Stars like the Sun are remarkably constant. They vary in brightness by only 0.1% over years and decades, thanks to the fusion of hydrogen into helium that powers them. This process will keep the Sun shining steadily for about 5 billion more years, but when stars exhaust their nuclear fuel, their deaths can lead to pyrotechnics.The Sun will eventually die by growing large and then condensing into a type of star called a white dwarf. But stars more than eight times more massive than the Sun die vi ...read more

When you hear the words “reptilian” or “cold-blooded”, the first thing that comes to might be a miserly politician or an uncaring boss — in other words, probably not an actual crocodile or lizard. That’s because for decades, reptiles have been characterized as cold, unfeeling, and even primitive creatures.  But scientists agree that reptiles aren’t emotionless — they’re misunderstood. Extensive research has shown that reptiles experience a wide range of emotions, and that the ...read more

In 2022, we reported the DNA sequences of 33 medieval people buried in a Jewish cemetery in Germany. Not long after we made the data publicly available, people started comparing their own DNA with that of the 14th-century German Jews, finding many “matches.” These medieval individuals had DNA fragments shared with thousands of people who have uploaded their DNA sequence to an online database, the same way you share DNA fragments with your relatives.But what type of a relationship with a medi ...read more

Deep in the rainforests and eucalyptus woodlands of Australia and New Guinea lives an enigmatic creature known as the striped possum. Quiet, cute, and nocturnal, its favorite activity is boring holes into the trees and using its elongated fingers to extract ants and termites from the trunks within. While the striped possum is hard to spot in the wilds of Australia, it’s much more common in the lowlands of New Guinea. The Striped Possum: A Curious CreatureThe striped possum is less than a foot ...read more

Were Stone Age humans the first geologists?Humans living in what is now South Africa 70,000 years ago possessed a surprisingly sophisticated understanding of the various kinds of rock that made up their world, indicates a new study published in the Proceedings of the National Academy of Sciences of the United States of America.Not only did hunter-gatherers of the time know how to make finely crafted stone tools, but they understood exactly which rocks would yield the best combinations of ease of ...read more

In the age of air travel, the Calanais Standing Stones (or Callanish, in the anglicized spelling) are not so hard to get to, and yet, the site feels remote.The ancient stone megaliths are perched at the edge of the village that shares their name, on the west coast of the Isle of Lewis, part of the Outer Hebrides chain of islands that sits off the northwestern coast of Scotland. Having read of Calanais’ status as the “Stonehenge of the North,” I was determined to make the journey; it had be ...read more

Tanzania’s Serengeti ecosystem is like a time machine. As one of the world’s last remaining fully intact grazing ecosystems it provides a glimpse of what others in Australia, Eurasia and the Americas might have looked like when communities of large grazing mammals roamed freely across these continents.During the Late Pleistocene, which spanned from 129,000 to 11,700 years ago and is sometimes referred to as the “ice age”, populations of these grazing animals collapsed all over the world. ...read more

Throughout history, humans have recognized that the night sky has the ability to mark moments of significance. For Muslims, for instance, the sighting of the moon has long signaled the start of the month of Ramadan, a period of fasting and religious reflection that traces its roots to the seventh century C.E.Since then, Muslims have turned to the skies to guide their Ramadan observances. So how, specifically, has astronomy informed the traditions of Ramadan, and how has that changed over time? ...read more

The 5-year-old girl lay limp in her father’s arms, fast asleep, as he rushed her into the doors of the pediatric emergency department.“We can’t wake her up,” he pleaded, eyes wide and voice rushed with desperation.“Maddie’s never slept this deeply. It’s strange,” he continued frantically. “She fell asleep in the car on the way home from camping. We yelled, pinched her, splashed cold water on her face. She just stays zonked.”She looked like Sleeping Beauty; her cheeks were pin ...read more

Stars within the center of our home galaxy are constantly threatened by collision, as they orbit around the Milky Way's supermassive black hole, Sagittarius A (Sgr A). How close the stars are to Sgr A decides whether they crash into other nearby stars, stuck in a merging steadfast clash, or only lose their outer layer and keep hurtling into orbit."They whack into each other and keep going," said Sanaea Rose, study lead author and astrophysicist at Northwestern University, in a press release. "Th ...read more