This post was originally published on here
This ‘Galaxy That Wasn’t’ Never Bore Any Stars
Astronomers have announced the discovery of a new kind of cosmic object, something that is very nearly a galaxy, save for one crucial, missing ingredient: stars.
The almost-galaxy is about 14 million light-years from Earth. It was the ninth cloud found to be associated with a nearby spiral galaxy, leading to its serendipitous name: Cloud-9. The object is starless, consisting of only a haze of hydrogen gas that astronomers believe is swaddled in a much more massive clump of dark matter, the invisible substance that permeates the cosmos and shapes its overarching structure.
“There’s nothing like this that we’ve found so far in the universe,” Rachael Beaton, an astronomer at the Space Telescope Science Institute, said at a meeting of the American Astronomical Society in Phoenix last week. She added, “It’s basically a galaxy that wasn’t.”
Cloud-9 is the first confirmed example of what astronomers call a RELHIC, short for Reionization-Limited H I Cloud and pronounced “relic.” Such objects are rich in gaseous hydrogen but devoid of any stars. They are failed galaxies nearly as old as time itself, primordial fossils that can help astronomers understand the conditions required for galaxies to grow.
Studying such objects could help explain how exactly dark matter influences the shape of the universe that can be seen.
Astronomers in China reported Cloud-9 as a potentially starless object in 2023. Follow-up observations, by the Green Bank Telescope in West Virginia and the Very Large Array in New Mexico, strengthened the hunch that the object did not contain any stars. — KATRINA MILLER
Why This Fish Actually Needs a Hole in the Head
Ten years ago, Kory Evans, an evolutionary biologist, was staring at an unusual fish in a lab. The fish, a rockhead poacher, was tiny and chunky, he said, and looked “so different from all the other guys around it.”
But the feature that made it stand out the most was the “big old hole” in the middle of its head, he said. For more than a century, the poacher’s head cavity had puzzled scientists.
Daniel Geldof, an undergraduate at the University of Washington at the time, made a comment in passing to Evans about how the fish could be using the pit to produce sound.
Last year, Geldof presented his master’s thesis to advisers at Louisiana State University that was the culmination of years of research and hours of laborious scanning. It explains that the rockhead poacher uses the hole in its head as a percussion instrument, like a drum, or a maraca. As its ribs hit the cavity, a buzzing sound emerges.
“I clearly underestimated how much he was going to test this hypothesis,” said Evans, who is now a researcher at Rice University.
Kassandra Ford, an evolutionary biologist at the University of Minnesota who was not involved in the study, said, “It makes total sense.” She considered Geldof’s methods a “creative way” of figuring out the “really funky and unique behaviors in this particular species of fish.” — ALEXA ROBLES-GIL
Scientists Discover Oldest Poison, on 60,000-Year-Old Arrows
Today it seems obvious: Dip a sharp object in a poisonous substance, and then use that weapon to take down your prey. But when did humans figure out this deadly strategy? A new study pushes back the timeline of this innovative hunting technique by tens of thousands of years.
Researchers led by Sven Isaksson, a professor of archaeological science at Stockholm University, have discovered poison residues on 60,000-year-old arrow tips unearthed in South Africa. With the next-oldest trace of poison use dated to 35,000 years ago, these tips preserve the earliest evidence of poisoned weapons by a wide margin. “It’s a big leap,” Isaksson said of the discovery, which was published in the journal Science Advances.
The finding reinforces existing evidence that early Homo sapiens had cognitive abilities nearing the sophistication of our own. That’s because in order to tip an arrow with poison, hunters needed knowledge of local plants and their effects, as well as the ability to craft special weapons with the right dosages.
“It takes a developed working memory to be able to predict that if I put this arrowhead into that plant, it will shorten the delay before I get my hands on this meat,” Isaksson said.
Isaksson’s team examined specimens that were discovered in 1985 at the Umhlatuzana Rock Shelter in eastern South Africa. The shelter contains layers of archaeological remains that were left tens of thousands of years ago. The researchers were inspired to look more closely at quartz arrow tips lodged in sediments estimated to be 60,000 years old. — BECKY FERREIRA
This article originally appeared in The New York Times.
