AKAKOR GEOGRAPHICAL EXPLORING

This image shows a flattened (Mercator) projection of the Huygens probe’s view of Saturn’s moon Titan from 10 kilometers altitude. The images that make up this view were taken on Jan. 14, 2005, with the descent imager/spectral radiometer onboard the European Space Agency’s Huygens probe. The Huygens probe was delivered to Titan by the Cassini spacecraft, managed by NASA’s Jet Propulsion Laboratory, Pasadena, Calif. Credit: ESA/NASA/JPL/University of Arizona photo

A study led by Western astrobiologist Catherine Neish shows the subsurface ocean of Titan—the largest moon of Saturn—is most likely a non-habitable environment, meaning any hope of finding life in the icy world is dead in the water.

This discovery means it is far less likely that space scientists and astronauts will ever find life in the outer solar system, home to the four ‘giant’ planets: Jupiter, Saturn, Uranus and Neptune.

“Unfortunately, we will now need to be a little less optimistic when searching for extraterrestrial lifeforms within our own solar system,” said Neish, an Earth sciences professor. “The scientific community has been very excited about finding life in the icy worlds of the outer solar system, and this finding suggests that it may be less likely than we previously assumed.”

The identification of life in the outer solar system is a significant area of interest for planetary scientists, astronomers and government space agencies like NASA, largely because many icy moons of the giant planets are thought to have large subsurface oceans of liquid water. Titan, for example, is thought to have an ocean beneath its icy surface that is more than 12 times the volume of Earth’s oceans.

“Life as we know it here on Earth needs water as a solvent, so planets and moons with lots of water are of interest when looking for extraterrestrial life,” said Neish, a member of Western’s Institute for Earth and Space Exploration.

In the study, published in the journal Astrobiology, Neish and her collaborators attempted to quantify the amount of organic molecules that could be transferred from Titan’s organic-rich surface to its subsurface ocean, using data from impact cratering.

Comets impacting Titan throughout its history have melted the surface of the icy moon, creating pools of liquid water that have mixed with the surface organics. The resulting melt is denser than its icy crust, so the heavier water sinks through the ice, possibly all the way to Titan’s subsurface ocean.

Using the assumed rates of impacts on Titan’s surface, Neish and her collaborators determined how many comets of different sizes would strike Titan each year over its history. This allowed the researchers to predict the flow rate of water carrying organics that travel from Titan’s surface to its interior.

Neish and the team found the weight of organics transferred in this way is quite small, no more than 7,500 kg/year of glycine—the simplest amino acid, which makes up proteins in life. This is approximately the same mass as a male African elephant. (All biomolecules, like glycine, use carbon—an element—as the backbone of their molecular structure.)

“One elephant per year of glycine into an ocean 12 times the volume of Earth’s oceans is not sufficient to sustain life,” said Neish. “In the past, people often assumed that water equals life, but they neglected the fact that life needs other elements, in particular carbon.”

Other icy worlds (like Jupiter’s moons Europa and Ganymede and Saturn’s moon Enceladus) have almost no carbon on their surfaces, and it is unclear how much could be sourced from their interiors. Titan is the most organic-rich icy moon in the solar system, so if its subsurface ocean is not habitable, it does not bode well for the habitability of other known icy worlds.

“This work shows that it is very hard to transfer the carbon on Titan’s surface to its subsurface ocean—basically, it’s hard to have both the water and carbon needed for life in the same place,” said Neish.

An artist’s rendering shows a Dragonfly quadcopter landing on the surface of Saturn’s moon Titan, unfolding its rotors and lifting off again to survey the landscape and atmosphere. Credit: Steve Gribben/Johns Hopkins

Flight of the Dragonfly

Despite the discovery, there is still much more to learn about Titan, and for Neish, the big question is, what is it made of?

Neish is a co-investigator on the NASA Dragonfly project, a planned 2028 spacecraft mission to send a robotic rotorcraft (drone) to the surface of Titan to study its prebiotic chemistry, or how organic compounds formed and self-organized for the origin of life on Earth and beyond.

“It is nearly impossible to determine the composition of Titan’s organic-rich surface by viewing it with a telescope through its organic-rich atmosphere,” said Neish. “We need to land there and sample the surface to determine its composition.”

To date, only the Cassini–Huygens international space mission in 2005 has successfully landed a robotic probe on Titan to analyze samples. It remains the first spacecraft to land on Titan and the farthest landing from Earth a spacecraft has ever made.

“Even if the subsurface ocean isn’t habitable, we can learn a lot about prebiotic chemistry on Titan, and Earth, by studying the reactions on Titan’s surface,” said Neish. “We’d really like to know if interesting reactions are occurring there, especially where the organic molecules mix with liquid water generated in impacts.”

When Neish started her latest study, she was worried it would negatively impact the Dragonfly mission, but it has actually led to even more questions.

“If all the melt produced by impacts sinks into the ice crust, we wouldn’t have samples near the surface where water and organics have mixed. These are regions where Dragonfly could search for the products of those prebiotic reactions, teaching us about how life may arise on different planets,” said Neish.

“The results from this study are even more pessimistic than I realized with regards to the habitability of Titan’s surface ocean, but it also means that more interesting prebiotic environments exist near Titan’s surface, where we can sample them with the instruments on Dragonfly.”

A shallow coral reef on Australia’s Great Barrier Reef. Credit: Chris Roelfsema

University of Queensland-led research has shown there is more coral reef area across the globe than previously thought, with detailed satellite mapping helping to conserve these vital ecosystems.

Dr. Mitchell Lyons from UQ’s School of the Environment, working as part of the Allen Coral Atlas project, said scientists have now identified 348,000 square kilometers of shallow coral reefs, up to 20–30 meters deep. The research paper is published in Cell Reports Sustainability.

“This revises up our previous estimate of shallow reefs in the world’s oceans,” Dr. Lyons said.

“Importantly, the high-resolution, up-to-date mapping satellite technology also allows us to see what these habitats are made from.

“We’ve found 80,000 square kilometers of reef have a hard bottom, where coral tends to grow, as opposed to soft bottom like sand, rubble or seagrass.

“This data will allow scientists, conservationists, and policymakers to better understand and manage reef systems.”

More than 1.5 million samples and 100 trillion pixels from the Sentinel-2 and Planet Dove CubeSat satellites were used to capture fine-scale detail on a high-resolution global map.

“This is the first accurate depiction of the distribution and composition of the world’s coral reefs, with clear and consistent terminology,” Dr. Lyons said.

“It’s more than just a map—it’s a tool for positive change for reefs and coastal and marine environments at large.”

A diver on a shallow coral reef on Australia’s Great Barrier Reef. Credit: Chris Roelfsema

UQ’s Associate Professor Chris Roelfsema said the reef mapping project, a collaboration with more than 480 contributors, is already being used in coral reef conservation around the world.

“The maps and associated data are publicly accessible through the Allen Coral Atlas and Google Earth Engine, reaching a global audience,” Dr. Roelfsema said.

“They’re being used to inform projects in Australia, Indonesia, the Timor and Arafura Seas, Fiji, Solomon Islands, Tonga, Vanuatu, Panama, Belize, Bangladesh, India, Maldives, Sri Lanka, Kenya and western Micronesia.

“The details provided by these maps empower scientists, policymakers and local communities to make informed decisions for the preservation of our coral reefs.”

The Allen Coral Atlas was conceived by the late Paul Allen’s Vulcan Inc. and managed by Arizona State University along with partners from Planet, the Coral Reef Alliance and The University of Queensland.

Tridentinosaurus antiquus was discovered in the Italian alps in 1931 and was thought to be an important specimen for understanding early reptile evolution—but has now been found to be, in part a forgery. Its body outline, appearing dark against the surrounding rock, was initially interpreted as preserved soft tissues but is now known to be painted. Credit: Dr. Valentina Rossi

A 280-million-year-old fossil that has baffled researchers for decades has been shown to be—in part—a forgery, following new examination of the remnants.

The discovery has led the team, headed by Dr. Valentina Rossi of University College Cork, Ireland (UCC) to urge caution in how the fossil is used in future research.

Tridentinosaurus antiquus was discovered in the Italian Alps in 1931 and was thought to be an important specimen for understanding early reptile evolution. Its body outline, appearing dark against the surrounding rock, was initially interpreted as preserved soft tissues. This led to its classification as a member of the reptile group Protorosauria.

However, this new research, published in the journal Palaeontology, reveals that the fossil renowned for its remarkable preservation is mostly just black paint on a carved lizard-shaped rock surface.

The purported fossilized skin had been celebrated in articles and books but never studied in detail. The somewhat strange preservation of the fossil had left many experts uncertain about which group of reptiles this strange lizard-like animal belonged to, and more generally its geological history.

Dr. Valentina Rossi with an image of Tridentinosaurus antiquus. The fossil, discovered in the Italian alps in 1931, was thought to be an important specimen for understanding early reptile evolution—but has now been found to be, in part a forgery. Its body outline, appearing dark against the surrounding rock, was initially interpreted as preserved soft tissues but is now known to be paint. Credit: Zixiao Yang

Dr. Rossi, of UCC’s School of Biological, Earth and Environmental Sciences, said, “Fossil soft tissues are rare, but when found in a fossil they can reveal important biological information, for instance, the external coloration, internal anatomy and physiology. The answer to all our questions was right in front of us; we had to study this fossil specimen in details to reveal its secrets—even those that perhaps we did not want to know.”

The microscopic analysis showed that the texture and composition of the material did not match that of genuine fossilized soft tissues.

Preliminary investigation using UV photography revealed that the entirety of the specimen was treated with some sort of coating material. Coating fossils with varnishes and/or lacquers was the norm in the past and sometimes is still necessary to preserve a fossil specimen in museum cabinets and exhibits. The team was hoping that beneath the coating layer, the original soft tissues were still in good condition to extract meaningful paleobiological information.

The findings indicate that the body outline of Tridentinosaurus antiquus was artificially created, likely to enhance the appearance of the fossil. This deception misled previous researchers, and now caution is being urged when using this specimen in future studies.

The team behind this research includes contributors based in Italy at the University of Padua, Museum of Nature South Tyrol, and the Museo delle Scienze in Trento.

Co-author Prof Evelyn Kustatscher, coordinator of the project “Living with the supervolcano,” said, “The peculiar preservation of Tridentinosaurus had puzzled experts for decades. Now, it all makes sense. What it was described as carbonized skin is just paint.”

However, not all is lost, and the fossil is not a complete fake. The bones of the hindlimbs, in particular, the femurs seem genuine, although poorly preserved. Moreover, the new analyses have shown the presence of tiny bony scales called osteoderms—like the scales of crocodiles—on what perhaps was the back of the animal.

This study is an example of how modern analytical paleontology and rigorous scientific methods can resolve an almost century-old paleontological enigma.

In an ejection that would have caused its rotation to slow, a magnetar is depicted losing material into space in this artist’s concept. The magnetar’s strong, twisted magnetic field lines (shown in green) can influence the flow of electrically charged material from the object, which is a type of neutron star. Credit: NASA/JPL-Caltech

What’s causing mysterious bursts of radio waves from deep space? Astronomers may be a step closer to providing one answer to that question. Two NASA X-ray telescopes recently observed one of such events—known as a fast radio burst—mere minutes before and after it occurred. This unprecedented view sets scientists on a path to understand these extreme radio events better.

While they only last for a fraction of a second, fast radio bursts can release about as much energy as the sun does in a year. Their light also forms a laser-like beam, setting them apart from more chaotic cosmic explosions.

Because the bursts are so brief, it’s often hard to pinpoint where they come from. Prior to 2020, those that were traced to their source originated outside our own galaxy—too far away for astronomers to see what created them. Then a fast radio burst erupted in Earth’s home galaxy, originating from an extremely dense object called a magnetar—the collapsed remains of an exploded star.

In October 2022, the same magnetar—called SGR 1935+2154—produced another fast radio burst, this one studied in detail by NASA’s NICER (Neutron Star Interior Composition Explorer) on the International Space Station and NuSTAR (Nuclear Spectroscopic Telescope Array) in low Earth orbit.

The telescopes observed the magnetar for hours, catching a glimpse of what happened on the surface of the source object and in its immediate surroundings before and after the fast radio burst. The results, described in a new study published in the journal Nature, are an example of how NASA telescopes can work together to observe and follow up on short-lived events in the cosmos.

The burst occurred between two “glitches” when the magnetar suddenly started spinning faster. SGR 1935+2154 is estimated to be about 12 miles (20 kilometers) across and spinning about 3.2 times per second, meaning its surface was moving at about 7,000 mph (11,000 kph). Slowing it down or speeding it up would require a significant amount of energy.

That’s why study authors were surprised to see that in between glitches, the magnetar slowed down to less than its pre-glitch speed in just nine hours, or about 100 times more rapidly than has ever been observed in a magnetar.

“Typically, when glitches happen, it takes the magnetar weeks or months to get back to its normal speed,” said Chin-Ping Hu, an astrophysicist at National Changhua University of Education in Taiwan and the lead author of the new study. “So clearly, things are happening with these objects on much shorter time scales than we previously thought, and that might be related to how fast radio bursts are generated.”

Spin cycle

When trying to piece together exactly how magnetars produce fast radio bursts, scientists have a lot of variables to consider.

For example, magnetars (which are a type of neutron star) are so dense that a teaspoon of their material would weigh about a billion tons on Earth. Such a high density also means a strong gravitational pull: A marshmallow falling onto a typical neutron star would impact with the force of an early atomic bomb.

The strong gravity means the surface of a magnetar is a volatile place, regularly releasing bursts of X-rays and higher-energy light. Before the fast radio burst that occurred in 2022, the magnetar started releasing eruptions of X-rays and gamma rays (even more energetic wavelengths of light) that were observed in the peripheral vision of high-energy space telescopes. This increase in activity prompted mission operators to point NICER and NuSTAR directly at the magnetar.

“All those X-ray bursts that happened before this glitch would have had, in principle, enough energy to create a fast radio burst, but they didn’t,” said study co-author Zorawar Wadiasingh, a research scientist at the University of Maryland, College Park and NASA’s Goddard Space Flight Center. “So it seems like something changed during the slowdown period, creating the right set of conditions.”

What else might have happened with SGR 1935+2154 to produce a fast radio burst? One factor might be that the exterior of a magnetar is solid, and the high density crushes the interior into a state called a superfluid. Occasionally, the two can get out of sync, like water sloshing around inside a spinning fishbowl. When this happens, the fluid can deliver energy to the crust. The paper authors think this is likely what caused both glitches that bookended the fast radio burst.

If the initial glitch caused a crack in the magnetar’s surface, it might have released material from the star’s interior into space like a volcanic eruption. Losing mass causes spinning objects to slow down, so the researchers think this could explain the magnetar’s rapid deceleration.

But having observed only one of these events in real time, the team still can’t say for sure which of these factors (or others, such as the magnetar‘s powerful magnetic field) might lead to the production of a fast radio burst. Some might not be connected to the burst at all.

“We’ve unquestionably observed something important for our understanding of fast radio bursts,” said George Younes, a researcher at Goddard and a member of the NICER science team specializing in magnetars. “But I think we still need a lot more data to complete the mystery.”