On the horizon
Dwarf discovery in deep space
Astronomers have found a pair of brown dwarfs - stellar wannabes that never gained enough mass to ignite and shine - some 1,500 light-years away in the constellation Orion. The pair is locked in an orbital embrace that sends one in front of the other. Astronomers used these eclipses to calculate the most precise estimates yet of masses, sizes, and other properties of brown dwarfs.
The find represents "a Rosetta stone" for understanding these enigmatic objects, says Keivan Stassun, a Vanderbilt University astronomer who led the team. Despite their rap as being among the dimmest bulbs on the cosmic shelf, brown dwarfs could be the most common type of stars in the galaxy, some astronomers suggest.
The pair is about 10 million years old. Both have roughly half the sun's diameter. One tips the scales at 5 percent of the sun's mass, the other at 3 percent. The results appear in Thursday's issue of Nature.
Deep-sea hydrothermal vents have served up a zoo of unusual creatures. Among the latest: the "Yeti crab" (below). Formally known as Kiwa hirsuta, the crab represents a new genus, species, and family among the likes of lobsters and crabs, according to the international team that found the creature last March during a visit to a hydrothermal vent some 1,000 miles south of Easter Island.
Its hairy arms and snow-white appearance earned it the "Yeti" label. The creature, about 6 inches long, is blind. Only thin membranes appear where the eyes should be. Researchers say that the fur along its claws and legs could be a habitat for bacteria that help the creature survive the harsh chemical environment around the deep-sea vents. The results appear in the French journal, Zoosystema.
Easter Island, with its monumental statues, has long been seen as an example of how a small band can settle in an area, grow in number, and finally ruin the environment.
Now a pair of archaeologists say the arrival, growth, and collapse of the island's population took place over a much shorter period than had been believed. Writing in the current issue of the journal Science, University of Hawaii researcher Terry Hunt and Cal State Long Beach's Carl Lipo argue that the Polynesians who colonized the island arrived around AD 1200, some 400 to 800 years later than previously believed.
The team excavated a section of the island's only sand dune, which appears to be the initial occupation site. Radiocarbon studies of artifacts from the bottom of the dig yielded dates around 1200. The pair concludes that the culture's demise resulted more from contact with Europeans, beginning in 1722, than in the damage they had inflicted on their environment.
