Tau Ceti a Star for Life to Avoid
Tau Ceti, a star with a dust disk astronomers had hoped might be an example of a planetary system under construction, is more like a war zone. A press release from the Royal Observatory calls it “Asteroid Alley – an Inhospitable Neighbor.” Using the James Clerk Maxwell Telescope in Hawaii, the astronomers detected 10 times the quantity of asteroids and comets as around our sun. Jane Greaves, the lead scientist, explained the implications of this finding: “We don’t yet know whether there are any planets orbiting Tau Ceti, but if there are, it is likely that they will experience constant bombardment from asteroids of the kind that is believed to have wiped out the dinosaurs. It is likely that with so many large impacts life would not have the opportunity to evolve.”
The press release says, “The discovery means that scientists are going to have to rethink where they look for civilisations outside our Solar System.” Another astronomer suggests that our solar system may have been swept clean of impactors by a passing star. Whatever the reason for the difference, Tau Ceti is “clearly a place you would not wish to be,” concludes Ian Holliday, Chief Executive of the Particle Physics and Astronomy Research Council (PPARC) of the Royal Observatory, Edinburgh.
Evolution: always assumed, never demonstrated. Dinosaur extinction via impact: a media mythoid that persists despite falsifying evidence (see 12/03/2003 and 06/02/2003 headlines).
Tau Ceti was the darling of astrobiologists who assumed its dust disk was evidence of an evolving solar system similar to ours. Now chalk up another tally for the Privileged Planet hypothesis (see 06/24/2004 headline). Even so, these measurements are too indirect to know for sure what it’s like out there at the Whale, without Han Solo to drive us through Asteroid Alley.