An enormous asteroid might have killed the dinosaurs, but the craters left behind by such impacts may become burgeoning hotspots for life on Earth, and possibly even Mars, says a UK researcher.
Charles Cockell at the British Antarctic Survey presented data on rocks - thriving with microbial life - found in the Haugton Crater in the Canadian Arctic to the British Association for the Advancement of Science Festival in Exeter, UK, on Thursday.
The crater is the depression caused by an impact event 23 million years ago. The energy of the event is estimated at 100 million times the size of the Hiroshima atomic bomb.
“People usually associate impact events with destruction. But asteroids or comets might actually be good for life,” says Cockell.
Between 1998 and 2004, Cockell and his colleagues gathered rock specimens from the 24-kilometre-wide crater on Devon Island.
They found that much of the dark or opaque minerals, such as feldspar, had vaporised during the initial explosion. This left a several-centimetre thickness of near-translucent rocks, riddled with holes.
Back in the lab, they looked at the samples under both traditional and scanning electron microscopes and found them to be packed with microbes. Photosynthetic bacteria had colonised the translucent upper layer of the rocks, absorbing sunlight through clear silicate deposits.
As well as nurturing present day microbes, says Cockell, impact craters might even be responsible for the beginnings of life on Earth. The heat would have lasted for about 10,000 years and could have provided enough energy for simple organic compounds to form into more complex ones, such as amino acids, possibly even forming pre-biotic molecules.
“The good thing about a hole in the ground is that water seeps into it. So you’ve got water, organics and heat all in the same place, which is good for the evolution of life on Earth,” says Cockell.
The results suggest that meteorite craters may be one of the best places to look for life on other planets. Craters cover the surface of Mars, and there is evidence of liquid water in the red planet’s past, making it one of the most likely places for extraterrestrial life in the solar system.
Cockell also suggests that impact events may have temporarily melted any frozen water on Saturn's moon, Titan, potentially giving life a chance to thrive.
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10:45 10 October 2008
19:00 09 October 2008
