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Everyone knows that solar energy is free and almost limitless here on Earth. The same is true for spacecraft operating in the inner Solar System. But in space, the Sun can do more than provide electrical energy; it also emits an unending stream of solar wind.

Solar sails can harness that wind and provide propulsion for spacecraft. NASA is about to test a new solar sail design that can make solar sails even more effective.

Solar pressure pervades the entire Solar System. It weakens with distance, but it’s present. It affects all spacecraft, including satellites. It affects longer-duration spaceflights dramatically. A spacecraft on a mission to Mars can be forced off course by thousands of kilometres during its voyage by solar pressure. The pressure also affects a spacecraft’s orientation, and they’re designed to deal with it.

Though it’s a hindrance, solar pressure can be used to our advantage.

A few solar sail spacecraft have been launched and tested, beginning with Japan’s Ikaros spacecraft in 2010. Ikaros proved that radiation pressure from the Sun in the form of photons can be used to control a spacecraft. The most recent solar sail spacecraft is the Planetary Society’s LightSail 2, launched in 2019. LightSail 2 was a successful mission that lasted over three years.

The Red Sea and the Nile River, from the LightSail 2 spacecraft. LightSail 2 was a successful demonstration mission that lasted more than two years. Image Credit: The Planetary Society.

Solar sail spacecraft have some advantages over other spacecraft. Their propulsion systems are extremely lightweight and never run out of fuel. Solar sail spacecraft can perform missions more cheaply than other spacecraft and can last longer, though they have limitations.

The solar sail concept is now proven to work, but the technology needs to advance for it to be truly effective. A critical part of a solar sail spacecraft is its booms. Booms support the sail material; the lighter and stronger they are, the more effective the spacecraft will be. Though solar sails are much lighter than other spacecraft, the weight of the booms is still a hindrance.

“Booms have tended to be either heavy and metallic or made of lightweight composite with a bulky design – neither of which work well for today’s small spacecraft.”

Keats Wilkie, ACS3 principal investigator, NASA

NASA is about to launch a new solar sail design with a better support structure. Called the Advanced Composite Solar Sail System (ACS3), it’s stiffer and lighter than previous boom designs. It’s made of carbon fibre and flexible polymers.

Though solar sails have many advantages, they also have a critical drawback. They’re launched as small packages that must be unfurled before they start working. This operation can be fraught with difficulties and induces stress in the poor ground crew, who have to wait and watch to see if it’s successful.

This image shows the ACS3 being unfurled at NASA’s Langley Research Center. The solar wind is reliable but not very powerful. It requires a large sail area to power a spacecraft effectively. The ACS2 is about 9 meters (30 ft) per side, requiring a strong, lightweight boom system. Image Credit: NASA

ACS3 will launch with a twelve-unit (12U) CubeSat built by NanoAvionics. The primary goal is to demonstrate boom deployment, but the ACS3 team also hopes the mission will prove that their solar sail spacecraft works.

To change direction, the spacecraft angles its sails. If boom deployment is successful, the ACS3 team hopes to perform some maneuvers with the spacecraft, angling the sails and changing the spacecraft’s orbit. The goal is to build larger sails that can generate more thrust.

“The hope is that the new technologies verified on this spacecraft will inspire others to use them in ways we haven’t even considered.”

Alan Rhodes, ACS3 lead systems engineer, NASA’s Ames Research Center

The ACS3 boom design is made to overcome a problem with booms: they’re either heavy and slim or light and bulky.

“Booms have tended to be either heavy and metallic or made of lightweight composite with a bulky design – neither of which work well for today’s small spacecraft,” said NASA’s Keats Wilkie. Wilke is the ACS3 principal investigator at Langley Research Center. “Solar sails need very large, stable, and lightweight booms that can fold down compactly. This sail’s booms are tube-shaped and can be squashed flat and rolled like a tape measure into a small package while offering all the advantages of composite materials, like less bending and flexing during temperature changes.”

ACS3 will launch from Rocket Lab’s launch complex 1 on New Zealand’s north island. Image Credit: Rocket Lab

ACS3 will be launched on an Electron rocket from Rocket Lab’s launch complex in New Zealand. It’ll head for a Sun-synchronous orbit 1,000 km (600 miles) above Earth. Once it arrives, the spacecraft will unroll its booms and deploy its sail. It’ll take about 25 minutes to deploy the sail, with a photon-gathering area of 80 square meters, or about 860 square feet. That’s much larger than Light Sail 2, which had a sail area of 32 square meters or about 340 square feet.

As it deploys itself, cameras on the spacecraft will watch and monitor the shape and symmetry. The data from the maneuvers will feed into future sail designs.

“Seven meters of the deployable booms can roll up into a shape that fits in your hand,” said Alan Rhodes, the mission’s lead systems engineer at NASA’s Ames Research Center. “The hope is that the new technologies verified on this spacecraft will inspire others to use them in ways we haven’t even considered.”

ACS3 is part of NASA’s Small Spacecraft Technology program. The program aims to deploy small missions that demonstrate unique capabilities rapidly. With unique composite and carbon fibre booms, the ACS3 system has the potential to support sails as large as 2,000 square meters, or about 21,500 square feet. That’s about half the area of a soccer field. (Or, as our UK friends mistakenly call it, a football field.)

With large sails, the types of missions they can power change. While solar sails have been small demonstration models so far, the system can potentially power some serious scientific missions.

“The Sun will continue burning for billions of years, so we have a limitless source of propulsion. Instead of launching massive fuel tanks for future missions, we can launch larger sails that use “fuel” already available,” said Rhodes. “We will demonstrate a system that uses this abundant resource to take those next giant steps in exploration and science.”

A solar flare as it appears in extreme ultraviolet light. The Sun is a free source of energy that’s not going away anytime soon, yet it’s also hazardous. Credit: NASA/SFC/SDO

Solar sail spacecraft don’t have the instantaneous thrust that chemical or electrical propulsion systems do. But the thrust is constant and never really wavers. They can do things other spacecraft struggle to do, such as taking up unique positions that allow them to study the Sun. They can serve as early warning systems for coronal mass ejections and solar storms, which pose hazards.

The new composite booms also have other applications. Since they’re so lightweight, strong, and compact, they could serve as the structural framework for lunar and Mars habitats. They could also be used to support other structures, like communication systems. If the system works, who knows what other applications it may serve?

“This technology sparks the imagination, reimagining the whole idea of sailing and applying it to space travel,” said Rudy Aquilina, project manager of the solar sail mission at NASA Ames. “Demonstrating the abilities of solar sails and lightweight, composite booms is the next step in using this technology to inspire future missions.”

The post NASA’s Next Solar Sail is About to Go to Space appeared first on Universe Today.

How can future lunar exploration communicate from the far side of the Moon despite never being inline with the Earth? This is what a recent study submitted to IEEE Transactions on Aerospace and Electronic Systems hopes to address as a pair of researchers from the Polytechnique Montréal investigated the potential for a wireless power transmission method (WPT) comprised of anywhere from one to three satellites located at Earth-Moon Lagrange Point 2 (EMLP-2) and a solar-powered receiver on the far side of the Moon. This study holds the potential to help scientists and future lunar astronauts maintain constant communication between the Earth and Moon since the lunar far side of the Moon is always facing away from Earth from the Moon’s rotation being almost entirely synced with its orbit around the Earth.

Here, Universe Today discusses this research with Dr. Gunes Karabulut Kurt, who is an associate professor at IEEE Polytechnique Montréal and the study’s co-author, regarding the motivation behind the study, significant results, follow-up research, and implications for WPT. So, what was the motivation behind this study?

“This research is motivated by the objective of overcoming the logistical and technical challenges associated with using traditional cables on the Moon’s surface,” Dr. Kurt tells Universe Today. “Laying cables on the Moon’s rough, dusty surface would lead to ongoing maintenance and wear problems, as lunar dust is highly abrasive. On the other hand, transporting large quantities of cables to the Moon requires a significant amount of fuel, which adds considerably to the mission’s costs.”

For the study, the researchers used a myriad of calculations and computer models to ascertain if one, two, or three satellites are sufficient within an EMLP-2 halo orbit to maintain both constant coverage of the lunar far side (LFS) and line of sight with the Earth. For context, EMLP-2 is located on the far side of the Moon with the halo orbit being perpendicular—or sideways—to the Moon’s orbit. The calculations involved in the study included the distances between each satellite, the antenna angles between the satellites and surface receiver, the amount of LFS surface coverage, and the amount of transmitted power between the satellites and LFS surface antennae. So, what were the most significant results from this study?

Dr. Kurt tells Universe Today their models concluded that three satellites in an EMLP-2 halo orbit and operating at equal distances from each other could “achieve continuous power beaming to a receiver optical antenna anywhere on the lunar far side” while maintaining 100 percent LFS coverage and line of sight with the Earth. “Aside triple satellite scheme that provides continuous LFS full coverage, even a two-satellite configuration provides full coverage during 88.60% of a full cycle around the EMLP-2 halo orbit,” Dr. Kurt adds.

Schematic from Figure 1 of the study displaying the wireless power transmission and receiver on the lunar far side with three satellites (SPS-1, SPS-2, and SPS-3) in a halo orbit at the Earth-Moon Lagrange Point 2. (Credit: Donmez & Kurt (2024))

Regarding follow-up research, Dr. Kurt tells Universe Today, “Our future studies will focus on more complex harvesting and transmission models to get closer to reality. On the other hand, an approach that takes into account the irregular nature of lunar dust and the variation in its density due to environmental factors such as subsolar angle and others. In the future, if research in this field continues, explore this experimentally with lunar dust simulants and lasers.”

This study comes as NASA is preparing to send astronauts to the Moon for the first time since 1972 with the Artemis program, whose goal will be to land the first woman and person of color on the lunar surface. With the success of the Artemis 1 mission in November 2022 that consisted of an uncrewed Orion capsule orbiting the Moon, NASA is currently targeting September 2025 for their Artemis 2 mission, which is scheduled to be a 10-day, 4-person crewed mission using the Orion capsule for a lunar flyby, whose goal will be to conduct a full systems checkout of the Orion capsule. Therefore, what implications can this study have for the upcoming Artemis missions, or any future human exploration of the Moon?

“The findings have implications for the design of energy transmission systems on the Moon,” Dr. Kurt tells Universe Today. “A better understanding of the wireless transmission disruptors such as lunar dust can lead to the development of more efficient and reliable systems for powering lunar missions and infrastructure, including those related to the Artemis program and future human exploration efforts.”

If successful, Artemis 2 will be followed by Artemis 3 in September 2026, which will also consist of a 4-person crew with two crew members landing on the lunar surface and an approximate mission duration of 30 days. This will be followed by Artemis 4, Artemis 5, and Artemis 6, which are currently scheduled for September 2028, September 2029, and September 2030, respectively, with each mission increasing in both the number of astronauts landing on the lunar surface along with anticipated deliveries of lunar habitat modules and lunar rovers, as well.

“Moreover, the Artemis mission is targeting the lunar south pole for its landing sites,” Dr. Kurt tells Universe Today. “This region is of particular interest due to the presence of peaks of eternal light (PELs), which receive almost continuous sunlight and permanently shadowed regions (PSRs), which are potential sites for resources such as water ice. These contrasting conditions are ideal for the application of wireless energy transmission (laser power beaming technology), which could provide a continuous power supply in shadowed areas by transmitting energy wirelessly from illuminated regions.”

The reason these PSRs exist is due to the Moon’s low obliquity, or axial tilt, which the study notes is 6.68 degrees. For context, the Earth’s obliquity is 23.44 degrees. This means there are areas, and specifically craters, at both the north and south poles on the Moon that do not receive any sunlight, hence the name “permanently shadowed regions”. As noted by Dr. Kurt, these PSRs could be home to deposits of water ice within these deep, dark craters that astronauts could use for water, fuel, and other needs.

The Artemis missions plan to deliver not only astronauts to the lunar surface, but a habitat and lunar rovers with the goal of establishing a permanent human presence on the Moon. This will provide opportunities for demonstrating new space technologies that can be used for both lunar exploration and future human missions to Mars, which are a part of NASA’s Moon to Mars Architecture.

“Current missions plan to re-use Earth-proven technology,” Dr. Kurt tells Universe Today. “This mindset may undermine the blue-sky design approach, where researchers are encouraged to think freely, explore creative ideas, and push the boundaries of what’s possible without being confined by constraints such as specific project requirements or backward compatibility. In our work we aim to include multi-functionality aspects, which are not a necessity for terrestrial applications but may turn out to be essential for future space missions.”

How will this wireless power transmission method help improve communication from the far side of the Moon to Earth 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 Wireless Power Transmission Could Enable Exploration of the Far Side of the Moon appeared first on Universe Today.

Millions of people took a trip over to the US or Mexico to try and catch a glimpse of the 2024 total solar eclipse. Whether you took the trip or not, if you have since been bitten by the eclipse bug then there are three upcoming eclipses over the next couple of years. August 2026 sees an eclipse passing from Greenland, Iceland and Spain, 2027 sees an eclipse over North Africa and in 2028 Australia all be the place to be. With loads of possibilities for all locations, it’s time to get planning. 

Many people across the World make attempts to witness solar eclipses, often travelling hundreds if not thousands of kilometres. I tried such a journey back in 1999 travelling from my home in Norfolk, UK to Cornwall, a journey of over 600 kilometres. Alas, and like many eclipse chasers before me, cloud thwarted my view. However, the experience of the daylight turning to dusk in a few seconds at the onset of totality, the birds singing as the ‘Sun came out again’, it was all such an incredible amazing experience. 

Since that cloudy experience in Cornwall I committed to one day, actually seeing a total solar eclipse. I have seen partials, and they are wonderful but nothing like the majesty of a total solar eclipse.

What are we talking about? Well, the Moon travels around the Earth and the Earth travels around the Sun. It’s these changing relative positions that lead to the lunar phases. When the Moon is broadly between the Sun and Earth we experience a new moon phase. You might therefore wonder why we don’t experience a total solar eclipse every new moon! The answer lies in the obits; the orbit of the Moon around Earth is tilted by about 5 degrees in reference to the Earth’s orbit around the Sun. During most new moons the Moon is slightly above or below the Sun when viewed from Earth. It’s only when the two orbits intersect at a new moon that we see a total solar eclipse. 

This is exactly what happened on 8 April 2024, a total solar eclipse became visible as the Moon silently passed directly between the Earth and Sun. When we get a perfect alignment of three celestial bodies like this its called a Syzygy, a wonderful word and great for a game of Scrabble. Totality for this eclipse lasted for about 4 minutes depending on the location of the observer. That’s the chief difference between a solar eclipse and a lunar eclipse. Lunar eclipses are visible anywhere on Earth that the Moon is visible but solar eclipses are only visible from very specific locations on Earth. 

Over the next few years there are some great opportunities to see total solar eclipses. Unless you are lucky, you will have to travel but the next opportunity takes place on 12 August 2026. You will need to be travelling to either Greenland, Iceland or Spain to catch this eclipse. Greenland and Iceland are the best option as Spain will only get the eclipse toward the end of the day. Next up is 2027 when an eclipse takes place on the 2 August visible from North Africa. After that, it’s 2028 but for southern hemisphere observers so its a trip to Australia. 

Wherever you venture to observe a total solar eclipse, it is imperative that you be careful when observing it. The ONLY time it is safe to observe a solar eclipse directly is during the moments of totality. As soon as the bright parts of the solar photosphere are visible, then direct observing is dangerous and will lead to damage to your eyes. If you are planning a trip to observe a total solar eclipse, be sure you are prepared and know exactly when and how you can observe it to ensure your eyesight remains safe. 

Source : Time and Date Eclipse Calendar

The post Here are the Next Three Total Solar Eclipses Coming Up appeared first on Universe Today.

It’s a measure of human ingenuity and curiosity that scientists debate the possibility of life on Venus. They established long ago that Venus’ surface is absolutely hostile to life. But didn’t scientists find a biomarker in the planet’s clouds? Could life exist there, never touching the planet’s sweltering surface?

It seems to depend on who you ask.

We’ll start with phosphine.

Phosphine is a biomarker, and in 2020, researchers reported the detection of phosphine in Venus’ atmosphere. There should be no phosphine because phosphorous should be oxidized in the planet’s atmosphere. According to the paper, no abiotic source could explain the quantity found, about 20 ppb.

Subsequently, the detection was challenged. When others tried to find it, they couldn’t. Also, the original paper’s authors informed everyone of an error in their data processing that could’ve affected the conclusions. Those authors examined the issue again and mostly stood by their original detection.

At this point, the phosphine issue seems unsettled. But if it is present in Venus’ atmosphere and is biological in nature, where could it be coming from? Venus’s surface is out of the question.

That leaves Venus’ cloud-filled atmosphere as the only abode of life. While the idea might seem ridiculous at first glance, researchers have dug into the idea and generated some interesting results.

In a new paper, researchers examine the idea of microscopic life that lives and reproduces in water droplets in Venus’s clouds. The title is “Necessary Conditions for Earthly Life Floating in the Venusian Atmosphere.” The lead author is Jennifer Abreu from the Department of Physics and Astronomy, Lehman College, City University of New York. The paper is currently in pre-print.

Spacecraft have struggled to contend with the harsh conditions on Venus’s surface. The Soviet Venera 13 lander captured this image of the planet’s surface in March of 1982. NASA/courtesy of nasaimages.org

“It has long been known that the surface of Venus is too harsh an environment for life,” the authors write. “Contrariwise, it has long been speculated that the clouds of Venus offer a favourable habitat for life but regulated to be domiciled at an essentially fixed altitude.” So, if life existed in the clouds, it wouldn’t be spread throughout. Only certain altitudes appear to have what’s needed for life to survive.

The type of life the authors envision aligns with other thinking about Venusian atmospheric life. “The archetype living thing <being> the spherical hydrogen gasbag isopycnic organism,” they state. (Isopycnic means constant density; the other terms are self-explanatory.)

Here’s how the authors think it could work.

Venus is shrouded in clouds so thick we can only see the surface with radar. The clouds reach all the way around the globe. The cloud base is about 47 km (29 miles) from the surface, where the temperature is about 100 C (212 F.) At equatorial and mid-latitudes, they extend up to a 74 km (46 miles) altitude, and at the poles, they extend up to about 65 km (40 miles.)

Cloud structure in the Venusian atmosphere in 2016, revealed by observations in two ultraviolet bands by the Japanese spacecraft Akatsuki. Image Credit: Kevin M. Gill

The clouds can be subdivided into three layers based on the size of aerosol particles: the upper layer from
56.5 to 70 km altitude, the middle layer from 50.5 to 56.5 km, and the lower layer from 47.5 to 50.5 km. The smallest droplets can float in all three layers. But the largest droplets, which the authors call type 3 droplets with a radius of 4 µm, are only present in the middle and lower layers.

“It has long been suspected that the cloud decks of Venus offer an aqueous habitat where microorganisms can grow and flourish,” the authors write. Everything life needs is there: “Carbon dioxide, sulfuric acid compounds, and ultraviolet (UV) light could give microbes food and energy.”

Because of temperature, life in Venus’ clouds would be restricted to a specific altitude range. At 50 km, the temperature is between 60 and 90 degrees Celsius (140 and 194 degrees Fahrenheit). The pressure at that altitude is about 1 Earth atmosphere.

This figure from the research shows the temperature and pressure throughout Venus’s atmosphere. Image Credit: Image Credit: S. Seager et al. 2021. doi:10.1089/ast.2020.2244

There’s a precedent for life existing in the clouds. It happens here on Earth, where scientists have observed bacteria, pollen, and even algae at altitudes as high as 15 km (9.3 miles.) There’s even evidence of bacteria growing in droplets in a super-cooled cloud high in the Alps. The understanding is that these organisms were carried aloft by wind, evaporation, eruptions, or even meteor impacts. But there’s an important difference between Earth’s and Venus’ clouds.

Earth’s clouds are transient. They form and dissolve constantly. But Venus’ clouds are long-lasting. They’re a stable environment compared to Earth’s clouds. In Earth’s clouds, aerosol particles are sustained for only a few days, while in Venus’ clouds, the particles can be sustained for much longer periods of time.

Add it all up, and you get stable cloud environments where aerosol particles can sustain themselves in an environment where energy and nutrients are available. The researchers say that though eventually aerosol particles and the life within them will fall to the surface, they have time to reproduce before that happens.

This image shows the cycle of Venusian aerial microbial life. Image Credit: S. Seager et al. 2021. doi:10.1089/ast.2020.2244

The idea of a microbial life cycle in Venusian clouds was developed by other researchers in their 2021 paper “The Venusian Lower Atmosphere Haze as a Depot for Desiccated Microbial Life: A Proposed Life Cycle for Persistence of the Venusian Aerial Biosphere.”

There are five steps in Venus’s proposed cloud lifecycle:

1. Dormant desiccated spores (black blobs) partially populate the lower haze layer of the atmosphere.
2. Updrafts transport them up to the habitable layer. The spores could travel up to the clouds via gravity waves.
3. Shortly after reaching the (middle and lower cloud) habitable layer, the spores act as cloud condensation nuclei, and more and more water gathers into a single droplet. Once the spores are surrounded by liquid with the necessary chemicals, they germinate and become metabolically active.
4. Metabolically active microbes (dashed blobs) grow and divide within liquid droplets (shown as solid circles in the figure). The liquid droplets continue to grow by coagulation.
5. Eventually, the droplets are large enough to settle out of the atmosphere gravitationally; higher temperatures and droplet evaporation trigger cell division and sporulation. The spores are smaller than the microbes and resist further downward sedimentation. They remain suspended in the lower haze layer (a depot of hibernating microbial life) to restart the cycle.

In this new work, the researchers focus on time.

“One of the key assumptions of the aerial life cycle put forward in Seager et al. 2021 is the timescale on which droplets would persist in the habitable layer to empower replication,” the authors write. “It is this that we now turn to study.”

This table from the research shows generation times for some common Earth bacteria. Image Credit: Abreu et al. 2024.

The authors used E. Coli generation times under optimal conditions in their work. In aerobic and nutrient-rich conditions, E. Coli can reproduce in 20 minutes. So, the E. Coli population will double three times in one hour. Bacteria must reproduce faster than they fall to the surface to sustain itself. They need to form a colony.

The researchers calculated that to sustain itself, the time it takes for bacteria to fall from the habitable part of the atmosphere to the inhabitable has to be longer than half an Earth day. As droplet size increases, the droplets would begin to sink. “As the droplet size approaches 100 µm, the droplets would start sinking to the lower haze layers,” they explain. However, their detailed calculations show that reproduction outpaces the fallout rate.

According to the team’s work, a population of bacteria could sustain itself in Venus’ clouds.

There are, obviously, still some questions. How certain are we that nutrients are available? Is there enough energy? Are there updrafts that can loft spores into the right layer of the atmosphere?

But the real big question is how was this all set in motion?

“An optimist might even imagine that the microbial life actually arose in a good-natured surface habitat, perhaps in a primitive ocean, before the planet suffered a runaway greenhouse, and the microbes lofted into the clouds,” the authors write. If that’s the case, this unique situation arose billions of years ago. Is there any other possibility? Could life have originated in the clouds?

Much scientific investigation into Venus, phosphine, clouds, and life relies on scant evidence. Few are willing to go out on a limb and proclaim that Venus can and does support life. We need more evidence.

For that, we have to wait for missions like the Venus Life Finder Mission. It’s a private mission being developed by Rocket Lab and a team from MIT. Who knows what VLF and other missions like DAVINCI and VERITAS will find? Stronger evidence of phosphine? Better data on Venus’ atmospheric layers and the conditions in them?

Life itself?

Artist’s impression of the Rocket Lab Mission to Venus. Credit: Rocket Lab

The post Could Life Exist in Water Droplet Worlds in Venus’ Atmosphere? appeared first on Universe Today.

Pink Floyd was wrong, there is no dark side to the Moon. There is however, a far side. The tidal effects between the Earth and Moon have caused this captured or synchronous rotation. The two sides display very different geographical features; the near side with mare and ancient volcanic flows while the far side displaying craters within craters. New research suggests the Moon has turned itself inside out with heavy elements like titanium returning to the surface. It’s now thought that a giant impact on the far side pushed titanium to the surface, creating a thinner more active near side. 

There have been a number of theories for the formation of the Moon; the capture theory and the accretion theory to name two of them. Perhaps the most accepted theory now is the giant impact theory which suggests Earth was struck by a large object, causing a lot of debris to be ejected into orbit. This material eventually coalesced to form the Moon we know and love today. 

In the decades that followed the Apollo missions, scientists studied the rocks returned by the astronauts. The studies revealed that many of the surface rocks contained unexpectedly high concentrations of titanium. More surprisingly was that satellite observations revealed these titanium rich minerals were far more common on the nearside and absent on the far-side. What is known is that the Moon formed fast and hot and would have been covered for a short period in an ocean of molten magma. The magma cooled and solidified forming the Moon’s crust but trapped below was the more dense material including titanium and iron. 

Sample collection on the surface of the Moon. Apollo 16 astronaut Charles M. Duke Jr. is shown collecting samples with the Lunar Roving Vehicle in the left background. Image: NASA

The dense material should have sunk to greater depths inside the Moon however over the years that followed something strange seems to have happened. The denser material did indeed sink, mixed with mantle but melted and returned to the surface as titanium rich lava flows. Debates have been raging whether this is exactly what happened but a new piece of research by a team at the University of Arizona Lunar and Planetary Laboratory offer more details about the process and how the interior of the Moon evolved.

It has already been suggested that the Moon may have suffered a giant impact on the far side causing the heavier elements to be forced over to the near side but the new study highlighted supporting evidence from gravitational anomalies. The team measured tiny variations in the Moon’s gravitational field from data from the GRAIL mission. GRAIL – or Gravity Recovery and Interior Laboratory – orbited the Moon to create the most accurate gravitational map of the Moon to date. Using GRAIL data the team discovered that titanium-iron oxide minerals had migrated to the near side and sunk to the interior in sheetlike cascades. This was consistent with models suggesting the event occurred more than 4.22 billion years ago. 

Global map of the Moon, as seen from the Clementine mission, showing the differences between the lunar near- and farside. Credit: NASA.

As paper co-author and LPL associate professor Jeff Andrews-Hanna said “The moon is fundamentally lopsided in every respect.” The near side feature known as Oceanus Procellarum is a great example. It is lower in elevation and has a lava flow covered thinner crust with high concentrations of titanium rich elements. This is very different on the far side. The strange and unique structure of the region is thought to be key in understanding the event that happened billions of years ago to shape the Moon we see today.

Source : How the Moon turned itself inside out

The post Finally, an Explanation for the Moon’s Radically Different Hemispheres appeared first on Universe Today.

There’s a lot we don’t know about the planet nearest to us. Venus is shrouded in clouds, making speculation about what’s happening on its surface a parlor game for many planetary scientists for decades. But one idea that always seems to come up in those conversations – volcanoes. It’s clear that Venus has plenty of volcanoes – estimates center around about 85,000 of them in total. However, science is still unclear as to whether there is any active volcanism on Venus or not. A new set of missions to the planet will hopefully shed some light on the topic – and a new paper from researchers from Europe looks at how we might use information from those missions to do so.

The authors break the question of whether there is active volcanism on Venus into two distinct approaches. First, can Venus maintain its current atmospheric composition without adding gases from volcanic sources? Second, is there any evidence for “transient” effects that would only be possible if active volcanoes existed? 

Let’s explore the first approach first. One major data point to consider with this approach is the variability of sulfur dioxide in the atmosphere over periods as long as decades. Some researchers have pointed to this variability as clear evidence of volcanism. Still, some take a more nuanced view and point out that the variability could be caused by unknown surface-atmosphere interactions or even interactions between two layers of the atmosphere itself.

Fraser has a particular interest in Venus – here’s why.

Transient effects in the atmosphere could include any number of features, ranging from water vapor to particulate matter (e.g., volcanic ash). So far, data collected on this has been limited and mainly done with remote sensing missions. However, at least a few of the new missions to Venus will involve taking data as they descend through the atmosphere. 

One of those – DAVINCI – plans to take measurements in situ in the atmosphere. It will come with a couple of spectrometers, inertial measurement units, and high-tech cameras to collect data in the planet’s lower atmosphere. The spectrometers themselves should be able to directly and clearly detect trace volcanic gases in the atmosphere. Ionic concentrations, such as the deuterium/hydrogen ratio, would also indicate ongoing volcanic outgassing.

But what about gases higher up in the atmosphere? EnVision, another mission, will specialize in that area of the planet using different types of near-IR and ultraviolet spectroscopy. It might help solve some mysteries in Venus’ cloud tops, including where an unknown reservoir of sulfur dioxide is located, as it seems to be a feedstock to an unknown process taking place in the clouds that defies current modeling efforts.

Venera was one of the previous efforts to map the surface of Venus. Fraser discusses its history here.

Though it is beyond the scope of the current paper, another potentially interesting sensor on a cloud-based platform would be an infrasound sensor – as it would be able to directly detect pressure differences caused by volcanic eruptions. Unfortunately, no current planned mission would maintain position in the atmosphere for long enough for such a sensor to do its work, though a few have been proposed in recent years.

There’s still going to be a long wait time before any of these analytical techniques can be put to good use. Of the three main missions heading to Venus shortly, the earliest – DAVINCI – isn’t planned to launch for at least another five years, with arrival at Venus a few years later. That’s plenty of time for theorists to fine-tune their ideas about what the mission might find. And hopefully, it will help us answer the question of volcanism on our closest neighbor once and for all.

Learn More:
Wilson et al. – Possible Effects of Volcanic Eruptions on the Modern Atmosphere of Venus
UT – Potentially Active Volcanoes Have Been Found on Venus
UT – We Now Have a Map of all 85,000 Volcanoes on Venus
UT – Volcanoes on Venus May Still Be Active

Lead Image:
Maat Mons Volcano on Venus
Credit – NASA / JPL

The post How Much of Venus’s Atmosphere is Coming from Volcanoes? appeared first on Universe Today.

In 2009, NASA launched the Lunar Reconnaissance Orbiter (LRO.) Its ongoing mission is to map the lunar surface in detail, locating potential landing sites, resources, and interesting features like lava tubes. The mission is an ongoing success, another showcase of NASA’s skill. It’s mapped about 98.2% of the lunar surface, excluding the deeply shadowed regions in the polar areas.

But recently, the LRO team’s skill was on display for another reason: it captured images of another satellite speeding over the lunar surface.

The Republic of Korea, or what most of us call South Korea, launched their Danuri lunar orbiter in August 2022. It’s the nation’s first lunar orbiter, and its mission is to develop and test technologies—including the space internet—and make a topographic map of the lunar surface. The map will help select future landing sites and identify resources such as uranium, helium-3, silicon, aluminum, and water ice. Danuri carries a suite of instruments, including a spectrometer, a magnetometer, and different cameras. Significantly, it contains a camera that will allow it to image the shadowed polar regions beyond the LRO’s capabilities.

A rendering of South Korea’s Danuri, Korean Pathfinder Lunar Orbiter (KPLO). Image Credit: Korean Aerospace Research Institute.

NASA contributed to the Korea Aerospace Research Institute’s (KARI) Danuri mission. NASA built the Shadowcam instrument that images the shadowed regions at the lunar poles.

As a sort of high-five to their fellow space-faring nation, the LRO captured images of Danuri as it sped by under the LRO.

On March 5th and 6th, the pair of orbiters sped by each other at a combined velocity of 11,500 km/h (7,200 mp/h). There were three orbits that put the LRO in a position to capture images of the swiftly moving Danuri. During each orbit, the vertical separation between the two was different.

The LRO was 5 km (3 miles) above Danuri in the first image. The LRO had to change its angle. To catch Danuri, it had to aim 43 degrees down from its usual angle.

Danuri looks like a streak in this LRO image taken 5 km above it. Image Credit: NASA/Goddard/Arizona State University

On the second orbit, only 4 km (2.5 miles) separated the pair of orbiters.

During the second orbit, the LRO captured this image of Danuri from only 4 km (2.5 miles) above it. The LRO was oriented 25 degrees toward the South Korean orbiter. Image Credit: NASA/Goddard/Arizona State University

On the third and final orbit, the separation between the two spacecraft was greater: 8 km (5 miles.) This time, the LRO was oriented at a 60-degree angle.

In the image on the right, the Danuri pixels are unsmeared. The LRO was 8 km (5 miles) above Danuri when it captured this image. The image is rotated 90 degrees to look like what a person would see if they onboard the LRO and looking out a window. Image Credit: NASA/Goddard/Arizona State University

Danuri is difficult to see in the final image.

NASA says Danuri is in the white box near the right-hand corner of the image. If you can see it, you should consider becoming a citizen scientist. For perspective, the crater above the white box is 12 km (7.5 miles) wide. Image Credit: NASA/Goddard/Arizona State University

This isn’t the first time the pair of orbiters have played the imaging game. Back in April 2023, it was Danuri’s turn to take a picture of the LRO. At the time, the Korean spacecraft passed about 18 km (11 miles) above the LRO and imaged it with its ShadowCam instrument.

Danuri captured this image of the LRO when the NASA satellite was 18 km (11 miles) below it. The combined velocity of both spacecraft was 11,000 km/h (7,000 mp/h.) Image Credit: NASA/KARI/Arizona State University

This isn’t the first time lunar orbiters have captured each other’s portraits. In 2014, the LRO captured NASA’s Lunar Atmosphere and Dust Environment Explorer (LADEE) before it was sent to impact the lunar surface. Read about it here.

The post US Satellite Photographs a South Korean Satellite from Lunar Orbit appeared first on Universe Today.

On Monday, April 8th, people across North America witnessed a rare celestial event known as a total solar eclipse. This phenomenon occurs when the Moon passes between the Sun and Earth and blocks the face of the Sun for a short period. The eclipse plunged the sky into darkness for people living in the Canadian Maritimes, the American Eastern Seaboard, parts of the Midwest, and northern Mexico. Fortunately for all, geostationary satellites orbiting Earth captured images of the Moon’s shadow as it moved across North America.

One such satellite was the Geostationary Operational Environmental Satellite-16 (GOES-16), part of the Earth observation network jointly run by NASA and the National Oceanic and Atmospheric Administration (NOAA). The GOES-16 (GOES-East) satellite is the first of the series, regularly monitoring space weather and providing continuous imagery and atmospheric measurements of Earth’s western hemisphere. From its orbit at a distance of 36,000 km (~22,370 mi) from Earth, GOES-16 captured the passage of the eclipse across North America from approximately 10:00 A.M. to 05:00 P.M. EST (07:00 A.M. to 02:00 P.M. PST).

Solar eclipses take several forms, which include what many residents in North America witnessed yesterday (i.e., the Moon completely blocking the face of the Sun). There’s also an annual eclipse, which happens when the Moon passes between the Sun and Earth when it is at or near its farthest point from Earth. As a result, the face of the Sun is not completely obscured and is visible as a bright ring in the sky. There’s also a partial eclipse, which happens when the Sun, Moon, and Earth are not perfectly lined up, making the Sun appear crescent-shaped.

There’s also what is known as a hybrid solar eclipse, which can appear to shift between annular and total (due to Earth’s curvature) as the Moon’s shadow moves across the globe. A total eclipse, however, is the rarest of these events, where people located directly in the center of the Moon’s shadow will see only the Sun’s outer atmosphere (the corona). The next total eclipse is not expected to occur until August 12th, 2026, and will be visible to residents in Greenland, Iceland, Spain, Russia, and a small area of Portugal. For people in Europe, Africa, and North America, the same eclipse will appear as a partial one.

The passage of the Moon’s shadow across Earth’s surface is known as the “path of totality.” As the images show, this path spanned across the North American continent from Mexico to the eastern tip of Canada. Aside from GEOS-16, images were also taken by the European Space Agency’s (ESA) Copernicus Sentinel-3 mission using its Sea and Land Surface Temperature Radiometer (SLSTR). This satellite monitors Earth’s oceans, land, glaciers, and atmosphere to monitor and improve our understanding of global weather dynamics.

In addition to providing a rare glimpse at what a total eclipse looks like from space, the combined images are also an effective tool for researching how an eclipse influences Earth’s weather. As the Moon obscures light and heat from the Sun, air temperatures drop in the path of totality and can cause cloud formations to evolve in different ways. Data from GOES-16, Sentinel-3, and other Earth Observation satellites is now being used to explore these effects.

Further Reading: ESA

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In 2013, the Hubble Space Telescope spotted water vapour on Jupiter’s moon Europa. The vapour was evidence of plumes similar to the ones on Saturn’s moon Enceladus. That, and other compelling evidence, showed that the moon has an ocean. That led to speculation that the ocean could harbour life.

But the ocean is obscured under a thick, global layer of ice, making the plumes our only way of examining the ocean. The plumes are so difficult to detect they haven’t been confirmed.

The lead author of the paper presenting Hubble’s 2013 evidence is Lorenz Roth of Southwest Research Institute. He said, “By far, the simplest explanation for this water vapour is that it erupted from plumes on the surface of Europa. If those plumes are connected with the subsurface water ocean we are confident exists under Europa’s crust, then this means that future investigations can directly investigate the chemical makeup of Europa’s potentially habitable environment without drilling through layers of ice. And that is tremendously exciting.”

It is, but first, scientists have to find the plumes.

“We pushed Hubble to its limits to see this very faint emission. These could be stealth plumes because they might be tenuous and difficult to observe in visible light,” said Joachim Saur of the University of Cologne, co-author of the 2013 paper.

This artist’s illustration shows plumes erupting through Europa’s icy surface. Gigantic Jupiter lurks in the background. Image Credit: NASA/ESA/K. Retherford/SWRI

Describing them as tenuous stealth plumes turned out to be prophetic.

Recently, a team of researchers went looking for the plumes. Their results are in a presentation given to the IAU Symposium 383 titled “ALMA Spectroscopy of Europa: A Search for Active Plumes.” The lead author is M.A. Cordiner from the Solar System Exploration Division at NASA’s Goddard Space Flight Center.

“The subsurface ocean of Europa is a high-priority target in the search for extraterrestrial life, but direct investigations are hindered by the presence of a thick exterior ice shell,” the authors write. The researchers used ALMA to search for molecular emissions from atmospheric plumes. They were investigating processes under the ice that could help them understand Europa’s ocean and its chemistry.

The Solar System is full of icy bodies, including comets, Kuiper Belt Objects, dwarf planets, and moons like Europa. Europa has a high density compared to other icy bodies, indicating a substantial rocky interior. Its ocean makes up about 10% of the moon and is covered by an icy shell of uncertain thickness. It could be several tens of kilometres thick. Scientists learned much of this from NASA’s Galileo mission.

In recent years, Europa and its ocean have leapt to the top of the list of targets in the search for life. The reasons aren’t obscure: liquid water is an irresistible beacon in our search for habitable places. The plumes from Europa’s ocean are our only way to study the ocean and its potential habitability.

This illustration shows what the interior of Europa might look like. Geysers might erupt through cracks and fissures in the ice. Image Credit: NASA/JPL-Caltech/Michael Carroll)

Over the years, different telescopes have examined Europa, searching for more evidence of the plumes. They’ve found potential intermittent plume activity near the moon’s south pole. But confirmation of the plumes the Hubble spotted in 2013 is elusive. In 2023, the JWST examined Europa. Those observations “found no evidence for active plumes, indicating that any present-day activity must be localized and weak; robust confirmation of the initial HST plume results also remains challenging,” the authors write.

In an attempt to find the plumes, the authors employed ALMA, the Atacama Large Millimeter/submillimeter Array. They observed Europa on four separate days to cover the moon’s surface. Unfortunately, they found no plumes.

These are four ALMA images of Europa. The researchers observed the moon on four different days so they could image almost the entire surface. They found no plumes. Image Credit: Cordiner et al. 2024.

“Despite near-complete coverage of both Europa’s leading and trailing hemispheres, we find no evidence for gas phase molecular absorption or emission in our ALMA data,” the researchers write. “Using ALMA’s unique combination of high spectral/spatial resolution and sensitivity, our observations have enabled the first dedicated search for HCN, H2CO, SO2 and CH3OH in Europa’s exosphere and plumes. No evidence was found for the presence of these molecules.”

Finding no evidence doesn’t quite mean that those molecules aren’t there. Rather, it means that if they are there, their concentrations are so low they’re below the detection threshold. In this case, some concentrations would be lower than those detected in Enceladus’ plumes, which are confirmed.

One chemical in particular illustrates this point: CH3OH (methanol.) “For the CH3OH abundance, on the
other hand, our ALMA upper limit of < 0.86% would not have been sensitive enough to detect this molecule at the Enceladus plume abundance of 0.02%,” the authors write.

There are some interesting relationships between Europa and other icy objects in the Solar System. It has to do with abundance limits. The researchers established upper limits for H2CO (formaldehyde) on Europa. “Indeed, our H2CO abundance upper limit is significantly lower than measured by Cassini in the Enceladus plume, implying a possible chemical difference.”

Despite the fact that it didn’t find any plumes, the observations were still valuable. By setting detection limits it helps subsequent efforts to search for them. And this won’t be scientists’ final attempt at finding plumes. Anything that provides clues to Europa’s ocean is too tantalizing to ignore, and this research shows that ALMA is suited to this type of investigation.

“Our results show that ALMA is a powerful tool in the search for outgassing from icy bodies within the Solar System and that follow-up searches for other molecules at additional epochs (on Europa and other icy bodies) are justified,” the researchers conclude.

The post If Europa has Geysers, They’re Very Faint appeared first on Universe Today.

NASA’s Parker Solar Probe has been in studying the Sun for the last six years. In 2021 it was hit directly by a coronal mass ejection when it was a mere 10 million kilometres from the solar surface. Luckily it was gathering data and images enabling scientists to piece together an amazing video. The interactions between the solar wind and the coronal mass ejection were measured giving an unprecedented view of the solar corona. 

The Sun is a fascinating object and as our local star, has been the subject of many studies. There are still mysteries though and it was hoping to unravel some of these that the NASA Parker Solar Probe was launched. It was sent on its way by the Delta IV heavy back in 2018 and has flown seven times closer to the Sun than any spacecraft before it. 

Illustration of the Parker Solar Probe spacecraft approaching the Sun. Credits: Johns Hopkins University Applied Physics Laboratory

By the time Parker completes its seven year mission it will have completed 24 orbits of the Sun and flown to within 6.2 million kilometres to the visible surface. For this to happen, its going to get very hot so the probe has a 11.4cm thick carbon composite shield to keep its components as cool as possible in the searing 1,377 Celsius temperatures. 

Flying within the Sun’s outer atmosphere, the corona, the probe picked up turbulence inside a coronal mass ejection as it interacted with the solar wind. These events are eruptions of large amounts of highly magnetised and energetic plasma from within the Sun’s corona. When directed toward Earth they can cause magnetic and radio disruptions in many ways from communications to power systems. 

Image of a coronal mass ejection being discharged from the Sun. (Credit: NASA/Goddard Space Flight Center/Solar Dynamics Observatory)

Using the Wide Field Imager for Parker Solar Probe (WISPR) and its prime position inside the solar atmosphere, unprecedented footage was captured (click on this link for the video). The science team from the US Naval Research Laboratory revealed what seemed like turbulent eddies, so called Kelvin-Helmholtz instabilities (KHIs) in one of the images. Turbulent eddy structures like these have been seen in the atmosphere of terrestrial planets. Strong wind shear between upper and lower cloud levels causes thin trains of crescent wave like clouds. 

Member of the WISPR team Evangelos Paouris PhD was the eagle eyed individual that spotted the disturbance. Paouris and team analysed the structure to verify the waves. The discovery of these rare features in the CME have opened up a whole new field of investigations.  

The KHIs are the result of turbulence which plays a key role in the movement of CMEs as they flow through the ambient solar wind. Understanding the CMEs and their dynamics of CMEs and a more fuller understanding of the Sun’s corona. This doesn’t just help us understand the Sun but also helps to understand the effect of CMEs on Earth and our space based technology.

Source : WISPR Team Images Turbulence within Solar Transients for the First Time

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In a couple billion years, our Sun will be unrecognizable. It will swell up and become a red giant, then shrink again and become a white dwarf. The inner planets aren’t expected to survive all the mayhem these transitions unleash, but what will happen to them? What will happen to the outer planets?

Right now, our Sun is about 4.6 billion years old. It’s firmly in the main sequence now, meaning it’s going about its business fusing hydrogen into helium and releasing energy. But even though it’s about 330,000 times more massive than the Earth, and nearly all of that mass is hydrogen fuel, it will eventually run out.

In another five billion years or so, its vast reservoir of hydrogen will suffer depletion. As it burns through its hydrogen, the Sun will lose mass. As it loses mass, its gravity weakens and can no longer counteract the outward force driven by fusion. A star is a balancing act between the outward expansion of fusion and the inward force of gravity. Eventually, the Sun’s billions-of-years-long balancing act will totter.

With weakened gravity, the Sun will begin to expand and become a red giant.

This illustration shows the current-day Sun at about 4.6 billion years old. In the future, the Sun will expand and become a red giant. Image Credit: By Oona Räisänen (User:Mysid), User:Mrsanitazier. – Vectorized in Inkscape by Mysid on a JPEG by Mrsanitazier (en:Image: Sun Red Giant2.jpg). CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=2585107

The Sun will almost certainly consume Mercury and Venus when it becomes a red giant. It will expand and become about 256 times larger than it is now. The inner two planets are too close, and there’s no way they can escape the swelling star. Earth’s fate is less certain. It may be swallowed by the giant Sun, or it may not. But even if it isn’t consumed, it will lose its oceans and atmosphere and become uninhabitable.

The Sun will be a red giant for about one billion years. After that, it will undergo a series of more rapid changes, shrinking and expanding again. But the mayhem doesn’t end there.

The Sun will pulse and shed its outer layers before being reduced to a tiny remnant of what it once was: a white dwarf.

An artist’s impression of a white dwarf star. The material inside white dwarfs is tightly packed, making them extremely dense. Image credit: Mark Garlick / University of Warwick.

This will happen to the Sun, its ilk, and almost all stars that host planets. Even the long-lived red dwarfs (M-dwarfs) will eventually become white dwarfs, though their path is different.

Astronomers know the fate of planets too close to the stars undergoing these tumultuous changes. But what happens to planets further away? To their moons? To asteroids and comets?

New research published in The Monthly Notices of the Royal Astronomical Society digs into the issue. The title is “Long-term variability in debris transiting white dwarfs,” and the lead author is Dr. Amornrat Aungwerojwit of Naresuan University in Thailand.

“Practically all known planet hosts will evolve eventually into white dwarfs, and large parts of the various components of their planetary systems—planets, moons, asteroids, and comets—will survive that metamorphosis,” the authors write.

There’s lots of observational evidence for this. Astronomers have detected planetary debris polluting the photospheres of white dwarfs, and they’ve also found compact debris disks around white dwarfs. Those findings show that not everything survives the main sequence to red giant to white dwarf transition.

“Previous research had shown that when asteroids, moons and planets get close to white dwarfs, the huge gravity of these stars rips these small planetary bodies into smaller and smaller pieces,” said lead author Aungwerojwit.

This Hubble Space Telescope shows Sirius, with its white dwarf companion Sirius B to the lower left. Sirius B is the closest white dwarf to the Sun. Credit: NASA, ESA, H. Bond (STScI) and M. Barstow (University of Leicester).

In this research, the authors observed three white dwarfs over the span of 17 years. They analyzed the changes in brightness that occurred. Each of the three stars behaved differently.

When planets orbit stars, their transits are orderly and predictable. Not so with debris. The fact that the three white dwarfs showed such disorderly transits means they’re being orbited by debris. It also means the nature of that debris is changing.

“The unpredictable nature of these transits can drive astronomers crazy—one minute they are there, the next they are gone.”

Professor Boris Gaensicke, University of Warwick

As small bodies like asteroids and moons are torn into small pieces, they collide with one another until nothing’s left but dust. The dust forms clouds and disks that orbit and rotate around the white dwarfs.

Professor Boris Gaensicke of the University of Warwick is one of the study’s co-authors. “The simple fact that we can detect the debris of asteroids, maybe moons or even planets whizzing around a white dwarf every couple of hours is quite mind-blowing, but our study shows that the behaviour of these systems can evolve rapidly, in a matter of a few years,” Gaensicke said.

“While we think we are on the right path in our studies, the fate of these systems is far more complex than we could have ever imagined,” added Gaensicke.

This artist’s illustration shows the white dwarf WD J0914+1914 (Not part of this research.) A Neptune-sized planet orbits the white dwarf, and the white dwarf is drawing material away from the planet and forming a debris disk around the star. Image Credit: By ESO/M. Kornmesser – https://www.eso.org/public/images/eso1919a/, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=84618722

During the 17 years of observations, all three white dwarfs showed variability.

The first white dwarf (ZTF J0328?1219) was steady and stable until a major catastrophic event around 2011. “This might suggest that the system underwent a large collisional event around 2011, resulting in the production of large amounts of dust occulting the white dwarf, which has since then gradually dispersed, though leaving sufficient material to account for the ongoing transit activity, which implies continued dust production,” the researchers explain.

The second white dwarf (ZTF J0923+4236) dimmed irregularly every couple of months and displayed chaotic variability on the timescale of minutes. “These long-term changes may be the result of the ongoing disruption of a planetesimal or the collision between multiple fragments, both leading to a temporarily increased dust production,” the authors explain in their paper.

The third star (WD 1145+017) showed large variations in numbers, shapes and depths of transits in 2015. This activity “concurs with a large increase in transit activity, followed by a subsequent gradual re-brightening,” the authors explain, adding that “the overall trends seen in the brightness of WD?1145+017 are linked to varying amounts of transit activity.”

But now all those transits are gone.

“The unpredictable nature of these transits can drive astronomers crazy—one minute they are there, the next they are gone,” said Gaensicke. “And this points to the chaotic environment they are in.”

But astronomers have also found planetesimals, planets, and giant planets around white dwarfs, indicating that the stars’ transitions from main sequence to red giant don’t destroy everything. The dust and debris that astronomers see around these white dwarfs might come from asteroids or from moons pulled free from their giant planets.

“For the rest of the Solar System, some of the asteroids located between Mars and Jupiter, and maybe some of the moons of Jupiter may get dislodged and travel close enough to the eventual white dwarf to undergo the shredding process we have investigated,” said Professor Gaensicke.

When our Sun finally becomes a white dwarf, it will likely have debris around it. But the debris won’t be from Earth. One way or another, the Sun will destroy Earth during its red giant phase.

“Whether or not the Earth can just move out fast enough before the Sun can catch up and burn it is not clear, but [if it does] the Earth would [still] lose its atmosphere and ocean and not be a very nice place to live,” explained Professor Gaensicke.

The post What Happens to Solar Systems When Stars Become White Dwarfs? appeared first on Universe Today.

Galactic collisions, meteor impacts and even stellar mergers are not uncommon events. neutron stars colliding with black holes however are a little more rare, in fact, until now, we have never observed one. The fourth LIGO-Virgo-KAGRA observing detected gravitational waves from a collision between a black hole and neutron star 650 million light years away. The black hole was tiny though with a mass between 2.5 to 4.5 times that of the Sun. 

Neutron stars and black holes have something in common; they are both the remains of a massive star that has reached the end of its life. During the main part of a stars life the inward pull of gravity is balanced by the outward push of the thermonuclear pressure that makes the star shine. The thermonuclear pressure overcomes gravity for low mass stars like the Sun but for more massive stars, gravity wins. The core collapses compressing it into either a neutron star or a black hole (depending on the progenitor star mass) and explodes as a supernova – in the blink of an eye. 

In May 2023, as a result of the fourth observing session of the LIGO-Virgo-KAGRA (Laser Interferometer Gravitational Wave Observatory-Virgo Gravitational Wave Interferometer and Kamioka Gravitational Wave Detector) network, gravitational waves were picked up from a merger event. The signal came from an object 1.2 times the mass of the Sun and another slightly more massive object. Further analysis revealed the likelihood that one was a neutron star and the other a low mass black hole. The latter falls into the so called ‘mass gap’, more massive than the most massive neutron star and less massive than the least massive black hole.

Interactions between objects can generate gravitational waves. Before they were detected back in 2015, stellar mass black holes were typically found through X-ray observations. Neutron stars on the other hand, were usually found with radio observations. Between the two, was the mass gap with objects lacking between three and five solar masses. 

It has been the subject of debate among scientists with the odd object found which fell within the gap, fuelling debate about its existence. The gap has generally been considered to separate the neutron stars from the black holes and items in this mass group have been scarce. This gravitational wave discovery suggests maybe objects in this gap are not so rare after-all. 

One of the challenges of detecting mass gap objects and mergers between them is the sensitivity of detectors. The LIGO team at the University of British Columbia researchers are working hard to improve the coatings used in mirror production. Enhanced performance on future LIGO detectors will further enhance detection capabilities. It’s not just optical equipment that is being developed, infrastructure changes are also being addressed including data analysis software too. Improving sensitivity in all aspects of the gravity wave network is sure to yield results in future runs. However for now, the rest of the first half of the observing run needs analysing with 80 more candidate signals to study. 

Source : New gravitational wave signal helps fill the ‘mass gap’ between neutron stars and black holes

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Sometimes, the easy calculations are the most interesting. A recent paper from Balázs Bradák of Kobe University in Japan is a case in point. In it, he takes an admittedly simplistic approach but comes up with seven known exoplanets that could hold the key to the biggest question of them all – are we alone?

Dr. Bradák starts with a simple premise – there is a chance that life on Earth might have started via panspermia. There is also a case that panspermia was intention – an advanced civilization could theoretically have purposefully sent a biological seed ship to our local solar system to spread life here, essentially from scratch.

With those admittedly very large assumptions in place, Dr. Bradák works out a few characteristics about the planets that could have been the starting point for such a civilization. First, he assumes, as much of the astrobiological community does, that for an advanced civilization to arise on a planet, that planet has to be at least partially covered in an ocean. 

Sun-like stars aren’t the only potential hosts for habitable planets, as Fraser discusses here.

To meet that requirement, the planet has to be both the right size and the right temperature. The two size categories of exoplanets that Dr. Bradák originally selected were “terrestrial” – planets similar to Earth, including so-called “Super-Earths” – and “sub-Neptunes” – planets that are significantly larger than Earth but smaller than the ice giant in the outer fringes of our solar system.

Any such exoplanet also has to be in the habitable zone of its parent star. That alone dramatically narrows the potential field of planetary candidates. For simplicity’s sake, Dr. Bradák also eliminates sub-Neptunes as a potential planetary class. However, one other factor comes into play as well: age.

We know it took around 4.6 billion years for life to evolve to a point where it could theoretically send objects to other star systems – as we have now with Voyager. Since the original planet would also have to have evolved such a civilization, it would be double the time for its minimum age – or 9.2 billion years old.

The idea of panspermia has been around for decades, as Fraser discusses.

Dr. Bradák adds some additional argument that lowers the required age of the system – and he also assumes that the planetary system of a star forms at a similar time gap as our planetary system did. The distance to most of these stars is inconsequential on the scale of billions of years, so the travel time for the seed ship was discounted in this calculation. 

After all that pruning, Dr. Bradák turned to NASA’s Exoplanet Archive, which currently contains 5271 known exoplanets. Of those 5271, only 7 meet the specified age, size, and habitable zone placement criteria. In other words, according to our current knowledge of exoplanets and how life evolved, only a few planets could potentially have been the starting point for an intentional panspermia campaign.

One planet in particular stands out – Kepler-452 b, which has a star similar to ours and an orbit similar to ours. That system is only 1,400 light years away, relatively close by astronomical standards. If nothing else, it points to that system as a potentially interesting focal point for exoplanet surveys, including assessments of exoplanet atmospheres. However, we’ll likely have to wait for the next generation of grand telescopes.

For now, this was an interesting, though brief, speculative exercise. Astronomers are always looking for exciting things, and this paper contributes to the arguments about why it’s so important to spend time looking in detail at some of the exoplanets we already know about.

Learn More:
B. Bradák – A BOLD AND HASTY SPECULATION ABOUT ADVANCED CIVILIZATION-BEARING PLANETS
APPEARING IN EXOPLANET DATABASES
UT – A Super-Earth (and Possible Earth-Sized) Exoplanet Found in the Habitable Zone
UT – A New Place to Search for Habitable Planets: “The Soot Line.”
UT – Want to Find Life? Compare a Planet to its Neighbors

Lead Image:
Artist’s illustration of a habitable planet.
Credit – Wikipedia / VP8/Vorbis

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You’ve likely heard of the Breakthrough Starshot (BTS) initiative. BTS aims to send tiny gram-scale, light sail picospacecraft to our neighbour, Proxima Centauri B. In BTS’s scheme, lasers would propel a whole fleet of tiny probes to the potentially water-rich exoplanet.

Now, another company, Space Initiatives Inc., is tackling the idea. NASA has funded them so they can study the idea. What can we expect to learn from the effort?

Proxima b may be a close neighbour in planetary terms. But it’s in a completely different solar system, about four light-years away. That means any probes sent there must travel at relativistic speeds if we want them to arrive in a reasonable amount of time.

That’s why Space Initiatives Inc. proposes such tiny spacecraft. With their small masses, direct lasers can propel them to their destination. That means they must send a swarm of hundreds or even one thousand probes to get valuable scientific results.

This is much different than the architecture that missions usually conform to. Most missions are a single spacecraft, perhaps with a smaller attached probe like the Huygens probe attached to the Cassini spacecraft. How does using a swarm change the mission? What results can we expect?

“We anticipate our innovations would have a profound effect on space exploration.”

Thomas Eubanks, Space Inititatives Inc.

A new presentation at the 55th Lunar and Planetary Science Conference (LPSC) in Texas examined the idea. It’s titled “SCIENTIFIC RETURN FROM IN SITU EXPLORATION OF THE PROXIMA B EXOPLANET.” The lead author is T. Marshall Eubanks from Space Initiatives Inc., a start-up developing 50-gram femtosatellites that weigh less than 100 grams (3.5 oz.)

Tiny probes like these can only do flybys. They’re too tiny and low-mass for anything else. When designing a mission like this, the first consideration is whether the probes will operate as a dispersed or coherent swarm. In a dispersed swarm, the probes reach their destination sequentially. In a coherent swarm, the probes are together when they do their flyby. Both architectures have their merits.

In either case, these tiny solar sail probes will be very thin. But thanks to technological advances, they can still gather high-resolution images by working together.

The image below shows 247 probes forming an array as they fly by Proxima b. Together, they have the light-collecting area of a three-meter telescope. This arrangement should enable sub-arc-second resolutions at optical wavelengths. Spectroscopy should be equally as fine.

“While both erosion by the Interstellar Medium (ISM) and image smearing will degrade imaging, we anticipate these systems will enable sub-arcsecond resolution imaging and spectroscopy of the target planet,” the authors write.

This image from the presentation shows how the probe swarm would arrive at Proxima b. (Note that the planned swarm dispersion is much smaller than is indicated here.) Image Credit: Eubanks et al. 2024.

These tiny spacecraft could do some course correction, but not much. So, getting the navigation right is critical. Unfortunately, our data on Proxima b’s orbit is not as well-understood as the planets in our own Solar System. It all comes down to ephemeris.

Ephemeris tables show the trajectory of planets and other objects in space. But in Proxima b’s case, the ephemeris error is potentially quite large.

Added to that is the distance. If the probes can travel at 20% of light speed, reaching the planet will take over 21 years. The authors calculate that if they can restrict Proxima b’s ephemeris error to 100,000 km and send 1,000 probes, at least one will come within 1,000 km of the planet. “Meeting this ephemeris error goal will require improved astrometry of the Proxima system,” the authors write.

The probes would perform science observations on their way to Proxima b. As they travel, the swarm would have dozens or even hundreds of opportunities to use microlensing to study stellar objects. A stellar mass microlensing event requiring one month on Earth would only take one hour.

“It is now possible to predict lensing events for nearby stars; BTS probe observations of dozens or hundreds of predicted microlensing events by nearby stars will offer both a means of observing these systems and a novel means of interstellar navigation,” the authors explain.

The swarm would be only the third mission to leave our Solar System. The Voyage spacecraft left the heliosphere, but only inadvertently. So, the swarm could observe the interstellar medium (ISM) during its 20+ year journey. One of the questions we have about the local ISM concerns clouds. We only have poor data on the nature of these clouds, and scientists aren’t certain if our Solar System is in the Local Interstellar Cloud (LIC.)

“In situ observation of the properties of these clouds will be a primary scientific goal for mission science during the long interstellar voyage,” the researchers write.

There are clouds in the ISM near our Solar System. But we don’t know much about them, including if our Solar System is in the LIC or if it’s leaving it. Image Credit: Interstellar Probe/JHUAPL

Opportunistic science during the voyage is great, but arrival at Proxima b is the meat of the mission. One day before the probes arrive, they would still be 35 AU away. At that point, the mission could begin imaging. Proxima b would still only be several pixels across, but it’s enough to see any visible moons.

“At this point, it would be worth turning some probes to face forward and begin imaging the Proxima system to search for undiscovered planets, moons and asteroids in the system, and to begin a Proxima b approach video,” the researchers explain.

Upon arrival at Proxima Centauri b, a one-meter aperture telescope 6,000 km away from the planet could attain a six-meter resolution on the surface. That’s an idealistic number, as not all of the planet’s surface could be imaged at that resolution. PCb is also tidally locked to its star, meaning one side is in darkness. Because of that, the mission should be designed to gather low-light and infrared images of the night side. “Night-side illumination imagery might also be the most conclusive technosignature from an initial Proxima mission,” the authors write.

As probes pass through Proxima b’s shadow, they could use the light from the star to perform spectroscopy. Probes passing behind Proxima b could use the Earth laser system for spectrometry, and if the probes are in a coherent swarm, they could use the lasers from pairs of probes on either side of the planet.

“Transmission spectroscopy, which for Proxima b cannot be done from Earth,” the researchers explain, “will likely provide the best means of determining the existence of a biology or even a technological society on Proxima b through the search for the spectral lines of biomarkers and technomarkers.”

As humanity’s first mission to Proxima Centauri b, the swarm would face some hurdles and uncertainties. But in a coherent swarm architecture, the mission could also be almost too successful. “A BTS mission, especially with a coherent swarm, may collect more data than can be returned to Earth,” the authors write. If the data returned has to be selected autonomously by the swarm itself, that could be more demanding than deciding what data to collect in the first place.

Scientists have many questions about Proxima Centauri b. Should the swarm ever be launched, any amount of data it returns will be valuable. Even though it’ll take over four years for the data to be sent back to Earth.

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. Credit: NRAO/S. Dagnello.

Scientists don’t know how hot the planet is. They’re not certain if it even has liquid water. It looks like the planet is just over one Earth mass and has a slightly higher radius. But those measurements are uncertain. Scientists are also uncertain about its composition. The star it orbits is a flare star, which means the planet could be subjected to extremely powerful bursts of radiation. That’s a lot of uncertainty.

But it’s the nearest exoplanet, the only one we could feasibly reach in a realistic amount of time. That alone makes it a desirable target.

There’s no final plan for a mission like this. It’s largely conceptual. But the technology to do it is coming along. NASA has funded a mission study, so it definitely has merit.

“Fortunately, we don’t have to wait until mid-century to make practical progress – we can explore and test swarming techniques now in a simulated environment, which is what we propose to do in this work,” said report lead author Thomas Eubanks from Space Initiatives Inc. “We anticipate our innovations would have a profound effect on space exploration, complementing existing techniques and enabling entirely new types of missions, for example, picospacecraft swarms covering all of cislunar space or instrumenting an entire planetary magnetosphere.”

Eubanks also points out how a swarm of probes could investigate interstellar objects that pass through our inner Solar System, like Oumuamua.

But the main mission would be the one to Proxima Centauri b. According to Eubanks, that would happen sometime in the third quarter of this century.

The post What a Swarm of Probes Can Teach Us About Proxima Centauri B appeared first on Universe Today.

Life on Earth depends on six critical elements: Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorous, and Sulfur. These elements are referred to as CHNOPS, and along with several trace micronutrients and liquid water, they’re what life needs.

Scientists are getting a handle on detecting exoplanets that might be warm enough to have liquid water on their surfaces, habitability’s most basic signal. But now, they’re looking to up their game by finding CHNOPS in exoplanet atmospheres.

We’re only at the beginning of understanding how exoplanets could support life. To grow our understanding, we need to understand the availability of CHNOPS in planetary atmospheres.

A new paper examines the issue. It’s titled “Habitability constraints by nutrient availability in atmospheres of rocky exoplanets.” The lead author is Oliver Herbort from the Department of Astrophysics at the University of Vienna and an ARIEL post-doctoral fellow. The paper has been accepted by the International Journal of Astrobiology.

At our current technological level, we’re just beginning to examine exoplanet atmospheres. The JWST is our main tool for the task, and it’s good at it. But the JWST is busy with other tasks. In 2029, the ESA will launch ARIEL, the Atmospheric Remote-sensing Infrared Exoplanet Large survey. ARIEL will be solely focused on exoplanet atmospheres.

An artist’s impression of the ESA’s Ariel space telescope. During its four-year mission, it’ll examine 1,000 exoplanet atmospheres with the transit method. It’ll study and characterize both the compositions and thermal structures. Image Credit: ESA

In anticipation of that telescope’s mission, Herbort and his co-researchers are preparing for the results and what they mean for habitability. “The detailed understanding of the planets itself becomes important for interpreting observations, especially for the detection of biosignatures,” they write. In particular, they’re scrutinizing the idea of aerial biospheres. “We aim to understand the presence of these nutrients within atmospheres that show the presence of water cloud condensates, potentially allowing the existence of aerial biospheres.”

Our sister planet Venus has an unsurvivable surface. The extreme heat and pressure make the planet’s surface uninhabitable by any measure we can determine. But some scientists have proposed that life could exist in Venus’ atmosphere, based largely on the detection of phosphine, a possible indicator of life. This is an example of what an aerial biosphere might look like.

This artistic impression depicts Venus. Astronomers at MIT, Cardiff University, and elsewhere may have observed signs of life in the atmosphere of Venus by detecting phosphine. Subsequent research disagreed with this finding, but the issue is ongoing. Image Credits: ESO (European Space Organization)/M. Kornmesser & NASA/JPL/Caltech

“This concept of aerial biospheres enlarges the possibilities of potential habitability from the presence of liquid water on the surface to all planets with liquid water clouds,” the authors explain.

The authors examined the idea of aerial biospheres and how the detection of CHNOPS plays into them. They introduced the concept of nutrient availability levels in exoplanet atmospheres. In their framework, the presence of water is required regardless of other nutrient availability. “We considered any atmosphere without water condensates as uninhabitable,” they write, a nod to water’s primacy. The researchers assigned different levels of habitability based on the presence and amounts of the CHNOPS nutrients.

This table from the research illustrates the authors’ concept of atmospheric nutrient availability. As the top row shows, without water, no atmosphere is habitable. Different combinations of nutrients have different habitability potential. ‘red’ stands for redox, and ‘ox’ stands for the presence of the oxidized state of CO2, NOx, and SO2. Image Credit: Herbort et al. 2024.

To explore their framework of nutrient availability, the researchers turned to simulations. The simulated atmospheres held different levels of nutrients, and the researchers applied their concept of nutrient availability. Their results aim to understand not habitability but the chemical potential for habitability. A planet’s atmosphere can be altered drastically by life, and this research aims to understand the atmospheric potential for life.

“Our approach does not directly aim for the understanding of biosignatures and atmospheres of planets, which are inhabited, but for the conditions in which pre-biotic chemistry can occur,” they write. In their work, the minimum atmospheric concentration for a nutrient to be available is 10?9, or one ppb (part per billion.)

“We find that for most atmospheres at ( p gas, T gas) points, where liquid water is stable, CNS-bearing molecules are present at concentrations above 10?9,” they write. They also found that carbon is generally present in every simulated atmosphere and that sulphur availability increases with surface temperature. With lower surface temperatures, nitrogen (N2, NH3) is present in increasing amounts. But with higher surface temperatures, nitrogen can become depleted.

Phosphorus is a different matter. “The limiting element of the CHNOPS elements is phosphorus, which is mostly bound in the planetary crust,” they write. The authors point out that, at past times in Earth’s atmosphere, phosphorus scarcity limited the biosphere.

An aerial biosphere is an interesting idea. But it’s not the main thrust of scientists’ efforts to detect exoplanet atmospheres. Surface life is their holy grail. It should be no surprise that it still comes down to liquid water, all things considered. “Similar to previous work, our models suggest that the limiting factor for habitability at the surface of a planet is the presence of liquid water,” the authors write. In their work, when surface water was available, CNS was available in the lower atmosphere near the surface.

But surface water plays several roles in atmospheric chemistry. It can bond with some nutrients in some circumstances, making them unavailable, and in other circumstances, it can make them available.

“If water is available at the surface, the elements not present in the gas phase are stored in the crust condensates,” the authors write. Chemical weathering can then make them available as nutrients. “This provides a pathway to overcome the lack of atmospheric phosphorus and metals, which are used in enzymes that drive many biological processes.”

Artist’s impression of the surface of a hycean world. Hycean worlds are still hypothetical, with large oceans and thick hydrogen-rich atmospheres that trap heat. It’s unclear if a world with no surface can support life. Image Credit: University of Cambridge

This complicates matters on worlds covered by oceans. Pre-biotic molecules might not be available if there’s no opportunity for water and rock to interact with the atmosphere. “If indeed it can be shown that life can form in a water ocean without any exposed land, this constraint becomes weaker, and the potential for the surface habitability becomes mainly a question of water stability,” the authors write.

Some of the models are surprising because of atmospheric liquid water. “Many of the models show the presence of a liquid water zone in the atmospheres, which is detached from the surface. These regions could be of interest for the formation of life in forms of aerial biospheres,” Herbort and his colleagues write.

If there’s one thing that research like this shows, planetary atmospheres are extraordinarily complex and can change dramatically over time, sometimes because of life itself. This research makes some sense in trying to understand it all. Emphasizing the complexity is the fact that the researchers didn’t include stellar radiation in their work. Including that would’ve made the effort unwieldy.

The habitability issue is complicated, confounded by our lack of answers to foundational questions. Does a planet’s crust have to be in contact with water and the atmosphere for the CHNOPS nutrients to be available? Earth has a temporary aerial biosphere. Can aerial biospheres be an important part of exoplanet habitability?

But beyond all the simulations and models, as powerful as they are, what scientists need most is more data. When ARIEL launches, scientists will have much more data to work with. Research like this will help scientists understand what ARIEL finds.

The post Measuring the Atmospheres of Other Worlds to See if There are Enough Nutrients for Life appeared first on Universe Today.

Artificial Intelligence is making its presence felt in thousands of different ways. It helps scientists make sense of vast troves of data; it helps detect financial fraud; it drives our cars; it feeds us music suggestions; its chatbots drive us crazy. And it’s only getting started.

Are we capable of understanding how quickly AI will continue to develop? And if the answer is no, does that constitute the Great Filter?

The Fermi Paradox is the discrepancy between the apparent high likelihood of advanced civilizations existing and the total lack of evidence that they do exist. Many solutions have been proposed for why the discrepancy exists. One of the ideas is the “Great Filter.”

The Great Filter is a hypothesized event or situation that prevents intelligent life from becoming interplanetary and interstellar and even leads to its demise. Think climate change, nuclear war, asteroid strikes, supernova explosions, plagues, or any number of other things from the rogue’s gallery of cataclysmic events.

Or how about the rapid development of AI?

A new paper in Acta Astronautica explores the idea that Artificial Intelligence becomes Artificial Super Intelligence (ASI) and that ASI is the Great Filter. The paper’s title is “Is Artificial Intelligence the Great Filter that makes advanced technical civilizations rare in the universe?” The author is Michael Garrett from the Department of Physics and Astronomy at the University of Manchester.

“Without practical regulation, there is every reason to believe that AI could represent a major threat to the future course of not only our technical civilization but all technical civilizations.”

Michael Garrett, University of Manchester

Some think the Great Filter prevents technological species like ours from becoming multi-planetary. That’s bad because a species is at greater risk of extinction or stagnation with only one home. According to Garrett, a species is in a race against time without a backup planet. “It is proposed that such a filter emerges before these civilizations can develop a stable, multi-planetary existence, suggesting the typical longevity (L) of a technical civilization is less than 200 years,” Garrett writes.

If true, that can explain why we detect no technosignatures or other evidence of ETIs (Extraterrestrial Intelligences.) What does that tell us about our own technological trajectory? If we face a 200-year constraint, and if it’s because of ASI, where does that leave us? Garrett underscores the “…critical need to quickly establish regulatory frameworks for AI development on Earth and the advancement of a multi-planetary society to mitigate against such existential threats.”

An image of our beautiful Earth taken by the Galileo spacecraft in 1990. Do we need a backup home? Credit: NASA/JPL

Many scientists and other thinkers say we’re on the cusp of enormous transformation. AI is just beginning to transform how we do things; much of the transformation is behind the scenes. AI seems poised to eliminate jobs for millions, and when paired with robotics, the transformation seems almost unlimited. That’s a fairly obvious concern.

But there are deeper, more systematic concerns. Who writes the algorithms? Will AI discriminate somehow? Almost certainly. Will competing algorithms undermine powerful democratic societies? Will open societies remain open? Will ASI start making decisions for us, and who will be accountable if it does?

This is an expanding tree of branching questions with no clear terminus.

Stephen Hawking (RIP) famously warned that AI could end humanity if it begins to evolve independently. “I fear that AI may replace humans altogether. If people design computer viruses, someone will design AI that improves and replicates itself. This will be a new form of life that outperforms humans,” he told Wired magazine in 2017. Once AI can outperform humans, it becomes ASI.

Stephen Hawking was a major proponent for colonizing other worlds, mainly to ensure humanity does not go extinct. In later years, Hawking recognized that AI could be an extinction-level threat. Credit: educatinghumanity.com

Hawking may be one of the most recognizable voices to issue warnings about AI, but he’s far from the only one. The media is full of discussions and warnings, alongside articles about the work AI does for us. The most alarming warnings say that ASI could go rogue. Some people dismiss that as science fiction, but not Garrett.

“Concerns about Artificial Superintelligence (ASI) eventually going rogue is considered a major issue – combatting this possibility over the next few years is a growing research pursuit for leaders in the field,” Garrett writes.

If AI provided no benefits, the issue would be much easier. But it provides all kinds of benefits, from improved medical imaging and diagnosis to safer transportation systems. The trick for governments is to allow benefits to flourish while limiting damage. “This is especially the case in areas such as national security and defence, where responsible and ethical development should be paramount,” writes Garrett.

News reports like this might seem impossibly naive in a few years or decades.

The problem is that we and our governments are unprepared. There’s never been anything like AI, and no matter how we try to conceptualize it and understand its trajectory, we’re left wanting. And if we’re in this position, so would any other biological species that develops AI. The advent of AI and then ASI could be universal, making it a candidate for the Great Filter.

This is the risk ASI poses in concrete terms: It could no longer need the biological life that created it. “Upon reaching a technological singularity, ASI systems will quickly surpass biological intelligence and evolve at a pace that completely outstrips traditional oversight mechanisms, leading to unforeseen and unintended consequences that are unlikely to be aligned with biological interests or ethics,” Garrett explains.

How could ASI relieve itself of the pesky biological life that corrals it? It could engineer a deadly virus, it could inhibit agricultural food production and distribution, it could force a nuclear power plant to melt down, and it could start wars. We don’t really know because it’s all uncharted territory. Hundreds of years ago, cartographers would draw monsters on the unexplored regions of the world, and that’s kind of what we’re doing now.

This is a portion of the Carta Marina map from the year 1539. It shows monsters lurking in the unknown waters off of Scandinavia. Are the fears of ASI kind of like this? Or could ASI be the Great Filter? Image Credit: By Olaus Magnus – http://www.npm.ac.uk/rsdas/projects/carta_marina/carta_marina_small.jpg, Public Domain, https://commons.wikimedia.org/w/index.php?curid=558827

If this all sounds forlorn and unavoidable, Garrett says it’s not.

His analysis so far is based on ASI and humans occupying the same space. But if we can attain multi-planetary status, the outlook changes. “For example, a multi-planetary biological species could take advantage of independent experiences on different planets, diversifying their survival strategies and possibly avoiding the single-point failure that a planetary-bound civilization faces,” Garrett writes.

If we can distribute the risk across multiple planets around multiple stars, we can buffer ourselves against the worst possible outcomes of ASI. “This distributed model of existence increases the resilience of a biological civilization to AI-induced catastrophes by creating redundancy,” he writes.

If one of the planets or outposts that future humans occupy fails to survive the ASI technological singularity, others may survive. And they would learn from it.

Artist’s illustration of a SpaceX Starship landing on Mars. If we can become a multi-planetary species, the threat of ASI is diminished. Credit: SpaceX

Multi-planetary status might even do more than just survive ASI. It could help us master it. Garrett imagines situations where we can experiment more thoroughly with AI while keeping it contained. Imagine AI on an isolated asteroid or dwarf planet, doing our bidding without access to the resources required to escape its prison. “It allows for isolated environments where the effects of advanced AI can be studied without the immediate risk of global annihilation,” Garrett writes.

But here’s the conundrum. AI development is proceeding at an accelerating pace, while our attempts to become multi-planetary aren’t. “The disparity between the rapid advancement of AI and the slower progress in space technology is stark,” Garrett writes.

The difference is that AI is computational and informational, but space travel contains multiple physical obstacles that we don’t yet know how to overcome. Our own biological nature restrains space travel, but no such obstacle restrains AI. “While AI can theoretically improve its own capabilities almost without physical constraints,” Garrett writes, “space travel must contend with energy limitations, material science boundaries, and the harsh realities of the space environment.”

For now, AI operates within the constraints we set. But that may not always be the case. We don’t know when AI might become ASI or even if it can. But we can’t ignore the possibility. That leads to two intertwined conclusions.

If Garrett is correct, humanity must work more diligently on space travel. It can seem far-fetched, but knowledgeable people know it’s true: Earth will not be inhabitable forever. Humanity will perish here by our own hand or nature’s hand if we don’t expand into space. Garrett’s 200-year estimate just puts an exclamation point on it. A renewed emphasis on reaching the Moon and Mars offers some hope.

The Artemis program is a renewed effort to establish a presence on the Moon. After that, we could visit Mars. Are these our first steps to becoming a multi-planetary civilization? Image Credit: NASA

The second conclusion concerns legislating and governing AI, a difficult task in a world where psychopaths can gain control of entire nations and are bent on waging war. “While industry stakeholders, policymakers, individual experts, and their governments already warn that regulation is necessary, establishing a regulatory framework that can be globally acceptable is going to be challenging,” Garrett writes. Challenging barely describes it. Humanity’s internecine squabbling makes it all even more unmanageable. Also, no matter how quickly we develop guidelines, ASI might change even more quickly.

“Without practical regulation, there is every reason to believe that AI could represent a major threat to the future course of not only our technical civilization but all technical civilizations,” Garrett writes.

This is the United Nations General Assembly. Are we united enough to constrain AI? Image Credit: By Patrick Gruban, cropped and downsampled by Pine – originally posted to Flickr as UN General Assembly, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=4806869

Many of humanity’s hopes and dreams crystallize around the Fermi Paradox and the Great Filter. Are there other civilizations? Are we in the same situation as other ETIs? Will our species leave Earth? Will we navigate the many difficulties that face us? Will we survive?

If we do, it might come down to what can seem boring and workaday: wrangling over legislation.

“The persistence of intelligent and conscious life in the universe could hinge on the timely and effective implementation of such international regulatory measures and technological endeavours,” Garrett writes.

The post Does the Rise of AI Explain the Great Silence in the Universe? appeared first on Universe Today.

Missions to asteroids have been on a tear recently. Visits by Rosetta, Osirix-REX, and Hayabusa2 have all visited small bodies and, in some cases, successfully returned samples to the Earth. But as humanity starts reaching out to asteroids, it will run into a significant technical problem – bandwidth. There are tens of thousands of asteroids in our vicinity, some of which could potentially be dangerous. If we launched a mission to collect necessary data about each of them, our interplanetary communication and control infrastructure would be quickly overwhelmed. So why not let our robotic ambassadors do it for themselves – that’s the idea behind a new paper from researchers at the Federal University of São Paulo and Brazil’s National Institute for Space Research.

The paper primarily focuses on the control problem of what to do when a spacecraft is approaching a new asteroid. Current missions take months to approach and require consistent feedback from ground teams to ensure the spacecraft understands the parameters of the asteroid it’s approaching – especially the gravitational constant.

Some missions have seen more success with that than others – for example, Philase, the lander that went along with Rosetta, had trouble when it bounced off the surface of comet 67P/Churyumov-Gerasimenko. As the authors pointed out, part of that difference was a massive discrepancy between the actual shape of the comet and the observed shape that telescopes had seen before Rosetta arrived there. 

Fraser discusses the possibility of capturing an asteroid.

Even more successful missions, such as OSIRIS-Rex, take months of lead-up time to complete relatively trivial maneuvers in the context of millions of kilometers their overall journey takes them. For example, it took 20 days for OSIRIX-Rex to perform multiple flybys at 7 km above the asteroid’s surface before its mission control deemed it safe to enter a stable orbit.

One of the significant constraints the mission controllers were looking at was whether they could accurately calculate the gravitational constant of the asteroid they were visiting. Gravity is notoriously difficult to determine from far away, and its miscalculation led to the problems with Philae. So, can a control scheme do to solve all of these problems?

Simply put, it can allow the spacecraft to decide what to do when approaching their target. With a well-defined control scheme, the likelihood of a spacecraft failure due to some unforeseen consequence is relatively minimal. It could dramatically decrease the time missions spend on approach and limit the communication bandwidth back toward mission control on Earth. 

One use case for quick asteroid mission – mining them, as Fraser discusses here.

Such a scheme would also require only four relatively ubiquitous, inexpensive sensors to operate effectively – a LiDAR (similar to those found on autonomous cars), two optical cameras for depth perception, and an inertial measurement unit (IMU) that measures parameters like orientation, acceleration, and magnetic field. 

The paper spends plenty of time detailing the complex math that would go into the control schema – some of which involve statistical calculations similar to basic learning models. The authors also run trials on two potential asteroid targets of interest to see how the system would perform.

One is already well understood. Bennu was the target of the OSIRIX-Rex mission and, therefore, is well-characterized as asteroids go. According to the paper, with the new control system, a spacecraft could enter a 2000 m orbit within a day of approaching from hundreds of kilometers away, then enter an 800 m orbit the next day. This is compared to the months of preparatory work the actual OSIRIS-Rex mission had to accomplish. And it can be completed with minimal thrust and, more importantly, fuel – a precious commodity on deep-space missions.

Asteroid defense is another important use case for quick asteroid missions – as Isaac Arthus discusses in this video.
Credit – Isaac Arthur

Another demonstration mission is one to Eros, the second-largest asteroid near Earth. It has a unique shape for an asteroid, as it is relatively elongated, which could pose an exciting challenge for automated systems like those described in the paper. Controlling a spacecraft with the new schema for a rendezvous with Eros doesn’t have all the same advantages of a more traditional asteroid like Bennu. For example, it has a much higher thrust requirement and fuel consumption. However, it still shortens the mission time and bandwidth required to operate it.

Autonomous systems are becoming increasingly popular on Earth and in space. Papers like this one push the thinking about what is possible forward. Suppose all that’s required to eliminate months of painstaking manual technical work is to slap a few sensors and implement a new control algorithm. In that case, it’s likely that one of the various agencies and companies planning to rendezvous with an asteroid shortly will adopt that plan.

Learn More:
Negri et al. – Autonomous Rapid Exploration in Close-Proximity of an Asteroid
UT – Miniaturized Jumping Robots Could Study An Asteroid’s Gravity
UT – How to Make Asteroid Landings Safer
UT – A Spacecraft Could use Gravity to Prevent a Dangerous Asteroid Impact

Lead Image:
Artist’s conception of the Lucy mission to the Trojan asteroids.
Credit – NASA

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I remember reading about an audacious mission to endeavour to drill through the surface ice of Europa, drop in a submersible and explore the depths below. Now that concept may be taking a step closer to reality with researchers working on technology to do just that. Worlds like Europa are high on the list for exploration due to their potential to harbour life. If technology like the SLUSH probe (Search for Life Using Submersible Head) work then we are well on the way to realising that dream. 

The search for life has always been something to captivate the mind. Think about the diversity of life on Earth and it is easy to see why we typically envisage creatures that rely upon sunlight, food and drink. But on Earth, life has found a way in the most inhospitable of environments, even at the very bottom of the ocean. The Mariana’s Trench is deeper than Mount Everest is tall and anything that lives there has to cope with cold water, crushingly high pressure and no sunlight. Seems quite alien but even here, life thrives such as the deep-sea crustacean Hirondellea Gigas – catchy name. 

Location of the Mariana Trench. Credit: Wikipedia Commons/Kmusser

Europa, one of the moon’s of Jupiter has an ice crust but this covers over a global ocean of liquid water.  The conditions deep down in the ocean of Europa might not be so very different from those at the bottom of the Mariana’s Trench so it is here that a glimmer of hope exists to find other life in the Solar System. Should it exist, getting to it is the tricky bit. It’s not just on Europa but Enceladus and even Mars may have water underneath ice shelves. Layers of ice up to a kilometre thick might exist so technology like SLUSH has been developed to overcome. 

Natural color image of Europa obtained by NASA’s Juno spacecraft. (Credit: NASA/JPL-Caltech/SwRI/MSSS/Kevin M. Gill)

The technology is not too new though since melt probes like SLUSH have been tested before. The idea is beautifully simple.  The thermo-mechanical probe uses a drilling mechanism to break through the ice and then the heat probe to partially melt the ice chips, forming slush to enable their transportation to behind the probe as it descends. 

The probe, which looks rather like a light sabre, is then able to transmit data from the subsurface water back to the lander. A tether system is used for the data transmission using conductive microfilaments and an optical fibre cable. Intriguingly and perhaps even cunningly, should the fibre cable break (which is a possibility due to tidal stresses from the ice) then the microfilaments will work as an antenna.  They can then be tuned into by the lander to resume data transmission. The tether is coiled up and housed inside spools which are left behind in the ice as the spool is emptied. I must confess my immediate thought here was ‘litter’! I accept we have to leave probes in order to explore but surely we can do it without leaving litter behind! However there is a reason for this too. As the spools are deployed, they act as receivers and transmitters to allow the radio frequencies to travel through the ice. 

The company working on the device is Honeybee Robotics have created prototypes. The first was stand alone, had no data transmission capability and demonstrated the drilling and slushing technology in an ice tower in Honeybee’s walk in freezer. While this was underway, the tether communication technology was being tested too with the first version called the Salmon Probe. This was taken to Devon Island in the Arctic where the unspooling method is being put through its paces. The first attempts back in 2022 saw the probe achieving depths of 1.8m! 

A further probe was developed called the Dolphin probe and this was capable of getting to depths of about 100m but sea ice limitations meant it could only get to a depth of 2m! Thus far, all probes have performed well. Honeybee are now working on the Narwhal Probe which will have more measuring equipment on board, a deployable tether and spool and will be far more like the finished product. If all goes to plan it will profile the ice on Devon Island to a depth of 100m.  This is still quite short of the kilometre thick ice expected but it is most definitely fantastic progress toward exploring the cold watery depths of alien worlds. 

Source : SLUSH: AN ICE DRILLING PROBE TO ACCESS OCEAN WORLDS

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It has often been likened to talcum powder. The ultra fine lunar surface material known as the regolith is crushed volcanic rock. For visitors to the surface of the Moon it can be a health hazard, causing wear and tear on astronauts and their equipment, but it has potential. The fine material may be suitable for building roads, landing pads and shelters. Researchers are now working to analyse its suitability for a number of different applications.

Back in the summer of 1969, Armstrong and Aldrin became the first visitors from Earth to set foot on the Moon. Now, 55 years on and their footprints are still there. The lack of weathering effects and the fine powdery material have held the footprints in perfect shape since the day they were formed. Once we – and I believe this will happen – establish lunar bases and even holidays to the Moon those footprints are likely still going to be there. 

There are many challenges to setting up permanent basis on the Moon, least of which is getting all the material there. I’ve been embarking on a fairly substantial home renovation over recent years and even getting bags of cement and blocks to site has proved a challenge. Whilst I live in South Norfolk in UK (which isn’t the easiest place to get to I accept) the Moon is even harder to get to. Transporting all the necessary materials over a quarter of a million kilometres of empty space is not going to be easy. Teams of engineers and scientists are looking at what materials can be acquired on site instead of transporting from Earth. 

The fine regolith has been getting a lot of attention for this very purpose and to that end, mineralogist Steven Jacobsen from the Northwestern University has been funded by NASAs Marshall Space Flight Centre to see what it back be used for. In addition NASA has partnered with ICON Technology, a robotics firm to explore lunar building technologies using resources found on the Moon. A key challenge with the lunar regolith though is that samples can vary considerably depending on where they are collected from. Jacobsen is trying to understand this to maximise construction potential. 

ICON were awarded the $57.2 million grant back in November 2022 to develop lunar construction methods. Work had already begun on space based construction, again from ICON in their Project Olympus. This didn’t just focus on the Moon though, Mars was also part of the vision to create construction techniques that could work wherever they were employed. 

Artist’s concept for a lunar base using construction robots and a form of 3D printing contour-crafitng.

3D printing may play a part in the lunar construction approach. It is already being used by ICON and others like them to build houses here on Earth. Employing 3D technology on the Moon using raw lunar material could be one solution. 

One of the first priorities would be to establish a suitable permanent landing area on the Moon. Without it, every time a lander arrives, the fine regolith will get kicked up and disturbed and may very well play havoc with other equipment in the vicinity. The particles can be quite sharp too so it may be quite abrasive on equipment. 

Source : Examining lunar soil for moon-based construction

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The Vera C. Rubin Observatory, formerly the Large Synoptic Survey Telescope (LSST), was formally proposed in 2001 to create an astronomical facility that could conduct deep-sky surveys using the latest technology. This includes a wide-field reflecting telescope with an 8.4-meter (~27.5-foot) primary mirror that relies on a novel three-mirror design (the Simonyi Survey Telescope) and a 3.2-megapixel Charge-Coupled Device (CCD) imaging camera (the LSST Camera). Once complete, Rubin will perform a 10-year survey of the southern sky known as the Legacy Survey of Space and Time (LSST).

While construction on the observatory itself did not begin until 2015, work began on the telescope’s digital cameras and primary mirror much sooner (in 2004 and 2007, respectively). After two decades of work, scientists and engineers at the Department of Energy’s (DOE) SLAC National Accelerator Laboratory and their collaborators announced the completion of the LSST Camera – the largest digital camera ever constructed. Once mounted on the Simonyi Survey Telescope, this camera will help researchers observe our Universe in unprecedented detail.

The Vera C. Rubin Observatory is jointly funded by the U.S. National Science Foundation (NSF) and the U.S. Department of Energy (DOE) and is cooperatively operated by NSF NOIRLab and SLAC. When Rubin begins its ten-year survey (scheduled for August 2025), it will help address some of the most pressing and enduring questions in astronomy and cosmology. These include understanding the nature of Dark Matter and Dark Energy, creating an inventory of the Solar System, mapping the Milky Way, and exploring the transient optical sky (i.e., objects that vary in location and brightness).

A schematic of the LSST Camera. Note the size comparison; the camera will be the size of a small SUV. Credit: Vera Rubin Observatory/DOE

The LSST Camera will assist these efforts by gathering an estimated 5,000 terabytes of new raw images and data annually. “With the completion of the unique LSST Camera at SLAC and its imminent integration with the rest of Rubin Observatory systems in Chile, we will soon start producing the greatest movie of all time and the most informative map of the night sky ever assembled,” said Željko Ivezic, an astronomy professor at the University of Washington and the Director of Rubin Observatory Construction in a NoirLab press release.

Measuring 1.65 x 3 meters (5.5 x 9.8 ft), with a front lens over 1.5 m (5 ft) across, the camera is about the size of a small SUV and weighs almost 2800 kg (6200 lbs). Its large-aperture, wide-field optical imaging capabilities can capture light from the near-ultraviolet (near-UV) to the near-infrared (NIR), or 0.3 – 1 micrometers (?m). But the camera’s greatest attribute is its ability to capture unprecedented detail over an unprecedented field of view. This will allow the Rubin Observatory to map the positions and measure the brightness of billions of stars, galaxies, and transient objects, creating a robust catalog that will fuel research for years.

Said Kathy Turner, the program manager for the DOE’s Cosmic Frontier Program, these images will help astronomers unlock the secrets of the Universe:

“And those secrets are increasingly important to reveal. More than ever before, expanding our understanding of fundamental physics requires looking farther out into the Universe. With the LSST Camera at its core, Rubin Observatory will delve deeper than ever before into the cosmos and help answer some of the hardest, most important questions in physics today.”

In particular, astronomers are looking forward to using the LSST Camera to search for signs of weak gravitational lensing. This phenomenon occurs when massive galaxies alter the curvature of spacetime around them, causing light from more distant background galaxies to become redirected and amplified. This technique allows astronomers to study the distribution of mass in the Universe and how this has changed over time. This is vital to determining the presence and influence of Dark Matter, the mysterious and invisible matter that makes up 85% of the total mass in the Universe.

Similarly, scientists also want to study the distribution of galaxies and how those have changed over time, enabling them to identify Dark Matter clusters and supernovae, which may help improve our understanding of Dark Matter and Dark Energy alike. Within our Solar System, astronomers will use the LSST Camera to create a more thorough consensus of small objects, including asteroids, planetoids, and Near-Earth Objects (NEO) that could pose a collision risk someday. It will also catalog the dozen or so interstellar objects (ISOs) that enter our Solar System every year.

This is an especially exciting prospect for scientists who hope to conduct rendezvous missions in the near future that will allow us to study them up close. Now that the LSST Camera is complete and has finished being tested at SLAC, it will be shipped to Cerro Pachón in Chile (where the Vera C. Rubin Observatory is being constructed) and integrated with the Simonyi Survey Telescope later this year. Said Bob Blum, Director for Operations for Vera C. Rubin Observatory:

“Rubin Observatory Operations is very excited to see this major milestone about to be completed by the construction team. Combined with the progress of coating the primary mirror, this brings us confidently and much closer to starting the Legacy Survey of Space and Time. It is happening.”

The LSST Camera was made possible thanks to the expertise and technology contributed by international partners. These include the Brookhaven National Laboratory, which built the camera’s digital sensor array; the Lawrence Livermore National Laboratory and its industrial partners, who designed and built the lenses; the National Institute of Nuclear and Particle Physics in France, which built the camera’s filter exchange system and contributed to the sensor and electronics design.

Further Reading: NoirLab

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