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.
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.
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.
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.”
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.
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.”
“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.
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.
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.”
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.
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.
“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://ift.tt/8nLyhjz, Public Domain, https://ift.tt/b6CkaDM
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.
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.
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.”
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.
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.
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://ift.tt/y64wX3B, Public Domain, https://ift.tt/mZO1iwt
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://ift.tt/s9GKUjk
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.”
Saturn’s moon Titan is perhaps one of the most fascinating moons in the Solar System. It’s the second largest of all the moons in our planetary neighbourhood and is the only one with a significant atmosphere. It’s composed of 95% nitrogen and 5% methane and is 1.5 times as dense as the Earth’s atmosphere. The methane in the atmosphere of Titan is what puzzles scientists. It should have all be broken up within 30 million years causing the atmosphere to freeze but it hasn’t! There must be an internal process replenishing it, but what is it?
Titan is the largest moon of Saturn and second only in size to Ganymede, the largest moon of Jupiter. The surface of Titan is covered with dunes, icy mountains, and liquid hydrocarbon lakes—primarily composed of methane and ethane. Beneath its icy crust, scientists believe a vast subsurface ocean of water exists, raising the possibility of microbial life. NASA’s Cassini-Huygens mission provided detailed insights into Titan’s climate, seasonal changes, and its resemblance to early Earth, making it a target for future exploration.
Natural color image of Titan taken by Cassini in January 2012. (Credit: NASA/JPL-Caltech/Space Science Institute)
Dr. Kelly Miller from the South West Research Institute and Lead author of a paper about Titan’s atmosphere said “While just 40% the diameter of the Earth, Titan has an atmosphere 1.5 times as dense as the Earth’s, even with a lower gravity, walking on the surface of Titan would feel a bit like scuba diving!” To try and understand the existence of methane in the atmosphere Southwest Research Institute joined forces with the Carnegie Institution for Science to conduct some experiments with interesting results.
ASA’s Cassini spacecraft looks toward the night side of Saturn’s largest moon and sees sunlight scattering through the periphery of Titan’s atmosphere and forming a ring of color. Credit: NASA/JPL-Caltech/Space Science Institute
A model was proposed in 2019 that suggested just how the methane could be replenished over the years. It theorised that large amounts of organic materials are heated by the moon’s interior, releasing nitrogen and carbon based gas like methane. The gas seeps to the surface where it replenishes the atmosphere. The theory was developed off the back of data from NASA’s Cassini-Huygens spacecraft which arrived at the Saturnian system in 2004. It explored it for the next 13 years while the Huygens probe dropped onto the surface of Titan in 2005.
Artist depiction of Huygens landing on Titan. Credit: ESA
The team led by Miller arranged experiments to heat up organic materials to temperatures up to 500 degrees Celsius at pressures up to 10 kilobars. This simulated the conditions found under the surface of Titan. The process generated sufficient quantities of methane that would enable Titan’s atmosphere to be replenished to the levels we observe today.
To learn more about the atmosphere of Titan, NASA plans to launch another spacecraft to the Saturnian system in 2028. It’s been called Dragonfly and involves a quadcopter that will, like Ingenuity did on Mars, explore Titan’s atmosphere. The thick atmosphere and low surface gravity make it an ideal place to explore from the air. Not only will it help us to understand more about the atmospheric conditions but it will help to assess the moon’s habitability by analysing prebiotic molecules and searching for signs of past, or even present life!
