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5 December 2013 11:26 am ,
Vol. 342 ,
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
Snake venoms are remarkably complex mixtures that can stun or kill prey within minutes. But more and more researchers...
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
Since arriving on the island of Guam in the 1940s, the brown tree snake ( Boiga irregularis ) has extirpated native...
An animal rights group known as the Nonhuman Rights Project filed lawsuits in three New York courts this week in an...
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
- 5 December 2013 11:26 am , Vol. 342 , #6163
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ScienceShot: Older Vega Mature Enough to Nurture Life
3 December 2012 11:20 am
Shining just 25 light-years from Earth in the constellation Lyra, Vega (false-color infrared image shown) is the fifth brightest star in the night sky. In 1983, astronomers discovered dust orbiting the star, suggesting it had a solar system, and Carl Sagan (pictured) chose to make Vega the source of a SETI signal in his 1985 novel Contact, though the responsible aliens weren't native to the star: At the time, Vega was thought to be only about a couple hundred million years old, probably too young for any planets to have spawned life. Since then, however, estimates of Vega's age have increased, because astronomers learned that the star spins fast—once every 17 hours—which stirs up the star's interior and forces the surface composition to match the overall composition of the star. This discovery meant that scientists had been overestimating the star's abundance of heavy elements, which in turn meant they had been overestimating its mass—and thus underestimating its age, because less massive stars evolve more slowly. Now, scientists have studied Vega with the CHARA interferometer, an array of telescopes in California yielding crisp views of stars, and modeled the observations by using new computations of how fast-spinning stars age. As the researchers will report in The Astrophysical Journal Letters, Vega is 2.15 times as massive as the sun—agreeing with work from recent years—but considerably more mature than had been previously thought. The star is between 625 million and 850 million years old, so suitable planets have probably had sufficient time to develop primitive life.
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