The mysterious Clovis culture, which appeared in North America about 13,000 years ago, appears to be the forerunner of Native Americans throughout the Americas, a study of DNA evidence suggests. Remains from an infant buried more than 12,000 years ago at a Clovis site in modern Montana held the genetic key.
In ski jumping, athletes hurtle off ramps at 60 miles per hour and fly the length of a football field. How do they do it? Melissa Block talks with John Eric Goff about the physics behind the event at the Winter Olympics. Goff is head of the physics department at Lynchburg College in Virginia and author of the book Gold Medal Physics: The Science of Sports.
A long-running study has been raising questions about the value of mammography for younger women, and recently it has produced yet more evidence to cast doubt on routine screening. The study found no evidence that screening saved lives, even after 25 years of follow-up. Rather, screening may lead instead to unnecessary treatment for many women. The findings are unlikely to settle debate over the value of mammography.
As time runs out to put the brakes on global warming, world leaders seem loathe to reduce gas emissions, because it's politically hard, says social scientist Clive Hamilton. Instead, he worries, we'll try to engineer the atmosphere — a tech fix that sounds quicker and simpler – but is fraught with risk.
Researchers from California's Lawrence Livermore National Laboratory say they've figured out how to get their laser to squeeze hydrogen atoms together to make helium atoms, releasing energy in the process. It's an important step in the decades-long quest for fusion energy.
Over the last half a billion years, there have been five major mass extinctions, when the diversity of life on Earth suddenly and dramatically contracted. Scientists are currently monitoring the sixth extinction, predicted to be the most devastating since the asteroid impact that wiped out the dinosaurs. But this time around, writer Elizabeth Kolbert says, humans are causing the extinction.
Yale's William Nordhaus has been running the numbers on Earth's climate troubles. He says charging a fair price for any dumping of carbon dioxide into the air is a cost-effective solution. But at least half the planet must cooperate, his math suggests, or it will be all pain, no gain.
When "Benjamin," the world's last captive Tasmanian Tiger, died in 1936, a 23-million-year run of marsupial (pouch-bearing), doglike animals very likely disappeared from the planet. But before Benjy went, he had his revenge on the humans who hunted his kind to extinction.
As an acoustic engineer, Trevor Cox has spent most of his career getting rid of bizarre, unwanted sounds. But in The Sound Book, Cox turns up the volume on those sonic oddities. The book explores weird echoes and unexpected noises from around the globe — including "whisper galleries" and a chirping pyramid.
Why was Marius, a healthy 18-month-old giraffe, killed on Sunday at the Copenhagen Zoo? Employees say it's because Marius had genes too similar to other giraffes and was killed to avoid inbreeding. But the act has caused an uproar on social media and among animal activists. Robert Siegel talks to Bengt Holst, the scientific director at the Copenhagen Zoo, about the decision to put the giraffe down.
Skipping a meal triggers the munchies in a similar way that marijuana does, a study in mice finds. And it works, at least in rodents, by boosting the sense of smell. Receptors in the brain that get activated when the animals are stoned also light up after they've been fasting.
Today's political polarization makes it seem harder than ever to tackle climate change. Republican Bob Dixson says the goals of going green aren't only for liberals. His town of Greensburg was hit by an unusually strong tornado, and now he's working on a White House task force to prepare communities like his.