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The stromatolites in figure a are from Greenland; those in c and d are younger stromatolites from Western Australia. Figure b shows the layers created by microbes as they formed the Greenland stromatolites (blue lines). ‘Stroms’ are several overlapping stromatolites. Source: Guardian Photograph: Nature |
How quickly did life 'take off' on Earth?
The answer to this question is probably relevant to the likelihood that life will be found on other suitable planets too because it it happened quickly on Earth this suggests the process was not the vastly unlikely event that creationists try to present it as but a process (or processes) that can happen in just a few hundred million years if not even more quickly.
Yes, I know that a few hundred million years is not a short time but, compared to the 4.5 billion years or so that Earth has been around, it is during Earth's early childhood. It also suggests that Earth was not the hot, inhospitable, volcano-strewn and desiccated ball of rock that it was once thought to be but that it settled down quite quickly to be closer to what we have today (sans life, initially, of course). It also brings the early Mars within the timescale over which life could have arisen there at a time when Mars was thought to have been suitable, complete with liquid water, atmosphere, etc.
The discover of these stromatolites in Greenland rock pushes the earliest age at which cellular life was known to exist on Earth with a fair degree of certainty back to 3.7 billion years ago from the previous earliest known evidence dated at 3.48 billion years old found in Australian rocks.