The smaller object in this photo is thought to be a brown-dwarf companion that orbits the distant star Gliese 229. Some have worried that our sun has a similar companion whose gravitational effect periodically sends more comets toward Earth — but the latest analysis of cometary data shows no sign of such an effect.
By Alan Boyle
Doomsayers have been wringing their hands for years over the possibility that an unseen companion to our sun periodically diverts a hail of comets toward Earth, sparking mass extinctions like cosmic clockwork. Now an astronomer has shown that the evidence for such a cycle in the flux of comets or asteroids doesn't actually exist.
The research is the latest knock against claims that the dark companion, nicknamed Nemesis or the "Death Star," might be out to get us in 2012.
Like many other 2012 myths, the Nemesis hypothesis had a smidgen of scientific research behind it. Back in 1984, paleontologists proposed that there seemed to be a 27 million-year cycle of extinctions that may have had an extraterrestrial cause. The prime suspect was a hypothetical brown dwarf or red dwarf that disrupted the orbits of comets on the solar system's fringe and sent them screaming earthward.
Nemesis has gotten swept up with the Planet X hypothesis, which holds that an as-yet-undetected planet will wreak havoc on Earth — and both those hypotheses have fed into worries about a 2012 apocalypse supposedly foretold by the ancient Maya calendar.
You've probably already figured out that the worries are totally bogus, and not just because the "long count" calendar used by the Maya was merely a calendar and not a fortune-telling device.
Last year, researchers reported that if the Nemesis companion existed, it wouldn't orbit in a nice, precise 27 million-year cycle. That study, published in the Royal Astronomical Society Letters, was portrayed as the "final nail in the coffin" for the Nemesis hypothesis. But the researchers still couldn't explain why extinctions seemed to peak every 27 million years.
Read More: http://cosmiclog.msnbc.msn.com/_news/2011/08/02/7233108-2012-watch-death-star-debunked
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