ocean moons and explore its habitability by investigating links between its environment and its interior. The ESA should also search for signs of life, either extant or ancient, and try to identify any surface chemistry that could enable life.

Dr. Zita Martins, an astrobiologist at Instituto Superior Técnico, chaired the team of planetary scientists. “The mission concepts that we have recommended would provide tremendous scientific return, driving forward our knowledge, and would be fundamental for the successful detection of biosignatures on icy moons,” said Dr. Martins.

“I am very happy to have been part of this process, seeing first-hand the early steps that will potentially lead to the investigation of the moons of the giant planets by ESA,” said Dr. Martins. “The search for habitable conditions and for signatures of life in the Solar System is challenging from a science and technology point of view but very exciting!”

But which moon should the ESA focus on? Candidates include Jupiter’s moon Europa and Saturn’s moons, Enceladus and Titan. Strong scientific cases can be made for each of these, as each one hosts liquid water.

Europa, Enceladus, and Titan all have subsurface oceans, and all three are targets for potential exploration. Image Credits: NASA

But each moon is unique, and any mission to either of these moons would be uniquely complex. And expensive. Working alongside the science committee was a team of engineers from the ESA’s Concurrent Design Facility (CDF). Their job was to think ahead to the types of technologies that would be needed, and if they would be possible within a couple of decades.

“We commissioned three CDF studies focused on the most promising moons: Jupiter’s Europa and Saturn’s Enceladus and Titan,” elaborates Dr Frederic Safa, head of ESA’s Future Missions Department. “The team of scientists worked closely with the CDF engineers on the objectives of each study. The outcomes helped pin down what can be done with the resources that we will have in the 2040s.”

One had to be chosen, and the ESA chose Enceladus. Titan is second on the list, and Europa is third. (NASA is launching a mission to Europa in October 2024, and the ESA launched its JUICE mission to Jupiter last year.)

Enceladus has many qualities that attract planetary scientists interested in habitability: it has liquid water, an energy source, and some specific chemicals.

Data from the Cassini spacecraft is behind this global infrared mosaic of Saturn’s moon Enceladus. The intriguing ‘tiger stripes’ feature is prominent. Image Credit: NASA/JPL-Caltech/University of Arizona/LPG/CNRS/University of Nantes/Space Science Institute

Enceladus’ plumes are salty and chemically rich. Along with sodium, chlorine, and carbon trioxide, there are nitrogen, carbon dioxide, and hydrocarbons like methane and formaldehyde. There are also some simple organic compounds and larger organic molecules like benzene.

The water is kept liquid by the warmth from tidal heating. As Enceladus orbits Saturn, the gigantic planet tugs on the moon and deforms it. Each time it does, friction heats the moon. The moon also has a rocky core, and some of that rock is probably melted, creating magma chambers. It all adds up to an icy moon with a liquid ocean where the water interacts with the rock core, a critical part of it all. And it’s all kept warm despite a lack of radionuclides.

Unlike Earth’s core, Enceladus has no radionuclides to generate warmth. Instead, tidal heating keeps the moon warm and drives the movement of water. Image Credit: Surface: NASA/JPL-Caltech/Space Science Institute; interior: LPG-CNRS/U. Nantes/U. Angers. Graphic composition: ESA

Anybody who follows planetary science news knows some of this, and they know that Enceladus is begging to be explored. A mission to Enceladus would be great for everybody interested in planetary science but would be especially rewarding for the ESA itself.

“An investigation into signs of past or present life around Saturn has never been achieved before. It would guarantee ESA leadership in planetary science for decades to come,” said ESA Director of Science, Prof. Carole Mundell.

The ESA launched its JUICE (Jupiter Icy Moons Explorer) mission one year ago. It’ll reach the Jovian system in 2031 and explore Jupiter’s moons Europa, Ganymede, and Callisto. Together with an eventual mission to Enceladus and NASA’s Europa Clipper mission, we’re on the cusp of learning an awful lot more about icy ocean moons.

The mission won’t be launched until the early 2040s and would take about a decade to reach its target. It could explore the Saturn system with far more technologically advanced science instruments than its predecessor, Cassini-Huygens. It could mimic that mission by exploring the system before a grand finale took it up close to Enceladus for our best-ever look at the icy ocean moon.

The science team developing the mission concept says that collecting a sample from Enceladus’ plumes is a must. A lander could do it, though that introduces an order of magnitude more complexity and expense. But an orbiter could do it too, by flying through the plumes, collecting a sample, and examining it in an onboard lab.

The discovery of ocean moons with icy shells has changed our understanding of planetary science, our Solar System, habitability, and the search for life. If there are this many ocean moons in our Solar System, how many are there out there in the Milky Way?

Learning more about Enceladus, Europa, and the rest could teach us a lot about life in the Universe and potential exomoon habitability.

The post Europe Has Big Plans for Saturn’s Moon Enceladus appeared first on Universe Today.

Even with all we’ve learned about Mars in recent years, it doesn’t stack up against all we still don’t know and all we hope to find out. We know that Mars was once warm and wet, a conclusion that was less certain a couple of decades ago. Now, scientists are working on uncovering the details of Mars’s ancient water.

New research shows that the Gale Crater, the landing spot for NASA’s MSL Curiosity, held water for a longer time than scientists thought.

Life needs water, and it needs stability. So, if Gale Crater held water for a long time, it strengthens the idea that Mars could’ve supported life. We know that Gale Crater is an ancient paleolake, and this research suggests that the region could’ve been exposed to water for a longer duration than thought. But was it liquid water?

The research is titled “Ice? Salt? Pressure? Sediment deformation structures as evidence of late-stage shallow groundwater in Gale crater, Mars.” It’s published in the journal Geology, and the lead author is Steven Banham. Banham is from the Imperial College of London’s Department of Earth, Science, and Engineering.

The research centers on desert sandstone that Curiosity found.

We know that water played a role in shaping the Martian surface. Multiple rovers and orbiters have given us ample evidence of that. Orbital images show clear examples of ancient deltas. We also have many images of sedimentary rock, with its tell-tale layered structure, laid down in the presence of water. But beyond the initial creation of Martian sandstone, the details of the rock can tell scientists about what happened long after it formed.

The Eberswalde delta near Holden Crater on Mars is considered the ‘smoking gun’ for evidence of liquid water on Mars. By NASA/JPL/Malin Space Science Systems

This research focuses on Gale Crater and the landforms within it. Mount Sharp (aka Aeolis Mons) is the dominant feature in the crater and rises 5.5 km or about 18,000 feet. It’s made up of sedimentary layers that have been eroded over time. But it has substructures that show its detailed history.

One structure overlays Mount Sharp and post-dates Mount Sharp’s erosion. It’s characterized by the accumulation of aeolian strata under arid conditions. That means windborne deposits instead of waterborne deposits. So scientists can tell that there was a wet period during which fluviolacustrine sediments built Mt. Sharp. They can also tell that a dry period followed, during which wind-borne sediment created the overlying structure. That’s what you’d expect to find if the story ended here: Mars was wet, then it wasn’t.

“Surprisingly, we found that these wind-deposited layers were contorted into strange shapes, which suggests the sand had been deformed shortly after being laid down. These structures point to the presence of water just below the surface.”

Amelie Roberts, study co-author, Imperial College London’s Department of Earth Science and Engineering.

But scientists found something odd in the overlying windborne sandstone: deformed layers that could only have been formed in the presence of water. “The sandstone revealed that water was probably abundant more recently, and for longer, than previously thought – but by which process did the water leave these clues?” Banham said in a press release.

That’s more difficult to determine.

“This water might have been pressurized liquid, forced into and deforming the sediment; frozen, with the repeat freezing and thawing process causing the deformation; or briny, and subject to large temperature swings,” Banham said.

“What’s clear is that behind each of these potential ways to deform this sandstone, water is the common link.”

There’s a generally accepted understanding of Martian water among scientists. By the middle of Mars’ Hesperian Period, the planet lost its water. The Hesperian’s boundaries in time are uncertain, but it’s generally thought of as the transition from the heavy bombardment period to the dry Mars we know today. The Hesperian could’ve ended between 3.2 and 2.0 billion years ago. The Noachian preceded it, and the Amazonian followed it.

This research presents a new wrinkle. It suggests that Mars had abundant subsurface water toward the end of the Hesperian. The evidence is in MSL Curiosity’s images of different sedimentary rocks on Gale Crater’s Mt. Sharp.

“When sediments are moved by flowing water in rivers, or by the wind blowing, they leave characteristic structures which can act like fingerprints of the ancient processes that formed them,” said Banham.

MSL Curiosity slowly worked its way up Mt. Sharp, studying the rocks at different elevations as it ascended. As expected, it found younger rocks the higher it went. Eventually, it reached the Stimson formation. The Stimson formation is the remnant of an ancient windborne desert dune field.

An analysis of Curiosity’s images shows that Stimson formed after Mt. Sharp when Mars was thought to be dry. But Stimson isn’t entirely uniform. One of its features is named the Feòrachas structure, and it contains features that were clearly influenced by the presence of water.

“Usually, the wind deposits sediment in a very regular, predictable way,” said study co-author Amelie Roberts, a PhD candidate from Imperial College London’s Department of Earth Science and Engineering. “Surprisingly, we found that these wind-deposited layers were contorted into strange shapes, which suggests the sand had been deformed shortly after being laid down. These structures point to the presence of water just below the surface.”

This image from the study shows part of the Feorachas structure with undeformed features. Water played no role in shaping them. B shows wind-ripple laminations. The image also shows cross laminations, which are the result of additional sediments deposited by wind. Image Credit: Banham et al. 2024, NASA/JPL-Caltech/MSSS

In the Brackenberry outcrop feature, the sedimentary rocks show evidence of deformation by water. There are laminations in various states of deformity, becoming more pronounced in the feature geologists call the cusp core. In the cusp core, wind-ripple laminations bend toward the vertical and become incoherent.

This image from the research shows some features that are deformed by the presence of water. Vertical, incoherent sedimentary lines in the cusp core, oversteepened laminations, and vertically deformed laminations are all evidence of the presence of water. Image Credit: Banham et al. 2024, NASA/JPL-Caltech/MSSS

The authors explain that there are three mechanisms that can explain the deformed features, and they all involve water. They’re also not mutually exclusive.

High-pressure water could’ve overcome the strength of the rock and deformed it. Large ice deposits on top of the structure could’ve caused deformation, as could freeze/thaw cycles of water inside the rock. The third explanation involves sediment rock weakly bound together by evaporites. Thermal expansion and contraction of the evaporites can deform the rock.

This image from the research shows more examples of fluidization structures. A shows a feature named Up Helly Aa, and B is a zoomed-in image showing up warping and vertical laminations. C shows the Lamington feature, and D is a zoomed-in image showing more deformed laminations. Image Credit: Banham et al. 2024, NASA/JPL-Caltech/MSSS

“The layers of sediment in the crater reveal a shift from a wet environment to a drier one over time – reflecting Mars’ transition from humid and habitable environment to inhospitable desert world,” said co-author Roberts. “But these water-formed structures in the desert sandstone show that water persisted on Mars much later than previously thought.”

Mars is no exoplanet, but it’s inadvertently teaching us a lot about our quest to understand exoplanets and habitability.

“Determining whether Mars and other planets were once able to support life has been a major driving force for planetary research for more than half a century,” said Dr. Banham. “Our findings reveal new avenues for exploration – shedding light on Mars’ potential to support life and highlighting where we should continue hunting for new clues.”

“Our finding extends the timeline of water persisting in the region surrounding Gale crater, and so the whole region could have been habitable for longer than previously thought,” said Amelie.

Maybe one day in the far distant future, one of our rovers on a distant exoplanet will flip over a rock and watch something scuttle away. It’s easy to imagine.

But Mars is an instructive example. If it remained habitable for longer than we thought, it was likely only marginally inhabitable. We can’t say for sure, but complex life seems to be out of the question. This should prepare humanity for what we can expect to find in our quest for habitable exoplanets.

There are a bewildering number of variables that go into making Earth the living oasis that it is. We’re much more likely to stumble on other planets like Mars, which were once habitable and maybe even harboured simple life. If Earth’s long-lived habitability is the outlier, and Mars’ marginal, interrupted habitability is more likely, we can expect to find many planets like it that were once alive but are now long dead.

 

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In the constellation of Orion, there is a brilliant bluish-white star. It marks the right foot of the starry hunter. It’s known as Rigel, and it is the most famous example of a blue supergiant star. Blue supergiants are more than 10,000 times brighter than the Sun, with masses 16 – 40 times greater. They are unstable and short-lived, so they should be rare in the galaxy. While they are rare, blue supergiants aren’t as rare as we would expect. A new study may have figured out why.

We aren’t entirely sure how these massive stars form, though one idea is that they occur when a massive main sequence star passes through an interstellar cloud. By capturing gas and dust from the cloud, a star can shift off the main sequence to become a blue supergiant. Another idea is that they may form within stellar nurseries with a mass as great as 300 Suns. As a result, they quickly burn so brightly that they never become true main-sequence stars. Both of these models predict that blue supergiants are much more rare than the number we observe.

This new study starts by noting that blue supergiants, particularly the smaller ones known as B-type supergiants, are rarely seen with companion stars. This is odd since most massive stars form as part of a binary or multiple system. The authors propose that B-type blue supergiants aren’t often in binary systems because they typically are the product of binary mergers.

The team simulated a range of models where a giant main-sequence star has a smaller close-orbiting companion and then looked at what would result if the two stars merged. They then compared the results to observations of 59 young blue supergiant stars in the Large Magellanic Cloud. They found that not only can these mergers produce blue supergiants in the mass range of the Magellanic stars, but the spectra of the simulated mergers match the spectra of the 59 blue supergiants. This strongly suggests that many if not most B-type blue supergiants are the result of stellar mergers.

In the future, the team would like to carry this work further to see how blue supergiants evolve into neutron stars and black holes. This could help explain the type of mergers observed by gravitational wave observatories such as LIGO and Virgo.

Reference: Menon, Athira, et al. “Evidence for Evolved Stellar Binary Mergers in Observed B-type Blue Supergiants.” The Astrophysical Journal Letters 963.2 (2024): L42.

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Using ESA’s Gaia spacecraft, astronomers have tracked down two streams of stars that likely formed the foundation of the Milky Way. Named “Shakti and Shiva,” the two streams contain about 10 million stars, all of which are 12 to 13 billion years old and likely came together even before the spiral arms and disk were formed. These star streams are all moving in roughly similar orbits and have similar compositions. Astronomers think they were probably separate galaxies that merged into the Milky Way shortly after the Big Bang.,

“What’s truly amazing is that we can detect these ancient structures at all,” said lead author Khyati Malhan of the Max Planck Institute for Astronomy (MPIA) in Heidelberg, Germany, in an ESA press release. “The Milky Way has changed so significantly since these stars were born that we wouldn’t expect to recognize them so clearly as a group – but the unprecedented data we’re getting from Gaia made it possible.”

Astrometry Data

Gaia uses astrometry — the precise measurements of the positions and movements of stars and other celestial bodies – and is building the largest, most precise three-dimensional map of our Galaxy by surveying nearly two billion objects.

With Gaia’s data, the researchers were able to determine the orbits of individual stars in the Milky Way, as well as determine their content and composition. These ancient stars are all moving in very similar orbits and the structure of the two different star streams stood out because their stars contained a certain chemical composition.

“Shakti and Shiva populations possess an unconventional combination of orbital and abundance properties that have not been observed previously,” the researchers wrote in their paper, published in the Astrophysical journal. 

By compiling very detailed chemical abundance patterns for each, the astronomers determined these stars were the oldest stars in the galaxy, all born before the disc of the Milky Way had formed.

The components of the Milky Way Galaxy. This artist’s impression shows our roughly 13 billon-year-old ‘barred spiral galaxy’ that is home to a few hundred billion stars. Credit: Left: NASA/JPL-Caltech; right: ESA; layout: ESA/ATG medialab.

“The stars there are so ancient that they lack many of the heavier metal elements created later in the Universe’s lifetime,” said co-author Hans-Walter Rix, also of MPIA and the lead ‘galactic archaeologist’ in this research, which began in 2022. “These heavy metals are those forged within stars and scattered through space when they die. The stars in our galaxy’s heart are metal-poor, so we dubbed this region the Milky Way’s ‘poor old heart’. Until now, we had only recognized these very early fragments that came together to form the Milky Way’s ancient heart. With Shakti and Shiva, we now see the first pieces that seem comparably old but located further out. These signify the first steps of our galaxy’s growth towards its present size.”

While the two streams are similar, they aren’t exactly the same. Shakti stars orbit a little further from the Milky Way’s center and in more circular orbits than Shiva stars. The streams are named two divine beings from Hindu philosophy who worked together to create the Universe.

Because of Gaia’s ability to provide data to create incredibly detailed celestial maps, the researchers were able to build a dynamical map of that includes the two star streams plus other known components that have played a role in our galaxy’s formation.

“Revealing more about our galaxy’s infancy is one of Gaia’s goals, and it’s certainly achieving it,” said Timo Prusti, Project Scientist for Gaia at ESA. “We need to pinpoint the subtle yet crucial differences between stars in the Milky Way to understand how our galaxy formed and evolved. This requires incredibly precise data – and now, thanks to Gaia, we have that data. As we discover surprise parts of our galaxy like the Shiva and Shakti streams, we’re filling the gaps and painting a fuller picture of not only our current home, but our earliest cosmic history.”

Further reading:
ESA press release
Paper: Shiva and Shakti: Presumed Proto-Galactic Fragments in the Inner Milky Way

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In a win for planetary scientists, and planetary geologists in particular, it was announced at the recent 55th Lunar and Planetary Science Conference (LPSC) in Texas earlier this month that NASA’s VERITAS mission to the planet Venus has been reinstated into NASA’s Fiscal Year 2025 (FY25) budget with a scheduled launch date of 2031, with the unofficial announcement coming on the first day of the conference, March 11, 2024, and being officially announced just a few days later. This comes after VERITAS experienced a “soft cancellation” in March of last year when NASA revealed its FY24 budget, providing VERITAS only $1.5 million, which was preceded by the launch of VERITAS being delayed a minimum of three years due to findings from an independent review board in November 2022.

VERITAS is back in the budget!! ??? The project will get going full swing this fall (FY25). We’re looking at a 31 launch (TBC). Thanks to everyone who’s supported our return to Venus!! It’s going to be fabulous ?

— Sue Smrekar (@SueSmrekar) March 11, 2024 Dr. Sue Smrekar, who is the Principal Investigator for the VERITAS mission, announcing during LPSC 2024 that VERITAS has been reinstated.

Here, Universe Today speaks with Dr. Paul Byrne, who is an Associate Professor of Earth, Environmental, and Planetary Sciences at Washington University in St. Louis, and a huge proponent of exploring Venus, about his thoughts on VERITAS being reinstated, the alleged events that led to VERITAS’ reinstatement, his experience between VERITAS being postponed to now, and his thoughts on what science VERITAS hopes to accomplish at Venus. So, what are his thoughts on VERITAS being reinstated?

“First and foremost, it’s relief,” Dr. Byrne tells Universe Today. “Although VERITAS wasn’t cancelled per se, we in the planetary community weren’t sure if or where VERITAS would be reinstated. Although it’s disappointing to have a selected mission be delayed, it’s a very positive sign that VERITAS is back in the budget. Of course, there’s a flip side to this development: the mission’s stablemate, DAVINCI, has itself been delayed. It’s clear that the prevailing budget situation at NASA is very tough right now, and lots of missions are feeling it. Unfortunately, with two Venus missions in the pipeline, the Venus community is feeling this budget toughness most acutely.”

After years of being proposed as a NASA Discovery mission, VERITAS was officially selected in June 2021, along with DAVINCI (previously known as DAVINCI+) to explore the second planet from the Sun like never before. While VERITAS will be tasked with producing new surface maps of Venus, DAVINCI was tasked with conducting atmospheric science, as debate continues over the potential habitability of Venus’ atmosphere. With an initial scheduled launch date between 2028 and 2030, the November 2022 findings pushed this back to 2031, only to result in the “soft cancellation” just months later. With the planetary science community pushing for VERITAS to be reinstated over the last 12 months, what led to VERITAS being reinstated?

“A major part of it was, in my view, strong advocacy not only by the Venus community but by the planetary science community at large,” Dr. Byrne tells Universe Today. “Other advisory groups—volunteer groups charged with collating and representing to NASA the needs of a given portion of the planetary science community—voiced very loud, strong support for VERITAS beyond just the Venus community, in a wonderful example of community-wide support. Groups such as The Planetary Society also lent their voice to supporting VERITAS. That advocacy was noticed by NASA HQ and by Congress, which played no small role in getting VERITAS back into the budget.”

While not officially a member of the VERITAS mission team, Dr. Byrne has a myriad of publications about Venus, including as a co-author on five LPSC 2024 studies that discussed lava flow cooling, Venus’ potential habitability as an analog for other planets, predicting tectonic activity, predicting future volcanic activity, and current active volcanism. Additionally, Dr. Byrne has expressed his continued support via social media for both the second planet from the Sun and the VERITAS and DAVINCI missions throughout their respective journeys, and specifically when they were selected in June 2021. Therefore, what kind of emotional roller coaster has he experienced between VERITAS being canceled and now?

“It’s so hard to see a mission being selected for a science target NASA hasn’t been to in forty years, only for it to be postponed through no fault of the mission team itself,” Dr. Byrne tells Universe Today. “And it’s wonderful that we now know VERITAS will fly, even if it’s later than originally planned. But I’m keenly aware, as someone who’s not a member of the VERITAS team, that the highs and lows I’ve experienced are nothing compared with those of the team itself, who put their heart and soul (and at least three attempts!) to get VERITAS selected. Better late than never, but better on time than late. Still, we make do with the circumstances we face!”

As Dr. Byrne alluded to, the last NASA mission to Venus was the Magellan spacecraft, which was launched on May 4, 1989, from the Space Shuttle Atlantis during the STS-30R mission and arrived at Venus on August 10, 1990. Over the course of the next four years, Magellan used its synthetic aperture radar to map the entire surface of Venus since the extreme thickness of Venus’ clouds prevents direct imaging of the surface.

After Magellan’s first imaging cycle that lasted 243 days, it successfully mapped 83.7 percent of Venus’ surface, which increased to 96 percent after its second cycle and completed its mission at 98 percent after its third cycle. As a result, Magellan images identified a myriad of features across the Venusian surface, including volcanic evidence, tectonic activity, lava channels, pancake-shaped domes, and stormy winds across the surface. Therefore, with VERIATS equally tasked with mapping Venus’ surface, what science does VERITAS hope to achieve at Venus?

“VERITAS will carry a radar to Venus to obtain the most comprehensive, accurate, and highest-resolution radar image and topographic data ever acquired for the second planet,” Dr. Byrne tells Universe Today. “VERITAS will also be able to acquire spectral measurements of the surface in the infrared, offering us new insight into the composition of the planet’s surface materials. Moreover, the topographic and geodetic data VERITAS will return will in turn be used to help calibrate data from DAVINCI and the ESA EnVision mission, too.”

What new discoveries will VERITAS make about Venus in the coming years and decades? Only time will tell, and this is why we science!

As always, keep doing science & keep looking up!

The post NASA’s VERITAS Mission Breathes New Life appeared first on Universe Today.

If we could detect a clear, unambiguous biosignature on just one of the thousands of exoplanets we know of, it would be a huge, game-changing moment for humanity. But it’s extremely difficult. We simply aren’t in a place where we can be certain that what we’re detecting means what we think or even hope it does.

But what if we looked at many potential worlds at once?

It’s assumptions that plague us. Every chemical we detect in an exoplanet atmosphere, even with the powerful JWST, is accompanied by a set of assumptions. We simply don’t know enough yet for it to be any other way. This puts us in a difficult place, considering the magnitude of the question we’re trying to answer: is there life beyond Earth?

“A fundamental goal of astrobiology is to detect life outside of Earth,” write the authors of a new paper. It’s titled “An Agnostic Biosignature Based on Modeling Panspermia and Terraformation,” and it’s available on the pre-press site arxiv.org. The authors are Harrison B. Smith and Lana Sinapayen. Smith is from the Earth-Life Science Institute at the Tokyo Institute of Technology in Japan, and Sinapayen is from the Sony Computer Science Laboratories in Kyoto, Japan.

The fundamental goal that the pair of authors give voice to is a difficult one to reach. “This proves to be an exceptional challenge outside of our solar system, where strong assumptions must be made about how life would manifest and interact with its planet,” the authors explain. We only know how Earth’s biosphere works, and we’re left to assume what similarities there might be with other planets. We don’t have any consensus about how biospheres might be able to work. We’re not completely ignorant, as chemistry and physics make some things possible and others impossible. But we’re not an authority on biospheres.

Scientists are pretty good at modelling things and trying to generate useful answers, as well as generating relevant questions they might not have thought of without models. In this work, the pair of authors took a different approach to understanding life on other worlds and what effort we can make to detect it.

“Here we explore a model of life spreading between planetary systems via panspermia and terraformation,” the authors write. “Our model shows that as life propagates across the galaxy, correlations emerge between planetary characteristics and location and can function as a population-scale agnostic biosignature.”

The word ‘agnostic’ is key here. It means that they’re aiming to detect a biosignature that’s independent of the assumptions we’re normally saddled with. “This biosignature is agnostic because it is independent of strong assumptions about any particular instantiation of life or planetary characteristic—by focusing on a specific hypothesis of what life may do rather than what life may be,” the authors explain.

This approach is different. They analyze planets by their observed characteristics and then cluster them based on those observations. Then, they examine the spatial extent of the clusters themselves. That leads to a way to prioritize individual planets for their potential to harbour life.

Panspermia and terraforming play key roles. We know that rocks can travel between worlds, and that’s called lithopanspermia. Powerful impacts on Mars lofted rocks into space, some of which eventually fell to Earth. If dormant organisms like spores could survive the journey, it’s at least feasible that life could spread this way.

Panspermia is the idea that life is spread throughout the galaxy, or even the Universe, by asteroids, comets, and even minor planets. Credit: NASA/Jenny Mottor

Terraforming is self-explanatory for the most part. It’s the effort to engineer a world to be more habitable. If there are other technological, space-faring civilizations out there, one useful working assumption is that they’ll eventually terraform other worlds if they last long enough. In any case, even non-technological life can purposefully alter its environment. (Sit and watch beavers sometime.)

The authors make an interesting point regarding panspermia and terraforming. They’re both things that life already does, kind of. “Ultimately, our postulates of panspermia and terraformation are merely well-understood hallmarks of life (proliferation via replication and adaptation with bi-directional environmental feedback), escalated to the planetary scale, and executed on an interstellar scale,” they write.

The authors’ model shows that the way planets are distributed around stars, along with their other characteristics, could be evidence of life without even attempting to detect chemical biosignatures. This is the agnostic part of their work. It’s more powerful than a one-planet-at-a-time struggle to detect biosignatures, as plagued as that effort is by assumptions. Single planets with detected biosignatures can always be explained away by something anomalous. But that’s harder to do in this agnostic method.

“Hypothesizing that life spreads via panspermia and terraformation allows us to search for biosignatures while forgoing any strong assumptions about not only the peculiarities of life (e.g., its metabolism) and planetary habitability (e.g., requiring surface liquid water) but even the potential breadth of structure and chemical complexity underpinning living systems,” the authors explain.

This figure from the study helps illustrate the authors’ work. A shows a target planet selection, where an initial planet and its composition are randomly selected. This planet represents a terraformed parent planet. B shows the simulation run beginning with the initial parent planet, showing how nearby planets will be terraformed to more closely match the parent planet. C shows how each terraformed planet will retain some of its differences, about 10% in the researchers’ model. Image Credit: Smith and Sinapayen, 2024.

We’re accustomed to thinking about specific chemicals, and the types of atmospheres exoplanets have to determine the presence of biosignatures. But that’s not how this works. This model is agnostic, so it’s not really about specific chemical biosignatures. It’s more about the patterns and clusters we could detect in populations of planets that could signal the presence of life via panspermia and terraforming.

Terraformed planets can be identified from their clustering, the authors claim. That’s because when they’re terraformed, the planets need to reflect the originating planet.

This figure from the research shows how simulated terraformed planets would appear clustered on a graph. This is a projection of 3D planet locations in the 2D X-Y plane and the earliest time step where the researchers detect a cluster of planets meeting their selection criteria. True terraformed planets have a blue fill, while planets detected by their selection method have a red outline. Image Credit: Smith and Sinapayen, 2024.

There are obstacles to this method that limit its usefulness and implementation. According to the authors, they need to identify “… specific ways in which better understanding astrophysical and planetary processes would improve our ability to detect life,” the authors write.

But even without more specifics, the method is thought-provoking and creative. In the end, the authors’ model and method lead to a novel way to think about life’s hierarchies and how these hierarchies might be replicated on other planets.

If this method is strengthened and more fully developed, who knows what it might lead to?

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The only thing worse than drifting through space for an eternity is doing it alone. Observations with the Hubble Space Telescope show that brown dwarfs that once had companions suffer that fate. Binary brown dwarfs that were once bound to each other tend to drift apart as time passes.

Brown dwarfs are one of Nature’s genre-busters. They refuse to be pigeonholed into our definitions. They’re neither stars nor planets and are sometimes referred to as failed stars. They gathered too much mass to be called planets but not enough to be called stars. They live in a kind of twilight zone, where they go about their business fusing only deuterium. This fusion is enough to emit some light and warmth but nothing that rivals an actual main sequence star.

Brown dwarfs are too big to be planets but not quite massive enough to be stars. Credit: NASA/JPL-Caltech

Brown dwarfs are not necessarily brown in colour. Their name comes from their size. They’re in between white dwarf stars and “dark” planets, if that makes sense. Brown dwarfs fade over time as they deplete their deuterium. The warmest ones are red or orange, and the cooler ones are magenta or even black to our eyes. Astronomers think brown dwarfs will cool down forever.

Most stars are in binary pairs, and brown dwarfs are no exception. Up to 85% of stars in the Milky Way are in binary pairs, according to some research. But the Hubble shows that when it comes to brown dwarfs, divorce is more common than in Hollywood.

In a survey of stars in our solar neighbourhood, the HST didn’t find any binary brown dwarfs with widely separated companions. That implies that brown dwarfs can’t maintain their binary relationships, probably because they’re simply not massive enough.

“This is the best observational evidence to date that brown dwarf pairs drift apart over time,” said Clémence Fontanive, the lead author of a new paper. “We could not have done this kind of survey and confirmed earlier models without Hubble’s sharp vision and sensitivity.”

The new paper is in the Monthly Notices of the Royal Astronomical Society. Its title is “An HST survey of 33 T8 to Y1 brown dwarfs: NIR photometry and multiplicity of the coldest isolated objects.” The lead author is Clémence Fontanive from the Trottier Institute for Research on Exoplanets, Université de Montréal, Canada. Brown dwarfs occupy spectral types M, L, T, and Y, and the numbers in the title are sub-types.

“Our survey confirms that widely separated companions are extremely rare among the lowest-mass and coldest isolated brown dwarfs, even though binary brown dwarfs are observed at younger ages. This suggests that such systems do not survive over time,” said lead author Fontanive.

The researchers worked with a set of 33 nearby ultracool brown dwarfs, a sample large enough to be statistically significant. The survey was designed to be deeply sensitive to low-mass objects that could be companions. Though the survey unearthed some potential companions for some of the brown dwarfs, further analysis showed they’re background objects.

The fact that they detected no binary companions allowed the researchers to “place stringent upper limits on the occurrence of binary companions,” according to the paper. But the lack of detection also means they can’t place any constraints or limits on the binary orbital separation or mass ratio distributions of this population.

This survey only examined older, dimmer brown dwarfs. Younger brown dwarfs can still have their binary partners. Studies of younger brown dwarfs show that around eight percent of them have binary partners. In fact, the younger the brown dwarf, the more likely it is to have a binary partner. “These findings marginally confirm the idea that the decrease in binary frequencies with later type observed across the stellar and substellar regimes for the field population might continue throughout the substellar mass range down to the very lowest masses, as illustrated in Fig. 12,” the authors explain.

This is Figure 12 from the study, and it illustrates the rate of brown dwarf binary companions as brown dwarfs age. The binary frequency is shown on the y-axis, and the spectral type, which relates to age, is on the x-axis. Each mark inside the graph plots the results of a study of brown dwarf companions, including this one in pink. The graph clearly shows that younger brown dwarfs have more binary companions than aged brown dwarfs. Image Credit: Fontanive et al. 2024.

In a press release, lead author Fontanive explained why brown dwarfs lose their binary partners over time.

“Our Hubble survey offers direct evidence that these binaries that we observe when they’re young are unlikely to survive to old ages; they’re likely going to get disrupted. When they’re young, they’re part of a molecular cloud, and then, as they age, the cloud disperses. As that happens, things start moving around, and stars pass by each other. Because brown dwarfs are so light, the gravitational hold tying wide binary pairs is very weak, and bypassing stars can easily tear these binaries apart,” said Fontanive.

The authors point out that there’s an inevitable weakness in their results. Since brown dwarfs are so small and dim, the usual methods of detecting companions don’t work. Astronomers rely on the transit method and the radial velocity method to detect companion objects, whether planets orbiting stars or other objects in relationships with one another.

But their inherent dimness makes detecting transits very difficult. Their inherent low masses likewise make the radial velocity ineffective. That leaves them with the direct optical detection method the researchers in this study relied on.

There could be a better way.

“Astrometry might provide a more viable alternative approach to search for companions to faint brown dwarfs, although very little work has been carried out on this side, and no systems have been reported this way so far,” the authors write in the conclusion.

When it comes to astrometry, the ESA’s Gaia spacecraft is the standard-bearer. It has the power to detect Jupiter-mass companions when they’re orbiting main sequence stars, but detecting binary brown dwarfs is still difficult, even for Gaia. Gaia has detected many brown dwarfs, but for now, it’s up to direct imaging to detect brown dwarf binary pairs. In this study, direct imaging found no widely separated binary companions despite the HST’s effectiveness.

“With an excellent sensitivity and completeness to companions on wide orbital separations, our survey robustly confirms that wide companions are extremely rare in the Galactic field around the lowest mass systems,” the authors write. Any companions would need to be inside the 1 to 5 AU limit of this work.

“Our results, with no detection of wide companions out of 33 observed objects, reinforce the idea that the widely separated binaries with very low-mass primaries identified in young associations have no counterparts among isolated objects in the Solar neighbourhood,” the authors conclude.

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If you have a view of the southern celestial sky, on a clear night you might see two clear smudges of light set off a bit from the great arch of the Milky Way. They are the Large and Small Magellanic Clouds, and they are the most visible of the dwarf galaxies. Dwarf galaxies are small galaxies that typically cluster around larger ones. The Milky Way, for example, has nearly two dozen dwarf galaxies. Because of their small size, they can be more significantly affected by dark matter. Their formation may even have been triggered by the distribution of dark matter. So they can be an excellent way to study this mysterious unseen material.

In a recent study, a team looked at dwarf galaxies to see exactly what they would reveal about dark matter. Specifically, they were interested in how dark matter might interact with itself. One idea about dark matter particles is that when they collide with each other they could emit gamma-ray light. This would mean that the central regions of galaxies should show evidence of gamma radiation without a clear astrophysical source. There have been some studies looking for gamma rays within our own galaxy, but the results have been inconclusive.

This new study focused on dwarf galaxies because they are smaller and therefore less likely to obscure gamma-ray light from colliding dark matter. There are also plenty of dwarf galaxies within our local group. Using 14 years of archival data from the Fermi-Large Area Telescope (LAT), the team looked at 50 dwarf galaxies. Overall they didn’t find strong evidence of gamma-ray emissions from any of the galaxies, but in 7 of them they found a small statistical excess at around 2? – 3?. To be definitive we’d like to see it at a level of 5?, so this result is far from conclusive. But if we take the energy levels of the excess at face value, it would put the mass of dark matter particles around 30 – 50 GeV or 150 ? 230 GeV, depending on the way dark matter might decay. By comparison, protons have a mass of about 1 GeV.

So once again a study of dark matter fails to discover the elusive particles. But as with earlier studies, this research narrows down what dark matter might be. Specifically, the study rules out certain mass ranges for dark matter more than ever before. It’s yet another small step toward solving the mystery of dark matter.

Reference: McDaniel, Alex, et al. “Legacy analysis of dark matter annihilation from the Milky Way dwarf spheroidal galaxies with 14 years of Fermi-LAT data.” Physical Review D 109.6 (2024): 063024.

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Astronomers discovered another asteroid sharing Mars’ orbit. These types of asteroids are called trojans, and they orbit in two clumps, one ahead of and one behind the planet. But the origins of the Mars trojans are unclear.

Can this new discovery help explain where they came from?

There are now 14 known Mars Trojans and the name of the newest one is 2023 FW14. They’re in two groups, one 60 degrees ahead and one 60 degrees behind Mars. These are the Lagrange 4 and Lagrange 5 points.

Most of the Mars trojans are at the L5 point, and this newly discovered one is the second one found at the L4 point.

New research published in the journal Astronomy and Astrophysics presents the discovery. Its title is “Dynamics of 2023 FW14, the second L4 Mars trojan, and a physical characterization using the 10.4 m Gran Telescopio Canarias.” The lead author is Raul de la Fuente Marcos from the Earth Physics and Astrophysics Department at the Universidad Complutense de Madrid.

Scientists aren’t certain where the Mars trojans came from. Other trojans like the Jupiter trojans may have been captured by Jupiter in the Solar System’s early years. Or Jupiter may have captured them later when it migrated.

But Mars is a much less massive planet, and astronomers aren’t certain if Mars can capture trojans the same way Jupiter does. The Mars trojans could be as old as the Jupiter trojans, but some evidence suggests otherwise. The dozen or more trojans at the Mars L5 point seem to be a family from the same collision. The family is called Eureka, and their spectra indicate an olivine-rich composition.

Olivine is relatively rare in the main asteroid belt. That’s led some researchers to suggest that the L5 Mars trojans are debris from an ancient impact between Mars, where olivine is common, and a planetesimal.

The two L4 Mars trojans are different. They don’t have the same spectra as the L5 trojans, but the pair do show some similarities in their spectra, so a common origin for these two is a possibility.

In this paper, the researchers set out to determine 2023 FW14’s origins. They used the Gran Telescopio Canarias for their work. It’s a 10.4-meter telescope in Spain’s Canary Islands with an attached instrument called the OSIRIS camera spectrograph.

2023 FW14’s spectrum places it in the same class as an Xc-type asteroid. The X-type name contains several different types of asteroids with similar spectra but probably with different compositions. Xc-types are a sub-class of the X-types that are intermediate between C-type asteroids, the most common type of asteroid in the Solar System, and the uncommon K-type asteroids.

This graph from the research shows the spectrum of 2023 FW14 and several spectra of the other known L4 Mars Trojan (121514) 1999 UJ7. Orange shows 2023 FW14, with the red line representing the best asteroid taxonomical match, the Xc-type. Teal, blue, and green show different published spectra of 1999 UJ7. The gray area fills the entire domain between the mean B-type and D-type classes of asteroids. Image Credit: Marcos et al. 2024.

The researchers also used N-body simulations to try to understand the new asteroid’s resonance with Mars. Trojans follow what are known as tadpole orbits. Tadpole orbits are influenced by Earth’s gravity, which causes objects to librate or accelerate or decelerate alternately.

Tadpole orbits are complex. Asteroids on these orbits exchange large amounts of energy and angular momentum with a planet moving in a circular orbit. Tadpole loops are made of multiple overlapping epicyclic loops.

This video illustrates the tadpole orbit followed by an asteroid in Jupiter’s L4, not Mars’ L4, but the concept is the same.

2023 FW14 has a higher orbital eccentricity and lower inclination than Mars’ other L4 trojan. This means that it occupies an unstable region and orbits at the whim of several different resonances. That instability means that in a few million years, it’ll likely be ejected.

The researchers calculated its size as approximately 318 metres (+493/-199.) That makes it one of the smallest known trojans so far.

As for its origins, the authors say that there are two possibilities.

Its long-term behaviour, including its past, suggests that it was captured from the Near Earth Asteroid (NEA) population of Mars-crossing asteroids. But it could be a fragment of another trojan, as well, one that is so far undiscovered, or one that is no longer a trojan.

Spectral data suggests something else. Both of the L4 asteroids appear to be more primitive than Mars’ L5 trojans. 2023 FW14’s spectrum also supports the idea that it’s a captured Mars-crossing NEA. However, that data isn’t as clear, according to the authors, and can’t be used to rule out the other hypothesis, which is that the asteroid formed in situ. “Although incomplete, the data support the interpretation of 2023 FW14 as an interloper captured from the Mars-crossing NEA population, but they cannot be used to reject the competing hypothesis that 2023 FW14 was produced in situ,” they write.

Whatever its origins are, the researchers calculate that 2023 FW14 has about 10 million years before it’s ejected from its trojan orbit. It’s a temporary trojan, and this discovery could prove that Mars trojans can be temporarily captured, something that so far has been unproven.

The post An Asteroid Found Sharing the Orbit of Mars appeared first on Universe Today.

A 2023 expedition to the Pacific Ocean, searching for debris from a suspected extraterrestrial object, may have been looking in the wrong place. A new look at the infrasound data used to locate the point of impact suggests that they may have been confused by the rumblings of a truck driving past.

On 14 January 2018, a space rock hit the Earth’s atmosphere off the coast of Papua New Guinea. It was detected by what are mysteriously described as “US Government Sensors”, and given the catalogue entry “CNEOS 2014-01-08”. Based on the brightness of the fireball and its apparent speed, the physical rock likely survived without burning up completely. The observation was logged in a database kept by the Center for Near Earth Object Studies. Bolides like this can be a spectacular sight, when spotted by human eyes, but they are not rare; several are detected each week.

Extrasolar objects

A few years later, Oumuamua was discovered. Oumuamua was traveling at a high speed, along a path that showed it was not orbiting the Sun. Instead, it had come from interstellar space and was merely passing through. This was very exciting because it was the first time anybody had observed an interstellar rocky object, and so it attracted a lot of attention.

Some observations showed that Oumuamua’s path wasn’t steady, but kept making tiny changes. Most scientists agreed that this was almost certainly because of pockets of ice melting and jetting away in the Sun’s heat. This is a common phenomenon, that we often see happening with comets. More detailed observations and simulations showed that it had a long and skinny shape, more like a splinter than a boulder, which is very unusual among the asteroids and comets that we’re used to. But Oumuamua only really hit the mainstream press when a well-known and prestigious astrophysicist decided, in a surprising leap of logic, that all these details proved that it could be an alien spacecraft!

The Oumuamua discovery led many scientists to start searching for other interstellar objects. CNEOS 2014-01-08, with its high reported speed, looked like a promising candidate. The physicist who had made such a big deal about Oumuamua being artificial took a closer look at the bolide reports and concluded that it must have been traveling fast enough to be another extrasolar object. This claim was controversial, not only because the government sensors appear to be classified and so cannot be verified, but because meteor speeds are notoriously difficult to measure. Observers have mistakenly reported extrasolar meteors as far back as 1951!

But if CNEOS 2014-01-08 truly was from outside the Solar System, and we could find pieces of it, that would be an incredible discovery: The first actual geological samples from a planetary system outside our own!

The expedition

This is why an expedition was launched in 2023 to try and find it. The research team used seismic and infrasound data from seismic research stations in the area to try and find the exact place where the meteoroid would have splashed into the sea. They identified two likely signals from Geoscience Australia’s Passive Seismic Network. The signals were recorded by Manus Island, Papua New Guinea (AU.MANU) and Coen, Queensland, Australia (AU.COEN), at around the same time that the fireball was detected. They triangulated a precise location based on those recordings, and sailed out to search the ocean floor.

The expedition was widely reported as a success, after they found “metallic spherules”. These spherules had an unusual composition, which the expedition leader said was proof of a possible extraterrestrial origin. Like the speed calculations, though, this interpretation was widely challenged. Specialists in other fields have weighed in to argue that there was nothing unusual about the debris, and that various natural and human processes could have created them (My personal favorite: 19th century pollution!). With so much doubt as to where the spherules came from in the first place, it’s probably not wise to say that they are of “extraterrestrial technological” origin.

The area near the seismic station in Manus Island, based on satellite images. Image credit: Roberto Molar Candanosa and Benjamin Fernando/Johns Hopkins University, with imagery from CNES/Airbus via Google. The truck

The most recent challenge to the results of this expedition come from a team led by Dr Benjamin Fernando of Johns Hopkins University. Their report focuses on the seismic and infrasound data used to locate the impact site.

They noticed a number of problems with the expedition’s analysis, starting with the fact that none of the detections happened within 30 seconds of the fireball. But beyond that, these stations are located in the Pacific Ring of Fire, which is very tectonically active. They detect a great many earthquakes and other natural seismic events every day, and some of these happened at the same time as the meteorite impact. Separating the two signals is hard to do without distorting both of them. This adds a lot of error to any calculations based on those data.

Along with seismic data, these stations also have infrasound detectors, meant to detect and monitor nuclear weapons tests. But infrasound has a limited range, and is strongly affected by geography.

Fernando’s team concluded that only one station recorded an infrasound signal that could have come from CNEOS 2014-01-08, and that none of the seismic detections had anything to do with the bolide. Based on this, they believe that the expedition was looking in the wrong place, and that the debris they discovered had nothing at all to do with the 2014 bolide.

But their most damning claim is this: The strongest signal had an unusual pattern, lasting a long time and coming from a direction which changed halfway. They noticed that there is a road passing near the station, with a curve in it that matches the change in direction of the signal. They point out that the signals recorded by trucks driving that road are a far closer match than any natural event.

In other words, they believe that the expedition based its search location for an extraterrestrial meteoroid on the noise of somebody in a truck going for a drive.

In their defense

It’s tempting to laugh at the researchers on the expedition, especially since their leader was a respected astrophysicist who has recently developed a reputation for having crackpot ideas about aliens. But I think there is value in investigating these questions.

It’s easy to get tired of cranks and fools wasting our time with conspiracy theories and crazy stories about abductions. And we should always be skeptical of any claims about aliens, given what we know about the physics of interstellar travel and the absurd scale of the Universe.

But most astronomers agree that life has to exist elsewhere in the Universe, and many think that it could well be intelligent and technologically capable, like us. Nobody’s saying that they can’t possibly exist, only that it’s extremely unlikely that they are over here!

So we should be skeptical of these reports. It’s good to not waste too much time studying them, when there are other mysteries that are far more likely to be true. But that doesn’t mean we should ignore the possibility altogether. It would be disastrous if, by some chance, it turned out to be real, and the scientific community had simply refused to acknowledge it! When new evidence comes in, we must revisit our assumptions and go back and check our previous conclusions. And it’s important that somebody do this even when we’re certain that they’ll get a negative result.

To learn more, visit https://hub.jhu.edu/2024/03/07/alien-meteor-truck/

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Roughly two years and six months from now, as part of NASA’s Artemis III mission, astronauts will set foot on the lunar surface for the first time in over fifty years. Beyond this mission, NASA will deploy the elements of the Lunar Gateway, the Artemis Base Camp, and other infrastructure that will allow for a “sustained program of lunar exploration and development.” They will be joined by the European Space Agency (ESA), the China National Space Agency (CNSA), and Roscosmos, the latter two collaborating to build the International Lunar Research Station (ILRS).

Anticipating this process of lunar development (and looking to facilitate it), the Defense Advanced Research Projects Agency (DARPA) launched the 10-year Lunar Architecture (LunA-10) Capability Study in August last year. In recent news, the agency announced that it selected Northrop Grumman to develop a moon-based railroad network. This envisioned network could transport humans, supplies, and resources for space agencies and commercial ventures, facilitating exploration, scientific research, and the creation of a lunar economy.

According to DARPA, the seven-month LunA-10 study aims to establish “an analytical framework that defines new opportunities for rapid scientific and commercial activity on and around the Moon.” It also aims to foster the development of foundational technology to optimize lunar infrastructure, allowing space agencies to move away from individual efforts within isolated, self-sufficient systems and towards shareable, scalable, resource-driven systems that can operate together. In keeping with NASA’s long-term objectives, this work will complement the administration’s “Moon to Mars” objectives.

Artist rendition of construction of the Moon. Credit: NASA.

In layman’s terms, the plan is to develop the technologies that will allow space agencies and companies to access each others’ resources, facilities, and information to promote further growth opportunities. Several key sectors are identified in the solicitation that must be developed into services to sustain a long-term presence on the Moon based on an independent market analysis of the future lunar economy. They include construction, mining, transit, energy, agriculture, and research (e.g., medicine, robotics, and life sustainment) that will have applications for space exploration and life on Earth.

Other aspects include lunar and planetary science, communications, digital infrastructure, and Position, Navigation, and Timing (PNT) technology. Dr. Michael “Orbit” Nayak, a program manager in DARPA’s Strategic Technology Office, extolled DARPA’s long history of working with NASA during last year’s announcement:

“For 65 years, DARPA has pioneered and de-risked technologies vital to civil space advancement — from the rocket technology in the Saturn V that took humans to the Moon for the first time, to the recent DARPA-NASA partnership to enable faster space travel to the Moon and beyond with a nuclear thermal rocket engine.

“LunA-10 continues this rich legacy by identifying and accelerating key technologies that may be used by government and the commercial space industry, and ultimately to catalyze economic vibrancy on the Moon. Just like DARPA’s foundational node of ARPANET grew into the sprawling web of the internet, LunA-10 is looking for those connective nodes to support a thriving commercial economy on the Moon.”

As part of this 10-year plan, Northrop Grumman will be tasked with creating the infrastructure that will physically connect lunar facilities and allow for the movement of people and resources back and forth. Their responsibilities, as spelled out in their contract of opportunity, include defining the interfaces and resources required to build a lunar rail network; identifying cost, technological, and logistical risks; creating prototypes, demonstrations, and analyses of a concept design and architecture, and exploring robotics concepts for constructing and operating the system.

These robotics concepts must be able to operate on the lunar surface and carry out specific tasks, such as grading and foundation preparation, track placement and alignment, joining and finishing, inspection, maintenance, and repairs. Said Chris Adams, the vice president and general manager of strategic space systems at Northrop Grumman:

“This investment in key developmental research keeps our technology at the forefront of next-generation solutions. With our proven experience in the integration of complex systems and commercialized autonomous services, we will continue to create lasting change for a sustainable space ecosystem.”

Northrop Grumman and other selectees will receive an Other Transaction award of up to $1 million. They will present their work at the Spring meeting of the Lunar Surface Innovation Consortium (LSIC) in April 2024 and provide a final report in June 2024.

Further Reading: Northrop Grumman

The post Northrup Grumman is Studying How to Build a Railway on the Moon appeared first on Universe Today.

For nearly three decades now, it’s been clear that the expansion of the Universe is speeding up. Some unknown quantity, dramatically dubbed ‘dark energy’, is pushing the Universe apart. But the rate at which the Universe’s expansion is increasing – called the Hubble Constant – hasn’t yet been nailed down to a single number.

Not for lack of trying.

In fact, there are multiple ways of measuring it. The problem is that these methods don’t agree with each other. They each give different numbers, which is a confounding – and exciting – puzzle. It means there may be new physics to uncover, if we look carefully.

This mystery is known as the Hubble tension, and it’s only becoming more intractable as measurement techniques become more precise. So astronomers are on the hunt for new and better ways to measure the expansion of the Universe.

In a new paper this week, three Swiss scientists describe a method for significantly improving one measurement technique.

The method uses a specific subset of red giant stars: old stars that have burned away most of the hydrogen in their cores. As they age, red giants get larger, less dense, and dimmer. But at a certain point in their evolution, they switch from burning hydrogen to burning helium, a change that causes a dramatic uptick in brightness. Stars in this phase of their life are considered to have reached the ‘Tip-of-the-Red-Giant-Branch’, or TRGB.

When stars in the TRGB ignite helium, they achieve a known, reliably measured level of brightness: they become ‘standard candles’, making distance measurements between them more accurate.

But that brightness isn’t perfectly constant: there are oscillations – sound waves rippling through the layers of the star. Scientists knew about these acoustic oscillations from previous studies of stellar evolution, but they hadn’t yet been accounted for in attempts at resolving the Hubble tension.

That’s what this new paper sets out to do.

“Younger red giant stars near the TRGB are a little less bright than their older cousins,” says lead author Richard Anderson. “The acoustic oscillations that we observe as brightness fluctuations allow us to understand which type of star we’re dealing with: the older stars oscillate at lower frequency – just like a baritone sings with a deeper voice than a tenor!”

“Now that we can distinguish the ages of the red giants that make up the TRGB, we will be able to further improve the Hubble constant measurement based thereon,” says Anderson.

That’s good news, securing new confidence in our understanding of how the Universe expands. However, by itself, it isn’t likely to resolve the Hubble tension. The widest gap amongst different Hubble constant measurements is between recent Universe observations: type 1A supernovae, cepheid variables, kilonovae, and red giants; and early Universe observations: especially the cosmic microwave background.

That tension remains. Still, the more confident we can be about the accuracy of our measurements, the more sure we can be that there is something new about how the Universe works waiting to be discovered. Accounting for the TRGB oscillations is a concrete step in that direction.

Learn more:

“The baritone of Red Giants refines cosmic distance measurements.” EPFL.

Richard Anderson, Nolan Koblischke, and Laurent Eyer, “Small-amplitude Red Giants Elucidate the Nature of the Tip of the Red Giant Branch as a Standard Candle.” ApJL, March 7, 2024.

The post Red Giants Offer a New Way to Measure Distance in the Universe appeared first on Universe Today.

Fortunately, the real-world search for signs of extraterrestrial civilizations doesn’t have to deal with an alien armada like the one that’s on its way to Earth in “3 Body Problem,” the Netflix streaming series based on Chinese sci-fi author Cixin Liu’s award-winning novels. But the trajectory of the search can have almost as many twists and turns as a curvature-drive trip from the fictional San-Ti star system.

Take the Breakthrough Initiatives, for example: Back in 2016, the effort’s billionaire founder, Yuri Milner, teamed up with physicist Stephen Hawking to announce a $100 million project to send a swarm of nanoprobes through the Alpha Centauri star system, powered by light sails. The concept, dubbed Breakthrough Starshot, was similar to the space-sail swarm envisioned in Liu’s books — but with the propulsion provided by powerful lasers rather than nuclear bombs.

Today, the Breakthrough Initiatives is focusing on projects closer to home. In addition to the millions of dollars it’s spending to support the search for radio or optical signals from distant planetary systems, it’s working with partners on a miniaturized space telescope to identify planets around Alpha Centauri, a radio telescope that could someday be built on the far side of the moon, and a low-cost mission to look for traces of life within the clouds of Venus.

Pete Worden is the executive director of the Breakthrough Initiatives. (Credit: Breakthrough Initiatives)

Breakthrough Starshot, however, is on hold. “This looks to be quite feasible. However, it seems to be something that is still pretty, pretty expensive, and probably wouldn’t be feasible until later in the century,” says Pete Worden, executive director of the Breakthrough Initiatives. “So, we’ve put that on hold for a period of time to try to look at, are there near-term applications of this technology, which there may be.”

Worden provides a status report on the search for extraterrestrial intelligence — and sorts out science fact from science fiction — on the latest episode of the Fiction Science podcast.

“3 Body Problem” takes its name from a longstanding challenge in orbital mechanics: It’s devilishly difficult to predict the gravitational interactions of three massive bodies in a system, except in some special cases. In the Netflix series, and in the books on which the series is based, a Chinese radio astronomer makes contact with an alien civilization that suffers repeated crises because its home world is in an unstable triple-star system.

When the aliens learn of our existence, they set out on a 400-year mass migration to Earth — an onslaught that puts our own planet on edge. One of the key concepts in the book is the Dark Forest Theory. That’s the idea that civilizations shouldn’t broadcast their existence to the rest of the galaxy, for fear that other denizens of the “Dark Forest” will eventually come after them.

Worden admits that the Dark Forest Theory has had an effect on the Breakthrough Initiatives’ agenda.

“We initially had a program called Breakthrough Message. … Not that we were going to send anything, but we were going to think about it,” he recalls. “We got a lot of resistance to even thinking about sending messages. Interestingly enough, one of the key skeptics of this was Professor Stephen Hawking. He thought it was a bad idea for exactly the Dark Forest reason. Conversely, the chairman of our advisory committee — Lord Martin Rees, the Astronomer Royal of the U.K. — has the opposite view. He doesn’t think that’s a big issue.”

Worden’s personal view is that we’ve been sending out signs of our presence — ranging from radio transmissions to telltale pollutants in the atmosphere — for so long that “it’s probably too late to hide in the forest and be quiet.”

The Breakthrough Initiatives is counting on civilizations in other planetary systems to speak up, one way or the other. Starting in 2015, Breakthrough Listen has provided support for programs looking for radio signals or optical flashes that might have been transmitted by aliens. One signal in particular, known as BLC1, got hearts beating faster in 2019 — but astronomers eventually traced its origin to earthly radio interference rather than Proxima Centauri.

Another initiative, known as Breakthrough Watch, is working with Australian astronomers on a space telescope that would monitor the motions of the three stars in the Alpha Centauri system, looking for ever-so-slight gravitational wobbles that could point to the presence of Earthlike planets a little more than 4 light-years from Earth. The telescope is called TOLIMAN, which is the Arabic name for Alpha Centauri as well as an acronym for “Telescope for Orbit Locus Interferometric Monitoring of our Astronomical Neighborhood.”

Worden says launch is currently scheduled for the first half of 2025. “We’re still negotiating on the launch vehicles, but it’s most likely to be a piggyback mission, possibly on a SpaceX mission.” he says.

For what it’s worth, astronomers have already detected a super-Earth that’s orbiting Proxima Centauri — and in 2021, a team supported by Breakthrough Watch reported seeing tentative signs of a giant planet around Alpha Centauri A.

Meanwhile, Worden is working with CSIRO, the Australian government’s science agency, on a different sort of telescope.

“We think we can put a radio telescope for on the order of $100 million on the far side of the moon that looks for transients across the broad spectrum, mostly at higher frequencies,” he says. “That’s a good place, because right now it’s blocked from interference from the Earth. Just virtually everything you see is going to be something interesting.”

The Breakthrough team is also interested in extraterrestrial life in our own solar system: Years ago, Yuri Milner looked into the prospects for sending a probe to Enceladus, an icy moon of Saturn that may harbor hidden seas and perhaps even marine organisms. Today, Worden and his colleagues are collaborating with other interested parties — including Schmidt Sciences, researchers at MIT and engineers at Rocket Lab — to send a probe through Venus’ atmosphere to search for organic materials. Liftoff is set for as early as next January.

Getting to other stars

Even though Starshot is on hold, Worden is still thinking about interstellar travel, and he’s not the only one. Last weekend, SpaceX founder Elon Musk referred to the prospects of sending his company’s Starship super-rocket on trips beyond the moon and Mars.

“This Starship is designed to traverse our entire solar system and beyond to the cloud of objects surrounding us,” Musk said in a posting to X / Twitter, his social media platform. “A future Starship, much larger and more advanced, will travel to other star systems.”

Musk may not be thinking about using light sails, but NASA is. One of the proposals that won funding in the latest round of NASA Advance Innovative Concepts grants envisions developing swarms of sail-equipped, laser-propelled micro-probes that would take advantage of the same principle laid out by Breakthrough Starshot to get to the Alpha Centauri system.

Light sails are likely to start out being used for trips to far-out destinations in the solar system. Japan’s space agency tested a solar sail during an experiment in 2010 that sent the spacecraft on a flyby past Venus — and looked into a follow-up mission to a group of asteroids in Jupiter’s orbit. That idea was put on hold, but Japanese scientists are considering other missions that would use solar power sails.

An artist’s conception shows an early design for Breakthrough Starshot’s light sail. (Breakthrough Initiatives Illustration)

Worden thinks the best long-term approach to interstellar travel would be a combination of light sails to get the probes where they’re going, plus fusion power to slow them down once they get there. “I think that ultimately, something along that line is probably feasible in a century or so, maybe sooner,” he says.

A century may sound like a long time, but when you’re talking about sending probes to other stars, you have to adjust your time scales. After all, even the super-advanced aliens in “3 Body Problem” need 400 years to get to Earth. You can add interstellar travel to the other multi-generational challenges that are facing humanity, such as climate change. In fact, The New Yorker’s review of “3 Body Problem” notes that the approach of the aliens serves as “an unexpectedly potent metaphor for the looming perils of climate change.”

So, how long could it be before we connect with extraterrestrial civilizations? That’s the kind of question that can get alien-hunters in trouble. Two decades ago, the SETI Institute’s Seth Shostak speculated that we were likely to pick up signals from intelligent alien life by the year 2025 — a scenario that now seems extremely unlikely.

Worden prefers to think in terms of percentages.

“Within a decade, we’ll almost assuredly find life elsewhere,” he says. “We’ll probably find a life-bearing planet nearby. We’ll find life either on Mars, or Venus, or maybe the outer solar system moons. But an alien techno-civilization? I’d say, for any given decade, it’s probably a few percent. But if you don’t look, you don’t find it.”

It doesn’t bother him that he may not be around to answer one of life’s ultimate questions. “One of the cool things about science is that the journey is the fun part, and you never know what you’re going to find,” Worden says. “So, as a scientist, to me, you’re pursuing something that is unlikely, but really fundamental to our future. It’s the most fun thing I can imagine working on.”

If the aliens ever do arrive, let’s hope they find that oh-so-human trait endearing.

Take a look at the original version of this posting on Cosmic Log to get Worden’s recommendations for science-fiction stories about alien contact. Check out the Breakthrough Initiatives website to learn more about what Worden and his colleagues are up to, and tune into “3 Body Problem” on Netflix. There’s also a Chinese adaptation of Liu’s books, titled “Three-Body,” that’s available in the U.S. via PBS, Peacock, Amazon Prime and other streaming services.

My co-host for the Fiction Science podcast is Dominica Phetteplace, an award-winning writer who is a graduate of the Clarion West Writers Workshop and lives in San Francisco. To learn more about Phetteplace, visit her website, DominicaPhetteplace.com, and read “The Ghosts of Mars,” her novella in Asimov’s Science Fiction magazine.

Stay tuned for future episodes of the Fiction Science podcast via Apple, Google, Overcast, Spotify, Player.fm, Pocket Casts and Radio Public. If you like Fiction Science, please rate the podcast and subscribe to get alerts for future episodes.

The post Starshot … Not? Get a Reality Check on the Search for Alien Civilizations appeared first on Universe Today.

The JWST is enormously powerful. One of the reasons it was launched is to examine exoplanet atmospheres to determine their chemistry, something only a powerful telescope can do. But even the JWST needs time to wield that power effectively, especially when it comes to one of exoplanet science’s most important targets: rocky worlds orbiting red dwarfs.

Red dwarfs are the most common type of star in the Milky Way. Observations show that red dwarfs host many rocky planets in their habitable zones. There are unanswered questions about red dwarf habitable zones and whether the rocky planets in these zones are truly habitable because of well-documented red dwarf flaring. Astronomers want to examine these planets’ atmospheres and look for biosignatures and other atmospheric information.

New research suggests that it could take the capable JWST hundreds of hours of observing time to detect these atmospheres to a greater degree of certainty. The new research is “Do Temperate Rocky Planets Around M Dwarfs Have an Atmosphere?” The sole author is Rene Doyon from the Physics Department at the University of Montreal, Canada. The paper hasn’t been peer-reviewed yet.

Doyon points out that even though one of the JWST’s main goals is to probe exoplanet atmospheres, it’s only done that for a small handful of planets: Trappist-1d, e, f, g, LHS1140b, and the mini-Neptune K2-18b.

These results have shown that the JWST has the power to probe exoplanet atmospheres. But the effort has also shown how stellar activity poses an obstacle to even more success. The JWST examines exoplanet atmospheres by watching as the planet transits its star. The telescope dissects the light from the star as it passes through the exoplanet’s atmosphere, looking for the light signatures of different molecules.

One of the biggest questions in exoplanet science concerns rocky planets in red dwarf habitable zones. Do they have atmospheres? Without atmospheres and liquid water, they may as well be way outside of the habitable zones. Fortunately, M-dwarfs have lower masses and radii, making them and their planets better targets for spectrometry. “This is known as the ‘M-dwarf opportunity,” Doyon writes in his research.

But each opportunity has an obstacle attached to it, and when it comes to M-dwarfs, the obstacle is flaring. M-dwarfs are known for their powerful flaring, and in some cases, the flares are powerful enough to render nearby planets uninhabitable. The flares emit powerful X-ray and UV radiation that can erode their atmospheres. Over billions of years, they can be so degraded that they have no chance of being habitable.

Red dwarf flaring introduces another problem. All that stellar activity can make it harder for the JWST to study exoplanet atmospheres spectroscopically.

An artist’s conception of a violent flare erupting from the red dwarf star Proxima Centauri. Such flares can obliterate the atmospheres of nearby planets. They also make spectroscopy more difficult for exoplanet atmospheres. Credit: NRAO/S. Dagnello.

The JWST is our best tool for examining exoplanet atmospheres. But it won’t last forever. It should last up to ten years and is already about 18 months into its mission. When it comes to studying exoplanets, which is only one of its jobs, how can its time be best spent?

According to the author, it’s essential that we use the JWST’s exoplanet time not only to study atmospheres but also to prepare for future flagship missions and ground-based observatories that can pick up where the JWST leaves off.

“We contend that given JWST’s limited lifetime, a comprehensive program of both eclipse and transmission spectroscopy of a key sample of temperate planets is an essential way forward,” Doyon writes.

Doyon says that the JWST should prioritize what he calls the Golden-J sample of the best temperate exoplanets. This group of planets is cool enough to avoid the runaway greenhouse effect. They also need to have accurate radius and mass measurements, which leads to an accurate understanding of their density.

“These criteria limit the selection to only a handful of rocky planets: Trappist-1d, e, f, g, and LHS1140b,” Doyon writes. “We make an exception to include the temperate mini-Neptune K2-18b as a potential habitable world, despite its mass uncertainty of 18%.” This is the Golden-J sample.

Artist’s impressions of two exoplanets in the TRAPPIST-1 system (TRAPPIST-1d and TRAPPIST-1f). Credit: NASA/JPL-Caltech

The JWST has already examined these exoplanets, and so have other telescopes, including the Hubble. But the results contain some uncertainty. Doyon describes the JWST’s first looks at the Golden-J sample exoplanets as reconnaissance and thinks that in order to remove more of that uncertainty, the JWST should examine these planets more thoroughly with some of its remaining time.

The exoplanet LHS-1140 b has a prominent spot in Doyon’s work. “LHS1140b is arguably the best temperate planet from which liquid surface condition may be inferred indirectly through the detection of CO2 in its atmosphere,” he explains. But the JWST can only observe 4 of the planet’s transits and 4 of its eclipses in one year. The JWST could require 12 visits over three years to gather strong enough evidence in favour of liquid surface water.

This artist’s impression shows the exoplanet LHS 1140b, which orbits a red dwarf star 40 light-years from Earth and may be the new holder of the title “best place to look for signs of life beyond the Solar System.” Image Credit: By ESO/spaceengine.org – https://www.eso.org/public/images/eso1712a/, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=58165409

Doyon calls this effort to observe LHS-1140 b and the other exoplanets in the Golden-J sample more thoroughly ‘deep habitability reconnaissance.’

“Arguably, the single most important question that JWST should and can answer under the scientific theme, Planetary Systems and the Origin of Life, is the title of this paper: Do temperate rocky planets around M dwarfs have an atmosphere?” Doyon writes.

It’ll take time to do that, and Doyon has calculated how much JWST observing time is required. “This comprehensive reconnaissance effort would necessitate a minimum of 700 hours, including approximately 225 hours dedicated to eclipse photometry,” he explains.

This table from the research outlines the types of observations and the hours needed to complete a deep habitability reconnaissance of the Golden-J exoplanets. Image Credit: Doyon 2024.

“However, this 715-hour effort may not be enough in all circumstances. Imposing a higher detection threshold would require even more time. “Imposing a higher detection threshold (4-5?) for this reconnaissance program – as was published for the MIRI observations of Trappist-1b and c – would
significantly increase the total observing time, potentially ranging from 1300 to 2000 hours,” Doyon explains.

It could take even more time than that, especially if there are any particularly tantalizing results that require more follow-up observations.

This may sound like a good chunk of time to spend on a small handful of exoplanets. But the JWST was built to find answers, and if it takes this much time, it’s time well spent.

“Initiating such an extensive habitability program at the earliest opportunity is paramount,” Doyon writes.

The post Finding Atmospheres on Red Dwarf Planets Will Take Hundreds of Hours of Webb Time appeared first on Universe Today.

Can Europa’s massive, interior ocean contain the building blocks of life, and even support life as we know it? This question is at the forefront of astrobiology discussions as scientists continue to debate the possibility for habitability on Jupiter’s icy moon. However, a recent study presented at the 55th Lunar and Planetary Science Conference (LPSC) might put a damper in hopes for finding life as a team of researchers investigate how Europa’s seafloor could be lacking in geologic activity, decreasing the likelihood of necessary minerals and nutrients from being recycled that could serve as a catalyst for life.

Here, Universe Today speaks with Henry Dawson, who is a PhD student in the Department of Earth, Environmental, and Planetary Sciences at Washington University in St. Louis and lead author of the study, about his motivation behind the study, significant results, follow-up studies, and whether Dawson believes there’s life on Europa. So, what was the motivation behind this study?

Dawson tells Universe Today, “A large portion of the community has been looking at the habitability potential of the seafloor, and looking at processes that might occur at seafloor hydrothermal vents, or at water–rock interaction chemistry. However, it was never established that there would actually be any fresh rock exposed at the seafloor, or if the tectonic processes that drive hydrothermal vents would be present. The silicate interior of Europa is a similar size to that of Earth’s Moon, which is largely geologically dead on the surface.”

Artist’s cutaway illustration of Europa and its potential geologic activity. (Credit: NASA/JPL-Caltech/Michael Carroll)

For the study, Dawson and his colleagues examined the likelihood for geologic activity occurring on Europa’s seafloor through analyzing data on Europa’s geophysical characteristics and comparing them with known geologic parameters and processes, including the strength of potential fault lines and fractures within Europa’s rocky interior, how the strength of this rock changes with depth, and how the rock could react to ongoing stresses, commonly known as convection. Using this, they conducted a series of calculations to ascertain whether the seafloor crust could drive geologic activity. Therefore, what were the most significant results from this study?

“It looks a lot more difficult to expose fresh rock (which is required to drive the reactions that life would exploit) to the ocean,” Dawson tells Universe Today. “Tidal forces do not seem able to cause motion along faults, like it can on the surface, and so the seafloor is most likely still. All the rock that water is able to interact with through porosity was likely altered hundreds of millions to billions of years ago, and so the ocean and rock are in chemical equilibrium. This means that there is no present day, continuous input of nutrients into the ocean from the rocky core, and so any possible life would likely have to exploit nutrient input from the icy shell above the ocean.”

While this study focused on geologic stresses related to fractures and fault lines, Europa’s interior ocean is produced from another type of geologic stress known as tidal heating, which is induced from the constant stretching and compressing as Europa orbits the much more massive Jupiter. This same tidal process occurs between the Earth and its Moon, and we see this in action in the rising and falling of the Earth’s waters around the globe. For Europa, over the course of thousands to millions of years, the stretching and compressing leads to friction in Europa’s inner rocky core, which leads to becoming heated and melting the inner ice into the interior ocean that exists today. It is in this ocean that astrobiologists hypothesize that life could exist, possibly even life as we know it.

However, given these study’s unfortunate findings, Dawson and his colleagues give dire implications for the potential habitability on Europa, noting their calculations estimate that geologic activity on Europa’s seafloor is limited enough to indicate habitable conditions within Europa’s interior ocean could be limited, as well. However, the study was quick to note that other geologic processes could be examined to explain the present state of Europa’s seafloor geologic activity, including processes known as serpentinization and thermal expansion anisotropy.

“As rock is exposed to water and chemically alters, the new minerals that form may have a different molar volume than the unaltered minerals in the original rock,” Dawson tells Universe Today. “Serpentinization specifically is the process where peridotite, a typical mantle rock, is altered to serpentinite. This reaction has a net volume increase, which introduces new stresses. These stresses might lead to the fracturing of the rock, fresh rock faces exposed, and more alteration, leading to a self-propagating cycle. On the other hand, the new minerals might cement up pre-existing fractures, preventing further exposure, and creating a negative feedback loop. Thermal expansion anisotropy describes the process where different minerals have varying degrees of expansion upon heating. Thus, when a rock is heated or cooled, the mineral grains inside will push against each other, introducing porosity and interior stresses.”

Regarding the tidal forces responsible for producing Europa’s interior ocean, this icy moon and the Earth’s Moon are not the only planetary bodies in the solar system that could experience these unique forces. Others include Jupiter’s third Galilean Moon, Ganymede, Saturn’s icy moon, Enceladus, and Saturn’s largest moon, Titan, all of which are currently hypothesized to possess interior oceans from tidal heating. Like Europa, Ganymede exhibits a predominantly crater-free surface, which is indicative of frequent resurfacing, and Enceladus was observed on numerous occasions by NASA’s Cassini spacecraft to have geysers on its south pole region that frequently shoots out water into space.

Additionally, Cassini flew through these geysers to obtain data on the ejecta’s composition, discovering organic molecules. For Titan, Cassini data revealed that an interior ocean exists beneath its surface, which is currently hypothesized to contain a combination of ammonia and salts. But regarding this most recent research, what follow-up studies are currently being conducted or planned?

Dawson tells Universe Today, “I’m currently using the same model to estimate whether tidal forces are able to cause fracturing on other icy moons in the outer solar system, such as Ganymede, Enceladus, Titan, and the mid-size Uranian moons. Based on my preliminary results that I presented at LPSC, it appears that tidal forces are insufficient on those moons as well. In addition, our collaborator Austin Green is looking at whether seafloor volcanism might occur, based on the forces that volcanic dikes can exert on the rock that they are propagating through. For Europa, the lithosphere is too deep and too strong for magma to reach the seafloor, and so any melt that forms in the mantle stalls out at depth.”

Despite being discovered by Galileo Galilei in 1610, the fascination for finding life within Europa’s ocean has only come within the last few decades, thanks largely to the NASA Voyager missions, with Voyager 1 and Voyager 2 flying through the Jupiter system in 1979 and imaged the Galilean Moons up close and in detail for the first time, hinting that Europa was currently geologically active. This is because Europa has almost no visible craters throughout its entire surface, indicating specific processes are responsible for reshaping the small moon and covering up evidence of past impacts. Europa, being the second Galilean Moon, shares these traits with the first and third Galilean Moons, Io and Ganymede, respectively, while the fourth Galilean Moon, Callisto has a surface that is almost entirely covered by craters.

The Galilean moons of Jupiter: Io, Europa, Ganymede, and Callisto. (Credit: NASA/JPL-Caltech)

Thanks to further data obtained from proceeding missions, including NASA’s Galileo spacecraft, Hubble Space Telescope, and Juno, scientists are almost entirely convinced that an interior ocean lies beneath Europa’s icy crust, with some estimates putting the volume of liquid water at double of Earth’s oceans. Therefore, as we see on Earth, liquid water means life, which is why Europa’s interior ocean is a target for astrobiology research. But does Henry Dawson think there’s life on Europa?

Dawson tells Universe Today, “I think there’s still a lot more that I would like to understand before I make a yes or no statement on that. While I believe that Europa is one of the most likely candidates to host life, alongside Enceladus, the chance of life remains small, and this research reduces the probability even more.”

This study comes as NASA prepares to launch the Europa Clipper spacecraft this October with a planned arrival date of April 2030 and is designed to explore the habitability potential of Europa and its interior ocean. During its 3.5-year mission, Clipper will perform up to 44 close flybys of Europa ranging between 25 and 2,700 kilometers (16 to 1,678 miles) as the spacecraft will perform elongated orbits to keep from staying within Jupiter’s powerful magnetic field for too long. To assess Europa’s habitability potential, Clipper will carry a powerful suite of scientific instruments designed to analyze Europa’s chemistry, surface geology, and interior ocean characteristics.

Artist’s rendition of NASA’s Europa Clipper (published in January 2021). (Credit: NASA/JPL-Caltech)

Additionally, the European Space Agency’s Jupiter Icy Moons Explorer (JUICE) mission was launched in April 2023 with a planned orbital insertion at Jupiter in July 2031, followed by a departure from Jupiter and an orbital insertion around Ganymede in December 2034. Like Clipper, JUICE is designed to investigate the habitability potential of the icy moon, but will also examine Ganymede and Callisto, as well.

“Get excited for the Europa Clipper and JUICE missions! Dawson exclaims to Universe Today. “While it will still be 6 years before they reach Jupiter, once they arrive, we will be able to learn much more about what is going on at Europa. While they will not be able to directly measure the interior, observations of the ice shell, gravity field, and tidal forcing on Europa will help to constrain future models. As well, always be careful about the assumptions you make for other planetary bodies. While Europa may be covered with ice, it is truly a rocky world that happens to have a deep ocean, and the processes occurring at depth may not reflect what we see at Earth’s seafloor.”

Is Europa’s seafloor geologically active, and what new insights will Europa Clipper and JUICE make about this astonishing and intriguing icy moon in the coming years and decades? Only time will tell, and this is why we science!

As always, keep doing science & keep looking up!

The post Europa Might Not Be Able to Support Life in its Oceans appeared first on Universe Today.

You can tell a lot about a planetary body just by looking at its surface, especially if it has craters. Take Europa, for example. It has a fairly young surface—somewhere between 50 and 100 million years old. That’s practically “new” when you compare it to the age of the Solar System. And, Europa’s icy crust is pretty darned smooth, with only a few craters to change the topography.

Planetary scientists already know that Europa’s icy surface is a thin shell over a large interior ocean of salty water. How thin? To find out, a team of researchers led by Brandon Johnson and Shigeru Wakita at Purdue University studied images of large craters on Europa. They used what they saw, coupled with a variety of physical characteristics, to create computer models of that shell. “Previous estimates showed a very thin ice layer over a thick ocean,” said Wakita. “But our research showed that there needs to be a thick layer—so thick that convection in the ice, which has previously been debated, is likely.”

The thickness of that shell may well influence whether or not life exists at Europa. Its existence is a topic of intense interest since Europa could provide a reasonably habitable ecosystem for life. It has water, warmth, and organic materials for life to eat. That makes the search for life at Europa quite important. So, what do craters have to do with all this?

More About Craters

Impact cratering performs a lot of gardening in the Solar System, according to Johnson. He is the first author on a recently published paper discussing these features on Europa. “Craters are found on almost every solid body we’ve ever seen. They are a major driver of change in planetary bodies,” he said.

Four featured craters among many on the Moon: the triplet of Theophilus, Cyrillus and Catharina and Maurolycus. Many more craters can be seen across the lunar surface. Credit: Virtual Moon Atlas / Christian LeGrande, Patrick Chevalley

Just looking at images of different worlds in the Solar System, we can see some pretty heavily cratered surfaces. The Moon is a good example, as is Mars. And, we see it at many of the smaller bodies, such as the moons of the gas and ice giants. The more craters we see, the older the surface. In some places, multiple overlapping craters indicate a very old surface. In other places, such as at Europa, the craters are fewer and farther between. Something has “paved over” the craters such that any we CAN see were made after the repaving event. In addition, the craters reveal information about the surface as well as the “subsurface” of Europa.

“When an impact crater forms, it is essentially probing the subsurface structure of a planetary body,” said Johnson. “By understanding the sizes and shapes of craters on Europa and reproducing their formation with numerical simulations, we’re able to infer information about how thick its ice shell is.”

What Europa’s Craters Tell Us

This tiny moon is an enigma wrapped in shimmering ice. Its frozen surface hides a rocky inner core covered with a salt-water ocean. Like Earth, it experiences surface plate tectonics, driven by the core region’s heating. Inside, that heating drives currents of warmer water up from the core. That water gets forced to the surface, where it freezes and creates a new layer overlying any other features. This resurfacing happens every 50 to 100 million years.

Incoming impactors carve out new craters in that “freshened-up” surface, which gives scientists some pretty easy-to-study craters. They aren’t terribly deep, however, which tells scientists a lot about the structure of the icy shell. Johnson, Wakita, and their team studied images from the Galileo spacecraft to analyze Europa’s craters. In particular, they focused on two multi-ringed basins imaged on this moon. They show two or more concentric rings around the point of the impact that created them. Such basins are fairly rare and usually indicate some kind of large, energetic impact. On Europa, their appearance and formation give clues to the thickness of the icy shell and their thermal structure, which is a way to understand how the shell conducts heat.

Multi-ringed Crater Basins Tell a Tale

In their study, the Purdue team simulated a multi-ring basin with varying thicknesses of ice. Those thicknesses influence the degree of tidal heating in the shell itself. They also help scientists understand how heat exchange occurs between the bottom of the shell and the underlying ocean. The team found that icy shells thinner than about 15 kilometers don’t show the kinds of multi-ringed basins that exist on Europa. However, a thicker one does. In particular, the best-fit simulation used a 20+ kilometer-thick shell. It consists of two layers: a 6-8 kilometer-thick conductive “lid” that covers up a layer of warm, convecting ice.

One of Galileo’s images of the Tyre multi-ringed basin on Europa. There are at least 5-7 rings around the impact crater center. Courtesy: NASA/JPL/ASU.

In addition to studying the craters, the team also looked at the types of impactors needed to create those multi-ringed basins on Europa. From the structures seen in the Galileo images, they concluded that the impactors would need to be around 1.5 kilometers in radius to create the multi-ringed basins. Smaller ones wouldn’t create the structures they saw, and bigger impactors would result in very different-looking craters and rings.

What About Other Worlds?

Europa isn’t the only world at Jupiter with an icy crust. Both Ganymede and Callisto also show cratering, with multi-ring basins. This tells us that these worlds also have to have thick enough icy crusts where such basins can form. Planetary scientists have suggested their crusts are at least 80 to 105 kilometers thick. In their paper, the Purdue teams suggest that since Europa’s crust is likely to be at least 20 kilometers thick (if not more) it’s also likely that Ganymede and Callisto have much thicker crusts than current predictions suggest.

Callisto has many more craters than Europa and a thicker icy crust. Image credit: NASA/JPL

Finally, although the paper doesn’t specifically address this, the fact that the scientists can deduce impactor size from the characteristics of the resulting craters does provide insight into the sizes of impactors available in Jovian “airspace”. To sustain these kinds of multi-ringed basins, you need a good population of sizable impactors to do the job. Also, for Europa to be so recently “refreshed” really does give a clue to the impact environment in the Jupiter system. While Ganymede and Callisto both have very old surfaces, the existence of “fresh” ice at various cratering sites tells us that they’re still being bombarded in recent times, although they’re not actively resurfacing themselves. These are all additional data points to consider when understanding the habitability of environments, particularly at Europa (and possibly at places such as Enceladus at Saturn).

“Understanding the thickness of the ice is vital to theorizing about possible life on Europa,” Johnson said. “How thick the ice shell is controls what kind of processes are happening within it, and that is really important for understanding the exchange of material between the surface and the ocean. That is what will help us understand how all kinds of processes happen on Europa—and help us understand the possibility of life.”

For More Information

Planetary Scientists Use Physics and Images of Impact Craters to Gauge Thickness of Ice on Europa
Multiring Basin Formation Constrains Europa’s Ice Shell Thickness

The post What Can Europa’s Surface Tell Us About the Thickness of Its Ice? appeared first on Universe Today.

That stars can eat planets is axiomatic. If a small enough planet gets too close to a large enough star, the planet loses. Its fate is sealed.

New research examines how many stars eat planets. Their conclusion? One in twelve stars has consumed at least one planet.

The evidence comes from co-natal stars, which aren’t necessarily binary stars. Since these stars form from the same molecular cloud, they should have the same ingredients. Their metallicity should be nearly identical.

But for about one in twelve stars, there are clear differences.

The new research is titled “At least one in a dozen stars shows evidence of planetary ingestion,” and it’s published in the journal Nature. The lead author is Fan Liu, an ASTRO 3D Research Fellow in the School of Physics and Astronomy at Monash University, Melbourne, Australia.

“Astronomers used to believe that these kinds of events were not possible.”

Yuan-Sen Ting, co-author, ASTRO 3D researcher from the Australian National University

“Stellar chemical compositions can be altered by ingestion of planetary material and/or planet formation, which removes refractory material from the protostellar disk,” Liu and his colleagues write in their paper. “These ‘planet signatures’ appear as correlations between elemental abundance differences and the dust condensation temperature.”

The authors explain that these signatures are elusive. The key to finding them is to locate co-natal stars, stars that were born together and are still moving together through space.

“We looked at twin stars travelling together. They are born of the same molecular clouds and so should be identical,” said lead author Liu.

The researchers started by using the extreme accuracy of the ESA’s Gaia spacecraft. Gaia’s data allowed the researchers to identify 125 co-moving pairs of stars. Of those, 34 were considered too widely separated but were still used as a control group. The researchers then examined the remaining 91 pairs spectroscopically to determine their chemistry. They used powerful telescopes to gather this data: the Magellan Telescope, the Very Large Telescope, and the Keck Telescope. The large amount of accurate data generated by these ‘scopes allowed the researchers to detect chemical differences and made the findings possible.

“Thanks to this very high precision analysis, we can see chemical differences between the twins,” said Liu. “This provides very strong evidence that one of the stars has swallowed planets or planetary material and changed its composition.”

Liu points out that their findings don’t include stars like red giants that expand when they leave the main sequence and consume nearby planets. “This is different from previous studies where late-stage stars can engulf nearby planets when the star becomes a very giant ball,” Dr. Liu said.

This figure from the study illustrates some of the team’s findings. The top panel shows the different chemical abundances of some chemicals between one pair of co-natal stars. The bottom panel shows the same in percentage differences. Image Credit: Liu et al. 2024.

These results required some detailed analysis. When determining the metallicity of the co-natal stars and how planetary material could explain the different metallicities, the researchers had to account for atomic diffusion. Atomic diffusion can transport different chemicals around in stars, which can change how abundant different chemicals can appear to be. Stars from the same cluster, and co-natal stars, can show different abundances even though they’re the same overall.

However, atomic diffusion leaves a different chemical fingerprint, and the researchers were able to determine how atomic diffusion affects apparent abundance versus how the engulfment of planetary material affects it.

There’s a lot of specific scientific information in this figure from the study. But the primary takeaway is that the abundance of each chemical element in this pair of co-natal stars more closely matches a planet engulfment model (blue dashed line) than atomic diffusion (pink dashed line.) Image Credit: Liu et al. 2024

The results show that some co-natal stars have different metallicity, so some of them have absorbed planetary material. But the researchers point out that some of the results may not come from planetary engulfment. It’s possible that in some of these pairs, one star absorbed material from its protoplanetary disk, which would also change its metallicity.

“It’s complicated. The ingestion of the whole planet is our favoured scenario, but of course, we can also not rule out that these stars have ingested a lot of material from a protoplanetary disk,” he says.

Showing that stars can absorb planets puts another wrinkle into our understanding of stars and their planetary systems. Engulfment doesn’t happen a lot, according to these results, but the fact that it does is intriguing. It leads to questions. How and why does it happen? What situations lead to this engulfment? How does it affect the exoplanet population, and could it affect potential habitability somehow? Engulfment leaves its mark on the star; how does it affect the planetary system?

“Astronomers used to believe that these kinds of events were not possible, said study co-author Yuan-Sen Ting, ASTRO 3D researcher from the Australian National University. “But from the observations in our study, we can see that, while the occurrence is not high, it is actually possible. This opens a new window for planet evolution theorists to study.”

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Communication between spacecraft relies upon line of site technology, if anything is in the way, communication isn’t possible. Exploration of the far side of the Moon is a great example where future explorers would be unable to communicate directly with Earth.  The only way around this is to use relay satellites and the Chinese Space Agency is on the case. The first Queqiao-1 was able to co-ordinate communications with Chang’e-4 landers and now they are sending Queqiao-2 to support the Change’e-6 mission. 

If you have ever gazed upon the Moon you might have noticed that it always has the same hemisphere facing the Earth. This phenomenon is known as captured or synchronous rotation. It may look like the Moon isn’t rotating but in reality the time it takes to spin once on its axis is the same as the time it takes to complete one orbit around the Earth, keeping one hemisphere constantly facing us. Explorers on the near side of the Moon have no trouble communicating with transmissions taking just over one second to reach home. Explore the far side of the Moon and you have a problem. 

The Chang’e 5 test vehicle captured this beautiful view of Earth over the far side of the Moon on October 28, 2014. Credit: Chinese national space agency (CNSA) and Chinese Academy of Sciences (CAS)

To overcome the problem China have launched a 1.2 ton communication satellite known as Queqiao-2. It’s name originates from the mythological bridge made from magpies. In the Chinese tale, the magpies formed a bridge across the Milky Way to allow the lovers Vega and Altair to be together for one night once a year. Two miniature satellites were also launched Tiandu-1 and Tiandu-2 from the island of Hainan.

On arrival it will orbit the Moon and provide a relay for the Chang’e-6 lander which is slated to launch in May.  It will join satellites from United States, India and Japan to support the exploration of the far side of the Moon. Chang’e-6 will collected samples from an ancient basin. Not only will it serve the communications for Change-6, it will transfer communications for Chang’e-7 and ‘8. Both craft are to be launched in the years ahead 2026 and 2028 respectively. 

The orbit of Queqiao-2 will take it almost over the south pole in an elliptical orbit. It will reach an altitude of 8,600 km so that communication can be achieved for a little over eight hours. At its closest, it will sweep over the lunar surface at an altitude of 300 km.

The ultimate goal of the Chinese Space Agency is to create a network of satellites, not too dissimilar (but not quite on the same scale) to the growing Space X constellation which is building a global internet presence. The purpose of Tiandu-1 and Tiandu-2 is to test the concept of such a constellation. 

China’s longer term aspirations include a research station at the lunar south pole and for this to be viable, communication relays are essential to establish communication, navigation and remote sensing. 

Source : China launches signal relay satellite for mission to moon’s hidden side

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Totality and the April 8th total solar eclipse offers a rare chance to study the Sun.

We’re less than three weeks out now, until the April 8th total solar eclipse crosses North America. And while over 31 million residents live in the path of totality, many more will make the journey to briefly stand in the shadow of the Moon. Several scientific projects are also underway to take advantage of the event.

The eclipse traverses Mexico, the United States from Texas to Maine, and the Canadian Maritime provinces before heading out over the Atlantic. Maximum totality for this eclipse in 4 minutes and 27 seconds, longer than the 2017 total solar eclipse. This is the only total solar eclipse worldwide for 2024, and the final total solar eclipse for a generation for the contiguous United States until 2044.

A Brief History of Total Solar Eclipse Science

Eclipses have always offered astronomers a chance to carry out rare observations. The element helium (named after ‘Helios’ the Greek god of the Sun) was discovered in the solar chromosphere during the August 18th, 1868 total solar eclipse. Astronomers swept the sky near the eclipsed Sun in July 29th, 1878, looking for the hypothetical planet Vulcan. World War I thwarted astronomer’s plans to test Einstein’s Theory of General Relativity during the August 21st, 1914 eclipse. This had to wait until Arthur Eddington led an expedition to Principe in 1919. Eddington vindicated Einstein with measurements of the deflection of stars observed near the Sun during totality.

Stranger experiments continued right up into the 20th century. One of the more bizarre eclipse experiments was hunting for the elusive ‘Allais Effect,’ looking for the deflection of a pendulum during totality. Alas, Maurice Allais’ findings alluding to this fringe idea have never been replicated. Maybe LIGO Livingston just outside the path of totality on 2024 could take up the challenge?

Four Eclipse Science Projects

In 2023, NASA selected four major experiments to chase totality:

1. The Solar Patrol sunspot campaign: This effort is led by Thangasamy Velusamy out of NASA’s Jet Propulsion Laboratory. This initiative seeks to monitor subtle changes in the magnetic fields of active sunspot regions as the Moon passes over them. The team will use the 34-meter Goldstone Apple Valley Radio Telescope based in California (outside of the path of totality) to carry out this experiment. We’re headed towards the peak of Solar Cycle 25 over the coming year, so the odds are pretty good that the Sun will be dappled with multiple sunspots, come eclipse day.

2. SuperDARN to probe the ionosphere: Led by Bharat Kunduri out of Virginia Polytechnic Institute and State University, this experiment seeks to measure how the upper ionosphere reacts to the eclipse. Crucially, totality passes over three SuperDARN (Super Dual Auroral Radar Network) sites during the eclipse, offering an unprecedented opportunity.

3. Pro/AM ‘Listening Party’ to observe QSOs: Ham radio operators are familiar with the enhanced nighttime reflectivity of the upper ionosphere. This effect allows for reception of distant stations that are otherwise silent in the daytime. This sort of contact is known as a ‘QSO’ in ham radio-speak, and it also occurs during an eclipse, as totality briefly mimics the approach of night. Nathaniel Frissell of the University of Scranton is leading an effort to make QSO contacts on April 8th. A good strategy is to pick an AM station a few hundred miles distant and listen before, during and after totality passes. Even today, most cars still come equipped with AM/FM radios. This is also an experiment that can be done from outside of the path of totality.

A modified, eclipse-chasing WB-57 aircraft is towed out for a mission. NASA Chasing the Shadow

4. NASA’s WB-57 missions to take flight once again. The most ambitious endeavor is once again underway, as NASA’s two converted WB-57 Canberra aircraft will once again chase the shadow of the Moon. NASA owns the last three Canberra aircraft still in service. Two of these aircraft will fly out of Ellington Field outside of Houston, Texas on eclipse day. The jet aircraft will intercept the Moon’s shadow, which will be moving at over 2,500 miles per hour. This allows for an extra two minutes of totality. Both aircraft will carry a suite of cameras and spectrometers, allowing astronomers to analyze the inner corona very near the Sun. Studying the region could go a long ways towards solving the ‘coronal heating problem,’ a mystery evolving why the corona is exponentially hotter than the photosphere of the Sun.

Images of the Sun from GOES-16, versus the Sun during eclipse (far right) showing loops in the lower corona. NASA

Observations from the 2017 eclipse hinted that oscillations in the lower corona may feed ‘nano-flares’ that pump energy into the outer corona. This time, two new observatories will be on hand to back up NASA’s eclipse measurements. These are the European Space Agency’s Solar Observatory (SolO) and NASA’s Parker Solar Observatory.

The flight will also continue the campaign to scan the sky near the eclipsed Sun to hunt for elusive Vulcanoid asteroids interior to the orbit of Mercury. General Relativity did away with the need to evoke an inter-Mercurial world to explain the anomalous precession of Mercury’s orbit. The jury is still out, however, on whether smaller asteroids could still exist near the Sun. MESSENGER scoured the region near the Sun en route to Mercury. NASA will once again look for Vulcanoids as a secondary objective during the 2024 eclipse.

NASA has also chased eclipses aloft using Gulfstream III aircraft:

More Total Solar Eclipse Science

Other citizen-science projects are also planned for April 8th. One intriguing project is the Citizen Continental-America Telescope Eclipse network, known as Citizen CATE. This project sees volunteers setup along the total solar eclipse path, with the objective of augmenting corona observations.

An animation of the corona in polarized light, as seen during the 2017 total solar eclipse. NASA/Gopalswamy et al.

I have a deep respect for all those who are devoting precious time during totality to eclipse science. Perhaps, you’ll simply be happy will clear skies to enjoy the view. If you haven’t got your eclipse glasses yet to safely obverse the Sun, Astronomy For Equity still has ‘em available. Hey, they’re for a good cause…

Good luck and clear skies to all who are headed into the shadow of the Moon on eclipse day, whether its for the cause of science, or just to enjoy the view.

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