NASA Finds Young Stars Dim in X-rays Surprisingly Quickly - UNIVERSE

Trumpler 3 and NGC 2353 (Labeled).

X-ray: NASA/CXC/Penn State Univ/K. Getman; Optical/IR: PanSTARRS; Image Processing: NASA/CXC/SAO/N. Wolk

Scientists have found that young stellar cousins of our Sun are calming down and dimming more quickly in their X-ray output than previously thought, according to a new study using NASA’s Chandra X-ray Observatory. A paper describing the results published Monday in The Astrophysical Journal.

Unlike in the new movie “Project Hail Mary,” this quieting of young stars is a benefit for the prospects for life on orbiting planets around these stars — not a threat.

Astronomers used Chandra and other telescopes to monitor how powerful radiation from young stars — often in the form of dangerous X-rays — can pummel planets surrounding them. They did not know, however, how long this high-energy barrage continued.

This latest study looked at eight clusters of stars between the ages of 45 million and 750 million years old. The researchers found that Sun-like stars in these clusters unleashed only about a quarter to a third of the X-rays they expected.

"While science fiction – like the microbes in Project Hail Mary – imagines alien life that dims stellar output by consuming its energy, our real observations reveal a natural ‘quieting’ of young Sun-like stars in X-rays,” said Konstantin Getman, the lead author of the new study from Penn State University. “This is not because an outside force is consuming their light, but because their internal generation of magnetic fields becomes less efficient.”

In fact, this calming could be a boon to the formation of life on planets around stars that are younger versions of our own Sun. (Our Sun is about 4.6 billion years old, so significantly older than the stellar cousins in this study.) This is because large amounts of X-rays can erode a planet’s atmosphere and prevent formation of molecules necessary for organic life as we know it. On average, three-million-year-old stars with a mass equal to the Sun produce about a thousand times more X-rays than today's Sun. Meanwhile, 100-million-year-old solar-mass stars are about 40 times brighter in X-rays than the present Sun.

Illustration of a young Sun-like star eroding some of the atmosphere of an orbiting planet.

NASA/SAO/CXC/M. Weiss

“It’s possible that we owe our existence to our Sun doing the same thing, several billion years ago, that we see these young stars doing now,” said co-author Vladimir Airapetian of NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “This real-world dimming echoes the dramatic stellar change in fiction, but it may be even more fascinating because it highlights our own Sun's actual history.”

The researchers found that stars with about the same mass as the Sun quieted down relatively rapidly — after a few hundred million years — while ones with less mass kept up their high levels of X-ray emission for longer. Combined with a decrease in the energy of the X-rays and the disappearance of energetic particles, the Sun-sized stars are apparently better suited to host planets with robust atmospheres and possibly blossoming life than previously thought.

The research team also used data from ESA’s (European Space Agency’s) Gaia satellite and X-ray data from the ROSAT (ROentgen SATellite) mission. This data allowed them to identify the stars that were members of the clusters (not foreground or background stars). To measure the X-ray output from the stars, they made new Chandra observations of five clusters with ages between 45 million and 100 million years, in addition to using Chandra and ROSAT data from archives to study three older clusters with ages between 220 and 750 million years.

Astronomers have not been able to study the X-ray output of stars in this age range well before. Most astronomers have relied on sparse data and a derived relation that predicts the X-ray emission young stars should produce based on their ages and rates of spin. Older and more slowly rotating stars are usually fainter in X-rays, but the team found that X-ray output drops off about 15 times more rapidly than the derived relation predicts during this specific adolescent phase.

“We can only see our Sun at this current snapshot in time, so to really understand its past we must look to other stars with about the same mass,” said co-author Eric Feigelson, also of Penn State University. “By studying X-rays from stars that are hundreds of millions of years old, we have filled in a large gap in our understanding of their evolution.”

While they are still investigating the cause of this slower-than-expected activity, scientists think the process that generates magnetic fields in these stars may become less efficient. This would lead to the stars becoming quieter in X-rays more quickly, as they age. The researchers will continue to look at this and other potential causes for the rapid dimming of young Sun-like stars.

NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program. The Smithsonian Astrophysical Observatory's Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.

Read more from NASA’s Chandra X-ray Observatory

Learn more about the Chandra X-ray Observatory and its mission here: https://science.nasa.gov/chandra - https://chandra.si.edu 

Source: NASA Finds Young Stars Dim in X-rays Surprisingly Quickly - NASA Science 

The Cave That Rewrites Who We Are: Neanderthals and Humans Were Never Strangers

For most of modern history, the story we told about Neanderthals was simple: they were the other guys. Primitive. Separate. Eventually gone, replaced by us Homo sapiens, the smarter, more adaptable species that won the evolutionary race.

A cave in central Israel just tore that story apart.

What They Found

The first-ever published research on Tinshemet Cave reveals that Neanderthals and Homo sapiens in the mid-Middle Paleolithic Levant not only coexisted but actively interacted, sharing technology, lifestyles, and burial customs.

Since 2016, archaeologists working at Tinshemet Cave have uncovered the remains of five early humans dating back around 110,000 to 100,000 years ago, including two full skeletons and three isolated skulls. The cave, a dark crevice in central Israel’s rolling hills, has turned out to be one of the most important sites for understanding human evolution ever discovered.

The burials were in a fetal position, often accompanied by red ochre, and the arrangement closely mirrors what we see at other prehistoric sites like Skhul and Qafzeh caves, suggesting early human populations across the Levant shared cultural traditions.

They Didn’t Just Live Near Each Other, They Learned From Each Other

Stone tools from the site show manufacturing techniques common to all groups, suggesting direct knowledge transfer rather than independent parallel development. In other words, they weren’t just neighbors, they were teachers and students to one another.

The cave also yielded thousands of ochre fragments, some transported from distant sources, indicating deliberate collection rather than incidental use. Ochre, a vivid red-orange mineral pigment is one of the earliest known materials used for symbolic expression. The fact that both species were using it, in the same rituals, in the same place, says something profound about how connected they really were.

The World’s Oldest Cemetery?

The arrangement of burials at the site raises the possibility that Tinshemet Cave served as a dedicated burial area or even an early cemetery. Objects placed alongside the dead, including stone tools, animal bones, and pieces of ochre, may hint at early beliefs about an afterlife.

Formal burial customs began to appear around 110,000 years ago in the Levant, the earliest instances of intentional Homo burials anywhere in the world, predating formalized burial practices in Europe and Africa by tens of thousands of years. And crucially, these rituals didn’t belong to just one species. They were shared.

What This Changes

Lead researcher Prof. Yossi Zaidner of the Hebrew University of Jerusalem describes the region as a “melting pot” where diverse human groups met, interacted, and evolved together. “Our data shows that human connections and population interactions were fundamental in driving cultural and technological innovations throughout history.”

“The mixing of subgroups created opportunities for different groups of primitive humans to exchange knowledge or express their identity. It’s at this time that archaeologists see for the first time examples of primitive jewelry or body painting.”

The old narrative cast Neanderthals and humans as rivals. Tinshemet Cave tells a different story, one where connection, not competition, was the engine of human progress. Where two different kinds of people looked at the same dead and felt the same need to bury them with care, with objects, with meaning.

That instinct, to honor the dead, to mark identity, to pass on knowledge, didn’t belong to us alone.

It was always ours. Together.

Journal article: https://www.nature.com/articles/s41562-025-02110-y 

Source: The Cave That Rewrites Who We Are: Neanderthals and Humans Were Never Strangers – Scents of Science