World's Oldest Fossils Found On Australian Beach

TFA notes that this work was done by Martin Brasier's team and that Brasier has generally been a strong critic of a lot of the claims about early fossilized life. That may be strong evidence that this claim should be taken seriously. However, there have been times before where scientists have criticized claims coming from other groups even as they've made nearly identical claims. It looks like Brasier et al. have done much more careful chemical work than some of the other early life claims which makes this look promising but this probably won't be completely clear until a bit more work by other groups is done. It is also important to note that it is extremely unlikely that we are finding the very first life. Most likely, life had to be pretty common already in order for it to have a decent chance to leave fossils. This means that one can tentatively guess that life arose at least a few million years before when these fossils were formed.

We keep pushing farther and farther back in time when life arose on Earth. This is important since it helps us figure out just how likely life is to arise in general. The argument goes that if life is easy to start then we should expect to see life arise soon after heavy bombardment of Earth begins. And that's what we do seem to be seeing. This suggests that life may be plentiful. There's a substantial very recent argument against this line of reasoning by David Spiegel and Edwin Turner http://www.physorg.com/news/2011-07-astrophysicists-logic-downplay-probability-extraterrestrial.html [physorg.com]. Spiegel and Turner argued that if it generally takes a lot of time to get intelligent life to develop then intelligent life will have an observer bias since it will only arise on the planets where life started very early. This means that seeing life early on in our history might be something which we should expect even if life arises really rarely.

Source: http://rss.slashdot.org/~r/Slashdot/slashdotScience/~3/QAlJ7aeGpb8/Worlds-Oldest-Fossils-Found-On-Australian-Beach

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