On the horizon
The evolutionary path from dinosaurs to modern birds appears to have passed through the local duck pond.
Paleontologists working in China's Gansu Province have found the fossil remains of five birds dating to 115 million years ago. The remains exhibit many structural traits found in modern birds, including webbed feet. This suggests that the birds lived an aquatic lifestyle, much like today's loons or ducks, the team reports in the current issue of the journal Science.
The finds, which the team names Gansus yumenensis, lack skulls, so pinning down the fowls' diets is tough. The team speculates that the birds' smorgasbord may have included fish, insects, and plants. But the birds' upper bodies suggest they could take off and land in water, and the webbed feet and bony knees testify to their ability to swim, according to the group, headed by Peter Dodson at the University of Pennsylvania in Philadelphia.
The new finds represent the oldest specimens yet along the evolutionary branch that led to modern birds.
Why does stuff fall into a cosmic black hole? The answer tends to be: Because its gravity is so intense that nothing, not even light, can escape.
But there's more to it than gravity, researchers say. If gravity were the only force at work, nothing would fall in: It would orbit the black hole forever, held beyond the black hole's grasp by centrifugal force.
Gravity appears to be getting help from magnetic fields in the disk of doomed hot dust and gas that orbits a black hole, according to a team led by the University of Michigan astrophysicist Jon Miller. These fields set up conditions that sap the disk's energy and slow it enough to fall into the hole.
Using NASA's Chandra X-Ray Observatory, the team examined a binary system consisting of a stellar-mass black hole and star roughly twice as massive as the sun. The system is 10,400 light-years from Earth. The team's work appears in Thursday's issue of the journal Nature.
Near-Earth space is forever blowing bubbles – a surprising find by a team of physicists using satellite data to study the interaction of the Earth's magnetic field with the solar wind – a flow of particles streaming from the sun.
The "bubbles" appear above the sunlit side of our planet roughly between 50,000 and 75,000 miles away. There, vast pockets of gas display a density about 1/10th the density of the surrounding gas, but with temperatures from 100,000 to 10 million degrees C. The bubbles, perhaps 600 miles across, last for 10 seconds, burst, and are replaced with cooler gas from the solar wind.
Initially the researchers, led by George Parks of the University of California at Berkeley, thought the bubbles were flukes, evidence from flaky instruments. But when five satellites – four from Europe and one from China – recorded the unusual formations simultaneously, the team concluded that the bubble explanation was correct. The results appear in the current issue of the journal Physics of Plasma.
Who better to find invasive Burmese pythons than other Burmese pythons?
That is the approach biologists from the University of Florida are testing to track and capture the reptiles, which can reach 20 feet long and tip the scales at 200 pounds. Released by pet owners who didn't want them anymore, the snakes are seen as threatening many native animals in Florida's Everglades National Park. Now, scientists are capturing some, implanting them with small radio beacons, then releasing them again.
During a three-month experiment that began last December, researchers found that the snakes could travel nearly a mile from where they'd been caught and released, often making their homes in elevated patches of forest. And the snakes do find each other in the wild, increasing hopes that these "Judas" pythons will aid efforts to capture other snakes.
The results were reported at a recent meeting on Everglades restoration efforts in Lake Buena Vista, Fla.