Category: 7. Science

If humanity’s future really is in the stars, what will that mean when it comes to, well, making more humans? As a number of experts have pointed out, venturing into space also means exposing people to more cosmic rays than they’d experience on Earth — something that could have serious ramifications on human reproductive systems. That’s a very big impediment to the concept of humans becoming a spacefaring species.

An experiment conducted on board the International Space Station might help to clarify the science of pregnancy in space. A study published earlier this month in the journal Stem Cell Reports involved studying what the authors describe as “cryopreserved mouse spermatogonial stem cells” that spent six months on the ISS.

The scientists studying the mouse stem cells found that, after six months, that time spent in space “did not increase apoptosis or DNA damage” in the cells. Once the cells returned to Earth, the scientists undertook a process of “spermatogonial transplantation,” and then let the mice to, well, whatever mice get up to when no one’s watching.

“It is important to examine how long we can store germ cells in the ISS to better understand the limits of storage for future human spaceflight,” said the study’s lead author, Mito Kanatsu-Shinohara of Kyoto University, in a statement.

In an article for Space.com on the Kyoto University scientists’ findings, Jessica Rendall pointed out that this is only one part of a much larger ongoing inquiry into space travel and reproduction. While these particular stem cells seem to have gone through this process with no ill effects, there are many other questions to answer before we reach the point of — for lack of a better phrase — space babies. But it’s a promising start.

What role can the relationship between oxygen (O2) and ozone (O3) in exoplanet atmospheres have on detecting biosignatures? This is what a recent study submitted to Astronomy & Astrophysics hopes to address as an international team of researchers investigated novel methods for identifying and analyzing Earth-like atmospheres. This study has the potential to help scientists develop new methods for identifying exoplanet biosignatures, and potentially life as we know it.

For the study, the researchers used a series of climate models to examine how O3 could be used to identify O2 due to their nonlinear relationship, meaning their data follows a curved shaped instead of a straight line. This means low levels of O2 equal low levels of O3, and vice versa. The climate models included all types of stars, including sizes (largest to smallest: O, B, A, F, G, K, M), temperature classification (0 to 9), and current state of evolution (Roman numerals 0 to VI), including if it’s a main-sequence star (identified by a V). For context, our Sun is a G2V star.

This study is the third paper in a series of studies by this same team of researchers with the overall goal of using O3 to identify O2 in Earth-like atmospheres. The first paper examined the overall O2-O3 relationship, the second paper examined how nitrous oxide (N2O) influenced the O2-O3 relationship, and this most recent paper examines how methane (CH4) influences the O2-O3 relationship.

In the end, the researchers found that while fluctuating levels of CH4 alters the O2-O3 relationship, there is heavy reliance on the amount of O2 and the host star, specifically its temperature. Additionally, the team found that model scenarios that had high levels of CH4 and O2 orbiting stars with higher temperatures resulted in CH4 being converted to water (H2O), thus altering the atmospheric temperatures and influencing the amount of O3.

The study notes, “These results further complicate the usage of O3 as a proxy for O2, but also provide additional guidance for future observations. We have now shown in this study that varying CH4 impacts the O2-O3 relationship just as much as N2O, but in different ways. There are many scenarios where high CH4 could be increasing the O3 of an atmosphere, while high N2O would be working at the same time to deplete that O3. This shows that we would be required to think about variations of both species in order to use an O3 measurement to learn about the O2 content of the atmosphere.”

Of the nearly 6,000 confirmed exoplanets, there are currently dozens of examples of potential Earth-like exoplanets, including Kepler-186f, Kepler-1649c, and TRAPPIST-1e, which are located approximately, 580, and 301, and 40 light-years from Earth, respectively. While Kepler-186f and Kepler-1649c are both estimated to have masses and radii slightly larger than Earth, TRAPPIST-1e is estimated to have a mass and radius at 0.69 and 0.92 of Earth, respectively.

Additionally, all these exoplanets orbit M-type stars, which are smaller and cooler than our Sun. This similar pattern is observed with other potential Earth-like exoplanets, as more than half of them orbit M-type stars. This has altered the understanding of where we can identify Earth-like worlds since our Sun is a G-type star, thus scientists originally anticipated finding Earth-like exoplanets around similar stars.

However, while M-type stars are smaller and cooler, they also have longer lifespans than G-type stars. While G-type stars have lifespans of approximately 10 billion years, it is estimated that M-type stars can have lifespans of potentially hundreds of billions to trillions of years, which enhances the possibility of life potentially existing on exoplanets that orbit M-type stars.

How will O3 help scientists identify O2 in Earth-like atmospheres in the coming years and decades? Only time will tell, and this is why we science!

As always, keep doing science & keep looking up!

When NASA’s OSIRIS-REx spacecraft returned from its mission to asteroid Bennu in 2023, it brought back more than just ancient space rocks, it delivered answers to puzzles that have baffled astronomers for years. Among the most intriguing questions was why asteroids that should look identical through telescopes appear strikingly different colours from Earth.

The mystery cantered on two remarkably similar asteroids – Bennu and Ryugu which were both visited by sample return missions. These ancient rocks are made of the same dark, carbon rich materials and formed around the same time during the birth of our Solar System 4.5 billion years ago. Logic suggests they should reflect light identically, yet when studied by spacecraft, Ryugu appears faintly red while Bennu looks distinctly blue.

OSIRIS-REx in Launch Configuration (Credit : NASA Kennedy from United StatesNASA/Glenn Benson)

Michelle Thompson, a Purdue University planetary scientist and expert on space weathering, has been studying samples from both asteroids to crack this mystery. Her research, part of three newly published papers based on analysis of Bennu samples by worldwide experts, shows that these asteroids are undergoing the same weathering processes but at different stages of a repeating cycle.

Space weathering is the constant bombardment that rocky bodies endure from solar radiation, cosmic rays, and micrometeorite impacts. This constant assault gradually changes how asteroid surfaces reflect light, essentially giving them what we might call a ‘tan’ that alters their apparent colour when viewed from Earth.

The breakthrough came when Thompson and her colleagues compared the exposure ages of surface particles from both asteroids. They discovered that grains collected from Ryugu’s surface have been exposed to space for only a few thousand years, while surface grains from Bennu have been exposed for tens of thousands of years.

This is a coloured view of the C-type asteroid 162173 Ryugu, seen by the ONC-T camera on board of Hayabusa2 (Credit : ISAS/JAXA)

This age difference explains everything. Rather than representing two different weathering processes, the asteroids show two snapshots of the same cycle. Rubble pile asteroids regularly refresh their surfaces through impacts and gravitational shifts, exposing fresh material that then begins weathering again. Bennu’s bluer appearance indicates more advanced weathering, while Ryugu’s reddish tint represents an earlier stage.

With 1.45 million known asteroids in our Solar System, it’s neither economically nor physically feasible to visit even a fraction of them. Being able to extrapolate and understand the nature of various asteroids by analysing them from Earth is key to understanding these ancient remnants.

This research enables scientists to correlate what telescopes see with actual sample analysis. Such calibration is crucial for future asteroid exploration, whether for scientific study or potential mining operations. Knowing how surface weathering affects an asteroid’s appearance helps mission planners select targets with greater confidence.

But the Bennu samples reveal even more remarkable secrets about our Solar System’s origins. Earlier research discovered salts in the samples, including phosphates critical to life on Earth and essential for metabolism and DNA. Scientists found evidence of an environment well suited to kick start precursor compounds for the chemistry of life.

“Looking at the organic molecules from Bennu, we are getting an understanding of what kinds of molecules could have seeded life on early Earth. We won’t find life itself, but we’re looking at the building blocks that could have eventually evolved into life.” – Michelle Thompson from Purdue University

These materials remain pristine because asteroids are essentially time capsules, unchanged since the Solar System’s formation. Unlike Earth, where billions of years of geological and biological processes have mixed and transformed the original ingredients, asteroids preserve the raw materials from which planets formed.

The colour mystery’s solution demonstrates how sample return missions revolutionise our understanding of space. By bringing pieces of distant worlds back to Earth’s sophisticated laboratories, scientists can decode secrets that remain hidden when observing from afar, opening new windows into both our Solar System’s history and the potential origins of life itself.

Source : Planetary scientist decodes clues in Bennu’s surface composition to make sense of far-flung asteroids

Genomic studies show Papua New Guineans are closely related to Asians, shaped by isolation, adaptation, and Denisovan heritage.

Papua New Guineans are living proof of how isolation, ancient genetic mixing, and life on remote islands can preserve a distinct chapter of human history.

A group of European scientists has recently clarified their genetic origins, applying advanced Artificial Intelligence (AI) methods. Their findings show that Papua New Guineans are genetically close to other Asian populations, tracing back to the same ‘Out of Africa’ migration that gave rise to all non-African groups.

Despite this shared ancestry, Papua New Guineans have a noticeably different appearance from most Asian populations and display certain traits similar to Sub-Saharan Africans. These physical similarities once led to speculation that they might have descended from a separate branch of non-African humans.

According to lead author Dr. Mayukh Mondal, the unique physical features of Papua New Guineans probably come from natural selection: “Perhaps adaptations to tropical climates that make them look more like Sub-Saharan African groups, even though their genetics clearly link them to other Asian populations. More studies are needed to uncover how evolution shaped this remarkable population.”

The genetic origin remains unresolved

Most scientists agree that modern humans left Africa between 50,000 and 70,000 years ago, eventually spreading into Europe, Asia, and other regions. Early archaeological findings suggested that the ancestors of Papua New Guineans may have come from a distinct, earlier migration (the so-called ‘First Out of Africa’ hypothesis), following a coastal path through India and Southeast Asia. Supporting this idea, the oldest human site in Oceania is dated to about 50,000–60,000 years ago, which predates the earliest known sites in Europe and indicates that at least part of their ancestry could trace back to this early dispersal.

With the development of modern DNA sequencing, researchers have revisited the ‘First Out of Africa’ theory. Analyses of both maternal (mitochondrial) and paternal (Y-chromosome) DNA have found no strong evidence that the majority of Papuan ancestry came from this earlier wave. Instead, genetic data suggest closer links to other non-African populations, although a small contribution from ancient migrations cannot be completely dismissed.

Adding to this complexity, the genomes of Papua New Guineans contain a notable proportion of Denisovan DNA — an extinct human lineage related to Neanderthals. This genetic legacy likely came from interbreeding events in Southeast Asia or Oceania, further shaping their distinct ancestry.

Even with these insights, the origins of Papuan New Guineans are not fully resolved. Were they an early branch that diverged before Europeans and Asians? Did related populations mix into their genetic history? Do they preserve ancestry from the elusive ‘First Out of Africa’ group, or are they firmly within the broader Asian lineage? These questions remain open for future study.

Unique demographic history

In this study, scientists used high-quality genomic data and AI-powered models to compare different demographic scenarios for the origin of the Papuan New Guineans’ genetic diversity. Their results suggest that Papua New Guineans are a sister group to other Asian populations. Contribution from a ‘First Out of Africa’ migration might not be needed to explain their origins.

The researchers found that the ancestors of Papuan New Guineans went through a dramatic population bottleneck — most likely their numbers dropped sharply after reaching Papua New Guinea and stayed low for thousands of years. Unlike other non-African groups, they did not experience the farming-driven population boom that reshaped Europe and Asia. This unique demographic history left genetic signatures that, if misunderstood, could look like evidence of a contribution from an unknown population.

Reference: “Resolving out of Africa event for Papua New Guinean population using neural network” by Mayukh Mondal, Mathilde André, Ajai K. Pathak, Nicolas Brucato, François-Xavier Ricaut, Mait Metspalu and Anders Eriksson, 9 July 2025, Nature Communications.
DOI: 10.1038/s41467-025-61661-w

Funding: European Regional Development Fund, Horizon 2020 research and innovation program, European Regional Development Fund, Estonian Research Council, Estonian Research Council, European Union’s Horizon Europe research and innovation program, Estonian Research Council, French National Research Agency, Tartu University

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Chinese scientists turned succulents into glow-in-the-dark, rechargeable lights that shine in a variety of colors.

These are not the first bioluminescent houseplants, Nature noted: A genetically modified petunia that glows green went on sale in the US last year.

The new work takes a different approach, enabling the plants to shine in a variety of different colors, including blue, red, and purple. To make the fluorescent succulents, the team injected the plants with phosphor particles that can absorb energy from light at one wavelength, store some of it, and then re-emit it at another wavelength, similar to how glow-in-the-dark paint works.

The researchers say they hope their technique could be used to design sustainable, plant-based lighting.

A genetic study has finally solved the mystery of the worm inside mezcal bottles.

While speculation ranged from butterflies to weevils, DNA analysis revealed that all sampled larvae came from a single moth species, Comadia redtenbacheri. This insect is a traditional delicacy in Mexico, believed to offer health and even aphrodisiac benefits.

The Mystery of Mezcal’s Worm

A study in PeerJ Life & Environment set out to determine exactly which species of larva ends up in bottles of mezcal. Mezcal, a distilled spirit made from agave, is sometimes paired with orange slices and worm salt, a seasoning blend of chili peppers, salt, and crushed larvae from a species of moth called Hypopta agavis.

For decades, there has been debate over the true identity of the so-called “mezcal worm.” Are drinkers consuming the larva of the skipper butterfly Aegiale hesperiaris, or the moth Comadia redtenbacheri (a species thought to have declined in recent years)? Could the worm actually be a type of weevil, or perhaps an insect that has not yet been identified? To answer these questions, scientists analyzed the DNA of larvae found in 21 different brands of mezcal sold commercially.

Collecting the Specimens

The larvae were obtained from mezcal bottles purchased between 2018 and 2022. At first glance, they all looked nearly identical, with a defined head capsule and prolegs typical of caterpillars. Some were pale white, while others showed a pinkish-red tint. Of the 21 samples, DNA was successfully extracted and sequenced from 18.

DNA Evidence Revealed

The findings surprised the researchers. Mexico has a long tradition of eating insect larvae, with more than 60 species commonly consumed, among them the Tequila giant skipper (A. hesperiaris), whose name suggests it might also appear in tequila and mezcal.

Instead, the genetic analysis confirmed that every larva tested belonged to a single moth species, Comadia redtenbacheri. This discovery highlights the significance of C. redtenbacheri not only as an iconic part of mezcal culture but also as one of the most widely eaten edible insects in Mexico.

Adding larvae to Mexican beverages and foods (salts, garnishes, powders, etc.) is driven by health benefits and by beliefs that these larvae contain aphrodisiac properties (Contreras-Frias, 2013). This trend is resulting in greater demand, which is applying pressure to local larval populations.

In response to the declining number of mezcal larvae, researchers have begun to develop methods to cultivate these larvae in captivity.

For more on this research, see Scientists Discover the Unexpected True Identity of “Tequila” Worms.

Reference: “Mezcal worm in a bottle: DNA evidence suggests a single moth species” by Akito Y. Kawahara​, Jose I. Martinez, David Plotkin, Amanda Markee, Violet Butterwort, Christian D. Couch and Emmanuel F.A. Toussaint, 8 March 2023, PeerJ.
DOI: 10.7717/peerj.14948

A version of this article was initially published in March 2023.

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More than half a billion years ago, a tiny ancestor of today’s arthropods scuttled along the floor of a shallow sea in what’s now Yunnan, China. It had large grasping arms, stalked eyes, and a surprisingly modern-looking brain tucked into a head barely wider than the tip of a pencil.

Now, a new look at this ancient fossil – Jianfengia multisegmentalis – is reshaping what scientists thought they knew about how these animals first branched into two major evolutionary paths.

Arthropods rule the world

Insects, spiders, crabs, centipedes – all of them are arthropods. This massive group includes more than a million known species.

Arthropods live everywhere: in the ocean, on land, in the air, and even inside of other animals. Their tough exoskeletons, segmented bodies, and jointed legs have helped them survive and thrive for over 500 million years.

But one big puzzle has remained: where exactly did the two main branches of arthropods come from?

On one side, you have mandibulates – creatures like insects, crustaceans, and millipedes, which have antennae and use jaws (or mandibles) to eat. On the other hand, chelicerates – spiders, scorpions, and horseshoe crabs – have fangs or pincers instead of jaws.

Until now, scientists weren’t sure when or how these two groups split. That’s where Jianfengia comes in.

A fossil that tells a different story

At first, Jianfengia was thought to belong to a group called megacheirans, meaning “large hands” in Greek.

These extinct animals had long, claw-like limbs sticking out from their heads – similar to the claws of modern horseshoe crabs. Because of that, scientists had placed them in the chelicerate group.

But when researchers took a closer look at the fossilized brain of Jianfengia, they noticed something didn’t add up.

The research team, led by the University of Arizona, reconstructed the nervous system from four well-preserved specimens.

What they found was unexpected: a brain that looked a lot like that of a modern shrimp or crayfish. It even had features seen in simple freshwater crustaceans, like brine shrimp – the kind sold as “sea monkeys.”

The ancestors of antennae

“These megacheirans didn’t have antennules, which are antenna-like appendages that are common to crustaceans, insects and centipedes,” said lead researcher Nicholas Strausfeld, a professor in the U of A Department of Neuroscience.

“Instead we see these strange, quite sturdy head appendages that were specialized for reaching and clasping things.”

Turns out, those big “claws” weren’t early versions of spider fangs after all. Instead, they were likely the ancestors of antennae – the kind found in today’s insects and crustaceans.

Seeing with ancient eyes

Jianfengia’s head was only about 0.08 inches wide, but it packed in a lot of sensory power. It had stalked compound eyes, like those of insects and crabs, plus at least three single-lens eyes – the simple kind also seen in many modern arthropods.

In one fossil, the researchers even looked inside the compound eyes and saw fossilized cone cells that once supported light-sensitive parts of the eye.

“What we saw was unexpected: the brain looks really modern, comparable to that of a living crustacean,” Strausfeld said.

This level of detail is almost never seen in fossils this old. Soft tissues like brains usually break down long before they can fossilize. But thanks to the fine-grained rock and lucky conditions in this ancient seabed, a few rare specimens kept their delicate neural features.

Ancient cousins go separate ways

Another fossil – Alalcomenaeus – also belonged to the megacheiran group and had similar body parts. However, it turned out to be quite different on the inside. Its brain looked more like that of Limulus, the horseshoe crab, which is a chelicerate.

So even though these two creatures looked similar on the outside, their brains revealed that they were actually early members of different arthropod groups. One led to modern crustaceans and insects. The other led to spiders and scorpions.

“Many repeats of these comparisons revealed that in the arthropod tree of life, Jianfengia sat at or near the root of all mandibulates, whereas its putative cousin, Alalcomenaeus, has the same status, but within the chelicerate branch of the tree of life,” said co-author David Andrew of Lycoming College.

The key body part in all of this are the large claws sticking out of the head. Over hundreds of millions of years, evolution shaped them into very different things.

“In chelicerates, these ‘great appendages’ shrunk, so they eventually became the spider fangs,” said Strausfeld. “In mandibulates, evolution modified them into segmented antennules.”

Some tiny marine crustaceans alive today – called ostracods – still have antennules tipped with claspers, offering living proof of this evolutionary transition.

Arthropods from the inside out

Looking at a creature’s shell or limbs can tell scientists part of the story. But to really understand where an animal fits in the family tree, the brain may offer better clues.

“Our results demonstrate that close examination of fossilized neural remains can provide powerful data indicating evolutionary relationships impossible to obtain just from features of the exoskeleton,” Strausfeld said.

“One needs to know what to look for in the fossil brain because it tells us a lot about a fossil’s identity.”

Frank Hirth, a co-author from King’s College London, noted that the organization of their fossilized brains perfectly aligns with that of living arthropods, suggesting that their ancient constituents are extraordinarily robust, yet diverse.

This may explain why arthropods are the most successful inhabitants of this planet, said Hirth.

Ultimately, the tiny brain of a long-dead sea creature has helped scientists solve one of the oldest mysteries in animal evolution – where the arthropod family tree began to branch.

The full study was published in the journal Nature Communications.

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When the Space Shuttle lifted off from Kennedy Space Center in 1981, it was the first reusable spacecraft. The massive orange external fuel tank was the major component designed to be destroyed on every flight. However, parts of the Shuttle orbiter had to be swapped out before the spacecraft could safely venture back to orbit. The four tires mounted to the orbiter’s main landing gear had to be replaced after every flight because of the immense forces during touchdown.

Landing the Space Shuttle was highly demanding of both the pilot and the shuttle itself. After entering the atmosphere, the Space Shuttle glided to the runway. The astronaut at the controls had only one shot to land because the spacecraft was flying unpowered. In ideal conditions, the Shuttle would touch down at speeds approaching 250 miles per hour on a 2.84-mile runway specifically built for it in Florida at KSC. For comparison, Concorde landed at 187 mph. According to NASA, a main landing gear tire can carry three times the load of a tire used on the Boeing 747. With the main landing gear taking the brunt of the landing, the nose gear’s two tires actually had a two-flight lifespan.

Read more: These Mods May Look Good, But They’ll Just Make Your Car Slower

Michelin’s Space Shuttle Tires Designed To Survive

The Space Shuttle’s 205-pound bias ply tires were produced by Michelin’s aviation division. Engineers had to design tires that could survive the frigid void of space, then endure temperatures up to 140 degrees before reaching the runway. The tires were filled with nitrogen to a pressure of 340 pounds per square inch to remain stable while being ready for the harsh landing load. To illustrate the difference in toughness, Michelin Pilot Sport tires are 4-ply rated and the Shuttle’s main landing gear tires are 34-ply rated.

The Space Shuttle has been retired since 2011, but it’s still a coveted piece of technology. Senators Ted Cruz and John Cornyn attempted to steal the Space Shuttle Discovery through a congressional bill earlier this year. The legislators then snuck a $85 million budget allocation into President Trump’s “Big, Beautiful Bill” to move the spacecraft back to their home state of Texas. However, NASA handed ownership of Discovery to the National Air and Space Museum in 2011. The Smithsonian is independent of the federal government, with Congress unable to seize its property unilaterally.

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