- Joined
- Aug 7, 2001
- Messages
- 54,631
The earliest Meteor extinction event? Link.
Ellwood and four other researchers have just published an article in the journal Science in which they tie an early mass extinction to a meteor strike. This extinction happened 380 million years ago in what is called the middle Devonian. It was a time when only small plants, wingless insects and spiders inhabited the land and everything else lived in the sea. About 40 percent of all species disappeared from the fossil record at this time.
The extinction has been known to geologists for a long time but this is the first time it has been tied to a meteor strike. This is also the oldest known impact that has been tied to a mass extinction.
Ellwood is quick to point out that because the extinction and the meteor strike happened at the same time does not prove the impact caused the extinction -- but it certainly suggests it.
...
The past 550 million years are divided up by geologists into about 90 "stages." Each stage is distinguished from another by a change in the fossil record. To date, only four of these stages show strong evidence of a meteor strike, Ellwood's discovery being the latest, as well as the oldest. The most recent, best known extinction is the K-T boundary at which the dinosaurs died out, about 65 million years ago. There have been five major mass extinctions and many smaller ones since then.
"We know that meteors have struck the Earth hundreds of times," Ellwood said. "If I had to guess, I would say that once every 5 million years a meteor big enough to cause a mass extinction hits the Earth.
"We could protect ourselves if we wanted. We went to the moon, we can figure out how to destroy or deflect a meteor. All it takes is the political will -- and an awareness of the threat."