China’s Space Station Has Finally Fallen Back to Earth

China’s Tiangong-1 Space Station Has Fallen Back to Earth Over the Pacific Photo A radar image of Tiangong-1, the Chinese space station that re-entered Earth’s atmosphere. Credit Fraunhofer Institute, via Associated Press A Chinese space station the size of a school bus re-entered Earth’s atmosphere at about 5:16 p.m. Pacific time on Sunday, scattering its remaining pieces over the southern Pacific Ocean, according to the United States’ Joint Force Space Component Command.
The demise of the station, Tiangong-1, became apparent when radar stations no longer detected it passing overhead. There were no immediate reports of damage or injuries; the likelihood that pieces would land on someone was small, but not zero.
The station may have landed northwest of Tahiti, Jonathan McDowell, an astronomer at the Harvard-Smithsonian Center for Astrophysics, said on Twitter. That location is north of the Spacecraft Cemetery, an isolated region in the Pacific Ocean where space debris has frequently la..

Q&A: Hanging Out the Wash in the Fresh, Clean Air

Hanging Out the Wash in the Fresh, Clean Air
Q. When I hang my laundry outside to dry, what makes it smell so wonderfully of fresh air?
A. It may simply be the absence of bad smells that makes air-dried laundry smell good in comparison, air safety experts have suggested.
Indoor air, especially in a tightly enclosed environment, may have a buildup of scents both benign and dangerous, from cooking odors to mold and mildew to chemical pollutants like volatile cleaning products and heating fuel. Meanwhile, the occupants of the building are breathing the air and depleting it of oxygen, to some extent, and perhaps smoking tobacco.
All these problems are either absent or considerably diluted in the outside air.
Pleasant natural smells may be present, from sources like pine trees and other evergreens, if you are lucky. And the laundry has been cleansed of sweat, mold, bacteria and other potential odor-causing substances and dries quickly in a breeze, removing the moisture on which such smells..

Matter: A Few Species of Frogs That Vanished May Be on the Rebound

A Few Species of Frogs That Vanished May Be on the Rebound Photo A healthy variable harlequin frog with golden coloring in the streams of Panama. Credit Cori Richards-Zawacki In 2013, two biologists named Jamie Voyles and Corinne L. Richards-Zawacki spent weeks slogging up and down mountainsides in Panama. “We were bug-bitten and beat up,” recalled Dr. Voyles, now an assistant professor at the University of Nevada, Reno.
Near the end of their trek, they came to a stop. In front of them sat the object of their quest: a single gold-and-black frog.
“I can’t tell you what that moment was like,” Dr. Voyles said.
She had feared that variable harlequin frogs had disappeared entirely from Panama. As recently as the early 2000s, they had been easy to find in the country’s high-altitude forests.
“They used to be so abundant that you could barely walk without stepping on them,” Dr. Voyles said.
Continue reading the main story But in recent years, Dr. Voyles and her colleagues star..

Trilobites: Why Do Cracking Knuckles Make That Sound? You Might Need a Calculator

Why Do Cracking Knuckles Make That Sound? You Might Need a Calculator Photo Scans from a MRI machine in a 2015 study that looked at what happened inside a knuckle when it cracked. Credit University of Alberta In some households, cracking your knuckles is a declaration of war. Whether you’re in the camp that can’t stand the sound or the one that can’t see what the fuss is about, you might be surprised to learn that where exactly the sound is coming from — what precisely in the knuckle produces it — is still a subject of scientific research.
For more than 50 years people have been publishing scholarly papers about what is going on in your finger as you pull it. Lately an older theory, that the sound arises from the popping of a bubble in the joint, has been challenged by one that holds that the formation of the bubble itself is responsible. On Thursday in the journal Scientific Reports, the saga continued: A pair of researchers at the Ecole Polytechnique in France reveal a mathematical m..

Wreck of the Juneau Is Found, 76 Years After 5 Brothers Perished

Wreck of the Juneau Is Found, 76 Years After 5 Brothers Perished Photo A remotely controlled vehicle captured footage of guns aboard the sunken Juneau, more than two miles beneath the water’s surface in the South Pacific. Credit Paul Allen At the Battle of Guadalcanal during World War II, hundreds of sailors — including five from the same family — lost their lives while serving on the same ship for the United States Navy.
The ship, the cruiser Juneau, was blasted apart by a Japanese torpedo on Nov. 13, 1942. For decades it was lost, resting in pieces somewhere in the South Pacific.
It was found on Saturday when a team aboard the Petrel, a research vessel funded by the Microsoft co-founder and philanthropist Paul G. Allen, identified the wreckage about 2.6 miles underwater off the coast of the Solomon Islands.
Among the hundreds aboard the Juneau when it sank were five brothers from Waterloo, Iowa. Because they were all serving together, the sons of Thomas and Alleta Sullivan were well ..

The Ruthless Phronima, and Other Hidden Wonders of the Sea

The Ruthless Phronima, and Other Hidden Wonders of the Sea Photo The American Museum of Natural History’s latest exhibition, “Unseen Oceans,” welcomes visitors with a projection of sand and surf. Credit Denis Finnin/American Museum of Natural History Take the first step into “Unseen Oceans,” the new exhibition at the American Museum of Natural History, and you are bound to be tickled and enticed by the appearance of sand and surf beneath your feet.
It’s only video projected onto the floor, a simple enough technique, but I was sorely tempted to take off my shoes and wiggle my toes in the illusory foam. If I were to bring little ones to the exhibition, I’d keep an eye on their footwear. Promise them that if they keep walking there will be real sand that they can touch with their hands.
The exhibition is, of course, about hidden ocean wonders, but it features more than the usual suspects of blue whales and frighteningly enlarged microscopic plankton. The technology that allows scientists ..

Trilobites: What Makes Some Hair Curly? Not Quite What Scientists Thought

What Makes Some Hair Curly? Not Quite What Scientists Thought Photo Merino sheep on a farm in Alexandra, New Zealand. Scientists found that differences in the cells on a hair explain a sheep’s curls, and may offer insights for other mammals, like us. Credit Guy Frederick for The New York Times Every day is a curly hair day for sheep. Those curls and kinks are part of what makes woolen sweaters so cozy — the maze of fibers helps trap warm air, keeping it close to the body. But wrapped up in those curls may also be answers to a longstanding mystery: exactly how a strand of hair winds itself into a curl on the cellular level.
For many years, there were two competing theories to explain what makes hairs curl in sheep. Research by scientists in New Zealand and Japan published Thursday in the Journal of Experimental Biology finds that neither theory is exactly correct. But it remains likely that differences between certain cells on a hair may explain what makes a sheep’s wool curly. And whil..

150 Whales Beached in Australia, as Rescuers Fight to Save Them

150 Whales Beached in Australia, as Rescuers Fight to Save Them Photo More than 150 short-finned pilot whales were found beached in Hamelin Bay, Western Australia, on Friday. Credit Western Australia Department of Biodiversity Conservation and Attractions, via Agence France-Presse — Getty Images HONG KONG — More than 150 whales became stranded on a Western Australia beach, wildlife officials said Friday, as poor weather and the threat of frenzied sharks prevented rescuers from saving scores of them.
The short-finned pilot whales were spotted Friday morning on the coastline of Hamelin Bay, about 160 miles south of Perth. But by nightfall, all but seven of the whales were dead, according to the state’s Department of Biodiversity, Conservation and Attractions.
“Most of the whales beached themselves on dry land overnight and have not survived,” said Jeremy Chick of the department’s Parks and Wildlife Service, who was overseeing the rescue attempt.
Efforts were underway Friday evening to mo..