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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/

The post The Sound of an Interstellar Meteor Might Have Just Been a Rumbling Truck appeared first on Universe Today.

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.”

The post One in Twelve Stars Ate a Planet appeared first on Universe Today.

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

The post China’s Next Lunar Relay Satellite Blasts Off appeared first on Universe Today.

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.

The post NASA Experiments Planned for the April 8th Total Solar Eclipse appeared first on Universe Today.

After over 70 successful flights, a broken rotor ended the remarkable and groundbreaking Ingenuity helicopter mission on Mars. Now, NASA is considering how a larger, more capable helicopter could be an airborne geologist on the Red Planet. For the past several years scientists and engineers have been working on the concept, proposing a six-rotor hexacopter that would be about the size of the Perseverance rover.

Called the Mars Science Helicopter (MSH), it would not only serve as an aerial scout for a future rover, but more importantly, it could also carry up to 5 kg (11 lbs) of science instruments aloft in the thin Martian atmosphere and land in terrain that a rover can’t reach.

A new paper presented at the March 2024 Lunar and Planetary Science Conference outlines the geology work that such a helicopter could accomplish.

The paper, “Unraveling the Origin and Petrology of the Martian Crust with a Helicopter,” notes there are several outstanding questions about the makeup and history of Mars’ surface, especially with recent discoveries of unexpected dichotomies in the composition of basaltic rocks. In observations from the Mars rovers and orbital spacecraft, some regions appear to have been influenced by water while some have not.

“Up to last decade, we thought that magmatic rocks were only basaltic on Mars,” said Valerie Payré from the University of Iowa, the paper’s lead author. “But with recent rover and orbital measurements, we observed that there is a wide diversity of magmatic rocks similar to what we see on Earth.”

Payré explained via email that there are rocks on Mars with elevated silica concentrations called felsic rocks – feldspar and silicate — that are rich in elements and were not expected to be found on the Martian surface.

“We measured these with the Curiosity rover and have some hints of where there might be others using orbital measurements,” Payré said. “However, close-up images (millimetric scale) and composition analyses are lacking from the orbital dataset to know if these felsic rocks are widespread on Mars or just at a few locations. This is yet highly important to understand what the crust of Mars is made of and if it is similar to Earth’s crust, which has implications regarding the formation of the planet and even past climate.”

First X-ray view of Martian soil – feldspar, pyroxenes, olivine revealed (Curiosity rover at “Rocknest”, October 17, 2012). Credit: NASA/JPL-Caltech/Ames

Payré and her team feel that a helicopter would be perfect to explore places where a rover could never traverse, such as terrains that are too high in altitude, since landing there would require too much fuel.

The instruments they propose include a miniaturized visible and near-infrared (VNIR) spectrometer for small scale mineralogical mapping and a small Laser Induced Breakdown Spectrometer (LIBS) with a micro-imager, an instrument similar to the ChemCam laser instrument on both the Curiosity and Perseverance rovers. In their paper, the team writes that a helicopter with these instruments could travel kilometers to detect promising felsic terrains, and measure their composition at a micron scale.

“We could fly over these possible felsic terrains and look at their minerals using a visible/near infrared spectrometer, land on locations of interest, take close-up images, and measure the compositions of these rocks with the LIBS,” Payré said. “We could finally know what Mars’ crust is, and better constrain how it formed.”

A graphic show the parts of the Ingenuity helicopter. Credit: NASA

There could also be an onboard a magnetometer, which measures magnetic field anomalies, to better understand how Mars’ magnetic field operated, which is still uncertain. Mars does not presently have a global magnetic field, but had one early in its lifetime.

“Such payload would finally enable us to better understand the past climate on Mars by measuring the composition and minerals of sedimentary rocks of various age,” Payré told Universe Today.

A conceptual design paper published in 2020 proposed a Mars hexacopter with a mass of about 31 kg (70 lbs) and a total diameter of just over four meters (13 feet). Each set of rotors would have blades about 0.64 meters (2 ft) long.  The helicopter would be powered by a rechargeable solar cell. This would not only power the rotors, but the desired scientific instruments. 

A model of NASA’s Mars Science Helicopter concept. Credit: NASA.

This helicopter could move as fast as 30 meters a second (60 mph) but also could hover over a spot for as long as five minutes. Engineers from Ames Research Center, the Jet Propulsion Lab and the University of Maryland wrote that MSH could fly with a range of up to 10 km (6.2 miles) per flight. With this speed and range, MSH could potentially cover as much ground in a few days as rovers like Perseverance and Curiosity have traversed in years.

“The fact that a helicopter can fly would facilitate the mission to visit to places that would be inaccessible for a rover, and we could access locations that we never imagined before,” Payré said.

Payré and team proposed several landing sites including Gale Crater Gale crater where evolved felsic rocks were found by the Curiosity Rover; the massive canyon of Valles Marineris, where orbital observations have revealed a deep crust with feldspar-bearing rocks; and Hellas basin, 2,300 km impact crater known to have layers of feldspar. 

Annotated view of Valles Marineris from the High-Resolution Stereoscopic Camera (HRSC) on the Mars Express spacecraft. Credit: ESA/DLR/FU Berlin (G. Michael)

The post The Mars Science Helicopter Could be an Airborne Geologist on Mars appeared first on Universe Today.

The US Government budget announcement in March left NASA with two billion dollars less than it asked for. The weeks that followed have left NASA with some difficult decisions forcing cuts across the agency. There will be a number of cuts across the agency but one recent decision came as quite a shock to the scientific community. NASA have just announced they are no longer going to support the Chandra X-Ray Observatory which has been operational since 1999 and made countless discoveries. 

Chandra was launched back in 1999 and has become pivotal in the world of X-ray astronomy. X-ray observatories like Chandra have to be placed in orbit because the atmosphere blocks the X-ray radiation from reaching Earth. Like other high energy telescopes, the mirrors of Chandra have to be placed at shallow angles to the incoming high energy beams. If they were placed perpendicular the X-rays would zip straight through. Instead, multiple mirrors are placed at shallow angles to gently guide the radiation to a focus. 

Since its launch it has captured high resolution X-ray images of black holes, supernova remnants, pulsars and galaxy clusters. The X-rays allow us to look deep inside these extreme objects to show detail which is usually impossible to see. It’s first image was the supernova remnant Cassiopeia A, it revealed forward and reverse shockwaves and ejecta from the pre-supernova state.

This X-ray image of the Cassiopeia A (Cas A) supernova remnant is the official first light image of the Chandra X-ray Observatory. The 5,000 second image was made with the Advanced CCD Imaging Spectrometer (ACIS). Two shock waves are visible: a fast outer shock and a slower inner shock. The inner shock wave is believed to be due to the collision of the ejecta from the supernova explosion with a circumstellar shell of material, heating it to a temperature of ten million degrees Celsius. The outer shock wave is analogous to an awesome sonic boom resulting from this collision. The bright object near the center may be the long sought neutron star or black hole that remained after the explosion that produced Cas A.

NASAs budget statement was released on 11 March where it revealed its plans for 2025 and beyond. In the statement it read “The reduction to Chandra will start orderly mission drawdown to minimal operations.” Thankfully NASA has already identified a plan of action should Chandra experience mission-ending failure. The loss of funding and the decision to scale back Chandra activity has meant these procedures swing into action. They include the closedown of flight operations, finalisation of data and source catalog, documentation of calibration and other critical products and much more. 

The budget document went on with the rationale for the decision “The Chandra spacecraft has been degrading over its mission lifetime to the extent that several systems require active management to keep temperatures within acceptable ranges for spacecraft operations. This makes scheduling and the post processing of data more complex, increasing mission management costs beyond what NASA can currently afford.”

The statement refers to spacecraft degradation which does of course come to all spacecraft in time if not repaired and upgraded. One of the key issues it temperature control. To be effective Chandra needs to be kept at a specific temperature but since 2005 the temperature has been increasing. To overcome the problem, thermal models have been developed along with processes to counteract the rising temperature with no degradation in quality. However to continue operations the models need to be updated which takes time and money.

In April, NASA plans to go through a review process to see if operations may be able to continue in the future given the budget restrictions. For now though, it seems Chandra operations are set to be put on hold for the foreseeable future. 

Source : A Letter to the Chandra Community

The post NASA is Planning to Shut Down One of the Great Observatories to Save Money appeared first on Universe Today.

The Moon is practically begging to be explored, and the momentum to do so is building. The Artemis Program’s effort to return astronauts to the Moon for the first time since the Apollo missions captures a lot of attention. But there are other efforts underway.

In 2023, the ESA put out a call for small lunar missions. The call was associated with their Terra Novae exploration program, which will advance the ESA’s exploration of the Solar System with robotic scouts and precursor missions. “Humankind will benefit from the new discoveries, ambitions, science, inspiration, and challenges,” the ESA explains on their Terra Novae website.

Terra Novae has several goals, one of which is to “Land multiple scientific payloads on the surface of the Moon, prospecting for the presence of water and other volatile materials that will both reveal its history and help prepare sustainable exploration by locally sourced space resources.”

In response to the ESA’s call, a team of European researchers have proposed the LunarLeaper. The LunarLeaper is a hopping robot that would visit a lunar skylight, a collapsed part of a lunar lava tube. The robot would give us our first look at the lunar subsurface and the lava tubes.

This illustration shows the LunarLeaper in different locations around the rim of a skylight, a collapsed segment of a lunar lava tube. From its position on the rim, the robot would map the skylight and the tube floor and walls and take various scientific measurements, including detecting volatiles. Image Credit: LunarLeaper

There are good reasons to explore these lava tubes. The lunar surface is exposed to solar and cosmic radiation without the benefit of a protective atmosphere or magnetosphere like Earth. Astronauts could shelter in these tubes inside habitat modules. Several meters of rock overhead would provide protection from radiation and from the Moon’s temperature swings. There could be laboratory modules and other modules as well. The tubes, if suitable, could shelter an entire base.

The other reason is scientific. These tubes are a window into the Moon’s volcanic past. They’re a record of the magnitude and timing of volcanic activity.

The LunarLeaper is a ~10 kg (22 lbs) leaping robot with three legs. It’s based on the ETH SpaceHopper design which has been refined over four years of development. SpaceHopper is designed to visit asteroids with much weaker gravity than the Moon, but the design can be adapted to work on the lunar surface.

The LunarLeaper team proposes a mission to the Marius Hills region. It’s a region in Oceanus Procellarum, a vast lunar mare on the near side of the Moon. It’s a volcanic region covered in basalt floods from ancient volcanic activity. Marius Hills is named after the 41 km (25 mi) diameter crater Marius and is littered with volcanic features like rilles, domes, and cones.

The particular feature of interest in Marius Hills is the Marius Hills Pit (MHP), a collapsed skylight granting access into what might be an extensive lunar lava tube system. The Lunar Reconnaissance Orbiter captured an image of the intriguing opening featured in the lead image. That’s where the LunarLeaper would do its work.

The Marius Hills region is full of volcanic features and the MHP, an opening into underground lava tubes. Image Credit: NASA/USGS

The Leaper would move around the rim of the MHP, capturing images of the pit walls and the floor. It would also use its suite of scientific instruments to gather pertinent data. Its instrument suite would include a gravimeter, a ground-penetrating radar, a dedicated science camera, and hopefully a spectrometer.

The LunarLeaper team outlines four questions the mission hopes to answer:

1. Is there a lava tube under Marius Hills? It certainly appears like there could be, but there’s no confirmation yet, and only a mission to the region can answer the question for certain.
2. Could astronauts use the tube for habitation? If it’s stable enough they could, and that’s something the LunarLeaper can figure out.
3. How were the tube and pit formed? What volcanic processes were at work? There are lava tubes on Earth. Did they form the same way on the Moon? LunarLeaper can examine the layers on the walls of the tube for clues.
4. What’s contained in the regolith outside the tube? Are there ancient pieces of paleoregolith underground near the pit? Surface lunar rocks are degraded and eroded, but buried regolith could hold clues to the early Solar System, including the Sun.

Though there are hundreds of similar pits on the Moon, MHP appears to be the most promising one. It’s been imaged from different illumination angles, and the imaging supports the idea that a tube extends underground beyond the skylight. Since the Marius Hills is filled with volcanic features, an extended tube isn’t unlikely.

The LunarLeaper would travel around the surface near the MHP and use its ground-penetrating radar to uncover the extent of the tube system. Other proposed missions are aimed at lava tubes and skylights, but they tend to be more complex, larger, and more expensive. As a 10 kg hopping robot, LunarLeaper would be a wise choice for the first mission to characterize the MHP prior to sending a more complex, thorough mission.

When it comes to exploring the pit, the LunarLeaper has a significant advantage over a wheeled rover. Wheeled rovers select routes based on obstacle avoidance. They have some strict limitations when it comes to the terrain they can safely and effectively traverse.

However, the rim of the MHP is expected to be challenging. There is likely complex terrain and steep slopes right near the opening. Getting as close as possible to the rim will give better imaging and science results. The LunarLeaper has an advantage over wheeled rovers in this type of terrain, though the tradeoff is its much lighter payload.

However, as a first step in exploring the MHP, the LunarLeaper has some clear advantages.

This image from LunarLeaper shows some of the details of the area near the MHp and how the Leaper would go about exploring it. A shows the topography around the MHP and the nearby rille. B is a zoom-in of the white box in A. It shows a potential landing zone and the route the Leaper could follow to the MHP. It shows a large boulder en route as an example of an interesting object to examine on the way. C shows the MHP itself, with some of the challenging terrain visible, and also shows the slope in colour-coded degrees. Image Credit: LunarLeaper

The LunarLeaper team says that the small robot could be delivered to the lunar surface by one of the several small landers being designed by different companies. They peg the cost at about 50 million euros. They also say that this type of legged jumping robot could be a big part of future space exploration and that their mission, if chosen, could be a key development for the future.

The post It’s Time to Study Lunar Lava Tubes. Here’s a Mission That Could Help appeared first on Universe Today.

Nature often defies our simple explanations. Take comets and asteroids, for example. Comets are icy and have tails; asteroids are rocky and don’t have tails. But it might not be quite so simple, according to new research.

That nice, clean definition took a hit in 1996 when a pair of astronomers discovered that what was thought to be a main-belt comet was actually an asteroid. The object is named 7968 Elst–Pizarro after the two scientists. It displayed a comet-like dust tail at perihelion.

These images from the La Silla Observatory show the active asteroid 7968 Elst–Pizarro. Its tail is clearly visible. Image Credit: By ESO – https://www.eso.org/public/images/eso9637a/, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=26500568

7968 Elst-Pizarro was classified as a main-belt comet (MBC) because it orbits within the main asteroid belt between Mars and Jupiter. It’s still called an MBC sometimes. However, its icy component that sublimates into a vapour trail likely comes from a small surface crater with volatiles in it rather than from a homogenous ice component. That’s why it’s called an active asteroid.

Active asteroids are unusual and rare objects. To understand them and their place in the Solar System’s history, scientists want to find more of them. That led to the creation of NASA’s Active Asteroids Project.

Now, the Active Asteroids Project has announced the discovery of 15 new active asteroids. These findings are in a new paper published in The Astronomical Journal. It’s titled “The Active Asteroids Citizen Science Program: Overview and First Results,” and the lead author is Colin Chandler from the Dept. of Astronomy & the DiRAC Institute at the University of Washington in Seattle. Among the co-authors are nine volunteer citizen scientists.

“For an amateur astronomer like me, it’s a dream come true,” said volunteer Virgilio Gonano from Udine, Italy. “Congratulations to all the staff and the friends that also check the images!”

“Active objects are rare in large part because they are difficult to identify, so we ask volunteers to assist us in searching for active bodies in our collection of millions of images of known minor planets,” the authors of the paper write. Active asteroids aren’t the only objects they’re trying to find. There are several other types.

Centaurs are small Solar System bodies that orbit between Neptune and Jupiter. Centaurs have crossed the orbits of one or more giant planets, making their orbits unstable. They have traits in common with both comets and asteroids, and about 30 of them have dust-like comas. These are the active ones.

The Active Asteroid Project is also trying to identify active quasi-Hilda asteroids (QHAs). QHAs are beyond the asteroid belt but within Jupiter’s orbit. Astronomers have discovered about 3000 of them, and about 15 of them have tails of gas and dust.

Active asteroids have asteroid-like orbits but have tails or comae like comets do. Image Credit: Mark Garlick/SPL

The Project also hopes to identify Jupiter family comets (JFCs.) JFCs are comets with very short orbital periods of less than 20 years. They’re contained within Jupiter’s orbit but may be captured Kuiper Belt Objects. They likely originated from collisions between objects in the Kuiper Belt and then were captured by Jupiter.

All of these objects have something to tell us about how the Solar System formed. Beyond that, they can help unravel the mystery of Earth’s water. There’s another, more forward-thinking reason for wanting to find these active objects. Their water can be split into hydrogen for rocket fuel and oxygen for respiration in future missions, though that’s so far in the future it’s esoteric.

This image shows one of the active asteroids found by citizen scientists involved with the Active Asteroid project. It’s named 2015 VA108, and the green arrow highlights the asteroid and its tail. Image Credit: Colin Orion Chandler (University of Washington)

The commitment of the citizens taking part is admirable. Since the effort launched on August 31st, 2021, about 8300 volunteers have taken part. Collectively, they’ve examined about 430,000 images.

“I have been a member of the Active Asteroids team since its first batch of data,” said volunteer Tiffany Shaw-Diaz from Dayton, Ohio. “And to say that this project has become a significant part of my life is an understatement. I look forward to classifying subjects each day, as long as time or health permits, and I am beyond honoured to work with such esteemed scientists on a regular basis.”

The images in the project all come from the Dark Energy Camera (DECam.) DECam is a high-performance camera with a wide field of view that’s mounted on the Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory.

The images are filtered by query across multiple databases and image archives before they’re placed in front of the eyes of the citizen scientists. This includes the Minor Planet Center (MPC), the JPL Small-Body Database, the Canadian Astronomy Data Centre, and the National Optical and Infrared Laboratory (NOIRLab) AstroArchive. They also consider the observing telescope’s field-of-view, the objects’ coordinates and semi-major access, and multiple other factors.

The Project then uses scripts to download the desired data from astronomical archives. Then, they generate uniform DECam thumbnail images of each object. This results in millions of images of potential active asteroids or similar objects. There’s no possible way there are enough professional astronomers to handle this much work. So, the images are grouped up into “subject sets” and sent to the citizen scientists who put the effort in and make the project feasible.

Before the volunteers work with any real images, they’re trained on a set of images of objects that display some activity, like a tail or a coma. Then, the participants give them a score from zero (unidentifiable/missing;) to 9 (definitely active, overwhelming activity indicators.) “All training images in Active Asteroids are derived from those images to which we applied a score of ?5; our minimum threshold, for which we consider the activity to be highly likely,” the authors explain.

In each image, a green reticle identifies the object of interest. The citizen scientists are asked a fairly straightforward question: do they see activity (i.e., a tail or coma) coming from the central object?

This is one of the DECam thumbnail images in the project. It shows the active asteroid (62412) 2000 SY178. In the project’s analysis system, this object received a score of 0.35, below the threshold of 0.473 needed to classify it as an active object. Image Credit: Chandler et al. 2024/Active Asteroid Project.

Over time, most citizen scientists became more productive. But not always.

This figure from the study shows the number of images classified through time by 10 randomly selected participants, numbered from 0 to 9. Most got better over time, though number 7 seemed to buck that trend. Image Credit: Chandler et al. 2024/Active Asteroid Project.

Each subject set requires a certain amount of preparation by the professional astronomers. That has to be balanced by the work and time it takes a citizen scientist to go through it. After some experimenting, the project settled on sets of about 22,000 images, which took a citizen participant about four to eight weeks to go through.

The project takes place on the Zooniverse platform, home to many other citizen science projects. One of the benefits of that platform is that the citizen participants and the professional astronomers can talk with one another on the “Talk” discussion boards on Zooniverse. “Surprisingly, we have made discoveries that first come to light on the Talk pages, well before the subject set was fully retired,” the authors of the paper write.

This is just the first data release from the project. Finding 15 active asteroids and one Centaur is just the beginning. In fact, the project has produced more than 20 discoveries, resulting in multiple publications. And they’re not done.

They intend to continue working and improving their methods. The Project is also looking ahead to the Vera Rubin Observatory’s Legacy Survey of Space and Time (LSST), which will produce an enormous number of images for evaluation.

If you’re interested in participating, visit the project website.

“The Active Asteroids project is ongoing and can be accessed through the project website,” the authors write. “Participation is easy and intuitive and can take as little as a few minutes to contribute.”

The post Citizen Scientists Find Fifteen “Active Asteroids” appeared first on Universe Today.

The Earth’s place in space is a fairly familiar one with it orbiting an average star. The star – our Sun – orbits the centre of our Galaxy the Milky Way. From here onwards, the story is less well known. The Milky Way is part of a large structure called the Laniakea Supercluster which is 250 million light years across! That really is a whacking great area of space and it contains at least 100,000 galaxies. There are larger superclusters though like the newly discovered Einasto Supercluster which measures an incredible 360 million light years across and is home to 26 quadrillion stars!

When I give public lectures, I always get a strange satisfaction out of telling the audience that galaxies don’t exist! I go on to explain that, like a city which is a collection of stuff, galaxies are collections of things bound together under the force of gravity. A typical galaxy is simply a collection of stars, nebulae, clusters, planets, comets and so on, take them away and a galaxy won’t exist! Superclusters are largely the same, just a collection of galaxies bound together (well, not completely) under the force of gravity. 

Hot stars burn brightly in this image from NASA’s Galaxy Evolution Explorer, showing the ultraviolet side of a familiar face. At approximately 2.5 million light-years away, the Andromeda galaxy, or M31, is our Milky Way’s largest galactic neighbor. The entire galaxy spans 260,000 light-years across — a distance so large, it took 11 different image segments stitched together to produce this view of the galaxy next door. The bands of blue-white making up the galaxy’s striking rings are neighborhoods that harbor hot, young, massive stars. Dark blue-grey lanes of cooler dust show up starkly against these bright rings, tracing the regions where star formation is currently taking place in dense cloudy cocoons. Eventually, these dusty lanes will be blown away by strong stellar winds, as the forming stars ignite nuclear fusion in their cores. Meanwhile, the central orange-white ball reveals a congregation of cooler, old stars that formed long ago. When observed in visible light, Andromeda’s rings look more like spiral arms. The ultraviolet view shows that these arms more closely resemble the ring-like structure previously observed in infrared wavelengths with NASA’s Spitzer Space Telescope. Astronomers using Spitzer interpreted these rings as evidence that the galaxy was involved in a direct collision with its neighbor, M32, more than 200 million years ago. Andromeda is so bright and close to us that it is one of only ten galaxies that can be spotted from Earth with the naked eye. This view is two-color composite, where blue represents far-ultraviolet light, and orange is near-ultraviolet light.

Superclusters like Laniakea and Einasto (which is 3 billion light years away) are among the largest structures in the Universe. The discovery of this latest supercluster has been named after Professor Jaan Einasto who was a pioneer in the field of superclusters and celebrated his 95th birthday on 23 February 2024. 

When it comes to visualising the sheer size of these structures imagine an average coin (I really don’t think it matters too much which coin you imagine) on a football pitch. This coin represents the Milky Way Galaxy and the length of the pitch would be the extremities of the supercluster! You might also imagine the Sun as a golf ball and the entire collective mass of the supercluster as Mount Everest in comparison!

A study by MIT physicists suggest the Milky Way’s gravitational core may be lighter in mass, and contain less dark matter, than previously thought. Credits:Credit: ESA/Gaia/DPAC, Edited by MIT News

The announcement came from a group of international astronomers from the Tartu Observatory who also surveyed 662 other superclusters. Their work (which was published in the Astrophysical Journal) also revealed some interesting dynamics inside superclusters for example, they found that the galaxies within a supercluster are receding from each other slower than the general expansion of the universe. This is due to the gravitational pull of the supercluster acting as a brake on the expansion. Whilst it is slowing the expansion of the area it is not slowing it enough to stop the galaxies from drifting apart given enough time. Superclusters should be considered temporary, changing phenomena.

They also found that there was a relationship between the density and size of a supercluster. The relationship was an inverse square relationship meaning that the density of a supercluster decreases with the square of its size. 

Source : Einasto Supercluster: the new heavyweight contender in the universe

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There are plenty of craters on Mars, especially when compared to Earth. That is primarily thanks to the lack of weathering forces and strong plate tectonics that disrupt the formations of such impacts on our home planet. However, not all impact craters on Mars are directly caused by asteroid impacts. Many of them are caused by the ejecta from an asteroid impact falling back to the planet. One recent study showed how impactful this can be – it concludes that a single large impact crater on Mars created over two billion other smaller craters up to almost 2000 km away.

The study, released at the 55th annual Lunar and Planetary Science Conference in Texas, focuses on a crater called Corinto. It’s located in Elysium Planitia, only about 17 degrees north of the Red Planet’s equator. It’s a relatively young crater by Martian standards, with the scientists’ best estimate of its age being around 2.34 million years ago. It’s pretty massive for being that young, though, as the average time between impacts of its size is around 3 million years. As such, the scientists think it might be the most recent crater of its size on Mars.

That’s not why it’s interesting, though. It has an extensive “ray system”. That means that a significant amount of ejecta was cast out from the impact site and landed elsewhere on the planet, creating “rays” from the central impact point that can be seen on a map of the planet’s surface even today.

A video from JHU APL shows the details of how we understand how impact craters are made.
Credit – JHU APl YouTube Channel

Corinto crater is about 14 km in diameter and 1 km deep. Its interior bowl is pock-marked with other, smaller craters that happened its impact. Indications suggest it was full of water ice when it was hit, as there appeared to be some degassing of the superheated ice after the impact. Calculations point to a relatively steep impact angle of about 30-45 degrees from straight on – and the impactor appeared to be coming from the north.

As a result, much of the ejecta impact field lies to the south, especially the southwest, of the crater. While some secondary ejecta craters are sitting to the north of the main one, it appears clear that the impactor’s angle was significant enough to push most ejecta to the south. 

Tracking the path of this ejecta a few million years later isn’t easy. Scientists used data collected by HiRISE and the Context Camera (CTX) on the Mars Reconnaissance Orbiter (MRO) and analyzed characteristics of smaller craters surrounding the main Corinto crater. In particular, they looked for craters that looked like they would be caused by ejecta rather than by an interplanetary impactor.

Graphical Depiction of the Facies of Maritan craters around Corinto.
Credit – Golombek et al.

They grouped the different types of ejecta craters they found into five different “facies,” primarily focused on how far away they were from the main crater. Each facies has its distinct characteristics. For example, Facies 0, the one closest to the main crater, are semi-circular, don’t appear to have any ejecta, or have very distinct rims. On the other hand, Facies 3 craters are long and narrow rather than semi-circular (hinting that something rolled through to create them) and have shown up as very bright in the MRO images. 

Two main findings from the paper will probably turn the most heads. The scientists found that there are close to 2 billion secondary impact craters larger than 10 meters caused by the ejecta from Corinto. And those secondary craters appear up to 1850 km away. That would make it, by far, the most impactful (pun intended) of the recent Martian craters in terms of the sheer number and distance of its ejecta. 

The paper didn’t go into what that might mean for our larger understanding of these processes on the red planet, nor what future work might be completed – the version reviewed for this article was only two pages. But, as with most things in science, a new record for something – in this case, distance and amount of secondary impact craters, attracts additional research, so we’ll have to see what if any, future discoveries can be made regarding this interesting Martian crater.

Learn More:
Golombek et al. – CORINTO: A YOUNG, EXTENSIVELY RAYED CRATER THAT PRODUCED A BILLION
SECONDARIES ON MARS
UT – Here’s Something Rare: a Martian Crater That isn’t a Circle. What Happened?
UT – This Crater on Mars is Just a Couple of Years Old
UT – It’s Been Constantly Raining Meteors on Mars for 600 Million Years. Earth too.

Lead Image:
Corinto Crater
Credit – NASA

The post One Impact on Mars Produced More than Two Billion Secondary Craters appeared first on Universe Today.

We are all too familiar of the Moon’s effect on our planet. It’s relentless tug causes our tides but even Mars, which is always at least 55 million kilometres away, can have a subtle effect too. A study has revealed a 2.4 million year cycle in the geological records that show the gentle warming and cooling of our oceans. The records match the interactions between the orbits of Earth and Mars over the longest timescales. These are known as the ‘astronomical grand cycles’ but to date, not much evidence has been found. 

The rhythmical rising and falling of the oceans has been well documented. Even the Sun at an average distance of 150 million kilometres exerts enough of a pull to enhance the effect from the Moon, giving us the spring and neap tides. The Moon’s influence is easy to understand due to its proximity, the Sun’s too due to its enormous mass but Mars is a different story. After all, it’s about half the size of Earth and even at its closest is about 55 million kilometres away. 

It takes two to tango. The moon’s gravity raises a pair of watery bulges in the Earth’s oceans creating the tides, while Earth’s gravity stretches and compresses the moon to warm its interior. Illustration: Bob King

As Earth and Mars orbit around the Sun, their interactions, or rather the gravitational pull from each upon each other are cyclical. These are the astronomical grand cycles and for Earth and Mars they cycle every 2.4 million years.

A paper recently published in Nature Communications reports upon the work of scientists from the University of Sydney and Sorbonne University in France. The team used geological records from the deep sea and to their surprise found a connection between the astronomical grand cycles, global warming patterns and deep ocean circulation. They found a 2.4 million year waxing and waning of deep ocean currents and that seemed to link to increased climate. 

Satellites Detect Deep-Ocean Whirlpools

A definite link emerged but it should be noted that ocean currents are not the only cause of global temperature changes. The current temperature increases have a much stronger link to the human emission of greenhouse gasses.  The paper was authored by Dr Adriana Dutkiewicz and Professor Dietmar Muller from the University of Sydney and Associate Professor Slah Boulila from the Sorbonne University. They reached their conclusion following analysis of the deep-sea sediment records acquired from over half a century of drilling data from hundreds of sites worldwide. The 2.4 million year cycle they found can only have been caused by the interactions between Earth and Mars. 

The interaction of the gravitational field of the two planets means periods of higher incoming solar radiation every 2.4 million years and with it, an increase in global temperatures. Their analysis of the sediments showed breaks in the sedimentary deposits which related to periods of warmer temperatures and more vigorous deep ocean circulation.

The result helps us to understand how deep ocean eddies are key to warming ocean temperatures. Understanding these can help us to understand and model future periods of warming. It may even go some way to mitigate a temporary cessation in ocean currents due to a change in the Atlantic meridional overturning circulation.  This drives the Gulf Stream that helps to keep Europe and other temperature countries the nice warm climate it has become accustomed to. 

 Source : Mars attracts: how Earth’s planetary interactions drive deep-sea circulation

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We, and all other complex life, require stability to evolve. Planetary conditions needed to be benign and long-lived for creatures like us and our multicellular brethren to appear and to persist. On Earth, chemical cycling provides much of the needed stability.

Chemical cycling between the land, atmosphere, lifeforms, and oceans is enormously complex and difficult to study. Typically, researchers try to isolate one cycle and study it. However, new research is examining Earth’s chemical cycling more holistically to try to understand how the planet has stayed in the ‘sweet spot’ for so long.

Earth has supported complex life for hundreds of millions of years, possibly for more than a billion years. This is extremely rare, as far as we can tell. The vast majority of the exoplanets we’ve discovered are not in their stars’ habitable zones. They have very little chance of hosting any life, let alone complex life.

It’s possible that some planets experience a period of stability for much shorter periods of time than Earth. This may describe Mars. It was warm and wet and could’ve hosted simple life, but the planet lost most of its atmosphere and became uninhabitable. Now it’s cold, dry, and dead.

Earth robustly cycles the chemical elements through different systems and has done so for billions of years. Now, about 4.5 billion years after its formation, life is abundant on our precious planet. Biogeochemical cycles like the carbon cycle, the nitrogen cycle, and the methane cycle have allowed the planet to sustain its habitability.

New research published in the Proceedings of the National Academy of Sciences examines these cycles holistically, hoping to better understand the relationships between them. The research is “Balance and imbalance in biogeochemical cycles reflect the operation of closed, exchange, and open sets.” The lead author is Preston Cosslett Kemeny, a University of Chicago TC Chamberlain postdoctoral fellow.

“Overall, this work provides a systematic conceptual framework
for understanding balance and imbalance in global biogeochemical cycles.”

From “Balance and imbalance in biogeochemical cycles reflect the operation of closed, exchange, and open sets.”

Earth’s carbon cycle plays a dominant role in the climate. As carbon accumulates in the atmosphere, the planet warms. As carbon is sequestered into the mantle, the planet cools. Even though it’s been stable for a long time, research shows that small imbalances can upset the system.

What Kemeny and his co-researchers wanted to do was get back to the basics. They wanted to identify a framework for all the reactions, both large and small, that comprise Earth’s chemical cycles. What’s different in their work is that they didn’t specify how they all worked together, if they worked together, or how much they affected one another.

“Our approach provides a new way to identify the fundamental building blocks of stability in the chemical components of Earth’s climate—the underlying ways in which the climate can be stabilized over geological time due to the movement of elements across the ocean, atmosphere, and rock reservoirs,” said Kemeny.

Earth’s long-lasting habitability created the conditions for complex life like us to appear. That habitability is dependent on the complex interplay of chemistry between the ocean, atmosphere and land. This image, captured from the International Space Station 400km above Earth’s surface, shows our planet’s thin atmosphere. Image Credit: NASA

The researchers describe their effort as ‘agnostic’ and explain that it creates “… a systematic and simplified conceptual framework for understanding the function and evolution of global biogeochemical cycles.” They call it agnostic because it doesn’t specify the relationship between environmental conditions and the strength of biogeochemical processes. “By remaining agnostic to the relationships between environmental conditions and the intensity of biogeochemical processes, we sought to recognize and systematize patterns that underly the stability of major element cycles,” Kemeny explains on his website.

“This is an elegant, simplified way to think about an enormous problem, which organizes a lot of previous research on elemental cycles into packages of chemical reactions that can be balanced and understood,” said University of Chicago Assistant Professor Clara Blättler, senior author of the paper.

The complexity of Earth’s cycles makes them difficult to study. They work on long geological timescales, which puts us at a disadvantage. The planet’s carbon cycle illustrates this.

The movement of carbon plays an important role in regulating the planet’s climate. When carbon dioxide accumulates in the atmosphere, the atmosphere traps more heat, which warms up the oceans. However, carbon also creates a weak acid called carbonic acid that breaks rocks down faster. The carbon eventually finds its way to the ocean floor and becomes sequestered in rock. Carbon can also spend some time as part of living things before being sequestered into rock or fossil fuels. This sequestration of carbon eventually cools the planet but takes millions of years. Carbon is eventually returned to the atmosphere by volcanoes and by the burning of fossil fuels.

The Carbon cycle plays a dominant role in moderating Earth’s climate, but other chemical cycles influence it. Image Credit: U.S. DOE, Biological and Environmental Research Information System.

Trying to understand the carbon cycle is made more difficult by its interaction with other cycles. The Earth’s cycles also aren’t static. They change over time, adding to the complexity. There are also missing pieces from the large puzzle of Earth’s cycles. Researchers are forced to make assumptions to fill in the blanks.

Kemeny devotes much of his time to understanding Earth’s cycles, and he and his colleagues hope that their approach can yield better results. “Models of global element cycles seek to understand how biogeochemical processes and environmental conditions interact to sustain planetary habitability,” Kemeny writes on his website. “However, outcomes from such models often reflect specific interpretations of geochemical archives.”

The researchers think their approach may help overcome the obstacles to understanding Earth’s cycles. They employed a mathematical analysis to develop a framework identifying all of the major and minor cycles that contribute to Earth’s long-term habitability by balancing the carbon cycle.

The result was a new, more holistic way to look at Earth. The climate can be represented by a large set of interconnected chemical equations. These equations must balance over certain time periods to keep the carbon cycle stable and the Earth habitable.

The Sulphur Cycle is just one of Earth’s important cycles. It moves sulphur between rocks, water, and living things. Kemeny and his colleagues are trying to understand all of Earth’s cycles holistically rather than in isolation. Image Credit: By Bantle – Own work, CC0, https://commons.wikimedia.org/w/index.php?curid=20411832

Kemeny highlights one episode in Earth’s climate history to illustrate the point. The Cenozoic era began about 65.5 million years ago and is the era we live in now. The Cenozoic is a long-term cooling trend in Earth’s history, and the period that preceded it was a greenhouse climate. Kemeny and his colleagues say that their holistic approach can open a window into how the climate changed.

“For example, say that you are considering a hypothesis for why the climate changed in the past – such as the major cooling of the last 65 million years,” Kemeny said. “You can take this framework and use it to say: well, if X process increased or decreased, then it should have also caused Y to happen, or would have needed to be balanced by Z, and that you have to account for those outcomes—so with that prediction we can look for evidence for the joint operation of the whole geochemical system.”

Astrobiology and planetary habitability are key topics in space science. With the help of the JWST and other upcoming observatories and telescopes, scientists are getting a look at the atmospheres of distant exoplanets. But it’s a difficult process, made more difficult by our less-than-complete understanding of our own planet’s habitability. Understanding our own planet can help us better understand exoplanets.

But there’s a certain type of joy in understanding Earth for its own sake, and this new holistic approach should grow our understanding.

“We hope it’s a beautiful way to help understand all the chemistries that are involved in making Earth a safe place for life to evolve,” Blättler said.

“Overall, this work provides a systematic conceptual framework for understanding balance and imbalance in global biogeochemical cycles,” the authors conclude.

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