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On July 14th, 2015, the New Horizons probe made history by accomplishing the first flyby of Pluto and its largest satellite, Charon. The stunning images this mission took of these icy worlds have helped scientists address some of the key questions about Pluto and its massive moon, which have been shrouded in mystery for decades (owing to their great distance from Earth). One of the biggest mysteries that scientists have contemplated since Charon was first discovered in 1978 is how it came together with Pluto in the first place.

For decades, astronomers suspected that Pluto and Charon formed through a process similar to Earth and the Moon. This theory, known as the Giant Impact Hypothesis, states that roughly 4.5 billion years ago, primordial Earth was struck by a Mars-sized body named Theia. In a new study, a team of researchers from the University of Arizona challenged this assumption and offered an alternate theory known as “kiss and capture.” Their findings could help scientists better understand how planetary bodies in the outer Solar System form and evolve.

The study was led by Adeene Denton, a NASA postdoctoral fellow at the University of Arizona’s Lunar and Planetary Laboratory and the Southwest Research Institute (SwRI). She was joined by Erik Asphaug, a Planetary Science Professor in the School of Earth and Space Exploration (SESE) and the Lunar and Planetary Laboratory (LPL) at the University of Arizona; Robert Melikyan, an LPL Graduate Student, and Alexandre Emsenhuber, a Postdoctoral Researcher from the Space Research and Planetary Science (SRPS) at the University of Bern. The paper that describes their findings, “Capture of an Ancient Charon around Pluto,” was published in the journal Nature Geoscience. 

Previously, scientists believed that Pluto and Charon formed from a massive collision, similar to the Giant Impact Hypothesis. According to this theory, a Mars-sized planet named Theia collided with a primordial Earth roughly 4.5 billion years ago. This impact turned both bodies into molten debris that eventually coalesced to form the Earth and Moon, eventually settling into the Earth-Moon system. According to the team’s study, this theory does not fit when it comes to Pluto and Charon because it fails to take into account the structural strength of cold, icy worlds.

Using the University of Arizona’s high-performance computing cluster, the team conducted advanced impact simulations. This showed that when Pluto and a proto-Charon collided, they became temporarily stuck together and formed a single snowman-shaped object – not unlike Arrokoth, the first Kuiper Belt Object (KBO) that New Horizons surveyed on December 31st, 2018. Over time, they separated to become the binary system we observe there today. Said Denton in a U of A News story:

“Pluto and Charon are different – they’re smaller, colder and made primarily of rock and ice. When we accounted for the actual strength of these materials, we discovered something completely unexpected. Most planetary collision scenarios are classified as ‘hit and run’ or ‘graze and merge.’ What we’ve discovered is something entirely different – a ‘kiss and capture’ scenario where the bodies collide, stick together briefly, and then separate while remaining gravitationally bound.”

Their results also suggest that Pluto and Charon remained largely intact during their collision and retained much of their original composition. This challenges previous models that suggest that colliding bodies will exchange material during the impact. This is based on studies of the Apollo moonrocks, which indicated that the Earth and Moon are similar in composition, a finding that led scientists to conclude that the Earth-Moon system formed together. What’s more, their research offers a potential explanation for how Pluto may have developed an internal ocean.

View from the surface of Pluto, showing its large moon Charon in the distance. Credit: New York Times

The collision process, they state, combined with the tidal friction caused by the separation of Pluto and Charon, would have caused considerable internal heating for both bodies. This could have provided the necessary mechanism for creating a subsurface ocean, contrary to a previous theory where scientists have argued that Pluto formed during the very early Solar System when there were far more radioactive elements. However, scientists have expressed doubts about this theory because of the timing constraints it imposes.

Denton and her colleagues are now planning follow-up studies to explore several related questions about this system of icy bodies. This includes how tidal forces influenced Pluto and Charon’s early evolution when they were much closer together, how this formation scenario aligns with Pluto’s current geological features, and whether similar processes could explain the formation of other binary systems. Said Denton:

“We’re particularly interested in understanding how this initial configuration affects Pluto’s geological evolution. The heat from the impact and subsequent tidal forces could have played a crucial role in shaping the features we see on Pluto’s surface today.”

Further Reading: University of Arizona, Nature

The post Here's How Pluto and Charon Became a Bizarre Double Planet appeared first on Universe Today.

How old is the Moon? Astronaut-gathered samples from the lunar surface put its age at about 4.35 billion years. However, other evidence suggests it’s much older, around 4.53 billion years old. A team of scientists published a recent paper that suggests the Moon’s surface age was “reset” in a melting event.

The generally accepted theory about the Moon’s formation goes like this: about 4.5 billion years ago and about 200 million years after the solar system began to form, something happened. A single Mars-sized object named Theia (or possibly a series of objects) collided with or was somehow captured by infant Earth. That tumultuous crash sent a lot of molten rock and debris into space. Eventually, most of it coalesced to form the infant Moon, which settled into orbit around Earth. Debris from the inner solar system bombarded the pair for millions of years thereafter.

Fast-forward to the present day, where we can study rocks collected from the lunar surface during the Apollo missions. Scientists analyzed those samples and found them to be about 4.35 billion years old. That suggests the Moon is NOT 4.53 billion years old. Which is true? It turns out there’s strong evidence for an older Moon. It exists in some zircon minerals on the lunar surface. They’re at least 4.51 billion years old. thermal models and simulations also suggest a lunar age somewhere between 4.43 and 4.53 billion years. So, why are lunar surface rocks almost 200 million years younger?

Dating the Moon

As it turns out, both numbers could be true. The Moon could have formed very early, but it experienced something that changed its geological clock. According to UC Santa Cruz professor Francis Nimmo and a team of researchers, the Moon likely did form 4.51 million years ago in that catastrophic collision with baby Earth. But, 180 million years later, it may have experienced a “remelting”. That reset the ages of lunar rocks to around 4.35 billion years. That’s why the surface samples collected by the Apollo astronauts show a younger age.

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

“We predict that there shouldn’t be any lunar rocks that are older than 4.35 billion years because they should have experienced the same resetting,” said Nimmo. “Because this heating event was global, you shouldn’t find rocks anywhere on the Moon that are significantly older than that.”

Nimmo and his colleagues suggest that a global remelt of lunar rocks could account for the existence of younger surface rocks. The Apollo rocks suggest something happened, and the return of rocks from China’s Chang’e 6 mission could offer more evidence for that theory. For their paper, the authors used modeling to show that the Moon may have experienced sufficient tidal heating to cause this remelting approximately 4.35 billion years ago, which could “reset” the apparent formation age of these lunar samples.

Chang’e-6 lander on the lunar surface, as seen by a mini-rover nearby. (Credit: CLEP / CNSA) Modeling a Lunar Surface Reset

What could cause a global melting strong enough to reset the age of the Moon’s rocks? Nimmo suggest that the Moon experienced tidal heating due to the evolution of its orbit around Earth. This happened because the Moon was closer to Earth, and the orbit was pretty unstable during certain epochs. Thanks to the immense tidal pull from Earth, the Moon could have been heated, which led to the alteration of its geology and the “age reset” of its rocks.

It turns out that the Moon isn’t the only place in the solar system where this could happen. The volcanic moon Io in orbit around Jupiter experiences the same type of tidal attraction as it orbits. That helps explain Io’s extensive volcanic activity and surface “paving” by the frequent eruptions from its volcanic features. It also explains why we don’t see widespread craters on Io.

If the same thing happened to the infant Moon after its original formation, cooldown, and subsequent bombardment, we wouldn’t see any of its original craters. They’d have been covered by subsequent eruption and melting when the Moon’s orbit was stabilizing.

Why is the Lunar Surface Age Important?

The formation and evolution of the solar system and its many different bodies is still a hot area of study. Among other things, scientists want to understand the timing of events that shaped solar system objects. For that, they need a better understanding of the geology of each object. More data leads to better models of every aspect of solar system formation—from the first “push” in the protosolar nebula to such events as collisions, tidal heating, orbital dynamics, and surface evolution of different worlds. That’s where planetary science missions come in handy. They provide “in situ” data about each world (or object, in the case of asteroids, moons, comets, and rings), and they fill in gaps in the history of each place.

“As more data becomes available—particularly from ongoing and future lunar missions—the understanding of the Moon’s past will continue to evolve,” Nimmo said. “We hope that our findings will spark further discussion and exploration, ultimately leading to a clearer picture of the Moon’s place in the broader history of our solar system.”

For More Information

A “Remelting” of Lunar Surface Adds a Wrinkle to Mystery of Moon’s True Age
Tidally Driven Remelting Around 4.35 billion Years Ago Indicates the Moon is Old
Moon Formation

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Months after deciding that its previous plan for bringing samples back from Mars wasn’t going to work, NASA says it’s working out the details for two new sample return scenarios, with the aim of bringing 30 titanium tubes filled with Martian rocks and soil back to Earth in the 2030s.

One scenario calls for using a beefed-up version of NASA’s sky crane to drop the required hardware onto the Red Planet’s surface, while the other would use heavy-lift commercial capabilities provided by the likes of SpaceX or Blue Origin.

NASA Administrator Bill Nelson said the space agency plans to flesh out the engineering details for each option over the course of the next year and make its choice in 2026. But that all depends on what Congress and President-elect Donald Trump’s administration want to do.

An artist’s conception shows NASA’s sky crane system lowering a rover onto the Martian surface. One option calls for a similar system to be used to put a sample retrieval platform on Mars. (NASA Illustration / Ashwin R. Vasavada)

Nelson noted that China is planning to launch a Mars sample return mission in 2028.

“I don’t think we want the only sample return coming back on the Chinese spacecraft, and that’s just simply a grab-and-go kind of mission, whereas ours has been a very methodical process. … I think that the administration will certainly conclude that they want to proceed, so what we wanted to do was to give them the best possible options so that they can go from here,” he told reporters.

For years, NASA has been working on a plan that started out with the collection and caching of samples by the Perseverance rover in Mars’ Jezero Crater, which is considered prime territory for harboring potential evidence of ancient life. Those samples would have been gathered up and brought to a sample retrieval platform, where they would have been sent into Martian orbit on a rocket known as the Mars Ascent Vehicle. The samples would be transferred to a Mars orbiter built by the European Space Agency. That orbiter would then deliver the samples back to Earth for laboratory study.

It was a complex plan, and last year, NASA determined that the operation would have taken until 2040 to get the samples back, with a price tag of $11 billion. “That was just simply unacceptable,” Nelson said.

NASA asked its experts as well as commercial space ventures to come up with ideas for lowering the cost and speeding up the schedule, which resulted in the two options presented today.

The sky crane option would build upon the technology that used a rocket-powered, free-flying platform to lower NASA’s Curiosity and Perseverance rovers to the Martian surface. “You’re looking at cost in the range of $6.6 billion to $7.7 billion,” Nelson said.

The estimated price tag for the commercial heavy-lift option is in the range of $5.8 billion to $7.1 billion. “You all know that SpaceX and Blue Origin have already been ones that have expressed an interest, but it could be others as well, and a team is evaluating and researching all industry capability to include the schedule and the budget to determine the best strategy going forward,” Nelson said.

Both options would use many of the same elements proposed under the previous plan, but would trim costs by using a smaller Mars Ascent Vehicle as well as a simpler design for the sample retrieval platform, powered by a radioisotope thermoelectric generator rather than solar panels. The samples would be brought back from Mars and sent down to Earth by ESA’s Earth Return Orbiter. NASA said ESA is currently evaluating the options proposed by NASA.

The newly proposed schedule could lead to launches in the 2030-31 time frame, and delivery of the samples by as early as 2035. “But it could go out to 2039,” Nelson said. “Now, a good reason for why it could get extended out is if the Congress and the new administration do not respond.”

Nelson said Congress would have to commit at least $300 million during the current fiscal year to keep the Mars sample return campaign on track. “If they want to get this thing back on a direct return earlier, they’re going to have to put more money into it, even more than $300 million in fiscal year ’25, and that would be the case every year going forward,” he said.

Trump has been bullish on Mars exploration, in part due to the influence of SpaceX founder Elon Musk. So bullish, in fact, that Trump wants to have astronauts on the Red Planet by 2028, potentially forcing another overhaul of the Mars sample return campaign.

“We will reach Mars before the end of my term,” Trump said during a campaign rally last October. “Elon promised me he was going to do that. … He told me that we’re going to win, and he’s going to reach Mars by the end of our term, which is a big thing. Before China, before anybody.”

The post NASA Lays Out Two New Options for Mars Sample Return appeared first on Universe Today.

The long-awaited detection of gravitational waves has opened up a whole new world of astronomy. One of the key efforts is now to tie signals across multiple domains – for example, a gravitational wave and the associated electromagnetic radiation created by that same event, such as a black hole merger or a gamma-ray burst. We’ll need new equipment to detect such “multimodal” signals, especially electromagnetic ones. One such project is the Black Hole Coded Aperture Telescope (BlackCAT), which will be launched early this year by a team led by researchers at Penn State. 

BlackCAT is designed to replace aging equipment already capturing high energy emissions, such as X-rays, in space. Swift and Fermi, two leading such telescopes, will be at least 10 years over their expected design lifetimes when a series of new gravitational wave detectors come online. Their aging capabilities limit their usefulness in finding the electromagnetic analog of the once-weekly gravitational wave events that those new detectors hope to find.

Enter BlackCAT, a mission concept initially proposed in 2019. It is designed as a 6U Cubesat with one particular detector for “soft” X-ray detection. Soft X-rays are the lower-energy versions of “hard” X-rays typically used in X-ray astronomy. However, they have the added advantage of being easier to detect. They are also easier to isolate to a specific location in the sky, which is essential when mapping a particular EM signal to the source of a gravitational wave event.

Fraser discusses the shutdown of Chandra – a previous X-Ray telescope.

To detect those lower-energy X-rays, BlackCAT has two tools in its toolbox—an array of CMOS X-ray cameras and a coded mask imager. The array of cameras, which includes four separate cameras, is called “Speedster-EXD.” It is specifically designed to react quickly to signals but only measures about 2.2 cm2 in size. However, it is still capable of producing a 550×550 pixel image. These cameras have been tested on the ground and have shown sensitivity to the wavelengths of X-rays the mission is designed for.

The coded aperture mask that helps give BlackCAT its name is a tool used to provide a wide field of view for the sensor without needing a focal point – which is hard to design for X-rays that ignore typical focusing devices like lenses and mirrors. Instead, the aperture is a plate designed with a pattern of “open” and “closed” areas that produce shadows on the detector. A computer program can then recreate the original image based on the pattern of shadows that fall across the detector.

This combination of the broad field of view with a highly sensitive X-ray detector seemed right up NASA’s alley, as they funded the project in 2021 to the tune of $5.8M. The detector will interface with an off-the-shelf 6U CubeSat provided by Clyde Space, which includes standardized power, control, and attitude adjustment systems – acting like a platform for the detector. 

Fraser discusses GRBs, one of the things BlackCAT is designed to detect.

PSU’s research team is likely in the final touches of integrating with a launch vehicle, and the plan is to launch BlackCAT early this year. When it gets up there, it can open up a whole new world in X-ray astronomy for a surprisingly low cost. Hopefully, it will show how much can be accomplished by simple, expensive, but very focused CubeSat missions.

Learn More:
Chattopadhyay et al – BlackCAT CubeSat: A Soft X-ray Sky Monitor, Transient Finder, and Burst Detector for High-energy and Multimessenger Astrophysics
Colosimo et al – Current status of the BlackCAT CubeSat
UT – SpIRIT CubeSat Demonstrates a Operational Gamma and X-Ray Detector
UT – A Collection of New Images Reveal X-Rays Across the Universe

Lead Image:
Models of the coded aperture (left) and the BlackCAT Cubesat as a whole (right.
Credit – Colosimo et al.

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When it comes to exploring our planetary neighbours, Mars tends to get a lot of the attention. For one thing its easier to explore as the environment is far less hostile than other planets but it also offers the tantalising possibility of finding evidence of primitive life, past or present! Venus however is still a fascinating world and perhaps one that gives us a glimpse into our future if we don’t do something to check global warming. A team of scientists are proposing an official Venus Exploration Program for NASA similar to the existing Mars program. 

Venus is the second planet from the Sun and has often been referred to as Earth’s twin! This is chiefly due to its similar size and composition however, despite these similarities, Venus and Earth are worlds apart! Its thick carbon dioxide atmosphere traps heat causing the surface temperature to rocket to just under 500 degrees. It’s surface is hidden beneath thick clouds of sulfuric acid, and its atmospheric pressure is about 90 times that of Earth’s. There is no doubt, Venus is not somewhere you would want to go on your cosmic holidays. Despite all of this, and despite the challenges, Venus does remain a fascinating place to study.

Venus

Following a recommendation that NASA should develop scientific exploration strategies as it has for Mars; VEXAG, the Venus Exploration Analysis Group, was established. This community-driven initiative has been established by NASA to facilitate and provide scientific and mission support and planning to the exploration of one of our nearest planetary neighbours. VEXAG is composed of researchers, planners and engineers whose goal is to assess various scientific objectives to inform NASAs future mission to Venus. 

Radar image of Venus created by the Solar System Visualization project and the Magellan science team at the JPL Multimission Image Processing Laboratory. This is a single frame from a video released at the October 29, 1991, JPL news conference. (Credit: NASA/JPL)

The VEXAG mission to develop a new Venus exploration strategy by reflecting upon the 2021 selections of the VERITAS (an orbiter designed to reveal how the paths of Venus and Earth diverged, and how Venus lost its potential as a habitable world,) DAVINCI (to explore whether the inhospitable surface of Venus could once have been a twin of Earth,) and EnVision (studying atmosphere of Venus) missions. 

Illustration of NASA’s DAVINCI probe falling to the surface of Venus. (Credit: NASA GSFC visualization by CI Labs Michael Lentz and others)

There are still lots of unanswered questions surrounding Venus from how it loses heat to  how geologically active it is and how has the atmosphere evolved over time. These and other questions are the focus of the exploration strategy and it is the VEXAG objective to look at the scientific, technological and programmatic advances required to address them. 

The report is comprehensive and offers a much needed assessment of the exploration of Venus. The existing slated and previously highlighted missions to Venus will likely launch during the early part of the next decade provide for an opportunity to address some of the outstanding questions. 

It will take some months before the measurements provide the much needed insight however additional missions are needed to address all of the remaining questions. It is now down to organisations like NASA and its international peers to take the next step to develop a new strategy for the exploration of Venus. 

Source : A New Strategy for the Exploration of Venus

The post Venus is Important. We Should Take its Exploration Seriously. appeared first on Universe Today.

I’ve used this fact a gazillion times; every atom in your body has been through the core of a star! The carbon in our bones formed through fusion like many other elements and was thrown out into space to seed the cosmos with the elements for life. A team of researchers have been exploring this journey, tracking a giant conveyor belt that surrounds the Galaxy and the results are surprising. 

Carbon is one of the fundamental elements inside our bodies. The first elements that appeared after the Universe formed 13.7 billion years ago was mostly hydrogen and a little helium.  The carbon in our bodies has been synthesised inside stars in a process known as nucleosynthesis. 

As stars evolve, they undergo a series of fusion reactions fusing hydrogen atoms into helium, then helium nuclei into carbon. Three helium-4 atoms combine to create an atom of carbon-12. Temperatures of around 100 million kelvin are needed for this process and, as it progresses, an outward pushing force known as the thermonuclear force is generated. During the main part of a stars life, this is balanced by the inward force of gravity. 

This is an artist’s concept of the early stages of the young star FU Orionis (FU Ori) outburst, surrounded by a disk of material. A team of astronomers has used the Hubble Space Telescope’s ultraviolet capabilities to learn more about the interaction between FU Ori’s stellar surface and the accretion disk that has been dumping gas onto the growing star for nearly 90 years. NASA-JPL, Caltech

At a point in the evolution of the star which is determined by its mass, the material that composes the star is ejected out into space through a planetary nebula or supernova explosion. Ultimately these heavier elements find their way to new stellar nurseries where the next generation of stars and even planets and life may form. 

This colorful web of wispy gas filaments is the Vela Supernova Remnant, an expanding nebula of cosmic debris left over from a massive star that exploded about 11,000 years ago. This image was taken with the Department of Energy-fabricated Dark Energy Camera (DECam), mounted on the US National Science Foundation’s Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory in Chile, a Program of NSF’s NOIRLab. The striking reds, yellows, and blues in this image were achieved through the use of three DECam filters that each collect a specific color of light. Separate images were taken in each filter and then stacked on top of each other to produce this high-resolution image that contains 1.3 gigapixels and showcases the intricate web-like filaments snaking throughout the expanding cloud of gas.

Scientists from the United States and Canada have shown in their latest research that the liberated carbon atoms don’t just drift aimlessly through space until they find their new home. Instead, their studies reveal that in galaxies like the Milky Way where star formation is still underway, the atoms take a less direct route. Giant currents known as the circumgalactic medium circle the galaxy and extend out into intergalactic space. The currents drag the newly ejected stellar material out and draw it back in to the interior of the galaxy where it forms new stars. 

The Milky Way. This image is constructed from data from the ESA’s Gaia mission that’s mapping over one billion of the galaxy’s stars. Image Credit: ESA/Gaia/DPAC

To reach this conclusion, the team used the Cosmic Origins Spectrograph on the Hubble Space Telescope. This instrument enabled the study of the ultraviolet radiation in detail from nine distant quasars. They explored how they were effected by circumgalactic medium of 11 other galaxies that had active star forming regions. The results showed the absorption of light by carbon. One galaxy showed carbon caught up in the current extending to a distance of nearly 400,000 light years. To put that into context that is around four times the diameter of our own Milky Way Galaxy! 

This image of NASA’s Hubble Space Telescope was taken on May 19, 2009 after deployment during Servicing Mission 4. NASA

It’s quite an eye opening discovery and certainly repaints the picture of stellar evolution. Instead of the gentle drifting through space of elements ejected from stars, the journey is far more tumultuous. As always though, more research is needed to fully understand the circumgalactic medium and to understand its impact on stellar formation. Not only will we get a better understanding of the lives of stars but how galaxies evolve too and why some host active star formation and others are stellar deserts. 

Source : The carbon in our bodies probably left the galaxy and came back on cosmic ‘conveyer belt’

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Nature is filled with examples of extreme life (aka. extremophiles), which are so-called because they can withstand extreme conditions. These include organisms that can survive in extremely dry conditions, extreme temperatures, acidity, pressure, and even the vacuum of space. The study of these organisms not only helps scientists learn more about the kinds of environments life can survive (and even thrive) in. It also helps astrobiologists to speculate about possible life in the Universe. Perhaps the name “tardigrades” (aka. “water bears”) rings a bell, those little creatures that could survive in interstellar space?

Then you have Deinococcus radiodurans (D. radiodurans), which microbiologists call “Conan the Bacterium” due to its ability to tolerate the harshest conditions. This includes radiation doses thousands of times higher than what would kill a human, or any other organism on Earth, for that matter. In a new study, a team of researchers from Northwestern University and the Uniformed Services University (USU) characterized a synthetic organism inspired by Deinococcus radiodurans that could allow humans to withstand the elevated radiation levels in deep space, on the Moon, and Mars.

The research was led by Hao Yang, a Research Assistant Professor at Northwestern University’s Department of Chemistry. He was joined by Ajay Sharma, also a Research Assistant Professor of Chemistry at Northwestern; Michael J. Daly, a Professor of Pathology at the Uniformed Services University (USU); and Brian M. Hoffman, the Charles E. and Emma H. Morrison Professor of Chemistry and molecular biosciences at Northwestern. The paper detailing their findings appeared on November 8th in the Proceedings of the National Academy of Sciences (PNAS).

Image of the Martian atmosphere and surface obtained by the Viking 1 orbiter in June 1976. (Credit: NASA/Viking 1)

Hoffman is the Charles E. and Emma H. Morrison Professor of Chemistry and professor of molecular biosciences and a member of the Chemistry of Life Processes Institute and the Robert H. Lurie Comprehensive Cancer Center at Northwestern University. Daly, an expert on Deinococcus radiodurans, is also a member of the National Academies’ Committee on Planetary Protection. In a previous study, Hoffman and Daly investigated D. radiodurans‘ ability to withstand radiation on Mars. Earlier research has shown that the bacterium can survive 25,000 grays, which is five times the lethal dose for a human.

However, Hoffman and Daly found that D. radiodurans could withstand 140,000 grays when dried or frozen – 28,000 times the lethal dose for a human! This means that frozen microbes beneath the surface of Mars could survive the cosmic and solar radiation the planet is exposed to on a daily basis. The key to its resistance, they determined, is simple metabolites that combine with manganese to form a powerful antioxidant. They also found that the radiation dose a microorganism can survive is directly related to the amount of manganese antioxidants it contains.

In this latest study, the research team describes a synthetic designer antioxidant (MDP) inspired by D. radiodurans that is much more effective at resisting radiation. Building on their previous efforts, Hoffman and Daly’s team investigated a designer decapeptide (DP1) that, when combined with phosphate and manganese, forms the free-radical-scavenging agent MDP, which is even better at protecting against radiation damage than D. radiodurans. As Hoffman explained in a Northwestern Now news release:

“It is this ternary complex that is MDP’s superb shield against the effects of radiation. We’ve long known that manganese ions and phosphate together make a strong antioxidant, but discovering and understanding the ‘magic’ potency provided by the addition of the third component is a breakthrough. This study has provided the key to understanding why this combination is such a powerful — and promising — radioprotectant.”

An artist’s concept of Mars explorers and their habitat on the Red Planet. Courtesy NASA

“This new understanding of MDP could lead to the development of even more potent manganese-based antioxidants for applications in health care, industry, defense, and space exploration,” said Daly. Potential applications include synthetic antioxidants that could help protect astronauts from radiation during long-duration missions to deep space. In another study, Daly and his collaborators found MDP is effective in preparing irradiated polyvalent vaccines. This could also have applications for space medicine, ensuring that vaccines typically rendered inactive by radiation remain effective.

Further Reading: Northwestern Now, PNAS

The post This Superbacteria can Withstand Enough Radiation to Kill a Person appeared first on Universe Today.

In the last couple of decades, it’s become increasingly clear that massive galaxies like our own Milky Way host supermassive black holes (SMBHs) in their centres. How they became so massive and how they affect their surroundings are active questions in astronomy. Astronomers working with the James Webb Space Telescope have discovered an SMBH in the early Universe that is accreting mass at a very low rate, even though the black hole is extremely massive compared to its host galaxy.

What’s going on with this SMBH, and what does it tell astronomers about the growth of these gargantuan black holes?

The black hole, named GN-1001830, was discovered as part of JADES (JWST Advanced Deep Extragalactic Survey). It is one of the most massive SMBHs discovered by the JWST in the early Universe. While most present-day SMBHs account for about 0.1 % of the mass of their host galaxies, this one accounts for about 40% of its host galaxy’s mass.

The puzzling thing is that GN-1001830 is consuming the gas it needs to grow at a very low rate and is basically dormant. Is it taking a break? Did it experience accelerated bursts of growth in the past?

The findings are in new research published in Nature titled “A dormant overmassive black hole in the early Universe.” The lead author is Ignas Juodžbalis. Juodžbalis is a grad student at the Kavli Institute for Cosmology at the University of Cambridge.

“The early universe managed to produce some absolute monsters, even in relatively tiny galaxies.”

Ignas Juodžbalis, Kavli Institute for Cosmology, University of Cambridge

The JWST has found many SMBHs already in place, only a few hundred million years after the Big Bang. Some of them are overmassive yet dormant, like GN-1001830. Researchers have developed multiple different models to explain them.

This image shows the JWST Advanced Deep Extragalactic Survey (JADES) region of study. It’s in the same region as the Hubble’s Ultra Deep Field. Image Credit:

One model is the ‘heavy seed‘ model, where primordial gas clouds directly collapsed into black holes that grew to become SMBHs. Another model proposes light seeds that experience powerful bursts of accretion. Both models hold promise, but there’s no certainty. “Yet, current datasets are unable to differentiate between these various scenarios,” Juodžbalis and his co-authors write in their research article.

These overmassive black holes that appear to be dormant are testing astrophysicists’ understanding of how SMBHs form and grow. It’s likely that they go through bursts of growth, and in between those bursts, they lie dormant. One of the problems is that it’s very difficult to spot an SMBH that isn’t actively accreting gas. They’re visible when accreting because the accretion disk heats up and emits light.

This one was only spotted because it’s so massive.

“Even though this black hole is dormant, its enormous size made it possible for us to detect,” said lead author Juodžbalis. “Its dormant state allowed us to learn about the mass of the host galaxy as well. The early universe managed to produce some absolute monsters, even in relatively tiny galaxies.”

The Eddington Limit (also known as Eddington Luminosity) is an important factor in the growth of SMBHs. It is a theoretical upper limit on the mass and luminosity of stellar objects, explaining the luminosity we observe in accreting black holes. The Eddington limit is reached when the outward pressure of radiation exceeds the object’s gravitational power, and it can’t accrete more matter. Objects can also exceed this limit, and when that happens, it’s called Super Eddington accretion. Some researchers suggest that Super Eddington accretion was more common in the early Universe and that it explains not only this overmassive black hole but all of the other massive black holes the JWST has discovered in the Universe’s early times.

“It’s possible that black holes are ‘born big’, which could explain why Webb has spotted huge black holes in the early universe,” said co-author Professor Roberto Maiolino from the Kavli Institute and Cambridge’s Cavendish Laboratory. “But another possibility is they go through periods of hyperactivity, followed by long periods of dormancy.”

“It’s likely that the vast majority of black holes out there are in this dormant state.”

Professor Roberto Maiolino, Kavli Institute and Cambridge’s Cavendish Laboratory

The research is based on the detection of broad H-alpha emissions from the SMBH. Those emissions showed that the overmassive black hole has an estimated mass of approximately 4 × 10? (40 million) solar masses. That’s extremely massive for an object only about 800 million years after the Big Bang. For comparison, Sagittarius A*, the SMBH in the Milky Way, has an estimated mass of about 4.3 million solar masses.

The SMBH in question is one of the most overmassive objects the JWST has found. Its mass is almost 50% of the stellar mass of its host galaxy. That’s about 1,000 times more massive than the relation in local galaxies.

The researchers conducted computer simulations to probe the issue. Their research suggests that the SMBH’s periods of hyperactivity likely exceed the Eddington Limit. The SMBH’s long periods of dormancy and inactivity can last for 100 million years, where the accretion rate is only 0.02 times the Eddington Limit, and are punctuated by episodes of Super Eddington accretion that last for about five or ten million years.

“It sounds counterintuitive to explain a dormant black hole with periods of hyperactivity, but these short bursts allow it to grow quickly while spending most of its time napping,” said Maiolino.

Since these SMBHs spend far more time dormant than they do active, they’re more likely to be spotted during dormancy. However, they’re far more difficult to spot when they’re not actively accreting and emitting radiation from their accretion rings. That’s part of what makes this detection so valuable.

These results are agnostic when it comes to heavy or light seeds. Instead, they’re all about Super Eddington episodes. “It is tempting to speculate that our result favours light seed models. However, the same result would also hold if the models had started with heavy seeds. The key feature that allows the properties of GN-1001830 to be matched is the fact that accretion goes through super-Eddington phases, regardless of the seeding mechanism,” the authors explain.

This set of illustrations explains how a large black hole can form from the direct collapse of a massive cloud of gas a few hundred million years after the Big Bang. Panel #1 shows a massive gas cloud and a galaxy moving towards each other. If the formation of stars in the gas cloud is stalled by radiation from the incoming galaxy – preventing it from forming a new galaxy — the gas can instead be driven to collapse and form a disk and black hole. Panels #2 and #3 show the beginning of this gas collapse in the center of the cloud. A small black hole forms in the center of the disk (panel #4), and the black hole and disk then continue to grow (panel #5). This massive black hole “seed” and its disk then merge with the galaxy shown in panel #1. For a period of time, the black hole is unusually massive compared to the mass of the stars in the galaxy, making it an Overmassive Black Hole (panel #6). Stars and gas from the galaxy are pulled in by the black hole, causing the black hole and disk to grow even larger. Image Credit: NASA/STScI/Lea Hustak

“This was the first result I had as part of my PhD, and it took me a little while to appreciate just how remarkable it was,” said Juodžbalis. “It wasn’t until I started speaking with my colleagues on the theoretical side of astronomy that I was able to see the true significance of this black hole.”

“It’s likely that the vast majority of black holes out there are in this dormant state—I’m surprised we found this one—but I’m excited to think that there are so many more we could find,” said Maiolino.

The post An Early Supermassive Black Hole Took a Little Break Between Feasts appeared first on Universe Today.

Comet C/2024 G3 ATLAS may put on a quick show this month.

Comet G3 ATLAS on December 30th. Credit: Alan C. Tough

What ‘may’ be the best anticipated comet of 2025 is coming right up. Right now, there’s only one comet with real potential to reach naked eye visibility in 2025: Comet C/2024 G3 ATLAS. This comet reaches perihelion at 0.094 Astronomical Units (AU, 8.7 million miles or 14 million kilometers, interior to the orbit of Mercury) from the Sun on January 13th, and ‘may’ top -1st magnitude or brighter. At magnitude +4 in late December, Comet G3 ATLAS could become a fine object low in the dawn sky for southern hemisphere observers… if (a big ‘if) it holds together and performs as expected.

The comet actually produced an outburst over the first weekend of 2025, jumping from magnitude +4 to +1 (a sixteen-fold increase in brightness in a few short days). This could be a harbinger for good (or bad) things to come shortly.

“The comet has had an outburst in the last few days,” Nicolas Lefaudeux told Universe Today. “If the outburst is linked to disintegration, there would probably be nothing to see after perihelion. If the outburst is linked to new active areas or splitting of a large nucleus, the display could be much better than in the simulations.”

The prospects for the tail of Comet G3 ATLAS, around perihelion. Credit: Nicolas Lefaudeux

A recent International Astronomical Union Central Bureau for Astronomical Telegrams message suggests an optimistic peak of -3rd magnitude near perihelion post outburst, ‘if’ the comet holds together.

Comet G3 ATLAS low at dawn versus Mercury on January 11th. Credit: Starry Night. The Discovery

The comet was discovered by the Asteroid Terrestrial-Impact Last Alert System (ATLAS) survey as a +19th magnitude object in the southern hemisphere constellation Apus the Bee on the night of April 5th, 2024.

The orbital path for Comet G3 ATLAS through the inner solar system. Credit: NASA/JPL

The orbital period for this one is around 160,000 years. It’s unclear if Comet G3 ATLAS is a first-time visitor to the inner solar system, or a new denizen coming from the distant Oort Cloud. The last time the comet swung by the inner solar system (assuming it has done so in the past), wearing clothing was the hot new thing among our homo sapiens ancestors.

Comet G3 ATLAS from January 2nd. Credit: iTelescope/Tara Prystavski. Comet G3 at Perihelion: Perish or Prosper?

Prospects for seeing this comet will be tricky. Unlike last year’s Comet C/2023 A3 Tsuchinshan-ATLAS which unfurled a magnificent tail for its evening apparition, G3 ATLAS will be a timid one both before and after perihelion, as it departs our solar neighborhood hugging the southern horizon in the dusk sky.

Comet G3 ATLAS, post perihelion on January 15th at dusk. Credit: Starry Night.

A daytime comet could be in the offing if G3 ATLAS over-performs at perihelion… but it will be a challenging view, very near the Sun. Be sure to block the dangerous glare of the Sun fully out of view behind a building or structure if you attempt to spot the comet in daylight. Like A3 T-ATLAS, the joint NASA/ESA SOHO observatory will see the comet near perihelion crossing through its LASCO C3 viewer.

Comet G3 ATLAS versus SOHO through the month of January. Credit: Starry Night. Best Bets For Comet G3 ATLAS

Perihelion on Monday, January 13th, 2025 will see the comet just four degrees from the Sun. The comet also makes its closest approach to Earth at 0.938 AU distant on the same date. The comet ‘could’ reach -4th magnitude (about as bright as Venus) around the same time… if it manages to hold together at perihelion.

Here’s a recent remote telescope image of the comet taken from late December by Nick James:

Comet G3 ATLAS from December 15th. Credit: Nick James/BAA Comet Section/iTelescope.

Comet G3 ATLAS has been elusive thus far. The comet has been bashful, skimming just five degrees above the dawn horizon leading up to perihelion in early January for northern hemisphere observers. The comet reemerges low to the west after dusk, but again, folks up north only get a very brief view 5-10 degrees above the horizon at dusk, as the comet runs parallel with the horizon southward. As usually seems to be the case with comets, the southern hemisphere gets the better view.

Here’s a blow-by-blow of what to expect in the coming months from the comet. (Note that ‘passes near,’ denotes a conjunction of a degree or less):

January

6-Near the Lagoon Nebula (Messier 8)

7-Near the globular cluster (Messier 28)

8-Crosses the ecliptic plane northward

11-Enters SOHO LASCO C3 view

13-At perihelion, less than 5 degrees from the Sun

14-Crosses into the constellation Capricornus

15-Exits SOHO LASCO C3 view, and crosses the ecliptic plane southward

21-Nicks the corner of the constellation Microscopium

22-Crosses into the constellation Piscis Austrinus

The light curve for comet G3 ATLAS. Adapted from Seichii Yoshida’s Weekly Information About Bright Comets. February

1-May drop back down below +6th magnitude

6-Crosses into the constellation Grus

21-Nicks the corner of the constellation Sculptor

25-Crosses into the constellation Phoenix

March

March 1st: May drop back down below +10th magnitude.

Observing and imaging the comet will be challenging, owing to two main factors: first, it will never really leave the low-contrast, twilight sky for northern hemisphere observers. Second, said quoted magnitude for a comet gets ‘smeared out’ over its apparent surface area, knocking the comet’s apparent brightness down a notch or two. We can hope that Comet G3 ATLAS is an over-performer in this regard. My strategy is to find high ground to observe from and the lowest, flattest horizon (like, say, the ocean as seen from a beach) that you can find, and sweep the horizon at low power with binoculars for the fuzzball of a comet.

Good luck and clear skies on this, the first comet quest of 2025.

The post Will Comet G3 ATLAS Perform at Perihelion? appeared first on Universe Today.

One powerful way to study the galaxies is to study individual stars. By looking at the ages, types, and distribution of stars in the Milky Way, we’ve captured a detailed snapshot of how our galaxy formed and evolved. The only problem with this approach is that we can only do this for a handful of galaxies. Even with the most powerful telescopes, we can only see individual stars in the Milky Way and nearby galaxies such as Andromeda. For galaxies billions of light years away, individual stars blur together, and the best we can do is observe the overall spectra of galaxies, not individual stars. But thanks to a chance alignment, we can now observe dozens of stars in a galaxy so distant we see it at a time when the Universe was half its present age.

The results are published in Nature Astronomy, and they focus on JWST observations of a cluster of galaxies known as Abell 370. This galactic cluster is famous because it acts as a gravitational lens for more distant galaxies behind it. You can see them as arcs of light in the image above. One prominent arc, highlighted in the image, is known as The Dragon. It is made up of the lensed and magnified images of several galaxies, the light of which has traveled 5 to 7 billion years to reach us.

The Dragon has been studied before using observations from the Hubble Space Telescope, and from these studies astronomers have been able to see a handful of blue supergiant stars, which are the largest and brightest main sequence stars. But identifying individual stars is notoriously difficult. In this new study, the team used JWST observations of The Dragon from 2022 and 2023. Since the Webb is capable of capturing high-resolution images in the infrared, it’s perfectly suited to study the spectra of redshifted stars in the cosmic middle age.

Individual stars identified in the Dragon arc in 2022 and 2023. Credit: Yoshinobu Fudamoto, et al

But even the Webb would be hard-pressed to identify more than a few bright stars within The Dragon, were it not for a second effect of gravitational lensing known as microlensing. Within the distant galaxy, two stars can line up just so, and the more distant star is gravitationally magnified for a short time, like a flare. This allows astronomers to study the spectra of the distant star. So a galaxy from 7 billion years ago is lensed into a bright arc of light by the Abell 370 cluster, and within that galaxy stars are further microlensed by a stellar alignment.

The team was able to identify more than 40 microlensing events, and was therefore able to capture the spectra of more than 40 individual stars in the distant galaxy. Based on the spectra, these stars are red supergiants similar to Betelgeuse. The study shows that microlensing events such as these are common, so we should be able to see lots more stars in this distant galaxy in the future.

We know a great deal about red supergiants in the Milky Way. Since they are dying stars, red giants play a significant role in enriching the available elements in a galaxy, which determines things such as the formation of stars and even life. But by studying these distant red giants, we will be able to see how they impacted the chemical diversity of younger galaxies. It could even help us understand what the Milky Way was like when the Sun and Earth began to form.

Reference: Yoshinobu Fudamoto, et al. “Identification of more than 40 gravitationally magnified stars in a galaxy at redshift 0.725.” Nature Astronomy (2025).

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Getting a spacecraft to another star is a monumental challenge. However, that doesn’t stop people from working on it. The most visible groups currently doing so are Breakthrough Starshot and the Tau Zero Foundation, both of whom focus on a very particular type of propulsion-beamed power. A paper from the Chairman of Tau Zero’s board, Jeffrey Greason, and Gerrit Bruhaug, a physicist at Los Alamos National Laboratory who specializes in laser physics, takes a look at the physics of one such beaming technology – a relativistic electron beam – how it might be used to push a spacecraft to another star.

There are plenty of considerations when designing this type of mission. One of the biggest of them (literally) is how heavy the spacecraft is. Breakthrough Starshot focuses on a tiny design with gigantic solar “wings” that would allow them to ride a beam of light to Alpha Centauri. However, for practical purposes, a probe that small will be able to gather little to no actual information once it arrives there—it’s more of a feat of engineering rather than an actual scientific mission.

The paper, on the other hand, looks at probe sizes up to about 1000kg—about the size of the Voyager probes built in the 1970s. Obviously, with more advanced technology, it would be possible to fit a lot more sensors and controls on them than what those systems had. But pushing such a large probe with a beam requires another design consideration—what type of beam?

Fraser discusses how we might get to Alpha Centauri.

Breakthrough Starshot is planning a laser beam, probably in the visible spectrum, that will push directly on light sails attached to the probe. However, given the current state of optical technology, this beam could only push effectively on the probe for around .1 AU of its journey, which totals more than 277,000 AU to Alpha Centauri. Even that minuscule amount of time might be enough to get a probe up to a respectable interstellar speed, but only if it’s tiny and the laser beam doesn’t fry it.

At most, the laser would need to be turned on for only a short period of time to accelerate the probe to its cruising speed. However, the authors of the paper take a different approach. Instead of providing power for only a brief period of time, why not do so over a longer period? This would allow more force to build up and allow a much beefier probe to travel at a respectable percentage of the speed of light. 

There are plenty of challenges with that kind of design as well. First would be beam spread—at distances more than 10 times the distance from the Sun to the EartSunhow would such a beam be coherent enough to provide any meaningful power? Most of the paper goes into detail about this, focusing on relativistic electron beams. This mission concept, known as Sunbeam, would use just such a beam.

Fraser discusses another interstellar probe – Project Dragonfly

Utilizing electrons traveling at such high speeds has a couple of advantages. First, it’s relatively easy to speed electrons up to around the speed of light—at least compared to other particles. However, since they all share the same negative charge, they will likely repel each other, diminishing the beam’s effective push.

That is not as much of an issue at relativistic speeds due to a phenomenon discovered in particle accelerators known as relativistic pinch. Essentially, due to the time dilation of traveling at relativistic speeds, there isn’t enough relative time experienced by the electrons to start pushing each other apart to any meaningful degree.

Calculations in the paper show that such a beam could provide power out to 100 or even 1000 AU, well past the point where any other known propulsion system would be able to have an impact. It also shows that, at the end of the beam powering period, a 1,000kg probe could be moving as fast as 10% of the speed of light – allowing it to reach Alpha Centauri in a little over 40 years.

Multi-stage ships could be the key to interstellar travel – as Fraser discusses.

There are plenty of challenges to overcome for that to happen, though – one of which is how to get that much power formed into a beam in the first place. The farther a probe is from the beam’s source, the more power is required to transmit the same force. Estimates range up to 19 gigaelectron volts for a probe out at 100 AU, a pretty high energy beam, though well within our technology grasp, as the Large Hadron Collider can form beams with orders of magnitude more energy.

To capture that energy in space, the authors suggest using a tool that doesn’t yet exist, but at least in theory could – a solar statite. This platform would sit above the Sun’s surface, using a combination of force from the push of light from the star and a magnetic field that uses the magnetic particles the Sun emits to keep it from falling into the Sun’s gravity well. It would sit as close as the Parker Solar Probe’s closest approach to the Sun, which means that, at least in theory, we can build materials to withstand that heat. 

The beam forming itself would happen behind a massive sun shield, which would allow it to operate in a relatively cool, stable environment and also be able to stay on station for the days to weeks required to push the 1000kg probe out as far as it would go. That is the reason for using a statute rather than an orbit—it could stay stationary relative to the probe and not have to worry about being occluded by the Earth or the Sun.

Fraser discusses interstellar travel with Avi Loeb, a Harvard professor and expert in interstellar travel.

All this so far is still in the realm of science fiction, which is why the authors met in the first place – on the ToughSF Discord server, where sci-fi enthusiasts congregate. But, at least in theory, it shows that it is possible to push a scientifically useful probe to Alpha Centauri within a human lifetime with minimal advances to existing technology.

Learn More:
Greason & Bruhaug – Sunbeam: Near-Sun Statites as Beam Platforms for Beam-Driven Rockets
UT – Researchers are Working on a Tractor Beam System for Space
UT – A Novel Propulsion System Would Hurl Hypervelocity Pellets at a Spacecraft to Speed it up
UT – A Concentrated Beam of Particles and Photons Could Push Us to Proxima Centauri

Lead Image:
Depiction of the electro beam statite used in the study.
Credit – Greason & Bruhaug

The post Pushing A Probe To Alpha Centauri Using A Relativistic Electron Beam appeared first on Universe Today.

Between NASA, other space agencies, and the commercial space sector, there are some truly ambitious plans for humanity’s future in space. These plans envision the creation of permanent infrastructure on and around the Moon that will enable a permanent human presence there, complete with research, science, and commercial operations. They also call for the first crewed missions to Mars, followed by the creation of surface habitats that will allow for return visits. These plans present many challenges, ranging from logistical and technical issues to health and human safety.

Another challenge is coordinating operations across the lunar surface with those in orbit and back at Earth, which requires a system of standardized time. In a recent study, a team of NASA researchers developed a new system of lunar time for all lunar assets and those in cis-lunar space. They recommend that this system’s foundation be relativistic time transformations, known more generally as “time dilation.” Such a system will allow for coordination and effective timekeeping on the Moon by addressing discrepancies caused by gravitational potential differences and relative motion.

The study was conducted by Slava G. Turyshev, James G. Williams, Dale H. Boggs, and Ryan S. Park, four research scientists from NASA’s Jet Propulsion Laboratory (JPL). The preprint of their paper, “Relativistic Time Transformations Between the Solar System Barycenter, Earth, and Moon,” recently appeared online and is currently being reviewed for publication in the journal Physical Review D.

In this illustration, NASA’s Orion spacecraft approaches the Gateway in lunar orbit. Credits: NASA

Relativistic time transformations (RTT), as predicted by Lorentz Transformations and Einstein’s Special Theory of Relativity (SR), describe how the passage of time slows for the observer as their reference frame accelerates. When Einstein extended SR to account for gravity with his theory of General Relativity (GR), he established how acceleration and gravity are essentially the same and that the flow of time changes depending on the strength of the gravitational field. This presents a challenge for space exploration, where spacecraft operating beyond Earth are subject to acceleration, microgravity, and lower gravity.

As Turyshev told Universe Today via email, RTT will become a major consideration as humans begin operating on the Moon for extended periods of time:

“[RTT] account for how time flows differently depending on gravitational potential and motion. For example, clocks on the Moon tick slightly faster than those on Earth due to the weaker gravitational pull experienced at the Moon’s surface. Though these differences are small—on the order of microseconds per day—they become significant when coordinating space missions, where even a tiny timing error can translate to large positional inaccuracies or communication delays. In space exploration, precise timing is critical. Various time scales serve different roles, depending on the frame of reference.”

In their paper, the team identified three major timescales that come into play. They include:

• Terrestrial Time (TT): this timescale is used for Earth-based systems, representing time at mean sea level with corrections for Earth’s gravitational potential.
• Barycentric Coordinate Time (TCB): the time coordinate in the Barycentric Celestial Reference System (BCRS), centered at the Solar System barycenter. TCB accounts for relativistic effects due to both gravitational potentials and the motion of bodies relative to the barycenter, making it essential for high-precision modeling of celestial mechanics and dynamics.
• Barycentric Dynamical Time (TDB): derived from TCB but adjusted to run at the same average rate as Terrestrial Time (TT), this adjustment prevents a long-term secular drift relative to TT, ensuring that ephemerides remain consistent with Earth-based observations over long periods.

Illustration of NASA astronauts on the lunar South Pole. Mission ideas we see today have at least some heritage from the early days of the Space Age. Credit: NASA

“Relativistic corrections link these time scales, ensuring consistent timekeeping for spacecraft navigation, planetary ephemerides, and communication,” added Turyshev. “Without such corrections, spacecraft trajectories and mission timings would quickly become unreliable, even at relatively short distances.”

NASA’s Artemis Program includes multiple elements operating in cislunar space and on the lunar surface around the south pole region. These include the orbiting Lunar Gateway, multiple Human Landing Systems (HLSs), and the Artemis Base Camp – which will consist of the Lunar Terrain Vehicle (LTV), the Habitable Mobility Platform (HMP), and the Foundation Surface Habitat (FSH). In addition, the ESA plans to create its Moon Village, consisting of multiple transportation, power, and in-situ resource utilization (ISRU) elements.

China and Russia also have plans for a lunar habitat around the Moon’s south pole region, known as the International Lunar Research Station (ILRS). Based on multiple statements, this station could include a surface element (possibly in a lava tube), an orbital element, and other elements similar to the Artemis Base Camp and Moon Village. These will be followed and paralleled by commercial space interests, which could include harvesting, mining, and even tourism. And, of course, these operations must remain in contact with mission control as the Moon orbits the Earth.

As lunar exploration accelerates, says Turyshev, defining a dedicated Lunar Time (LT) scale and a Luni-centric Coordinate Reference System (LCRS) becomes increasingly important. Hence, he and his colleagues developed a TL scale to ensure precise timekeeping for activities on and around the Moon. Their approach involves applying relativistic principles used for Earth and adapting them to the Moon’s environment, including:

1. Weaker gravity on the Moon leads to a faster tick rate for lunar clocks than Earth clocks.
2. The Moon’s motion around Earth and the Sun introduces periodic time variations.
3. Local gravitational anomalies, known as mascons, subtly influence the Moon’s gravitational field and, thus, the flow of time.

Habitats grouped on the rim of a lunar crater, known as the Moon Village. Credit: ESA

“Our results show that lunar time drifts ahead of Earth time by about 56 microseconds per day, with additional periodic variations caused by the Moon’s orbit,” said Turyshev. “These periodic oscillations have an amplitude of around 0.47 microseconds, occurring over a period of approximately 27.55 days.”

To derive these transformations, Turyshev and his team relied on high-precision data from NASA’s Gravity Recovery and Interior Laboratory (GRAIL) mission, twin satellites that studied the Moon between 2011 and 2021. In addition to mapping the lunar surface, the twin satellites also mapped the Moon’s gravitational field in fine detail. This was combined with measurements made by Lunar Laser Ranging (LLR) experiments, which measure the Earth-Moon distance with millimeter-level precision. Said Turyshev:

“Using this data, we modeled the Moon’s gravitational potential and orbital dynamics, ensuring sub-nanosecond accuracy in the resulting time transformations. Key constants were introduced to describe the transformations, analogous to those used for Earth-based time systems. The most critical of these constraints are:

• LL, which represents the average rate of time transformation between the Moon’s center and its surface, compensating for the combined gravitational and rotational potential at the selenoid level.
• LM, analogous to LB for Earth, compensates for the average rate in time transformation between Barycentric Coordinate Time (TCB) and Lunar Time (TL).
• LH, representing the long-time average of the Moon’s total orbital energy in its motion around the solar system barycenter. It defines the rate difference between TCB and the luni-centric coordinate system time (TCL) and includes contributions from gravitational interactions with the Sun and planets.
• LEM, which represents the long-time average of the Moon’s total orbital energy in its motion around Earth, as observed from the Geocentric Celestial Reference System (GCRS).
• PEM, which accounts for periodic relativistic corrections arising from the Moon’s elliptical orbit and gravitational perturbations by the Sun and planets, resulting in time-dependent oscillations.

“These transformations form the basis of our highly accurate lunar timekeeping system, which is crucial for future mission planning and operations.”

Visualization of the ILRS, from the CNSA Guide to Partnership (June 2021). Credit: CNSA

As Turyshev and his colleagues establish in their paper, there are many reasons why creating a unified lunar time system is essential for mission success. These include:

1. Precision Navigation and Landing: With numerous missions targeting the lunar surface, from orbiters to landers and rovers, synchronized timekeeping will ensure precise positioning and reduce the risk of errors during critical mission phases.
2. Seamless Communication: Coordinating activities between Earth, orbiters, and lunar bases requires consistent time synchronization to avoid communication delays and ensure the correct ordering of data transmission.
3. Collaborative Science: A common time standard enables multiple missions—conducted by different space agencies and organizations—to share and compare data accurately, supporting large-scale studies of lunar geology, seismic activity, and gravitational anomalies.
4. Autonomous Operations: As lunar missions grow in complexity and duration, a dedicated lunar time system will allow bases and spacecraft to operate independently from Earth, reducing dependence on Earth-based timekeeping during periods when Earth is not visible. 

New systems of timekeeping are one of many adaptations that humanity must make to become an interplanetary species. A coordinated system of lunar time will become increasingly important as humanity’s presence on the Moon grows and becomes permanent in this century. Similar measures will need to be taken once regular crewed missions to Mars begin, and those efforts have already begun in earnest! Check out Mars Coordinated Time (MCT) and the Darian Calendar to learn more.

Further Reading: arXiv

The post If We Want to Live on Other Worlds, We're Going to Need New Clocks appeared first on Universe Today.

The launch of a rocket into orbit should never become routine. There was a time, probably around the 50’s and 60’s that a rocket launch hit the headlines. Now its just another launch. Last year (2024) saw a record breaking 263 launches. The US launched 158, China launched 68 and other countries/regions like Europe, Russian and Japan. Last year just 224 launches were completed and two years ago in 2022, 168 launches were completed. Surprisingly perhaps, prior to 2020 the record was set at 141 back in 1967, the future of rocket flight still seems quite alive! 

Surprisingly perhaps, rocket flight in its purest form dates back centuries with its origins in ancient China. The 9th century Chinese were recorded to have fired gunpowder propelled bamboo tubes at their enemies in the first examples of rocket flight. Modern rocketry only began to take shape in the 20th century thanks to the work from engineers and scientists like Konstantin Tsiolkovsky and Robert Goddard. 

Tsiolkovsky’s theoretical work laid the foundations for rocketry, while Goddard successfully launched the first liquid-fuelled rocket in 1926 in the United States. During World War II, rocket technology advanced rapidly driven sadly for the search for weaponry not exploration. The development of the V-2 rocket by Germany marked the first long-range ballistic missile while the Cold War rivalry between the United States and the Soviet Union further accelerated rocket development. Eventually this lead to the launch of Sputnik 1 in 1957 and the Apollo 11 Moon landing in 1969 and in the years that followed rocket launches for missions to explore distant planets and the establishment of space stations.

The Sputnik spacecraft stunned the world when it was launched into orbit on Oct. 4th, 1954. Credit: NASA

Perhaps one of the most spectacular developments over recent years and 2024 saw this demonstrated beautifully, spacecraft landing back successfully under rocket control. SpaceX have been driving this technology forward at pace firstly with the landing of their Falcon rockets on drone ships but last year saw a real milestone. 

A SpaceX Falcon 9 reusable first stage lands on the drone ship before being transported to Port Canaveral. Image: SpaceX

October saw the 5th test flight of the SpaceX Starship launch vehicle. Its the tallest launch vehicle to have flown, beating the Apollo Saturn V rocket by 11 metres. After its launch on 13 October and the upper stage being delivered into a suborbital trajectory (reached space but didn’t complete an orbit before returning) the booster returned! It didn’t just disintegrate or flat down attached to parachutes, it used the powerful Raptor engines to return to the launch pad. After descent, it slowed, almost hovering in mid air, before manoeuvring sideways to line up with launch pad before touching back down. As it returned to the arms of the launch tower, the arms grabbed the rocket and the engines shut down! 

SpaceX’s Starship Super Heavy booster settles back into the arms of its launch-pad cradle in Texas. (Credit: SpaceX)

It is no doubt that 2024 saw some amazing developments in rocket flight including but not limited to the SpaceX booster landings. What of 2025? What can we look forward to in the year ahead? Well I’m not sure we are going to see any pure rocket launch landmarks this year but there are some exciting missions ahead; NASA launching SPHEREx (new space observatory to map the sky in optical and near-infrared,) SpaceX launching to missions to surface of Moon (Texas built Blue Ghost and a Japanese lander,) a new commercial space station called Haven-1 and if all goes to plan we may finally see the return to Earth of Suni Williams and Butch Wilmore who have been stuck on the ISS since June after their planned 1 week mission!

This artist’s illustration shows NASA’s SPHEREx observatory in orbit. The mission will launch in 2025. Image Credit: By NASA/JPL – https://www.jpl.nasa.gov/missions/spherex, Public Domain, https://commons.wikimedia.org/w/index.php?curid=143819030

Source : Space Stats

The post There Were Over 260 Orbital Launches in 2024. A New Record appeared first on Universe Today.

Mars is well-known for its dust storms, which occur every Martian year during summer in the southern hemisphere. Every three Martian years (five and a half Earth years), these storms grow so large that they are visible from Earth and will engulf the entire planet for months. These storms pose a significant threat to robotic missions, generating electrostatic charges that can interfere with their electronics or cause dust to build up on their solar panels, preventing them from drawing enough power to remain operational.

While scientists have studied these storms for decades, the precise mechanisms that trigger them have remained the subject of debate. In a new study, a team of planetary scientists at the University of Colorado Boulder (CU Boulder) has provided new insight into the factors involved. According to their findings, relatively warm and sunny days may kick off the largest storms every few years. These could be the first step toward forecasting extreme weather on Mars, which is vital for future crewed missions to Mars.

The study was led by Heshani Pieris, a graduate student at the Laboratory for Atmospheric and Space Physics (LASP) at CU Boulder. She was joined by Paul Hayne, a researcher at LASP and an associate professor at the Department of Astrophysical and Planetary Sciences at CU Boulder. Their findings were presented at the 2024 meeting of the American Geophysical Union, which took place from December 9th to 13th in Washington, D.C.

Mars seen before, left, and during, right, a global dust storm in 2001. Credit: NASA/JPL/MSSS

Mars experiences dust storms regularly, which often begin as smaller storms that form around the polar regions, usually during the second half of the Martian year. These storms can grow rapidly as they move towards the equator until they cover millions of square kilometers. While these dust storms are not very powerful due to Mars’ thin atmosphere (roughly 0.5% as dense as Earth’s), they can still pose a significant hazard. In fact, global dust storms were responsible for the loss of the Opportunity rover in 2018 and the InSight lander last year.

“Dust storms have a significant effect on rovers and landers on Mars, not to mention what will happen during future crewed missions to Mars. This dust is very light and sticks to everything,” said Pieris in a recent NASA press release. “Even though the wind pressure may not be enough to knock over equipment, these dust grains can build up a lot of speed and pelt astronauts and their equipment,” added Hayne. “We need to understand what causes some of the smaller or regional storms to grow into global-scale storms. We don’t even fully understand the basic physics of how dust storms start at the surface.”

For their study, Pieris and Hayne focused on “A” and “C” storms, two weather patterns that tend to occur every year on Mars. This consisted of analyzing data gathered by the Mars Climate Sounder instrument aboard NASA’s Mars Reconnaissance Orbiter (MRO) over the course of 15 years (eight Mars years). Specifically, they searched for periods of unusual warmth, when more sunlight filtered through Mars’ thin atmosphere to heat the planet’s surface. They discovered that roughly 68% of major storms on the planet were preceded by a sharp rise in temperatures at the surface, which led to dust being kicked up.

Artist’s depiction of a dust storm on Mars. Credit: NASA

While these results don’t definitively prove that warmer conditions cause dust storms, they indicate that the same phenomena that trigger storms on Earth may be at work on Mars. During hot summers in dry regions, warm air near the surface can rise through the atmosphere, leading to large gray clouds that signal rain. Said Pieris:

“When you heat up the surface, the layer of atmosphere right above it becomes buoyant, and it can rise, taking dust with it. This study is not the end all be all of predicting storms on Mars. But we hope it’s a step in the right direction.”

Pieris and Hayne are now gathering more recent observations of Mars to continue investigating these explosive weather patterns. Eventually, they hope that scientists will be able to predict weather patterns on Mars based on live data from the planet.

Further Reading: UC Boulder, AGU24

The post New Study Explains How Mars Dust Storms Can Engulf the Planet appeared first on Universe Today.

CubeSats can be used in many different scenarios, and one of their most important uses is providing an easy path to understanding how to design, plan, and launch a mission. That was the idea behind AlbaSat, a 2U CubeSat currently under development by a team at the University of Padova with an impressive four different functional sensors packed into its tiny frame.

AlbaSat was initially developed as a student project at the University of Padova as part of ESA’s Fly Your Satellite (FYS) program, which, through its two iterations, has helped students get their CubeSat ideas off the ground – literally. AlbaSat was one of the more ambitious projects in the program, with four different key scientific objectives.

First was a study of the prevalence of space debris, which is becoming a growing problem, as the team noted in their paper describing the mission’s feasibility when they discussed Kessler Syndrome. Tracking small debris floating in orbit is a challenge from the ground, but a satellite in orbit itself could do better. To do so, the team developed the Impact Sensor, which would detect debris hitting AlbaSat itself. It consists of a resistive sensing element placed on top of some PTFE, which was prototyped in a project called DRAGONS by researchers at the Fraunhofer Institute for High-Speed Dynamics.

Video describing ESA’s Fly Your Satellite program, which AlbaSat is taking advantage of.
Credit – ESA YouTube Channel

AlbaSat will also carry a tri-axial MEMS accelerometer to complement that instrument to detect any micro-vibrations the satellite experiences in its orbit. It is important to understand what impact, if any, those vibrations might have on either satellite performance or orbital decay.

Another complementary payload is the laser rangefinder. This is intended to keep precise track of the satellite’s orbit by reflecting a laser from a ground station off of a series of “Corner Cube Retroreflectors” that can reflect the laser to the transmitting station. Understanding the orbital path is key to ensuring the other payloads onboard the tiny CubeSat work properly.

The final functional payload is a test rig for optical receivers that might someday be useful in proving novel communications technology. Known as the “QPL,” this subsystem consists of an active reflectometer that can receive signals intended for use in quantum communications systems. 

A NanoMind A3200 central computer, a NanoCom AX100 communication system, the necessary electrical subsystems, solar panels, and the functional payloads for energy collection. The mission is designed to last as long as possible, but its orbit will decay in less than 12 years, per ESA debris mitigation guidelines.

Fraser talks about the danger posed by Kessler Syndrome, one of the primary study areas of the AlbaSat mission.

Students from the University of Padova have been diligently working on the system. In February, they passed environmental testing of the impact sensor, which garnered them a press release from ESA itself. More recently, Space Voyaging published a detailed profile that tracked the team as they interfaced with ESA experts, helping them get their satellite into space.

When they do, it will be the University of Padova’s first foray into the CubeSat space. Hopefully, it will be a worthy addition to the stable of student-designed CubeSats that contribute valuable scientific data. It hopes to launch sometime this year, and it will carry many students’ hopes.

Learn More:
Mozzato et al – Concept and Feasibility Analysis of the Alba Cubesat Mission
ESA – AlbaSat Impact Sensor completes the environmental test campaign
Space Voyaging – AlbaSat: the First CubeSat of the University of Padua
UT – CubeSat Propulsion Technologies are Taking Off

Lead Image:
3D Mockup of AlbaSat
Credit – AlbaSat CubeSat / University of Padova

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Fast radio bursts (FRBs) are notoriously difficult to study. They are flashes of radio light that can outshine a galaxy but often last for only a fraction of a second. For years, all we could do was observe them by random chance and wonder about their origins. Now, thanks to wide-field radio telescopes such as CHIME, we have some general understanding as to their cause. They seem to originate from highly magnetic neutron stars known as magnetars, but the details are still a matter of some debate. Now a team has used a method known as scintillation to reveal more clues about this mysterious phenomenon.

Most FRBs occur in distant galaxies, meaning that their light must travel through the intergalactic medium and through the interstellar medium of the Milky Way to reach us. As a result, the light can be affected by gas and dust, causing it to distort a bit in frequency and polarization. Since different media affect different wavelengths of radio light, this can help us understand the origins of an FRB.

In this study, the team focused on an FRB named 20221022A, which originated in a galaxy 200 million light-years away. As the light traveled to us, interaction with the intergalactic medium caused the burst to flicker in brightness, known as scintillation. It’s similar to the way stars twinkle because their light passes through turbulent layers of Earth’s upper atmosphere.

One of the classic ways to distinguish a star from a planet in the night sky is that stars twinkle, but planets don’t. The light of both passes through the atmosphere, but since planets appear as a small disk of light, we don’t see them flicker. Stars appear as points of light, so we can see the flicker. The apparent size of a light source is the key factor.

In the same way, by looking at the scintillation of the FRB, the team was able to determine the size and location of the FRB light source. In this case, they found that FRB 20221022A had to have happened within 10,000 kilometers of a highly magnetic pulsar. This means the FRB must have originated within the magnetosphere of the pulsar, which confirms magnetars as the source of this particular FRB.

This study not only confirms magnetars as the source of FRBs; it proves that it is specifically an effect of their intense magnetic fields. Further observations such as this should allow us to understand how these magnetic fields can generate such intense radio light so quickly.

Reference: Nimmo, Kenzie, et al. “Magnetospheric origin of a fast radio burst constrained using scintillation.” Nature 637.8044 (2025): 48-51.

The post This Fast Radio Burst Definitely Came From a Neutron Star appeared first on Universe Today.

On October 19th, 2017, the Panoramic Survey Telescope and Rapid Response System-1 (Pan-STARRS-1) in Hawaii announced the first-ever detection of an interstellar object, named 1I/2017 U1 ‘Oumuamua (the Hawaiin word for “scout”). This object created no shortage of confusion since it appeared as an asteroid but behaved like a comet (based on the way it accelerated out of the Solar System). Since then, scientists have noticed a lot of other objects that behave the same way, known as “dark comets.”

These objects are defined as “small bodies with no detected coma that have significant nongravitational accelerations explainable by outgassing of volatiles,” much like ‘Oumuamua. In a recent NASA-supported study, a team of researchers identified seven more of these objects in the Solar System, doubling the number of known dark comets. Even more important, the researchers were able to discern two distinct populations. They consist of larger objects that reside in the outer Solar System and smaller ones in the inner Solar System.

The study was led by Darryl Z. Seligman, an NSF Astronomy and Astrophysics Postdoctoral Fellow from the Carl Sagan Institute at Cornell University and Michigan State University. He was joined by researchers from the European Space Agency’s Near-Earth Object Coordination Centre (NEOCC), the European Southern Observatory (ESO), the Planetary Science Institute (PSI), Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado Boulder, NASA’s Jet Propulsion Laboratory. Their findings were published on December 9th in the Proceedings of the National Academy of Sciences (PNAS).

Astronomers are discovering more objects that look like asteroids but behave like comets. Credit: N. Bartmann (ESA/Webb), ESO/M. Kornmesser and S. Brunier, N. Risinger (skysurvey.org)

Scientists got their hint that dark comets exist in 2016 when they found that the “asteroid” 2003 RM had deviated slightly from its expected orbit. This behavior could not be explained by the Yarkovsky effect, where asteroids absorb solar energy and re-radiate it into space as heat. Said study co-author Davide Farnocchia of NASA JPL said in a NASA press release:

“When you see that kind of perturbation on a celestial object, it usually means it’s a comet, with volatile material outgassing from its surface giving it a little thrust. But try as we might, we couldn’t find any signs of a comet’s tail. It looked like any other asteroid — just a pinpoint of light. So, for a short while, we had this one weird celestial object that we couldn’t fully figure out.”

The next piece of the puzzle came in 2017 with the detection of the first interstellar object (‘Oumuamua). While it appeared as a single point of light to telescopes and had no coma, its trajectory changed as if it were outgassing volatile material from its surface. “‘Oumuamua was surprising in several ways,” said Farnocchia. “The fact that the first object we discovered from interstellar space exhibited similar behaviors to 2003 RM made 2003 RM even more intriguing.”

By 2023, seven dark comets had been identified, leading the astronomical community to designate them as a distinct category of celestial objects. With this latest study, the authors identified seven more of these objects in the Solar System and noticed some interesting traits among them. “We had a big enough number of dark comets that we could begin asking if there was anything that would differentiate them,” said Seligman. “By analyzing the reflectivity,” or albedo, “and the orbits, we found that our solar system contains two different types of dark comets.”

Artist’s impression of the interstellar object, `Oumuamua, experiencing outgassing as it leaves our Solar System. Credit: ESA/Hubble, NASA, ESO, M. Kornmesser

One group, which the team calls “outer dark comets,” is similar to the “families” of asteroids that orbit Jupiter. In addition to being larger, measuring hundreds of meters or more across, the first group has highly elliptical orbits. The second group, “inner dark comets,” are smaller (tens of meters or less) and travel in nearly circular orbits within the orbits of Mercury, Venus, Earth, and Mars. In addition to expanding astronomer’s knowledge of dark comets, the team’s research raises several additional questions regarding their origin, behavior, and composition.

Of particular interest is whether these objects could contain water ice, which would have implications for our understanding of how water (and possibly life) was distributed throughout the Solar System billions of years ago. “Dark comets are a new potential source for having delivered the materials to Earth that were necessary for the development of life,” said Seligman. “The more we can learn about them, the better we can understand their role in our planet’s origin.”

Further Reading: NASA, PNAS

The post NASA Scientists Discover “Dark Comets” Come in Two Populations. appeared first on Universe Today.

Mars is often considered to be the planet most similar to the Earth. Earth however, is capable of supporting life, Mars on the other hand could not. There was once a time when it was warmer and wetter and could support life. Exploring life on Earth shows us that bacteria known as extremophiles can live in the most harsh conditions on Earth, it may just be possible that there are places on Mars that could also support these hardy forms of life. A new paper explores that possibility by studying the most extreme Earth-based bacteria that could survive under ground on Mars. 

Mars, often referred to as the “Red Planet” because of its reddish appearance. It’s the fourth planet from the Sun orbiting at an average distance of 228 million kilometres. It has a thin atmosphere, made up mostly of carbon dioxide with surface temperatures from about -125°C to 20°C. Mars has some fascinating geological features including the largest volcano in the solar system; Olympus Mons, and a vast canyon system; Valles Marineris. Unlike Earth, Mars has two moons Phobos and Deimos which are thought to be captured asteroids. 

A full-disk view of Mars, courtesy of VMC. Credit: ESA

The atmosphere of Mars is thin and, whilst carbon dioxide is the main component, there is also methane in small amounts, around 0.00003% of the whole. It’s origins in the Martian atmosphere are not fully understood and it may be that it is there as a result of biological processes such as the metabolism of microbes. It could also be there due to geological processes such as volcanic eruptions. The presence of methane has also excited researchers who have been exploring whether Mars could in anyway support more extreme forms of primitive life. 

Image of the Martian atmosphere and surface obtained by the Viking 1 orbiter in June 1976. (Credit: NASA/Viking 1)

In a paper recently authored by Butturini A from the University of Barcelona and team, they explore the Martian environment and its suitability to support extremophiles known as methanogens (from the Methanobacteriaceae family.) These primitive forms of bacteria are found in some of the most inhospitable regions of Earth. They have been found thriving in the hot groundwater of Lidy Hot Springs in Idaho, and are based upon methane biology. It raises an interesting possibility that areas of Mars could provide a habitat for them. 

The conditions on the surface of Mars are well understood. With high energy radiation from cosmic rays and solar radiation, along with dry and cold conditions and a high temperature differential between day and night, the surface is not conducive to any known forms of life. Look a little deeper however and the conditions seem a little more favourable. Lower levels on Mars however may be more habitable than the surface. A few metres underground and the surface material offers protection from the incoming radiation. Temperatures lower down would be higher and less variable too giving the possibility that liquid water may be present. It has already been seen that subsurface water has in some areas of Mars found its way to the surface only to evaporate when met with the surface conditions. With the presence of salt too the subsurface water can be present as liquid at a lower temperature. 

The team conclude that methanogens seem to be thriving in hostile environments on Earth which are analogous to some areas of Mars. They identify the southern area of Acidalia Planitia as somewhere to search due to the high levels of radiogenic heat producing elements which suggest subsurface water may be present. It raises the interesting possibility that, theoretically at least, primitive life could exist on Mars, even today, we just need to find it!

Source:  Potential habitability of present-day Mars subsurface for terrestrial-like methanogens

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Potentially habitable exoplanets are so incredibly common that astronomers have started to consider more unusual situations where life might arise. Perhaps life can be found on the moon of a hot Jupiter or lingering in the warm ocean of a rogue planet. Recently, there has even been the idea that habitable worlds might orbit white dwarfs. We know some white dwarfs have planets, and despite lacking nuclear fusion, white dwarfs do emit enough light and heat to have a habitable zone. But the question remains whether a planet could retain a water-rich environment through the red giant stage of a star before it becomes a white dwarf. This is the focus of a new study on the arXiv.

The study starts by stating the obvious. Any habitable world around a main-sequence star will likely be stripped of its atmosphere and water as the star swells to a red giant. By the time the star becomes a white dwarf, any planet that was habitable will be barren, if not consumed by its star. The work then goes on to consider more distant worlds in a system. Perhaps a cold and icy hycean world might become habitable in the white dwarf stage.

It turns out there are two critical stages. The first is that an ocean world would need to retain a large portion of its water during the dying stage of the main sequence star. As you might expect, the more distant a planet is from its star, the more water it retains. For a sunlike star, an ocean world would need to be more than three times Earth’s distance to retain water. To retain vast oceans similar to Earth, the planet would have to be about 10 AU away, or roughly the distance of Saturn.

Water retention for planets at different distances. Credit: Becker, et al

The second critical stage is orbital migration. Once the star becomes a white dwarf, an ocean world at Saturn’s orbit would be an ice planet far beyond the habitable zone. To become a living world, it would need to move inward to a close, warm orbit. This is possible both through interaction with the nebula formed during the red giant stage, as well as through gravitational interactions between planets. Our own solar system, for example, had a migration phase in its youth. As the study shows, however, the timing of this migration is critical. If the inward migration of a world happens too soon, then much of the water will boil off. If it happens too late, then the system will have stabilized to the point that the world won’t be able to enter the habitable zone.

Overall, the study finds that most worlds around a white dwarf will either be dry before entering the habitable zone, or retain water and remain at the outer edge of the system. But as the authors point out, it is *possible* for an outer hycean world to migrate at just the right time to retain water and become a warm Earth-like world. Not likely, but possible.

So finding a habitable planet around a white dwarf is a long shot. But given how easy it might be to study the atmospheres of these worlds, it’s certainly worth taking a look.

Reference: Becker, Juliette, Andrew Vanderburg, and Joseph Livesey. “The Fate of Oceans on First-Generation Planets Orbiting White Dwarfs.” arXiv preprint arXiv:2412.12056 (2024).

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One of the more daunting questions related to astrobiology—the search for life in the cosmos—concerns the nature of life itself. For over a century, biologists have known that life on Earth comes down to the basic building blocks of DNA, RNA, and amino acids. What’s more, studies of the fossil record have shown that life has been subject to many evolutionary pathways leading to diverse organisms. At the same time, there is ample evidence that convergence and constraints play a strong role in limiting the types of evolutionary domains life can achieve.

For astrobiologists, this naturally raises questions about extraterrestrial life, which is currently constrained by our limited frame of reference. For instance, can scientists predict what life may be like on other planets based on what is known about life here on Earth? An international team led by researchers from the Santa Fe Institute (SFI) addressed these and other questions in a recent paper. After considering case studies across various fields, they conclude that certain fundamental limits prevent some life forms from existing.

The research team was led by Ricard Solé, the head of the ICREA-Complex Systems Lab at the Universitat Pompeu Fabra and an External Professor at the Santa Fe Institute (SFI). He was joined by multiple SFI colleagues and researchers from the Institute of Biology at the University of Graz, the Complex Multilayer Networks Lab, the Padua Center for Network Medicine (PCNM), Umeå University, the Massachusetts Institute of Technology (MIT), the Georgia Institute of Technology, the Tokyo Institute of Technology, and the European Centre for Living Technology (ECLT).

Artist’s impression of Earth during the Archean Eon. Credit: Smithsonian National Museum of Natural History

The team considered what an interstellar probe might find if it landed on an exoplanet and began looking for signs of life. How might such a mission recognize life that evolved in a biosphere different from what exists here on Earth? Assuming physical and chemical pre-conditions are required for life to emerge, the odds would likely be much greater. However, the issue becomes far more complex when one looks beyond evolutionary biology and astrobiology to consider synthetic biology and bioengineering.

According to Solé and his team, all of these considerations (taken together) come down to one question: can scientists predict what possible living forms of organization exist beyond what we know from Earth’s biosphere? Between not knowing what to look for and the challenge of synthetic biology, said Solé, this presents a major challenge for astrobiologists:

“The big issue is the detection of biosignatures. Detecting exoplanet atmospheres with the proper resolution is becoming a reality and will improve over the following decades. But how do we define a solid criterion to say that a measured chemical composition is connected to life? 

“[Synthetic biology] will be a parallel thread in this adventure. Synthetic life can provide profound clues on what to expect and how likely it is under given conditions. To us, synthetic biology is a powerful way to interrogate nature about the possible.”

The sequence where amino acids and peptides come together to form organic cells. Credit: peptidesciences.com

To investigate these fundamental questions, the team considered case studies from thermodynamics, computation, genetics, cellular development, brain science, ecology, and evolution. They also consider previous research attempting to model evolution based on convergent evolution (different species independently evolve similar traits or behaviors), natural selection, and the limits imposed by a biosphere. From this, said Solé, they identified certain requirements that all lifeforms exhibit:

“We have looked at the most fundamental level: the logic of life across sales, given several informational, physical, and chemical boundaries that seem to be inescapable. Cells as fundamental units, for example, seem to be an expected attractor in terms of structure: vesicles and micelles are automatically formed and allow for the emergence of discrete units.”

The authors also point to historical examples where people predicted some complex features of life that biologists later confirmed. A major example is Erwin Schrödinger’s 1944 book What is Life? in which he predicted that genetic material is an aperiodic crystal—a non-repeating structure that still has a precise arrangement—that encodes information that guides the development of an organism. This proposal inspired James Watson and Francis Crick to conduct research that would lead them to discover the structure of DNA in 1953.

However, said Solé, there is also the work of John von Neumann that was years ahead of the molecular biology revolution. He and his team refer to von Neumann’s “universal constructor” concept, a model for a self-replicating machine based on the logic of cellular life and reproduction. “Life could, in principle, adopt very diverse configurations, but we claim that all life forms will share some inevitable features, such as linear information polymers or the presence of parasites,” Solé summarized.

The first implementation of von Neumann’s self-reproducing universal constructor. Three generations of machines are shown: the second has nearly finished constructing the third. Credit: Wikimedia/Ferkel

In the meantime, he added, much needs to be done before astrobiology can confidently predict what forms life could take in our Universe:

“We propose a set of case studies that cover a broad range of life complexity properties. This provides a well-defined road map to developing the fundamentals. In some cases, such as the inevitability of parasites, the observation is enormously strong, and we have some intuitions about why this happens, but not yet a theoretical argument that is universal. Developing and proving these ideas will require novel connections among diverse fields, from computation and synthetic biology to ecology and evolution.”

The team’s paper, “Fundamental constraints to the logic of living systems,” appeared in Interface Focus (a Royal Society publication).

Further Reading: Santa Fe Institute, Interface Focus

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