Universe Today Feed

When we first began searching for planets around other stars, one of the surprising discoveries was that there are planets orbiting white dwarfs. The first exoplanets we ever discovered were white dwarf planets. Of course, these planets were barren and stripped of any atmosphere, so we had to look at main sequence stars to find potentially habitable worlds. Or so we thought.

As we discovered more white dwarf planets, it became clear that some of them might retain atmospheres and water. Perhaps they were an outer planet with a thick atmosphere before their star swelled to a red giant, or perhaps some of the gas ejected by the star to become a white dwarf was captured by the world. Regardless of the method, a small percentage of white dwarf planets retain an atmosphere. But to be habitable, they would need to migrate inward to the white dwarf in order to enter the habitable zone. We knew that planets could migrate during the red giant stage of their star, but it wasn’t until recently that computer simulations showed they could move close enough and remain in stable orbits within the potentially habitable zone of a white dwarf. So we now know that while the odds are long, it is possible for white dwarf stars with water-rich atmospheres to exist.

But there’s one other problem. White dwarfs don’t have nuclear engines in their cores. They can’t continue to generate heat for billions of years, but rather cool down gradually over time. This means that on a cosmic scale, their habitable zone shrinks and moves inward over time. Any planet in the center of the zone would soon find itself on the outer edge of the zone and eventually in the cold, inhospitable beyond. But a new study contradicts this idea, at least for some white dwarfs.

Habitable zone for a paused white dwarf. Credit: Vanderburg, et al

The study notes that about 6% of white dwarfs seem to pause their rate of cooling. This is likely due to a process known as distillation. Although the core of a white dwarf doesn’t undergo fusion, there are still processes such as radioactive decay and other nuclear interactions. As neutron-rich isotopes such as neon-22 distill, the interior of the white dwarf shifts, releasing a great deal of gravitational energy. This continues to heat the star, allowing it to maintain its temperature.

The team found that this distillation process can pause the cooling of a white dwarf for 10 billion years, meaning that the habitable zone of the white dwarf would be stable for that time. That’s roughly the same timespan as the lifetime of the Sun, so there would be plenty of time for life to evolve and thrive. This only occurs in a fraction of white dwarfs, but it means that our search for life on white dwarf stars should focus on those with paused cooling.

Reference: Vanderburg, Andrew, et al. “Long-lived Habitable Zones around White Dwarfs undergoing Neon-22 Distillation.” arXiv preprint arXiv:2501.06613 (2025).

The post White Dwarfs Pause Their Cooling, Giving Planets a Second Chance for Habitability appeared first on Universe Today.

In the more than sixty years where scientists have engaged in the Search for Extraterrestrial Intelligence (SETI), several potential examples of technological activity (“technosignatures”) have been considered. While most SETI surveys to date have focused on potential radio signals from distant sources, scientists have expanded the search to include other possible examples. This includes other forms of communication (directed energy, neutrinos, gravitational waves, etc.) and examples of megastructures (Dyson Spheres, Clarke Bands, Niven Rings, etc.)

Examples of modern searches include Project Hephaistos, the first Swedish Project dedicated to SETI. Named in honor of the Greek god of blacksmiths, this Project is focused on the search for technosignatures in general rather than looking for signals deliberately sent toward Earth. In a recent paper, a team led by the University of Manchester examined a Dyson Sphere candidate identified by Hephaistos. Their results confirmed that at least some of these radio sources are contaminated by a background Active Galactic Nucleus (AGN).

The team was led by Tongtian Ren, a Ph.D. student in astrophysics from the Jodrell Bank Centre for Astrophysics at the University of Manchester. He was joined by Prof. Michael Garrett, his supervisor at the University of Manchester, the Leiden Observatory, and the Institute of Space Sciences and Astronomy at the University of Malta; and Andrew Siemion, an Associate Research Astronomer at the Berkeley SETI Research Center, the SETI Institute, and the University of Oxford. The paper that describes their findings recently appeared in the Monthly Notices of the Royal Astronomical Society.

Dyson Spheres are a class of megastructures originally proposed by physicist Freemon Dyson, who proposed how advanced civilizations could create structures large enough to enclose their stars (thus harnessing all of their energy). Project Hephaestos, led by Prof. Erik Zackrisson, has published numerous papers exploring possible Dyson Sphere candidates using different methods and data sources. The fourth and most recent paper in the series focused on seven potential candidates (designated A to G) around M-type stars from a sample of 5 million detected by the ESA’s Gaia Observatory.

Previously, Ren and his team have investigated these candidates to identify possible natural explanations. As they explored in a previous paper, these include dust-rich debris disks that absorb light and re-emit it as infrared radiation. This will lead to an observed infrared excess, which Dyson proposed as a possible indication of his proposed megastructure. However, as they indicate in their most recent paper, the Project’s measurements do not appear to resemble typical debris disks. As Garrett explained to Universe Today via email:

“When I saw the original results from Project Hephaestos last year, I was skeptical – they had surveyed 5 million stars, and if you do that, there is a good chance your measurements might include emission from background sources. You don’t expect stars to show radio emission at this level, and it basically tells you that the radio emission is probably coming from background (radio) galaxies. But then you also need a special kind of galaxy that is faint in the optical but very bright in the infrared – the only galaxies I knew that had this characteristic are DOGs – Dust Obscured Galaxies.”

The team was also inspired by another paper by Jason T. Wright, a professor of astronomy and astrophysics at Penn State, the director of the Penn State Extraterrestrial Intelligence Center (PSETI), and a member of the Center for Exoplanets and Habitable Worlds (CEHW). In this paper, Wright hypothesized that a true Dyson Sphere might use radio emissions to discharge waste heat. This led them to consider the possibility that these candidates were indeed Dyson Spheres.

Artist’s impression of a bright, very early active galactic nucleus. Credit: NSF/AUI/NSF NRAO/B. Saxton

As Tongtian explained, they were also inspired by previous research by Garrett:

“Mike briefly argued in 2015 that even in a Kardashev Type I Civilization, where energy consumption is significantly higher than that of humans on Earth, their radio communication signals are too weak to detect. However, the Dyson Spheres could correspond to a Kardashev Type II Civilization—one that harnesses over a billion times more energy than a Type I Civilization. Therefore, regardless of whether the beings reside on planets or elsewhere near the Dyson Sphere, it might be possible to detect their use of similar electromagnetic technologies.”

To investigate these possibilities further, the team searched through data obtained by the enhanced Multi-Element Radio Linked Interferometer Network (e-MERLIN) and the European VLBI Network (EVN) for data on the brightest radio source (candidate G). To their surprise, they found that three candidates from Project Hephaestos had radio counterparts in the astronomy databases. As Tongtian explained, the most logical explanation is that these signals (including candidate G) were due to contamination from bright radio sources – Active Galactic Nuclei (AGN) – in the background:

“They shouldn’t belong to one civilization. Otherwise, many anomalous stars would be connected as a swarm in the sky, not isolated seven. At that moment, we realized that either different extraterrestrial civilizations located hundreds of light-years away all have mastered the same or similar advanced radio emission technologies, or these signals originate from some form of natural contamination. We preferred to assume that they were some natural objects beyond the Milky Way – and most likely to be hot DOGS.”

These results effectively confirmed their earlier hypothesis that at least some of the candidates identified by Project Hephaistos are contaminated by bright radio sources that are also very bright in the infrared wavelength. This causes them to mimic the characteristics that Freeman Dyson predicted and what astronomers expect from Dyson Spheres. However, this does not rule out the remaining six candidates and highlights the importance of thoroughly analyzing each candidate with high-resolution radio observations.

Artist’s impression of a Dyson Sphere, a megastructure associated with a Type II Civilization. Credit: SentientDevelopments.com

“We don’t know that all of the candidates are contaminated, but some, maybe all, probably are. I really hope some of them are indeed good Dyson Sphere candidates,” said Garrett. “This all shows that a multiwavelength approach is really required when looking for candidates in order to rule out background contamination.”

“The development of new astronomical instruments does not follow the rapid update cycles of consumer electronics—it takes decades,” added Tongtian. “Gaia (launched in 2013 and recently decommissioned) and WISE (launched in 2009 and expired in 2024) provided a crucial observational window. The next generation of similar probes may not be available for a long time, making it unlikely that a large-scale Dyson Sphere search program like Project Hephaistos will be conducted again in the near future. So the current seven Dyson Sphere candidates deserve to be carefully examined.”

Further Reading: arXiv, MNRAS

The post High-Resolution Imaging of Dyson Sphere Candidate Reveals no Radio Signals appeared first on Universe Today.

Sailing has been a mainstay of human history for millennia, so it’s no surprise that scientists would apply it to traveling in space. Solar sailing, the most common version, uses pressure from the Sun to push spacecraft with giant sails outward in the solar system. However, there is a more technologically advanced version that several groups think might offer us the best shot at getting to Alpha Centauri – light sailing. Instead of relying on light from the Sun, this technique uses a laser to push an extraordinarily light spacecraft up to speeds never before achieved by anything humans have built. One such project is supported by the Breakthrough Starshot Initiative, initially founded by Yuri Milner and Stephen Hawking. A new paper by researchers at Caltech, funded by the Initiative, explores how to test what force a laser would have on a light sail as it travels to another star.

The general concept of pushing something with light seems simple enough, but the devil is in the details in terms of how it will operate in space. The laser and spacecraft have to synchronize over millions of miles. If either so much as slightly move the angle they are set to, perhaps because a micrometeoroid hit them, then the mission fails either because the craft ends up in a different part of the galaxy or the laser doesn’t provide enough power to get it there in a reasonable amount of time.

Testing is the way to ensure such a disaster doesn’t happen, but even understanding how the physics of a light sail will work over such large distances is difficult. So, the researchers at Caltech, led by postdoc Lior Michaeli and PhD student Ramon Gao, built a setup to test those physics.

Lithographical image of the sample test bed, including springs connecting the corners of the sample.
Credit – Michaeli et al. / Caltech

Images provided as part of a press release to accompany their paper in Nature Photonics show a small square sample of light sail connected to a larger, hollowed-out square membrane by a set of four springs attached to each corner of the sample. What the images don’t do a good job of capturing is just how small the sample is —40 microns by 40 micros isn’t much compared to the 10 m2 for the final light sail design.

But it is a start, and the test rig introduced some interesting engineering challenges. The square is only 50 nm thick and made of silicon nitride. The springs are made of the same material, and the overall setup “looks like a microscopic trampoline,” according to the press release. 

When the sample was subjected to an argon laser, it vibrated. The researchers knew that this vibration was caused primarily by heat from the laser, and they needed to differentiate the vibration caused by heating from the force applied by the light itself. To do so, they turned to an instrument commonly used in space exploration—an interferometer.

Fraser discusses the difficulties of reaching another star.

In this case, it was a type known as a common-path interferometer. In this setup, the two laser beams of the interferometer travel essentially the same path and, therefore, encounter the same environmental conditions. When one laser hits a moving object, and one hits a stationary one, the difference in movement can be subtracted to tease out the signal the experimenter is looking for—in this case, the radiation pressure of the laser itself.

One further step was to integrate the interferometer with a microscope and a vacuum chamber, which eventually allowed measurements down to the level of a picometer in terms of the sample’s displacement. They also collected information about the mechanical properties of the silicon nitride springs used to hold the sample in place.

Once the test setup was confirmed, the next step was to move the angle, like they potentially would in a real-world scenario. In this case, they only angled the laser beam but still noticed a significant loss of pushing power. They theorized that light hitting the edge of the sail diffracted, causing a loss of that power that would otherwise be used to push the sail.

Fraser discusses Project Starshot in detail.

This test setup will allow researchers to test how to avoid such a fate for the long-term light sail mission. They already have some ideas about integrating nanomaterials and self-correcting forces that would allow the light sail to automatically move back into its optimal path. But any such advancements are a long way off. Despite the long journey ahead, developing this test bed is a step (or maybe a laser push) in the right direction.

Learn More:
Caltech – The Pressure to Explore: Caltech Researchers Take First Experimental Steps Toward Lightsails that Could Reach Distant Star Systems
UT – What Should Light Sails Be Made Out Of?
UT – What’s the Most Effective Way to Explore our Nearest Stars?
UT – Lightweight Picogram-Scale Probes Could be the Best way to Explore Other Star Systems

Lead Image:
Image of a free-floating lightsail (left) and depiction of the test-setup used at Caltech.
Credit – Michaeli et al. / Caltech

The post Measuring Lightsail Performance in the Lab appeared first on Universe Today.

The Hakuto-R 2 mission launched on January 15, 2025. It’s the successor to Hakuto-R, which launched in December 2022 but failed when it lost communications during its descent. Both missions carried rovers, and this image was captured by the rover Resilience as it travels toward the Moon.

The company behind Hakuto-R 1 and 2 is ispace. ispace develops robotics and other technologies that they intend to use to compete for commercial contracts. These missions are technology demonstration missions. Hakuto-R 1 carried the Emirates Lunar Mission, a rover named Rashid. Hakuto-R 2 carries ispace’s own micro-rover named Resilience.

ispace posted this image on social media with the text, “The RESILIENCE lander remains in excellent health as it continues to orbit Earth in its planned trajectory towards the Moon!”

“RESILIENCE knows what it means to be alone in the vastness of space. Looking back at Earth on Jan. 25, 2025, the lander was about 10,000km from our Blue Marble, poignantly capturing Point Nemo, the most remote place on our planet, about 2,688 kilometres from the nearest land.”

The most well-known picture of our Blue Marble came from astronauts on Apollo 17 in 1972. It appeared during a boom in environmental activism and helped people around the world understand the planet they live on and consider its future and our impact on it.

The Blue Marble image of Earth from Apollo 17. Image Credit: NASA

The second most well-known image of Earth is probably Carl Sagan’s Pale Blue Dot image. Voyager 1 captured that image in 1990 on its way to the outer Solar System. The spacecraft captured the image from 6 billion km away when it passed Saturn. Carl Sagan proposed the idea not for scientific reasons but to drive home the idea that humanity’s home was just a tiny dot in the dark.

The “pale blue dot” of Earth captured by Voyager 1 in Feb. 1990 (NASA/JPL)

It seems de rigueur now for space missions to turn around and capture an image of Earth on their way to their destinations.

OSIRIS REx did it.

Black and white image of Earth taken by the OSIRIS-REx’s NavCam 1 instrument. Image Credit: NASA/OSIRIS-REx team and the University of Arizona

So did Artemis 1’s Orion spacecraft.

On Flight Day 9, NASA’s Orion spacecraft captured imagery looking back at the Earth from a camera mounted on one of its solar arrays. Image Credit: NASA

So have Lucy and many others. Now, they’re as common as pictures of their homes that young people take as they leave for college.

Yet, we don’t seem to ever tire of them. For some reason.

Maybe it’s because we’re accustomed to looking at maps with borders and labels on them, emphasizing how we see our planet through a political and historical lens. In those images, the context is human.

But images of Earth from space have none of that. They show the true context of our planet. It’s a brilliant blue sphere, rippling with life, delicate and precious. It’s at the mercy of greater events that go on elsewhere in the Solar System and beyond, events beyond our control.

The people at ispace might not have intended their image to trigger this type of thinking. But regardless, this image takes its place in a long lineage of images of Earth captured by our departing spacecraft.

Hopefully, that lineage will continue for a long time.

The post Japanese Lander Looks Back at Earth as it Heads to the Moon appeared first on Universe Today.

A galactic merger is a chaotic event. When two massive structures like galaxies merge, their powerful gravitational forces wrench stars out of their usual orbits in a process called violent relaxation. In essence, the merging galaxies are evolving rapidly, and small perturbations can be amplified as the system moves toward a more stationary state.

Intuition suggests that this chaos should disrupt the galaxy, including its star formation, but new observations of the Arp 220 galaxy merger show that something else happens: the merger creates a massive magnetic field that traps gas and encourages more stars to form.

Arp 220 is one of the closest galaxy mergers to us. It’s also extremely bright in infrared and is considered to be the prototypical ULIRG—an Ultraluminous Infrared Galaxy. It’s the result of two spiral galaxies merging. The galaxies are gas-rich, which triggers starburst activity in Arp 220’s central regions. In new research, scientists from the Harvard and Smithsonian Center for Astrophysics and other institutions probed these central regions with the Submillimeter Array on Maunakea in Hawaii to better understand the magnetic fields.

The research is “Polarized Dust Emission in Arp220: Magnetic Fields in the Core of an Ultraluminous Infrared Galaxy.” It will be published in the Monthly Notices of the Royal Astronomical Society, and the lead author is David Clements from the Department of Physics at Imperial College in the UK.

ULIRGs are characterized by intense star formation and extreme luminosity in the infrared. “Arp 220 is the merger of two gas-rich spiral galaxies and hosts a massive starburst forming stars at a rate of ~ 100 solar masses per year,” the authors explain. The star formation is concentrated in two distinct nuclei in Arp 220’s center.

Since Arp 220 is the prototypical ULIRG, it’s a natural laboratory and a case study for understanding these objects and their starburst nature. The researchers aimed the Submillimeter Array (SMA) at Arp 220’s central regions to detect polarized light coming from polarized dust there. Since dust grains align themselves with magnetic fields, the SMA can detect and characterize magnetic fields by measuring polarity.

“Despite the potential impact of magnetic fields on galaxy structure, sub-mm observations of polarization in extragalactic sources remain sparse,” the authors explain in their paper. The first large-scale effort to measure this polarization was in 2002 when researchers published the first galaxy-averaged detection of sub-mm polarization. SOFIA (Stratospheric Observatory for Infrared Astronomy) provided another limited sample of dust polarization observations, but SOFIA ended in 2022.

Other efforts were made to detect the magnetic fields in the starburst regions, but they lacked the resolution to see the two regions separately. If each region or nuclei had different polarizations, the low resolution would dilute the polarization, possibly even making the magnetic fields undetectable. The authors explain that their efforts have overcome this problem. “We here present the results of sub-mm polarization observations of Arp220 at subarcsecond resolution using the Submillimeter Array. These are capable of resolving the separate nuclei and thus avoiding this dilution problem,” the authors write.

The authors explain that they detected polarized dust with a 6 sigma significance associated with the brighter, western nucleus. Six Sigma is a very strong detection, indicating a significant level of polarization created by powerful magnetic fields.

For Arp 220 to be undergoing starburst activity, a lot of cold gas needs to be concentrated in the starburst regions. However, starburst activity means a lot of young stars are forming. Young stars generate a lot of heat that disperses gas, creating an obstacle for continued star formation.

“To stop this happening, you need to add something to hold it all together – a magnetic field in a galaxy, or the lid and weight of a pressure cooker,” said lead author Clement in a press release.

NASA/ESA/CSA/STScI

“This is the first time we’ve found evidence of magnetic fields in the core of a merger,” Clements said, “but this discovery is just a starting point. We now need better models to see what’s happening in other galaxy mergers.”

Astronomers have long been puzzled by starburst galaxies, especially their unusually high star formation rate (SFR). When galaxies merge and become starburst galaxies, they appear to convert gas into stars more efficiently than standalone galaxies.

Astrophysicists have theorized about this property of starburst galaxies and what could cause it. Previous theoretical models have suggested that magnetic fields could help restrict the gas from dissipating, driving the starburst activity. However, this is the first time scientists have observed these fields.

This figure from the study shows the polarization angle on the left and the magnetic field angle on the right. “We detect polarized dust emission in Arp220 for the first time, with a peak polarized flux intensity
of 2.7 +/- 0.45 mJy close to the position of the western nucleus,” the authors write. The ellipses represent the rotating molecular disks, with the white crosses representing the positions of the nuclei. Image Credit: Clements et al. 2025.

According to study co-author Qizhou Zhang, also from the CfA, the magnetic fields do more than suppress the dispersal of star-forming gas. “Another effect of the magnetic field is that it slows down the rotation of gas in the disks of merging galaxies. This allows the force of gravity to take over, pulling the sluggish gas inward to fuel starbursts,” said Zhang. “The SMA has been one of the leading telescopes for high angular resolution observations of magnetic fields in molecular clouds in the Milky Way. It’s great to see that this study breaks new ground by measuring magnetic fields in merging galaxies.”

In contrast with observations of other nearby galaxies, the direction of the magnetic fields doesn’t seem to correspond with galactic outflow directions.

There are some other critical findings regarding the orientation of Arp 220’s magnetic fields. “Dust emission polarization is oriented roughly perpendicular to the molecular disk in the western nucleus,” the authors write. The polarization of dust emission is directly related to the orientation of the magnetic field, and this perpendicular orientation indicates that the magnetic field is oriented to the plane of the galactic disk. However, the magnetic field could be in the process of being reordered as the pair of nuclei interact. This points out how complex the merger environment is and how the magnetic fields are affected.

Finding these magnetic fields in Arp 220 strongly indicates that they’re behind the unexpected starburst activity. But it’s only one data point. A larger sample is needed to reaffirm these findings. The research team’s next step is to aim ALMA, the SMA’s big brother, at other galaxies like Arp 220 to see if they also have these magnetic fields.

“While the observations described here deal with just a single target, the nearest and brightest ULRG, Arp220, they suggest that magnetic fields may play a significant role in the processes underway in the innermost regions of major mergers,” the authors explain in their paper’s conclusion. “Observations in
search of dust polarization in the inner regions of other local ULIRGs and other DSFGs (Dusty Star-Forming Galaxy) are thus likely to bring new insights into these objects and how they evolve.”

Press Release: Astronomers Detect Missing Ingredient in Cooking Up Stars

New Research: Polarized Dust Emission in Arp220: Magnetic Fields in the Core of an
Ultraluminous Infrared Galaxy

The post Star Formation Might Depend on Galactic Magnetic Fields appeared first on Universe Today.

Every exoplanet discovery is an opportunity to refine models of planet formation, solar system architecture, habitable zones, and habitability itself. Each new planet injects more data into the scientific endeavour to understand what’s going on and how things got this way. However, some planets have such unusual characteristics that they invite a deeper focus and intense follow-up observations.

That’s the case for one new exoplanet. It’s a super-Earth on an unusual orbit that’s giving astronomers an opportunity to test the ideas of habitability and optimistic and pessimistic habitable zones.

The planet is named HD 20794 d, and it orbits a Sun-like star about 20 light-years away. Its eccentric orbit takes it from 0.7 to 1.5 AU from its host star. It spends half of its time beyond the putative habitable zone before travelling back into the zone and slightly inside of it.

Could life somehow survive on a planet like this?

In stellar terms, the exoplanet is right next door, and since the star is bright, the planet is in a great location for observation and study. The discovery of the planet was first reported in 2023, and in new research, a team of astronomers confirms its existence and points out how it’s in a prime location for further study.

The new research is “Revisiting the multi-planetary system of the nearby star HD 20794,” and it’s published in the journal Astronomy and Astrophysics. The lead author is N. Nari from the Instituto de Astrofísica de Canarias in Spain.

Though HD 20784 d was discovered a couple of years ago, it remained a candidate until this new research confirmed it. The planet was known as the 640 d planet because it appeared to have an approximately 640-day orbit around its star. This new study adds more observational details to the planet, including how it’s a great candidate for follow-up atmospheric study. Because it moves in and out of its star’s habitable zone, it’s an opportunity to learn more about habitability and to test and refine scientific models.

“HD 20794, around which HD 20794 d orbits, is not an ordinary star,” explains Xavier Dumusque, Senior Lecturer and researcher in the Department of Astronomy at the University of Geneva and co-author of the study. “Its luminosity and proximity make it an ideal candidate for future telescopes whose mission will be to observe the atmospheres of exoplanets directly.”

Since it’s so close and bright, it’s already been the target of observations. Exoplanetologists have 20 years of data from facilities like HARPS and ESPRESSO to work with. HARPS is the High Accuracy Radial Velocity Planet Searcher, and ESPRESSO is the Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations.

“HD 20794 has been part of long radial velocity (RV) surveys dedicated to the search for low-amplitude long-period signals around solar-type stars, with hundreds of nights of observations with HARPS and ESPRESSO spanning more than 20 years available,” the paper states.

Detecting the super-Earth was difficult. Twenty years of data helped, but it took the development of a new algorithm to find the planet in the data. It’s called YARARA, and it’s a data reduction algorithm recently developed at the University of Geneva (UNIGE). Planets are often obscured by noise in the data, and YARARA can sift through the data and filter out the noise.

“We analyzed the data for years, carefully eliminating sources of contamination,” explained Michael Cretignier, a post-doctoral researcher at Oxford University, co-author of the study and developer of YARARA. Cretignier is also the lead author of the 2023 paper that reported the initial detection of HD 20794 d.

The discovery of HD 20794 d has made astronomers want to monitor the star more closely. “The low stellar activity level and the brightness of HD 20794 has made this target one of the most well-suited candidates for this purpose,” the authors explain.

The system hosts three planets, and this research concludes that all three of them are super-Earths, though there’s some possibility that HD 20794 d could be a mini-Neptune with a non-negligible H/He atmosphere. It follows an elliptical orbit with an eccentricity of 0.45 and has about 5.8 Earth masses.

The planet’s most interesting feature is its orbit. “The orbital period of HD 20794 d resides both in the optimistic and conservative HZ,” the authors write in their research. “This is an interesting result because we do not have many examples of planets with M < 10 Earth masses with mass measurement from RVs in the HZ of Sun-like stars.”

The planet travels between the inner edge of its star’s HZ (0.75 AU) and outside of it (2 AU) as it follows its eccentric orbit. If the planet hosts water, it would shift from its frozen state to its liquid state and back again repeatedly.

This figure from the new research shows how HD 20794 d’s eccentric orbit takes it in and out of both the optimistic and pessimistic habitable zones during its 647-day orbit. Image Credit: Nari et al. 2025.

This is an exciting planet. Not only does it follow an unusual orbit, but it’s close to and orbits a bright star. “The closeness of the planetary system, summed with the distance of the star and the planet and the planet-to-star contrast ratio, makes this planet a good candidate for future atmospheric characterization through direct imaging facilities,” the authors write.

One of those facilities is the ANDES instrument on the European Southern Observatory’s Very Large Telescope (VLT). ANDES stands for ArmazoNes high Dispersion Echelle Spectrograph. AndES is a high-resolution instrument that can search for signs of life on Earth-like planets. The detection of biosignatures from exoplanet atmospheres is listed as one of the instrument’s top science cases.

Signs of biosignatures on HD 20794 d won’t jump out at scientists. It’ll take a lot of work among multiple scientific disciplines. Some of that work has begun.

Researchers at the Centre for Life in the Universe (CVU) at the UNIGE’s Faculty of Science are already studying the conditions for the planet’s habitability.

Press Release: A super-Earth laboratory for searching life elsewhere in the Universe

Paper: Revisiting the multi-planetary system of the nearby star HD 20794

The post A Super-Earth to Test the Limits of Habitability appeared first on Universe Today.

According to the Giant Impact Hypothesis, the Moon formed from a massive impact between a primordial Earth and a Mars-sized object (Theia) roughly 4.5 billion years ago. This is largely based on the study of sample rocks retrieved by the Apollo missions and seismic studies, which revealed that the Earth and Moon are similar in composition and structure. Further studies of the surface have revealed features that suggest the planet was once volcanically active, including lunar maria (dark, flat areas filled with solidified lava).

In the past, researchers suspected that these maria were formed by contractions in the interior that occurred billions of years ago and that the Moon has remained dormant ever since. However, a new study conducted by researchers from the National Air and Space Museum (NASM) and the University of Maryland (UMD) revealed small ridges on the Moon’s far side that are younger than those on the near side. Their findings constitute another line of evidence that the Moon still experiences geological activity billions of years after it formed.

The research was conducted by Cole Nypaver and Thomas R. Watters, a postdoctoral student and Senior Geologist with the NASM’s Center for Earth and Planetary Studies at the Smithsonian Institute. They were joined by Jackie Clark, an Assistant Research Scientist with UMD’s Department of Geology. The paper detailing their findings, “Recent Tectonic Deformation of the Lunar Farside Mare and South Pole–Aitken Basin,” recently appeared in the Planetary Science Journal.

Based on previous research, scientists have determined that the Moon once had a magnetic field. Like Earth’s, this field was powered by a dynamo in the Moon’s interior caused by a liquid outer core (surrounding a solid inner core) that rotated opposite to its axial rotation. However, crystallization began in the Moon’s core about 4 billion years ago, causing this dynamo to disappear between 2.5 and 1 billion years ago. This led to the disappearance of its magnetosphere and volcanic activity, ceasing about 3 billion years ago. As Clark summarized in a recent UMD press release:

“Many scientists believe that most of the Moon’s geological movements happened two and a half, maybe three billion years ago. But we’re seeing that these tectonic landforms have been recently active in the last billion years and may still be active today. These small mare ridges seem to have formed within the last 200 million years or so, which is relatively recent considering the moon’s timescale.”

Using advanced mapping and modeling, Nypang, Watters, and Clark found 266 previously unknown small ridges on the Moon’s far side. These were largely arranged in groups of 10 to 40 ridges that likely formed in narrow areas 3.2 to 3.6 billion years ago where underlying weaknesses in the lunar crust may have existed. Based on a technique known as “crater counting,” the team found that these ridges were notably younger than other features in their surroundings.

“Essentially, the more craters a surface has, the older it is; the surface has more time to accumulate more craters,” said Clark. “After counting the craters around these small ridges and seeing that some of the ridges cut through existing impact craters, we believe these landforms were tectonically active in the last 160 million years.”

New measurements of lunar rocks have demonstrated that the ancient Moon generated a dynamo magnetic field in its liquid metallic core (innermost red shell). Credit: Hernán Cañellas/Benjamin Weiss

The team also noted that the ridges observed on the far side of the Moon were similar in structure to ones found on the near side. This suggests both were created by the same forces, possibly by shallow moonquakes first detected by the Apollo missions. Scientists have since deduced that these are caused by a combination of shifts in the Moon’s orbit and its gradual shrinking – which explains why the Moon still experiences landslides. Understanding the factors that shape the lunar surface is of immense importance to future lunar missions.

As Clark indicated, this presents opportunities for further studies of lunar evolution:

“We hope that future missions to the moon will include tools like ground penetrating radar so researchers can better understand the structures beneath the lunar surface. Knowing that the moon is still geologically dynamic has very real implications for where we’re planning to put our astronauts, equipment and infrastructure on the moon.”

Further Reading: University of Maryland, The Planetary Science Journal

The post Evidence of Recent Geological Activity on the Moon appeared first on Universe Today.

The odds of a sizable asteroid striking Earth are small, but they’re never zero. Large asteroids have struck Earth in the past, causing regional devastation. A really large asteroid strike likely contributed to the extinction of the dinosaurs. So we shouldn’t be too surprised that astronomers have discovered an asteroid with a better than 1% chance of striking our world. Those odds are large enough we should keep an eye on them, but not large enough that we should start packing bags and fleeing to the hills.

The rock, named 2024 YR4, is somewhere between 40 – 100 meters wide, which would make it a “city killer” asteroid. If it does strike Earth, it wouldn’t decimate human civilization and cause mass extinctions, but it could destroy a heavily populated area if it struck a city, or trigger a tsunami if it struck the ocean. It would back a punch similar to the 1908 Tunguska event in Northern Siberia.

So what is the overall risk of 2024 YR4? The scale most commonly used for asteroid impact risks is known as the Torino Scale. It combines the overall size and relative speed of an object with its odds of impact to assign a number ranging from 0 to 10, where 0 means there is no risk of impact and 10 means it’s time to call Bruce Willis to save us all from extinction. That said, the highest number any asteroid has had on the scale is 4. This was for the asteroid Apophis soon after its discovery, which has now been downgraded to 0.

Currently, 2024 YR4 has a 3 on the scale, which means it “merits attention by astronomers.” It is currently the only object with a number other than 0 on the Torino Scale, and it means a couple of things come into play. The first is that the International Asteroid Warning Network (IAWN) will work to pin down the orbit of the asteroid. Chaired by NASA, the IAWN coordinates with observatories around the world to make detailed observations of 2024 YR4. It will take time to gather enough data. But what will likely happen is that they will determine there is no risk of collision, and 2024 YR4 will be demoted to 0 on the scale.

The second thing initiated is the Space Mission Planning Advisory Group (SMPAG), chaired by the European Space Agency. They have a scheduled meeting next week when there will be some initial discussions about a possible mission to 2024 YR4 to shift its orbit. If we do find there is a real risk of impact, this group would ramp up quickly. But again, this isn’t likely.

Statistically, asteroids the size of 2024 YR4 strike Earth every couple thousand years or so. This is why astronomers track these objects and are constantly looking for more. So even though the odds of an impact are never zero, with planning and preparation we should be able to ensure that any real risk can be mitigated.

The post An Asteroid Has a 1% Chance of Impacting Earth in 2032 appeared first on Universe Today.

Mars haunts us as a vision of a planet gone wrong. It was once warm and wet, with rivers flowing across its surface and (potentially) simple life residing in its water bodies. Now it’s dry and freezing.

Could Earth suffer this fate? Are there innumerable other worlds throughout the Universe that were habitable for a period of time before becoming uninhabitable?

To answer those questions, we have to answer one of the big questions in space science: What drove the changes on Mars? New research shows that hydrogen played a critical role in keeping ancient Mars warm for periods of time, as the planet’s temperature oscillated between warm and cold.

The research is “Episodic warm climates on early Mars primed by crustal hydration.” It’s published in Nature Geoscience, and the lead author is Danica Adams, a postdoctoral fellow in the Department of Earth and Planetary Sciences at Harvard University.

“Early Mars is a lost world, but it can be reconstructed in great detail if we ask the right questions.”

Robin Wordsworth, Harvard University.

There’s ample evidence of flowing surface water on ancient Mars. NASA’s Perseverance rover is exploring Jezero Crater, an ancient paleolake with deep sediment deposits carried there by flowing water. Satellite views show numerous ancient river channels. There’s also clear evidence of ancient lakes.

For a long time, the dominant scientific thought was that Mars was once warm and then became cold. In recent years, more thorough evidence suggests that Mars oscillated between being a warm and a cold planet.

If that’s true, what drove those oscillations?

The first difficulty in explaining early warm periods on Mars is the faint young Sun paradox. Astrophysicists calculate that the young Sun emitted only 70% of the energy it does now. How could Mars have had liquid surface water with so little solar output?

“It’s been such a puzzle that there was liquid water on Mars, because Mars is further from the sun, and also, the sun was fainter early on,” said lead author Danica Adams in a press release.

Evidence suggests that Mars once had enough water for an equivalent global ocean from 100 m to 1,500 m deep during the planet’s late Noachian period. Scientists have found hundreds of lakebeds from the Noachian, some as large as the Caspian Sea. However, the planet is suspected to have been too cold to host this much liquid water without a more efficient heat-trapping atmosphere. CO2 alone couldn’t do it, but researchers think that a more hydrogen-rich atmosphere could.

Lake Eridania, also known as the Eridania Sea, is a massive ancient lakebed on ancient Mars. It covered approximately 1.1 million sq. km. and was as deep as 1000 meters in some parts. Image Credit: By Jim Secosky chose this image NASA – https://photojournal.jpl.nasa.gov/figures/PIA22059_fig1.jpg, Public Domain, https://commons.wikimedia.org/w/index.php?curid=63303137

The problem is that hydrogen doesn’t tend to persist in atmospheres.

“Greenhouse gases such as H2 in a CO2-rich atmosphere could have contributed to warming through collision-induced absorption, but whether sufficient H2 was available to sustain warming remains unclear,” the authors write in their paper. Collision-induced absorption (CIA) is when molecules in a gas collide, and interactions from the collision allow molecules to absorb light. CIA could amplify the atmospheric CO2’s warming effect.

If there was a hydrogen source that allowed the atmosphere to replenish itself, that could explain how Mars oscillated between cold and dry and warm and wet. The researchers used a combined photochemical and climate model to understand how the atmosphere responded to climate variations and reactions between H2O and rock.

“Early Mars is a lost world, but it can be reconstructed in great detail if we ask the right questions,” said study co-author Robin Wordsworth from Harvard. “This study synthesizes atmospheric chemistry and climate for the first time to make some striking new predictions – which are testable once we bring Mars rocks back to Earth.”

The team’s research showed that early Mars had two distinct climate states that persisted for long timescales. The warm climate sustained surface liquid water and lasted between 100,000 and 10 million years. These periods were created and sustained by H2 from crustal hydration with some help from volcanic activity. During crustal hydration, water is lost to the ground, and H2 is released into the atmosphere. The cool climate lasted about 10 million years and featured a CO-dominated atmosphere caused by oxidant sinks in the planet’s surface.

This figure from the paper shows Mars’ H, C, and O chemistry, including ground sinks and escape processes. On the left are the cool and dry epochs triggered by oxygen lost to the crust. On the right are the warm and wet epochs driven by crustal hydration and oxidation that release H2. “In all epochs, CO2 and H2O photolysis (energy from photons represented in the cartoon as hv) drives the photochemistry, and escape of H, C and O is considered,” the authors write. In modern Mars, however, dissociative recombination is how oxygen primarily escapes. Image Credit: Adams et al. 2025.

“We find that H2 <molecular hydrogen> outgassing from crustal hydration and oxidation, supplemented by transient volcanic activity, could have generated sufficient H2 fixes to transiently foster warm, humid climates,” the authors explain.

The team’s models showed that Mars’ climate oscillated like this for about 40 million years during the Noachian and Hesperian periods. Each warm period lasted at least 100,000 years. According to the researchers, these timescales are in agreement with the length of time it took to carve Mars’ river valleys.

The planet’s atmospheric chemistry fluctuated during these periods. As sunlight struck CO2, it was converted to CO. During warm periods, the CO cycled back into CO2, and CO2 and H2 were dominant.

During cold periods, the CO recycling slowed down, CO built up in the atmosphere, and it triggered a more oxygen-reduced state. In this way, the redox state of the atmosphere oscillated dramatically over time.

“We’ve identified time scales for all of these alternations,” Adams said. “And we’ve described all the pieces in the same photochemical model.”

Mars’s modern-day surface supports the researchers’ alternating atmospheric redox hypothesis. The surface shows a “paucity of carbonates,” the researchers explain in their paper. These should form in an atmosphere dominated by CO2 where neutral pH water is present, as long as there is abundant open-system crustal alteration at the planet’s surface. Adams and her co-researchers say their hypothesis can explain the lack of carbonates.

Carbonates were first detected on Mars in 2008, and scientists expected to find large deposits of them. However, those large deposits were never found. If early Mars had abundant water for a long time, there would be abundant carbonates.

Though carbonates are present on Mars, they’re not abundant. If Mars had been wet for a long time, they should be abundant. Image Credit: ESA.

Mars’ surface rocks also contain both oxidized and reduced species of minerals. The authors say that is evidence the surface is far out of equilibrium, which their hypothesis supports. “While both oxidized and reduced species may form under one climate, the deposition rate of different species is sensitive to the climate. For example, warm climates preferentially deposit nitrate while cool climates preferentially deposit nitrite,” the authors write.

In any case, Mars is an extremely interesting puzzle. Without plate tectonics, its surface is largely unchanged from ancient times. Unlike Earth, which recycles its surface and erases evidence, evidence of Mars’ warm, wet periods is easy to see. “It makes a really great case study for how planets can evolve over time,” lead author Adams said.

Much of what scientists hypothesize about Mars can only be confirmed by in-situ measurements. The NASA rovers MSL Curiosity and Perseverance both have onboard labs to study rocks. Perseverance, however, is also caching rock samples for eventual return to Earth. Those samples, if they make it to Earth labs, will be critical in answering our questions about Mars.

“Hence, full interpretation of the redox paradox will require careful comparison of our alternating atmospheric redox hypothesis with chemical and isotopic datasets collected in situ and with igneous and water-altered rocks from the first 1–2 billion years of Mars’s history that comprise the samples presently being collected by the Perseverance rover,” the authors conclude.

This hypothesis raises questions about Mars’s habitability in the past. According to our understanding, oscillations between warm and wet and cold and dry pose a significant barrier to life starting and evolving. But that’s beyond the scope of this paper.

The post How Hydrogen Kept Early Mars Warm appeared first on Universe Today.

Sometimes, the best innovative ideas come from synthesizing two previous ones. We’ve reported before on the idea of having a balloon explore the atmosphere of Venus, and we closely watched the progress of the Mars Oxygen ISRU Experiment (MOXIE) as part of the Perseverance rover on Mars. When you combine the two, you can solve many of the challenges facing balloon exploration of Venus’ upper atmosphere – the most habitable place in the solar system other than Earth. That is the plan for Dr. Michael Hecht, the principal investigator of the MOXIE system and professor at MIT, and his team for the Exploring Venus with Electrolysis (EVE) project, which recently received as NASA Institute for Advanced Concepts (NIAC) Phase I grant as part of the 2025 NIAC awards.

Current ideas for balloon missions to Venus face two challenges. First, the buoyant gas they must use to stay afloat leaks out over time, limiting the mission duration. Second, they must carry large amounts of batteries to ensure their electronics (and, in some ways, the gases) can endure Venus’s 50-hour night cycle. If the gases inside the balloon get too cold, they depressurize, decreasing the balloon’s altitude.

Using a system akin to MOXIE would solve both of those problems. MOXIE famously created oxygen on Mars by splitting carbon dioxide in the atmosphere into carbon monoxide and oxygen by using a process called solid oxide electrolysis (SOE). Despite that project coming to an end, it showed the proof of concept that where there is carbon dioxide, we can make oxygen, even on other planets.

Technology has to be tough to last on Venus, as Fraser explains.

There is plenty of carbon dioxide in Venus’ upper atmosphere – in fact, that is primarily what the atmosphere there is composed of. Notably, both carbon monoxide and oxygen, the components the SOE process creates, are lighter than the carbon dioxide they’re created from. In other words, in Venus’ atmosphere, the outputs of the SOE process are buoyant.

But that’s not all – in an interview with Fraser, Dr. Hecht describes another advantage of using the SOE system. “When people ask me how MOXIE works, I always describe it as fuel cell running backwards” he said. But, during the Venusian night, “you could take some fraction, maybe 10% of the carbon monoxide and oxygen that you made during daytime and run it through the instrument backwards to get power a night.”

Not only would EVE get an unlimited amount of buoyant gases from the SOE process, but it would also essentially get unlimited electricity, even without sunlight and without the need for heavy batteries that would otherwise weigh it down. Other advantages include using carbon monoxide as a propellant for other powered aircraft for which the balloon could serve as a base station. Plenty of ideas come to mind when exploring the use cases of this platform.

There’s so much we don’t know about our sister planet – Fraser suggests we need to go back.

Doing this process on Venus has some added advantages as well. Given the thickness of the atmosphere, especially compared to Mars, the SOE system in Venus’ atmosphere would just need a fan rather than the miniaturized compressive pump used in the MOXIE system on Perseverance. Also, since Venus is much closer to the Sun, during the daytime, there will be abundant solar power to power the system, whereas on Mars, solar power is still an option, but the Perseverance rover ran off a radioisotope thermal generator instead.

Venus does have some unique challenges, though – there is also sulfuric acid, though not much of it, in the atmosphere. Dr. Hecht mentioned the need for a protective coating, like Teflon, on the components that would be exposed to the atmosphere. He didn’t seem worried about the mass increase either, mentioning, “How much mass is in your nonstick pan from the Teflon coating?”

However, a balancing act has to happen with the SOE process itself. Dr. Hecht mentions in his NIAC proposal the goal of a 75% conversion efficiency between CO2 and Oxygen/CO. If aiming for more than that – say 100% efficiency –  some of the CO created as part of the process is also electrolyzed, and the instrument becomes clogged with pure carbon (i.e., soot).

Fraser’s original interview with Dr. Hecht about the MOXIE system.

However, at the 75% efficiency range (which admittedly is about 3x more efficient than MOXIE was), the buoyancy of the oxygen and a combination of the leftover CO2 and CO is about equal, so you could split the two gas streams into separate chambers and have equal buoyancy, without tipping it one way or another.

Overall, this seems like an eminently practical solution to a problem with a long-standing idea in the future of Venus exploration. But why stop there? Dr. Hecht also mentioned that such a system would theoretically work on Titan and on other planets and moons with thick atmospheres. As EVE moves through the NIAC phases and the team starts detailed technical work on it, humanity will get closer to a technology that could revolutionize the exploration of our nearest planetary neighbor. 

Learn More:
NASA / Michael Hecht – Exploring Venus with Electrolysis (EVE)
UT – Perseverance Successfully Extracts Oxygen From the Martian Atmosphere. About 10 Minutes of Breathing Time for an Astronaut
UT – A Balloon Mission that Could Try to Confirm Life On Venus
UT – The Best Way to Learn About Venus Could Be With a Fleet of Balloons

Lead Image:
Artist concept highlighting the novel approach proposed by the 2025 NIAC awarded selection of Exploring Venus with Electrolysis (EVE)
Credit – NASA/Michael Hecht

The post A Balloon Mission That Could Explore Venus Indefinitely appeared first on Universe Today.

The study of asteroid samples is a highly lucrative area of research and one of the best ways to determine how the Solar System came to be. Given that asteroids are leftover material from the formation of the Solar System, they are likely to contain vital clues about how several key processes took place. This includes how water, organic molecules, and the building blocks of life were distributed throughout the Solar System billions of years ago. For this reason, space agencies have attached a high importance to the retrieval of asteroid samples that are returned to Earth for analysis.

This includes NASA’s Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer (OSIRIS-REx) mission. This spacecraft rendezvoused with asteroid (101955) Bennu on December 3rd, 2018, returning 121.6 grams of material (the largest sample ever) to Earth by September 2023. A recent analysis by scientists from NASA’s Goddard Space Flight Center revealed molecules key to life on Earth, including all five nitrogen bases – molecules required for building DNA and RNA. These findings support the theory that asteroids could have delivered the building blocks of life to Earth in the distant past.

The research was led by Daniel P. Glavin and Jason P. Dworkin, two senior scientists with the Solar System Exploration Division (SSED) at NASA Goddard. They were joined by multiple colleagues from the SSED, the Goddard Center for Research and Exploration in Space Science and Technology (CRESST), the Astromaterials Research and Exploration Science Division (ARES) at the NASA Johnson Space Center, and multiple universities and institutes. Their findings were presented in papers that appeared in Nature and Nature Astronomy.

A poster depicting all the compounds discovered in the OSIRIS-REx sample. ©NASA

Their results represent the first in-depth analyses of the minerals and molecules in the Bennu samples. Among the most compelling detections (reported in the Nature Astronomy paper) were 14 of the 20 amino acids life on Earth uses to make up protein cells. They also detected five nucleobases vital to DNA and RNA, which most complex lifeforms on Earth use to store and transmit genetic instructions, including how to arrange amino acids into proteins. As Associate Administrator Nicky Fox of the Science Mission Directorate at NASA Headquarters explained in a NASA press release:

“NASA’s OSIRIS-REx mission already is rewriting the textbook on what we understand about the beginnings of our solar system. Asteroids provide a time capsule into our home planet’s history, and Bennu’s samples are pivotal in our understanding of what ingredients in our solar system existed before life started on Earth.”

The teams also reported exceptionally high abundances of ammonia in the Bennu samples and formaldehyde. Ammonia is an important component in biology since it can react with formaldehyde to form complex molecules like amino acids. These building blocks have previously been detected in other rocky bodies, including meteorites retrieved on Earth. However, the way OSIRIS-REx found them in pristine condition on an asteroid supports the theory that objects that formed far from the Sun could have delivered the raw material for life throughout the Solar System. Said Glavin:

“The clues we’re looking for are so minuscule and so easily destroyed or altered from exposure to Earth’s environment. That’s why some of these new discoveries would not be possible without a sample-return mission, meticulous contamination-control measures, and careful curation and storage of this precious material from Bennu.”

Illustration of the asteroid Bennu. Credit: NASA Jet Propulsion Laboratory

Glavin and Dworkin’s team analyzed the Bennu samples for hints of compounds related to life on Earth. Meanwhile, Tim McCoy and Sara Russell, the curator of meteorites at the Smithsonian’s National Museum of Natural History in Washington and a cosmic mineralogist at the Natural History Museum in London (respectively), looked for evidence of where these molecules formed. As they reported in the study appearing in Nature, they discovered hints that they came from an ancient prebiotic environment.

These included traces of 11 minerals ranging from calcite to halite and sylvite, compounds that form from salts dissolved in water that become solid crystals (brines) once the water dissolves. Evidence of similar brines have been detected on Ceres, Saturn’s moon Enceladus, and other bodies in the Solar System. While scientists have also detected brines in meteorites that fell to Earth, they have never seen a complete set created by an evaporation process that could have lasted thousands of years or more. Moreover, some minerals found in Bennu have never been detected in other extraterrestrial samples.

Another analysis was carried out by members of the OSIRIS-REx sample analysis team, including researchers from the Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Hokkaido University, Keio University, Kyushu University, and Tohoku University. Together, they analyzed a 17.75 mg sample using high-resolution mass spectrometry for organic molecules with a ring structure containing carbon and nitrogen (N-heterocycles). This revealed a concentration of N-heterocycles 5-10 times higher than that reported from the sample taken from Ryugu (~5 nmol/g) by the Hayabusa2 mission.

In addition to the five nitrogenous bases, their analysis showed evidence of the purines xanthine, hypoxanthine, and nicotinic acid (vitamin B3). “In previous research, uracil and nicotinic acid were detected in the samples from asteroid Ryugu, but the other four nucleobases were absent,” said team member Dr. Toshiki Koga of JAMSTEC. “The difference in abundance and complexity of N-heterocycles between Bennu and Ryugu could reflect the differences in the environment to which these asteroids have been exposed in space.”

A mosaic image of asteroid Bennu, composed of 12 PolyCam images collected by the OSIRIS-REx spacecraft from a range of 24 kilometers. Credit: NASA/Goddard/University of Arizona

While these findings have provided compelling evidence of where the building blocks of life on Earth came from, several unanswered questions remain. For starters, amino acids can be created in “mirror-image” versions, similar to how complex lifeforms have a left and right side – hands, feet, brains, lungs, heat chambers, etc. While life on Earth almost exclusively exhibits the left variety, the Bennu samples contain an equal mixture of both. This could mean amino acids started in equal mixtures on Earth billions of years ago but made a left turn along the way.

This is not unlike theories regarding matter and antimatter in the early Universe and how “normal” matter came to be predominant. In any case, these findings are a key piece in the ongoing study of how and where life may have emerged in the Solar System. “OSIRIS-REx has been a highly successful mission,” said Dworkin. “Data from OSIRIS-REx adds major brushstrokes to a picture of a solar system teeming with the potential for life. Why we, so far, only see life on Earth and not elsewhere, that’s the truly tantalizing question.”

Further Reading: NASA, Hokkaido University, Nature Astronomy

The post The Building Blocks for Life Found in Asteroid Bennu Samples appeared first on Universe Today.

Though it’s a cold, dead planet, Mars still has its own natural beauty about it. This image shows us something we’ll never see on Earth.

Mars has only a thin, tenuous atmosphere, and most of it (95%) is carbon dioxide. When Martian winter arrives, CO2 freezes and forms a thick coating on the ground in the polar regions. It lies there dormant for months.

As Spring approaches, temperatures gradually warm. Sunlight passes through the translucent frozen layer of CO2, warming the ground beneath it.

The warming ground sublimates frozen CO2 into vapour that accumulates under the solid CO2. Eventually, the gas escapes through weak spots in the ice. It can erupt into geysers that spread darker material out onto the frozen surface.

Artist’s impression of geysers at the Martian south polar icecap as southern spring begins. Credit: NASA/JPL-Caltech/Arizona State University/Ron Miller

The HiRISE camera on NASA’s Mars Reconnaissance Orbiter captured this image of these geysers on Mars in October 2018. It has also captured other images of Martian CO2 geysers.

This HiRISE image shows different dark shapes and bright spots on sand dunes in Mars’ north pole region. The bright spots are where frozen CO2 sublimated into gas and erupted, spreading darker material on the surface. Image Credit: NASA/JPL-Caltech/Univ. of Arizona

Some of Mars’ CO2 geysers erupt and create dark spots as large as 1 km across. They are fueled by considerable power and can erupt at speeds up to 160 km/h.

Sometimes the eruptions create dark regions under the ice which look like spiders.

This NASA Mars Reconnaissance Orbiter image, acquired on May 13, 2018, during winter at the South Pole of Mars, shows a carbon dioxide ice cap covering the region and as the sun returns in the spring, “Mars spiders” begin to emerge from the landscape. Image Credit: NASA

Scientists are calling these features araneiform terrain or spider terrain. They are found in clusters that give the surface a wrinkled appearance. NASA scientists recreated these patterns in lab tests to understand the processes behind their formation. “The spiders are strange, beautiful geologic features in their own right,” said Lauren McKeown of NASA’s Jet Propulsion Laboratory in Southern California.

The process that explains how the CO2 cycle creates these features is called the Keiffer model. Hugh Keiffer was with the US Geological Survey when he and his colleagues published a paper explaining the model in 2006 in Nature titled “CO2 jets formed by sublimation beneath translucent slab ice in Mars’ seasonal south polar ice cap.”

“We propose that the seasonal ice cap forms an impermeable, translucent slab of CO2 ice that sublimates from the base, building up high-pressure gas beneath the slab. This gas levitates the ice, which eventually ruptures, producing high-velocity CO2 vents that erupt sand-sized grains in jets to form the spots and erode the channels,” Keiffer and his co-authors wrote in their paper.

This simple illustration shows what happens when Spring comes and frozen CO2 is warmed by solar insolation. As the CO2 sublimates into gas, pressure builds, and it erupts through weaknesses in the seasonal cap, carrying dust with it that creates dark spots on the surface. Image Credit: By BatteryIncluded – Own work by uploader: I scanned, cropped and resized the original image from a paper by Sylvain Piqueux. JGR, VOL. 108, no. E8, 5084, doi:10.1029/2002JE002007, 2003, Public Domain, https://commons.wikimedia.org/w/index.php?curid=7736765

Maybe humans are biased, but there’s nothing as beautiful and splendorous as Earth. Generations of poets have acclaimed its beauty to the point where it borders on the spiritual. However, when it comes to CO2 geysers and the natural patterns they create, Mars has something that Earth doesn’t.

“These processes are unlike any observed on Earth,” the authors of the 2006 paper stated.

Source: Geyser Season on Mars

The post These Bizarre Features on Mars are Caused by Carbon Dioxide Geysers appeared first on Universe Today.

What would you do for fun on another planet? Go ballooning in Venus’ atmosphere? Explore the caves of Hyperion? Hike all the way around Mercury? Ride a toboggan down the slopes of Pluto’s ice mountains? Or watch clouds roll by on Mars?

All those adventures, and more, are offered in a new book titled “Daydreaming in the Solar System.” But the authors don’t stop at daydreaming: York University planetary scientist John E. Moores and astrophysicist Jesse Rogerson also explain why the adventures they describe would be like nothing on Earth.

In the latest episode of the Fiction Science podcast, Moores says the idea behind the book was to tell “a little story that is really, really true to what the science is, and then give the reader an idea of what science there is that actually enables that story to take place.”

Trips to other worlds have been the stuff of science fiction for more than a century — going back to Jules Verne’s “From the Earth to the Moon” and continuing today with shows like “For All Mankind.” But most of those tales are told from the perspective of intrepid explorers who have to deal with life-threatening dramas.

In contrast, most of the stories in “Daydreaming in the Solar System” have to do with space travelers having fun, or handling the day-to-day challenges of living in an otherworldly locale.

John E. Moores and Jesse Rogerson tell tales of interplanetary adventures. (Credits: John E. Moores and York University)

“Often you’re visiting a place for the very first time, and of course it’s an amazing, awe-inspiring place, but you’re also very concerned about not dying,” Moores said. “So, we wanted to take that away — that bit of danger — so that people dive into the environment. Everywhere we went, we needed the right combination of an interesting activity, an interesting environment.”

Moores and Rogerson also use a second-person perspective. You’re the one riding a submarine through the hidden seas of Europa, an icy moon of Jupiter. You’re the one spelunking on Hyperion, a spongy Saturnian moon that appears to contain 40% empty space.

The end of each chapter takes a deeper dive into the peculiarities of each extraterrestrial environment. For example, riding a balloon around Venus makes sense because the surroundings at an altitude of 30 to 40 miles are similar to Earth’s when it comes to temperature and atmospheric pressure. In contrast, the surface of Venus is hellishly hot.

Ballooning on Venus is much more than a daydream. More than a decade ago, NASA engineers came up with a concept that called for sending habitable airships into the Venusian atmosphere. More recently, the Jet Propulsion Laboratory has been looking into a mission that would use robotic balloons to study the clouds of Venus.

“Daydreaming in the Solar System,” by John E. Moores and Jesse Rogerson. (Cover art by Michelle D. Parsons)

Similarly, the idea of sending mini-subs through Europa’s subsurface ocean is being considered as a follow-up to NASA’s Europa Clipper mission. A robotic submarine has also been proposed for exploring Titan’s hydrocarbon seas — although NASA’s Dragonfly mission to Titan, which relies on a rotorcraft, will be taking precedence.

The authors don’t shy away from the important issues: In one chapter, they describe in depth how to brew a delicious cup of coffee on Titan — and then explain why you could conceivably put on a pair of mechanical wings and flap your way through the Saturnian moon’s dense atmosphere after your morning cup of joe.

Will humans ever be able to experience the adventures described in the book? “I hope so,” Moores says.

“One thing that our publisher pointed out when we submitted our final manuscript, which wasn’t actually intentional, was that they felt that the book was actually very optimistic and very hopeful — just the framing of it, that you could imagine the future in a way that actually allows these things to happen,” he says. “So many other works are a little bit apocalyptic right now.”

My co-host for the Fiction Science podcast is Dominica Phetteplace, an award-winning writer who is a graduate of the Clarion West Writers Workshop and lives in San Francisco. To learn more about Phetteplace, visit her website, DominicaPhetteplace.com.

Check out the original version of this posting on Cosmic Log to get Moores’ recommendations for further reading, and stay tuned for future episodes of the Fiction Science podcast via Apple, Spotify, Player.fm, Pocket Casts and Podchaser. If you like Fiction Science, please rate the podcast and subscribe to get alerts for future episodes.

The post Science Points Out Paths to Interplanetary Adventures appeared first on Universe Today.

When astronomers detected the first long-predicted gravitational waves in 2015, it opened a whole new window into the Universe. Before that, astronomy depended on observations of light in all its wavelengths.

We also use light to communicate, mostly radio waves. Could we use gravitational waves to communicate?

The idea is intriguing, though beyond our capabilities right now. Still, there’s value in exploring the hypothetical, as the future has a way of arriving sooner than we sometimes think.

New research examines the idea and how it could be applied in the future. It’s titled “Gravitational Communication: Fundamentals, State-of-the-Art and Future Vision,” and it’s available on the pre-press site arxiv.org. The authors are Houtianfu Wang and Ozgur B. Akan. Wang and Akan are both with the Internet of Everything Group, Department of Engineering, University of Cambridge, UK.

“Gravitational waves can maintain consistent signal quality over immense distances, making them suitable for missions beyond the solar system.”

Houtianfu Wang and Ozgur B. Akan.

“The discovery of gravitational waves has opened a new observational window for astronomy and physics, offering a unique approach to exploring the depths of the universe and extreme astrophysical phenomena. Beyond its impact on astronomical research, gravitational waves have also garnered widespread attention as a new communication paradigm,” the authors explain.

Traditional electromagnetic communications have definite drawbacks and limitations. Signals get weaker with distance, which restricts range. Atmospheric effects can interfere with radio communications and diffuse and distort them. There are also line-of-sight restrictions, and solar weather and space activity can also interfere.

What’s promising about gravitational wave communication (GWC) is that it could overcome these challenges. GWC is robust in extreme environments and loses minimal energy over extremely long distances. It also overcomes problems that plague electromagnetic communication (EMC), like diffusion, distortion, and reflection. There’s also the intriguing possibility of harnessing naturally created GWs, which means reducing the energy needed to create them.

“Gravitational communication, also known as gravitational wave communication, holds the promise of overcoming the limitations of traditional electromagnetic communication, enabling robust transmission across extreme environments and vast distances,” the authors point out.

Artist’s impression of gravitational waves. Image credit: NASA

To advance the technology, researchers need to create artificial gravitational waves (GWs) in the lab. That’s one of the primary goals of GW research. GWs are extremely weak, and only enormous masses moving rapidly can generate them. Even the GWs we’ve detected coming from merging supermassive black holes (SMBHs), which can have billions of solar masses, produce only miniscule effects that require incredibly sensitive instruments like LIGO to detect.

Generating GWs that are strong enough to detect is a necessary first step.

“The generation of gravitational waves is pivotal for advancing gravitational communication, yet it remains one of the foremost challenges in contemporary technological development,” the authors write. “Researchers have explored various innovative methods to achieve this, including mechanical resonance and rotational devices, superconducting materials, and particle beam collisions, as well as techniques involving high-power lasers and electromagnetic fields.”

There is plenty of theoretical work behind GWC but less practical work. The paper points out what direction research should take to bridge the gap between the two.

Obviously, there’s no way to recreate an event as awesome as a black hole merger in a laboratory. But surprisingly, researchers have been considering the problem as far back as 1960, long before we’d ever detected GWs.

An artistic image inspired by a black hole-neutron star merger event. Credit: Carl Knox, OzGrav/Swinburne

One of the first attempts involved rotating masses. However, the rotational speed required to create GWs was impossible to achieve, partly because the materials weren’t strong enough. Other attempts and proposals involved piezoelectric crystals, superfluids, particle beams, and even high-power lasers. The issue with these attempts is that while physicists understand the theory behind them, they don’t have the right materials yet. Some attempts generated GWs, scientists think, but they aren’t strong enough to be detectable.

“High-frequency gravitational waves, often generated by smaller masses or scales, are feasible for artificial production under laboratory conditions. But they remain undetectable due to their low amplitudes and the mismatch with current detector sensitivities,” the authors explain.

More advanced detection technologies or some method to align generated GWs with existing detection capabilities are needed. Existing technologies are aimed at detecting GWs from astrophysical events. The authors explain that “Research should focus on designing detectors capable of operating across broader frequency and amplitude ranges.”

While GWs avoid some of the problems that EM communications face, they aren’t without problems. Since they can travel vast distances, GWC faces problems with attenuation, phase distortion, and polarization shifts from interacting with things like dense matter, cosmic structures, magnetic fields, and interstellar matter. These can not only degrade the signal’s quality but can also complicate decoding.

This conceptual illustration shows what effects GWs are subjected to as they propagate. “The signal first experiences large-scale influences such as gravitational and cosmological frequency shifts, followed by broad-scale amplitude attenuation due to cosmic expansion and weak scattering. Next, more region-specific factors induce polarization changes, and finally, localized distortions arise in the form of phase variations and fading effects caused by gravitational lensing and other fine-scale phenomena. Additive noise is introduced near the receiver end,” the authors write. Image Credit: Wang and Akan, 2025.

There are also unique noise sources to consider, including thermal gravitational noise, background radiation and overlapping GW signals. “Developing comprehensive channel models is essential to ensure reliable and efficient detection in these environments,” the authors write.

In order to ever make use of GWs, we also need to figure out how to modulate them. Signal modulation is critical to communications. Look at any car radio and you see “AM” and “FM.” AM stands for “Amplitude Modulation” and FM stands for “Frequency Modulation.” How could we modulate GWs and turn them into meaningful information?

“Recent studies have explored diverse methods, including astrophysical phenomena-based amplitude modulation (AM), dark matter-induced frequency modulation (FM), superconducting material manipulation, and nonmetricity-based theoretical approaches,” the authors write. Each one of these holds promise as well as being choked with obstacles.

For example, we can theorize about using dark matter to modulate GW signals, but we don’t even know what dark matter is. “Frequency modulation involving ultralight scalar dark matter (ULDM) depends on uncertain assumptions about dark matter’s properties and distribution,” the authors write, addressing an elephant in the room.

It might seem as if GWC is out of reach, but it holds so much promise that scientists are unwilling to abandon it. In deep space communications, EM communication is hamstrung by the vast distances and interference from cosmic phenomena. GWC offers solutions to these obstacles.

This image shows how GWC can be used in our own Solar System and in interstellar communications. Where conventional communications would simply fade away on the long journey between stars, GWC will not. Image Credit: Wang and Akan, 2025.

A better method to communicate over long distances is critical to exploring deep space, and GWC is exactly what we need. “Gravitational waves can maintain consistent signal quality over immense distances, making them suitable for missions beyond the solar system,” the authors write.

Practical gravitational wave communication is a long way off. However, what was once only theoretical is gradually shifting into the practical.

“Gravitational communication, as a frontier research direction with significant potential, is gradually moving from theoretical exploration to practical application,” Wang and Akan write in their conclusion. It will depend on hard work and future breakthroughs.

The pair of researchers know that much hard work is needed to advance the idea. Their paper is deeply detailed and comprehensive, and they hope it will be a catalyst for that work.

“Although a fully practical gravitational wave communication system remains unfeasible, we aim to use this survey to highlight its potential and stimulate further research and innovation, especially for space communication scenarios,” they conclude.

The post Communicating with Gravitational Waves appeared first on Universe Today.

To the casual observer, the Sun seems to be the one constant and never changing. The reality is that the Sun is a seething mass of plasma, electrically charged gas which is constantly being effected by the Sun’s magnetic field. The unpredictability of the activity on the Sun is one of the challenges that faces modern solar physicists. The impact of coronal mass ejections are one particular aspect that comes with levels of uncertainty of their impact. But machine learning algorithms could perhaps have given us more warning! A new paper suggests algorithms trained on decades of solar activity saw all the signs of increased activity from the region called AR13664 and perhaps can help with future outbursts.

Coronal Mass Ejections or CMEs, are massive bursts of plasma ejected from the Sun’s corona into space due to disruptions in the Sun’s magnetic field. These explosive events are often linked to flares and occur when magnetic field lines suddenly realign, releasing vast amounts of energy. CMEs can travel at speeds ranging from a few hundred to several thousand kilometres per second, sometimes reaching Earth within days, if their trajectory is in our direction. When they arrive, they can interact with our magnetosphere and trigger geomagnetic storms, potentially disrupting satellite communications, GPS systems, and power grids. Additionally, they can lead to auroral activity, creating breathtaking displays of the northern and southern lights.

A colossal CME departs the Sun in February 2000. erupting filament lifted off the active solar surface and blasted this enormous bubble of magnetic plasma into space. Credit NASA/ESA/SOHO

Accurately forecasting these types of events and how they impact our magnetosphere has been one of the challenges facing astronomers. In a study authored by a team of astronomers led by Sabrina Guastavino from the University of Genoa, they applied artificial intelligence to the challenge. They used the new technology to predict the events that were associated with the May 2024 storm, the corresponding flares from the region designated 13644 and CMEs. The storm unleashed intense solar events including a flare classed as an X8.7!

Earth’s magnetosphere

Using AI the team were able to point machine learning technology to the vast amounts of previously collected data to uncover complex patterns that were not easy to spot using conventional techniques. The 2024 event was a great, and unusual opportunity to test the AI capability to predict solar activity. The chief objective was to predict the occurrence of solar flares, at how they changed over time, CME production and ultimately, to predict geomagnetic storms here on Earth. 

They ran the process against the May 2024 event with impressive results.  According to their paper, the prediction revealed ‘unprecedented accuracy in the forecast with significant reduction in uncertainties with respect to traditional methods.’ The results of the CME travel times to Earth and the onset of geomagnetic storms was also impressively accurate. 

The impact of the study is profound. Power grid outages, communication and satellite issues can be a major disadvantage when CMEs hit Earth so the application of the machine learning AI toolset to predicting solar activity looks like an exciting advance. For those of us keen sky watchers, we may also get a far better forecast of auroral activity too. 

Source : Artificial Intelligence Could Have Predicted All Space Weather Events Associated with the May 2024 Superstorm

The post Machine Learning Could Have Predicted the Powerful Solar Storms in 2024 appeared first on Universe Today.

New images from NASA’s Juno spacecraft make Io’s nature clear. It’s the most volcanically active world in the Solar System, with more than 400 active volcanoes. Juno has performed multiple flybys of Io, and images from its latest one show an enormous hotspot near the moon’s south pole.

Juno was sent to Jupiter to study the giant planet, but that primary mission ended, and NASA extended the mission. Currently, it is performing flybys of three of the Galilean moons: Ganymede, Europa, and Io. We’ve reported on Juno’s Io flybys previously.

In its latest flyby, the orbiter imaged a volcanic hotspot on the moon’s south pole larger than Lake Superior. The images are from Juno’s JIRAM (Jovian Infrared Auroral Mapper) instrument. According to NASA, the hot spot’s eruptions are six times more energetic than all of Earth’s power plants and its radiance measured well above 80 trillion watts.

“The data supports that this is the most intense volcanic eruption ever recorded on Io.”

Alessandro Mura, Juno co-investigator, National Institute for Astrophysics in Rome

“Juno had two really close flybys of Io during Juno’s extended mission,” said the mission’s principal investigator, Scott Bolton of the Southwest Research Institute in San Antonio. “And while each flyby provided data on the tormented moon that exceeded our expectations, the data from this latest — and more distant — flyby really blew our minds. This is the most powerful volcanic event ever recorded on the most volcanic world in our solar system — so that’s really saying something,” Bolton said in a NASA press release.

A map of Io with prominent features labelled. The new hot spot is roughly in the vicinity of Lerna Regio. Image Credit: By NASA/JPL/USGS/Jason Perry – https://astrogeology.usgs.gov/Projects/JupiterSatellites/io.html, Public Domain, https://commons.wikimedia.org/w/index.php?curid=9096280

Io is volcanic because of tidal heating. Io is the innermost of Jupiter’s four Galilean moons and is roughly the same size as Earth’s Moon. However, it’s very close to the much larger Jupiter, follows an elliptical orbit, and completes one every 42.5 hours. Jupiter is roughly 300 times more massive than Earth. That means that Jupiter dwarfs Io, and as the moon orbits the gas giant, the gas giant has its way with it. Jupiter stretches and pulls on the little moon, causing it to flex and change shape, creating internal heat. The other Galilean moons also contribute.

This simple graphic explains tidal heating on Io. (A) Of the four major moons of Jupiter, Io is the innermost one. Gravity from these bodies pulls Io in varying directions. (B) Io’s eccentric orbit. Io’s shape changes as it completes its orbit. (C) Earth’s moon’s orbit is actually more eccentric than Io’s, but Earth’s gravity is much weaker than Jupiter’s, so Earth’s moon does not experience as much deformation. Image Credit: By Lsuanli – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=31959004

The heat is enough to melt the moon’s interior into molten rock. The tidal flexing creates an endless series of plumes and ash that make the moon the most volcanically active body in the Solar System. The ash also paints the small moon’s surface.

During its extended mission, Juno flies past Io on every other orbit, meaning the images can track any changes on the surface. During a previous flyby on February 3rd, 2024, Juno came within 1,500 km (930 mi) of the moon’s surface.

This image shows Juno’s path over Io on February 3rd, 2024, the spacecraft’s closest flyby of the volcanic moon. The path is colour-coded by altitude. Image Credit:

During this latest flyby, it was much further away. It only got to within about 74,400 kilometres (46,200 mi) of the moon, and its JIRAM instrument was pointed at the south pole.

“JIRAM detected an event of extreme infrared radiance — a massive hot spot — in Io’s southern hemisphere so strong that it saturated our detector,” said Alessandro Mura, a Juno co-investigator from the National Institute for Astrophysics in Rome. “However, we have evidence what we detected is actually a few closely spaced hot spots that emitted at the same time, suggestive of a subsurface vast magma chamber system. The data supports that this is the most intense volcanic eruption ever recorded on Io.”

This feature, which has yet to be named, dwarfs Loki Patera, the lake of lava detected in 2015 during a rare orbital alignment between Io and Europa. Loki Patera is 202 kilometres (126 mi) in diameter, covers 20,000 sq km (7,700 sq mi), and was the largest volcanic feature found on Io until these new observations revealed the hot spot in the south polar region. The new hot spot covers 100,000 sq km (40,000 sq mi).

Juno also captured images of the hot spot region with its JunoCam imager. Though the images were captured from different distances and are somewhat grainy, they still reveal surface colour changes near the south pole. Scientists know that these colour changes are associated with hot spots and volcanic activity.

Juno’s JunoCam imager captured these images of Io in 2024. They show significant and visible surface changes (indicated by the arrows) near the Jovian moon’s south pole. These changes occurred between the 66th and 68th perijove, or the point during Juno’s orbit when it is closest to Jupiter. Image Credit: NASA/JPL-Caltech/SwRI/MSSS. Image processing by Jason Perry

Juno will fly by Io again on March 3rd. It will examine the hotspot again and try to discern any more surface changes. Massive eruptions like this one leave their mark on the surface, and these marks can be long-lived. The eruptions can leave behind pyroclastic deposits, lava flows, and sulphur-rich deposits from plumes that colour the moon’s surface. It’s also possible that Earth-based observations can probe the same region.

Scientists have unanswered questions about Io’s extreme volcanic activity. They know tidal heating is the root cause, but they don’t have a clear understanding of how the heat moves through Io’s interior. They also don’t know if the moon has a global, subsurface lava ocean, though some studies suggest it does. They also wonder about the relationship between the volcanoes and Jupiter’s magnetosphere, where much of the material from the volcanoes goes. The long-term evolution of Io’s volcanic activity is also shrouded in mystery. How has it changed over time?

This is a map of the predicted heat flow at the surface of Io from different tidal heating models. Red areas are where more heat is expected at the surface, while blue areas are where less heat is expected. Figure A shows the expected distribution of heat on Io’s surface if tidal heating occurred primarily within the deep mantle, and Figure B is the surface heat flow pattern expected if heating occurs primarily within the asthenosphere. In the deep mantle scenario, surface heat flow concentrates primarily at the poles, whereas in the asthenospheric heating scenario, surface heat flow concentrates near the equator. Credit: NASA/Christopher Hamilton.

Answers to these questions will also tell scientists about volcanism on other worlds.

“While it is always great to witness events that rewrite the record books, this new hot spot can potentially do much more,” said Bolton. “The intriguing feature could improve our understanding of volcanism not only on Io but on other worlds as well.”

The post Juno Sees a Massive Hotspot of Volcanic Activity on Io appeared first on Universe Today.

Comet G3 ATLAS wows southern hemisphere observers and Universe Today readers before it fades from view.

Comet G3 ATLAS, captured along with the 6.5-meter Magellan Telescope at the Las Campanas Observatory in the Atacama Desert in Chile on January 22nd. Image credit: Yuri Beletsky.

Comets are always a true celestial treat to track. In a clockwork cosmos, the appearance of a potentially bright new comet is always a celestial question mark: will it perform up to expectations, or fizzle from view? Such was the case with Comet C/2024 G3 ATLAS.

Comet G3 ATLAS imaged from Namibia on January 20th courtesy of Clyde Foster. “The comet is putting on quite a show…” says Clyde. “And can’t have photos like that, without our beloved Namibian Camelthorn trees!”

Discovered on the night of April 25th, 2024 by the Asteroid Terrestrial-impact Last Alert System (ATLAS) survey, the comet showed potential near perihelion in 2025.

Comet G3 ATLAS as seen from Middlemarch Otago, New Zealand. Credit: Ian Griffin Demise of a Comet

Of course, such a close pass is always fraught with uncertainty: good cases in point are C/2012 S1 ISON which disintegrated on U.S. Thanksgiving Day 2013, and W3 Lovejoy which survived a blistering perihelion just 140,000 km (!) from the surface of the Sun, and went on to become another fine southern hemisphere comet in late 2011 and early 2012.

Comet C/2024 G3 ATLAS paired with Venus at dusk on January 24th over the Atacama Desert in Chile, courtesy of Daniele Gasparri. Daniele notes on Space Weather it was “…a scene of rare beauty: comet C/2024 G3 ATLAS was perfectly visible to the naked eye, its very long tail standing out against the colors of the sunset and extending all the way toward Venus. Between these two ‘giants’ of the sky, I could see Saturn, the zodiacal light, and a thin greenish band of airglow.”

Comet G3 ATLAS faced just such a perilous passage, reaching perihelion 14 million kilometers from the Sun on January 13th. SOHO’s venerable LASCO C3 imager caught the comet near the Sun, as it topped -3.8 magnitude, the brightest comet since P1 McNaught in 2007.

Comet G3 ATLAS crosses from SOHO’s LASCO C3 view, into STEREO Ahead’s Hi1 imager. Credit: NASA/STEREO/SOHO image compilation: Fred Deters. Amazing Comet Captures

Reader images soon poured in, as the comet took the plunge southward and unfurled a fine dust tail. The comet was a bashful one for folks up north, as it only popped up north of the ecliptic from January 8th until January 15th. It always seems that bright comets have a ‘thing’ for southern hemisphere skies.

Comet G3 ATLAS, as seen from the International Space Station. Credit: Don Pettit/NASA

Few observers saw the comet post-perihelion up north. A few skilled astrophotographers did manage to nab dusty streaks of the tail known as syndynes above the dusk horizon. One bizarre fact when it comes to comets: the tails are blown back by the solar wind, meaning the dust and ion tails of G3 ATLAS precede ahead of the comet outbound.

This capture of the comet by Filipp Romanov over the Sea of Japan shows just how difficult the comet was the see for observers up north.

Alas, perihelion seemed to have a delayed impact on the comet. Images taken around January 18th showed that the nucleus seemed to be in ill-health. G3 ATLAS soon became a ‘headless comet’ with a fading nucleus and a still-bright tail. The tail produced a remarkable striped look as a finale.

Lionel Majzik first discovered the breakup and demise of the nucleus of Comet G3 ATLAS, as seen in this amazing sequence spanning January 18th to the 23rd. The Future for Comet G3 ATLAS

Currently, comet G3 ATLAS shines at +5th magnitude and fading, in the constellation Piscis Austrinus.

The many tails of Comet G3 ATLAS, courtesy of Daniele Gasparri. “Comet G3 ATLAS seems unwilling to leave our sky,” Daniele notes.

The comet was on a 160,00 year orbit inbound. Estimates put in on an 600,000-year outbound orbit. That is, for whatever fragments may remain to revisit the inner solar system on a far off date.

…and be sure to catch astrophotographer Dylan O’Donnell’s story about the perils of comet hunting:

That does it. We’re moving to the southern hemisphere, to ‘comet country’. For now, though, we can all enjoy these spectacular views of Comet G3 ATLAS. Hopefully, this was the first good comet of 2025.

The post Requiem for a Comet: Amazing Reader Views of G3 ATLAS appeared first on Universe Today.

Novel propulsion systems are one of the most important ways to push space exploration forward – literally. Traditional propulsion systems, like chemical rockets, are good at getting spacecraft out of gravity wells but not so great at traveling in free space. More modern systems, like electric propulsion, are better at providing long-term propulsion but are very slow. Others haven’t even made it to space, like nuclear thermal rockets. But there’s one type that could trump them all – fusion propulsion. It has the benefit of significant thrust and excellent fuel efficiency and could open up the whole solar system in ways other systems could only dream of. One company, Helicity Space, thinks they are on the path to developing a working version of just such a fusion propulsion system, and they just received a NASA Institute of Advanced Concepts (NIAC) grant to continue its development.

The NIAC grant itself focuses on exploring the heliosphere—an area surrounding the Sun (including on top of it) that our star influences. It is huge in terms of the amount of space covered and not well understood because, typically, missions only stay in the plane of the ecliptic, and if they go far enough to reach the outer stretches of the heliosphere, it is only after decades of travel, like the Voyager space probes.

Helicity proposes using fusion rockets to send a constellation of spacecraft to all parts of the heliosphere with sensors to detect things such as plasma properties, the amount of energetic particles, and the amount of dust in a given region. This constellation could provide heliophysics with a much more complete picture of what the heliosphere looks like.

The idea of fusion rockets have been around for a long time, as Fraser discusses.

However, the real innovation the NIAC grant focuses on isn’t sensor instrumentation but the propulsion system. Fusion propulsion has been a dream of many space exploration enthusiasts for decades. Still, it has seemed to suffer from the same fate of technical development hell that its ground-based cousins, the large-scale power-positive fusion plants, have. The physics of plasma constraint and forced fusion are challenging, to say the least, so projects like the International Thermonuclear Experimental Reactor (ITER) cost billions of dollars and take decades to complete.

Helicity, on the other hand, is a scrappy start-up based in Pasadena, and they believe they can produce a functioning fusion engine well before ITER hits its full power in 2035. In an interview with Fraser, Setthivoine You, the company’s co-founder and chief technologist, explains that if you’re trying to make money from a fusion power plant, “you need to do net gains of 20, 30, 40, 50 [times] more fusion energy out than what you put in [and] you have to do it every single second, 24 hours a day, 365 days a year.”

On the other hand, Helicity’s engine doesn’t have to operate constantly and can produce net gains of only 10x, and only occasionally. In such an operational mode, the engineering challenge becomes much more tractable. The company has already built a prototype unit at its facility in Pasadena and has been presenting at several conferences and publishing academic papers detailing its progress all along.

Isaac Arthur covers the details of fusion propulsion systems.
Credit – Isaac Arthur YouTube Channel

The NIAC grant will allow them to start fleshing out the technical details of what the engine would require to complete the heliosphere mission, allowing them to tweak the engine to get to those performance metrics. But that’s not the only mission this system can be used for. Getting to Mars in about a month and a half, rather than the nine months using traditional propulsion, has been one of the space exploration community’s main selling points to such a system.

During the interview, Fraser mentioned even more outlandish missions, like one to the solar gravitational lens point, where we could use the Sun’s gravitational lensing effect to image exoplanets around other stars directly. Dr. You mentioned, “Our proposal could take us out there in less than 10 years”, dramatically shorter than any currently proposed propulsion system. Unlike alternatives like giant solar sails, it would also have the added benefit of slowing down and holding its position.

In addition to the advanced propulsion system, though, Helicity mentions developing additional technologies that could directly benefit people back on the ground as part of their proposal. Dr. You mentions “high-high solid-state switches, energy storage, systems, [and] magnetic coils” as potentially useful tools that would result from the development of the engine.

Where fusion rockets lie compared to other forms of propulsion in terms of power and efficiency.
Credit – Helicity Space

Much of the challenges facing the development team appear to focus on developing these “subsystems inside plasma sources,” which is one particular challenge Dr. You calls out, along with several other engineering challenges. Basically, proving the engine will work in space is the biggest technical hurdle at this point – and the Phase I NIAC grant is another step towards doing so.

It is not the first step, however—Helicity is backed by several VC firms and large aerospace companies, including Airbus and Lockheed Martin. The fact that they already have an experimental system up and running also lends credence to their ability to execute the mission of bringing fusion power to space. If they manage to do so, a long-held dream of space exploration enthusiasts will be realized, and the whole solar system will be opened up for human use.

Learn More:
NASA / Helicity Space – Fusion-Enabled Comprehensive Exploration of the Heliosphere
Helicity Space – Technology
UT – Magnetic Fusion Plasma Engines Could Carry us Across the Solar System and Into Interstellar Space
UT – Impatient? A Spacecraft Could Get to Titan in Only 2 Years Using a Direct Fusion Drive

Lead Image:
Image of the heliosphere and an artist’s concept of the fusion drive ship that could be sent to monitor it.
Credit – NASA / Helicity Space

The post Fusion-Enabled Comprehensive Exploration of the Heliosphere appeared first on Universe Today.

The mathematician Roger Penrose has many accolades for his work in extending our perception of the universe. While his research dominates most reviews of him, author Patchen Barss has taken up the challenge of writing a biography about the life of Roger Penrose, who at 93 is still alive and active. In Barss’ book “The Impossible Man–Roger Penrose and the Cost of Genius” the reader gets a full appreciation of the life of a person who’s contributed so much.

Barss presents Penrose starting from his early childhood age. He grew up in the difficult times of World War 2 under the tutelage of well-to-do Quaker parents. The father dominated the family, resulting in Penrose not gaining much experience in understanding and dealing with emotions. But his father did teach him much about critical thinking and puzzle solving. Barss suggests that this nurturing played a key part in establishing Penrose’s skill and tenacity at mathematical problem solving.

One interesting aspect presented is that Penrose, being university chair of mathematics, was much more comfortable with geometries and shapes, rather than with equations. His penchant and ability to extend imagery beyond two, three and even four dimensions served him during his studies on special relativity and general relativity. Perhaps this was his genesis for postulating conditions at black hole singularities which, in part, garnered him the Nobel prize. Currently, he is still progressing toward a unified theory of spacetime as well as formulating the conformal cyclic cosmology (CCC) into an accepted conveyance.

While this biography provides a description of Penrose’s mathematics, such as light cones and tessellation, it does not provide details or proofs. For these, a reader can peruse any of the many books written by Penrose himself. Where this biography excels is in connecting personal moments and events with human interactions. There’s much about his wives and muses. There’s a constant stream of other high-calibre researchers who briefly or extensively interconnect. Many discussions describe his search for optimal working environments such as having a trapdoor lead to a garage converted into a private study. Unexpectedly, you can also read how Penrose colluded with Joe Rogan to promote his ideas.

As for many high achievers, any biography could become nearly unlimited in extent. This one was six years in the writing with Barss spending significant time directly interviewing the subject. It does present many momentous events including the killing of John Kennedy. But can a reader use it? Does it provide fodder for the debate of nature over nurture? Does it provide a prescription for becoming a chair of mathematics? Does it champion solitary contemplation or vouchsafe boisterous social conversing? That will be for the reader to discover.

Whichever your aim, the book “The Impossible Man–Roger Penrose and the Cost of Genius” by Patchen Barss is a solid biography. Penrose has made significant contributions to his field of expertise and continues hard at work. This book chiefly addresses how he does it. It’s easy to read and while not technical, it does provide an overview of the life of this many honored mathematician.

The post Book Review: The Impossible Man appeared first on Universe Today.

A team of astronomers have discovered a rather curious exoplanetary system that has two gas giant planets that are messing up each other’s orbit! On of them is 3.8 times the mass of Jupiter and completes an orbit every 82 days, the other is just 1.4 Jupiter masses. Hiding in the wings is another mini-Neptunian world. The two gas giants are locked into a 2:1 orbital resonance and, as a result of their gravitational interactions, the orbit of the more massive can vary by up to 4 days!

Exoplanets are alien worlds that orbit around stars beyond our Solar System. They vary by size, mass, composition and environment and studying them provides insight into not only planetary formation but also the liklihood for the presence of alien life! Like all bodies that orbit a common host; moons around a planet or planets around a star, their orbits can become linked in what has become known as a resonance.

This artist’s illustration shows the Neptune-like exoplanet GJ 3470b, which has an atmosphere rich in sulphur. The planet’s atmosphere holds clues to how it and other similar planets formed. Image Credit: Department of Astronomy, UW–Madison

Orbital resonance occurs when two or more orbiting bodies exert regular, periodic gravitational influence on each other, creating a stable orbital relationship. It often results in simple integer ratios between their orbital periods, such as 2:1 or 3:2. Neptune and Pluto for example are in a 2:3 resonance, meaning Pluto completes two orbits around the Sun for every three of Neptune’s. In our solar system, Jupiter’s moons Ganymede, Europa, and Io follow a 4:2:1 resonance, affecting their geological activity. Resonances help maintain orbital stability over long timescales but can also lead to instability in some cases, influencing planetary formation, migration, and even asteroid belt structures.

Kirkwood Gaps, histogram of asteroids as a function of their average distance from the Sun. Regions deplete of asteroids are called Kirkwood Gaps, and those bodies may have been escavated from the main belt owing to orbital resonances (image credit: Alan Chamberlain, JPL/Caltech).

The planetary system just discovered, TOI-4504 was detected by the Transiting Exoplanet Survey Satellite (TESS.) As TOI-4504 c orbits the star, they pass directly in front of the host star causing its light to dim in a transit event. It was this dimming that was spotted by TESS. The orbit of exoplanet TOI-4504 c is affected by the non-transiting planet TOI-4504 d. The gravitational interaction of this planet causes the transit times of TOI-4504 c to vary by about 4 days. The orbit of exoplanet TOI-4504 d does not cause a transit event but if its orbit were such that it did then the orbital period would vary by up to 6 days. 

Illustration of NASA’s Transiting Exoplanet Survey Satellite. Credit: NASA’s Goddard Space Flight Center

The lead author fo the paper, PhD student Michaela Vítková from the AI CAS in Czech Republic said “We were surprised to see such a large amplitude of the variations in the transit times of TOI-4504 c.”  The results of the study relied upon data not only from TESS but also from FEROS (Fibre-fed Extended Range Optical Spectrograph) on the 2.2m telescope at ESO’s La Silla observatory in Chile. The planetary system is a complex one with another 10 Earth-mass planet on an inner orbit that takes 2.4 days to complete one trip around the star.

The study reveals yet again what a fascinating study exoplanetary systems are. TOI-4504 is a great example of how varied the systems and their planets can be. The orbital resonances of planets ‘c’ and ‘d’ make for a fascinating system that would benefit from further study.

Source : Violent dance of massive gas giant planets

The post Massive Gas Giant Planets Locked in a Gravitational Struggle appeared first on Universe Today.