Category: 7. Science

Houston-based company Axiom Space’s fourth crewed mission to space is nearing its end, and its four astronauts are filling every last minute with science, amazing views of Earth and pierogis.

The crew of Axiom-4 (Ax-4) have been aboard the International Space Station (ISS) since their SpaceX Crew Dragon capsule docked there on June 26. Their days have been filled with more than 60 research experiments and outreach events, breaking an Axiom mission record for on-orbit activities.

Lucie Low, Axiom’s chief scientist, spoke with the Ax-4 crew during a mission science briefing on July 5. The four astronauts discussed some of the experiments they have been working on during their time aboard the orbital laboratory.

Ax-4 is commanded by former NASA astronaut Peggy Whitson, who’s currently Axiom’s director of human spaceflight. She also holds the record for most cumulative days in space by an American, which is inching closer to 700 with each additional day she remains aboard the ISS. Before this mission, her record stood at 675. Whitson has been a helpful voice of experience as her crew navigates life in microgravity, according to Axiom.

Every day, our brain takes countless fleeting experiences — from walks on the beach to  presentations at work — and transforms them into long-term memories. How exactly this works remains a mystery, but neuroscientists believe that it involves a phenomenon called neural replay, in which neurons rapidly recreate the same activation sequences that occurred during the original experience. Surprisingly, neural replays can happen both before and after an experience, suggesting they help in both memory storage and also future planning.

In a new study, neuroscientists at the University of California, Berkeley, recorded activity from hundreds of neurons simultaneously in freely flying bats. It is the first time that an ensemble of neurons — rather than just individual neurons — have been studied in concert in bats as they fly around and behave naturally. The data provided surprising new insights into neural replay and theta sequences, another phenomenon which is believed to be involved in memory and planning. 

“For the past 20 years, we’ve been recording single neurons in bats and asking the question, ‘When animals are doing interesting things, what do individual neurons do?’” said study senior author Michael Yartsev, an associate professor of neuroscience and bioengineering and a Howard Hughes Medical Institute Investigator at UC Berkeley. “But in the brain, there are emerging properties that you only see when you’re looking at ensembles of neurons. In this study, we looked at these two phenomena — replay and theta sequences — that are only visible when you track many neurons at the same time.”

Better understanding the role of replay and theta sequences in the brains of animals could shed light on how long-term memories are formed and stored in humans, potentially leading to new treatments for neurological disorders like Parkinson’s disease and Alzheimer’s. 

The study, which was published online today (July 9) in the journal Nature, was supported by grants from the Air Force Office of Scientific Research, the National Institute of Neurological Disorders and Stroke and the Office of Naval Research.

‘A whole different ball game’

Studying neural replay and theta sequences is tricky because it requires listening in on tens or hundreds of neurons in the brain simultaneously. Over the past decade, Michael Yartsev’s lab has pioneered wireless neural recording technologies in Egyptian fruit bats, giving his team an unprecedented view inside the brains of these navigational experts as they forage in large environments. 

Previously, the wireless recording devices were only able to detect signals from small numbers of neurons at a time. In the new study, co-first authors Angelo Forli, Wudi Fan and Kevin Qi successfully utilized high-density silicon electrode arrays that can record hundreds of neurons at once from flying bats. These electrodes can also record local field potentials, a measure of the overall electrical activity in a region of the brain.

“It’s a whole different ball game to record such large ensembles of neurons wirelessly in a flying animal,” Yartsev said. “This was never possible before now.”

To study neural replay and theta sequences, the researchers tracked the activity of “place cells,” a type of neuron that is found in the hippocampus of many species. Individual place cells fire when an animal is in a specific location in space, creating an internal spatial map of their environment. 

“If you know that a place cell corresponds to a specific location in space, and the cell is active, then you can infer that the bat is in that location,” said Angelo Forli, who is a postdoctoral researcher at UC Berkeley. “If you can track multiple cells, you can know the path that the bat took.”

But place cells aren’t only active when an animal is moving around. Experiments in rodents have shown that they exhibit hippocampal replay during rest, essentially refiring in the same sequence as they did during the movement but in a shorter, time compressed format.

Place cells in rodents also exhibit patterns called theta sequences, which happen during movement, and are believed to represent the animal “looking ahead” just a few steps from its current location.

“Previously, these phenomena were exclusively investigated in rodents, because that’s what the technology allowed. We wanted to find out if they also exist in bats, and if they do, are they any different from what we see in rodents?” said Forli. “We discovered a series of differences that challenge established models.”

A fundamental unit of information processing

In the experiment, the researchers recorded the activity of bats’ place cells as they flew freely around a large flight room and identified which sequences of place cells corresponded with specific trajectories. They were then able to identify replay events, or moments when these same neural sequences occurred when the bats were at rest.

Most of what we know about replay has been gleaned from experiments on rodents in unnatural settings, such as a “sleep box,” to record replay events following behavioral runs. This introduces artificial boundaries between active and inactive states. In contrast, bats have many natural active periods and rest periods within the same experimental session, allowing for the capture of replay under less restrictive conditions. This led to the discovery that replays mostly occur minutes after the experience, and often at locations distant from where the experience took place. 

Surprisingly, the researchers also found that the length of these replay events was the same for all flight trajectories, no matter how long the flight was. Essentially, if one neural sequence corresponded to a 10-meter flight, and another neural sequence corresponded to a 20-meter flight, the replays of both of those sequences were time-compressed to the same length.

“We saw that replays for short versus long trajectories had the same duration,” Forli said. “It seems that information is cut down to the same chunk of time regardless of the length of the experience.”

The researchers hypothesize that this constant replay duration may represent an elemental unit of information processing in the brain.

“From a computational perspective, it’s incredibly advantageous to send fixed packets of information,” Yartsev said. “It’s very efficient because whatever is reading that information out knows it will arrive in these fixed sizes.”

The team’s next question concerned theta sequences, a type of ensemble phenomenon that is believed to support replay and to rely on theta oscillations in the hippocampus. However, unlike rodents, bats and humans both lack continuous theta oscillations, which occur at a frequency of approximately 8 Hertz, or eight wingbeats per second. Interestingly, the researchers found sequential network activity during flight in bats, akin to theta sequences in rodents, but with one major difference: unlike rodents, the fast sequences in bats had no relationship to theta oscillations, but were, instead, synced to the bats’ 8 Hz wingbeats. 

From the quivering of a mouse’s whiskers to the rhythms of human speech, there are countless other animal behaviors that occur at frequencies around 8 Hz. The researchers hypothesize that these theta sequences might provide a universal neural mechanism for how these behaviors are organized and directed in the animal brain. 

“There’s something about this frequency which is ubiquitous across species, particularly mammalian species,” Yartsev said. “Our findings may provide the beginning of a mechanistic understanding of the neural basis of these behaviors, not only in rats and bats, but maybe also in other species like humans.”

Additional support for this research was provided by the New York Stem Cell Foundation, the Vallee Foundation and the Howard Hughes Medical Institute.

Related Stories

An analysis of Northwest Africa (NWA) 16286, a lunar meteorite with a unique chemical signature, offers fresh insights into how the Moon’s interior evolved, highlighting the long-lived nature of its volcanic activity.

Found in Africa in 2023, NWA 16286 is only one of 31 lunar basalts officially identified on Earth.

The 311-gram meteorite’s distinct composition, with melted glassy pockets and veins, suggests it was likely shocked by an asteroid or meteorite impact on the Moon’s surface before being ejected and eventually falling to Earth.

The new analysis by University of Manchester scientists lends weight to a theory that the Moon retained internal heat-generating processes that powered lunar volcanic activity in several distinct phases.

Lead isotope analysis dates the rock’s formation to around 2.35 billion years ago, during a period from which few lunar samples exist, making it the youngest basaltic lunar meteorite discovered on Earth.

Its rare geochemical profile sets it apart from those returned by previous Moon missions, with chemical evidence indicating it likely formed from a lava flow that solidified after emerging from deep within the Moon.

“Lunar rocks from sample return missions are fantastic in the insights they provide us, but they are limited to the immediate areas surrounding those mission landing sites,” said University of Manchester’s Dr. Joshua Snape.

“By contrast, lunar meteorites can potentially be ejected by impact cratering occurring anywhere on the Moon’s surface.”

“As such, there’s some serendipity surrounding this sample; it just happened to fall to Earth and reveals secrets about lunar geology without the massive expense of a space mission.”

Containing relatively large crystals of mineral olivine, the rock is a type of lunar volcanic basalt called olivine-phyric basalt. It contains moderate levels of titanium, high levels of potassium.

In addition to the unusual age of the sample, the authors found that the lead isotope composition of the rock — a geochemical fingerprint retained from when the rock formed — points to it originating from a source in the Moon’s interior with an unusually high uranium-to-lead ratio.

These chemical clues may help identify the mechanisms that have enabled periods of ongoing internal heat generation on the Moon.

“The age of the sample is especially interesting because it fills an almost billion-year gap in lunar volcanic history,” Dr. Snape said.

“It’s younger than the basalts collected by the Apollo, Luna and Chang’e 6 missions, but older than the much younger rocks brought back by China’s Chang’e 5 mission.”

“Its age and composition show that volcanic activity continued on the Moon throughout this timespan, and our analysis suggests an ongoing heat generation process within the Moon, potentially from radiogenic elements decaying and producing heat over a long period.

“Moon rocks are rare, so it’s always interesting when we get something that stands out and looks different to everything else.”

“This particular rock provides new constraints about when and how volcanic activity occurred on the Moon.”

“There is much more yet to learn about the Moon’s geological past, and with further analysis to pinpoint its origin on the surface, this rock will guide where to land future sample return missions.”

The researchers presented their results today at the Goldschmidt Conference 2025 in Prague, the Czech Republic.

_____

Joshua F. Snape et al. Northwest Africa 16286: investigating the age and origin of a new lunar mare basalt. Goldschmidt Conference 2025

The question of how life began has captivated humanity for millennia. Now, a team of scientists are preparing to use NASA’s upcoming Habitable Worlds Observatory (HWO) to test different theories about life’s origins by studying planets beyond our Solar System.

Rather than searching for life in laboratories or on Mars, researchers led by Sukrit Ranjan from the University of Arizona propose using the HWO to examine patterns of life across multiple exoplanets. Their approach is really quite simple: different theories about how life begins make different predictions about where and how often life should appear. They propose that by observing enough planets, the theories can be tested against real data.

Artist Impression of the Habitable Worlds Observatory (Credit : NASA)

The research categorises origin of life theories into three main groups, each with distinct predictions. Some theories suggest life’s emergence requires so many precise conditions that it’s incredibly unlikely. They predict we might find no other life within about 33 light-years of Earth. For example, some chemical pathways to life require multiple specific environments to interact in just the right way, making successful emergence fo life from non-living matter vanishingly improbable.

Other theories, like the idea that life emerged around alkaline vents, suggest life emerges readily wherever basic conditions exist. This theory proposes that life will necessarily emerge on any planet with liquid water oceans, with alkaline hydrothermal vents and a carbon dioxide rich atmosphere because life naturally resolves the energy imbalances these systems create.

Thermal vents at the bottom of the mid-Atlantic ridge at a water depth of 3,300 metres where an ecosystem thrives (Credit : MARUM − Zentrum für Marine Umweltwissenschaften, Universität Bremen)

Many theories specify particular environmental requirements. The most developed example suggests ultraviolet light is essential for life’s emergence, with optimal conditions requiring specific UV radiation levels.

The HWO’s power lies in its ability to detect the chemical signs of life in planetary atmospheres. Even finding a single biosphere would falsify theories claiming life is ultra rare, while detecting no life on 20 to 50 planets would support the rarity hypothesis.

More nuanced tests become possible with larger samples. Simulated surveys suggest examining at least 50 exoplanets could reveal correlations between past UV irradiation and life’s presence, directly testing theories dependent on UV radiation. Similarly, correlations between biosignatures and planetary features like oceans or continents could validate specific origin scenarios.

Artist impression of Kepler 186f, a potentially habitable world. (Credit : NASA)

The research emphasises a crucial requirement, large sample sizes of 50 or more characterised planets are needed to provide meaningful data to test the theories. This finding has important implications for the HWO’s design, favouring broader surveys over detailed studies of fewer worlds.

The telescope will need to detect not just biosignatures but also planetary characteristics like the presence of an ocean, continental features, and atmospheric composition. Observations might also be needed to track how the brightness of a planet changes as it orbits the star as we view it from different angles to reveal ocean glint and continent signatures, while spectroscopic measurements would identify key atmospheric gases.

This research represents a great step forward in astrobiology. Rather than simply asking “Is there life out there?” scientists are preparing to ask “How does life begin?” The HWO won’t just catalog living worlds, it will test fundamental theories about life’s emergence that have been debated for centuries.

The implications extend far beyond academic curiosity though. Understanding how life begins could inform our search for habitable worlds, guide future missions, and help us understand our place in the universe.

Source : Testing Origin-of-Life Theories with the Habitable Worlds Observatory

On June 23 the Vera C. Rubin Observatory, located in Cerro Pachón, Chile, presented its inaugural data release of images that will drive a new generation of astrophysics research. It features first-of-its-kind technology, and the largest digital camera ever manufactured.

The observatory’s 8.4-meter Simonyi Survey Telescope can capture the largest field of view of any telescope currently in operation, covering the entirety of the night sky over the course of a few nights. It creates composite images approximately 70 times larger than the apparent size of the full moon. These images are 3,200-megapixel in resolution—more than 65x times more detailed than the latest iPhone.

For the U’s own astrophysics researchers, there is palpable excitement as they plan on utilizing the Rubin data for new research projects.

“We’ve all been preparing for this day, and it’s finally here! There’s already some cool science being done with just the First Look images; imagine what we can do with the full data set!” said Yao-Yuan Mao, assistant professor in the Department of Physics & Astronomy.

Mao has been involved with the Rubin research community for more than a decade, most actively in the Dark Energy Science Collaboration. The operation of the Rubin Observatory represents the culmination of years of design and planning.

“I am particularly excited about how Rubin data will enable us to find some of the smallest galaxies in our neighborhood, helping us understand how galaxies form and grow throughout the cosmic time and even reveal the nature of dark matter,” added Mao.

In addition to the ability to capture gigantic still pictures, the Rubin Observatory can also record the movements in the cosmos. The Observatory had been designed from its inception to detect up to 90% of near-Earth asteroids, advance the study of how our solar system formed, and observe phenomena such as supernovae or tidal disruption events with greater ability.

“I’m really excited for Rubin and have been looking forward to it for many years. For me, the most exciting part of Rubin will be its ability to detect tidal disruption events, which happen when a star comes too close to a massive black hole and is torn apart by the black hole’s gravity,” said Anil Seth, professor of physics and astronomy. “We have previously detected about a hundred of these events, but Rubin is predicted to detect more than 10 new tidal disruption events each night. My PhD student Christian Hannah has been working on predicting how we can use these events to understand for the first time whether small galaxies still all have massive black holes at their centers. These observations will help us understand the currently not understood formation mechanisms of the massive black holes we find at the centers of galaxies.”

The observatory honors the legacy of Vera C. Rubin, whose pioneering research on galaxy rotation produced the first accepted evidence of dark matter’s existence. All-in-all, this marks the beginning of a new and exciting era of astrophysics research. The Rubin Observatory is planned to operate for at least ten years for its Legacy Survey of Space and Time (LSST), producing hundreds of images and data for researchers and the general public.

The Rubin Observatory project was jointly funded by the U.S. National Science Foundation and the U.S. Department of Energy, Office of Science.

MEDIA & PR CONTACTS

• Lisa Potter
  Research communications specialist, University of Utah Communications
  949-533-7899
  lisa.potter@utah.edu

It turns out colour isn’t just fashionable for guppies: According to a new UBC study, the more orange a male, the more virile it is.

The research published in Nature Ecology & Evolution shines light on an enduring evolutionary mystery: why male guppies have such vibrant and varied colours and patterns.

Virile me up

Zoologists Drs. Wouter van der Bijl and Judith Mank used deep learning, genetic studies and bred three generations of increasingly orange guppies to investigate. They found the more colourful males were up to two times more sexually active, performing for females at a greater rate and for longer periods of time, and attempting to sneakily copulate more often.

Orange you glad to see me, baby?

It’s known that female guppies prefer orange, and unusual, patterns in their male partners, but the team found that the colour diversity of guppies comes from the same cells that are responsible for forming the brain, suggesting a genetic link between how guppies look and how they behave.

“Previously, people thought perhaps males realized that if they were more orange, they were more sexy. With the genetic link, it may be that they’re healthier and fitter,” said Dr. Mank.

Let’s recombine sometime

The researchers found the guppy colour genes, and the locations they appeared in, were tied to multiple chromosomes, creating a vast architecture of genetic possibilities. Seven orange and eight black colour types were identified overall, allowing for a potential 32,768 unique pattern combinations.

“Genetic variation is the raw material that evolution uses to produce resilient, adapted animals and plants, including for things like climate change or disease,” said van der Bijl. “We often look at extreme examples to understand where genetic variation comes from and how it’s maintained.”