very short history of planet earth

Kevin Kelly’s always-interesting current trends blog points to a very short history of planet earth… worth a read:

"The Earth has survived some remarkable disasters. To keep our tale brief, let us focus on four: the Big Splat about 4.55 billion years ago, the Late Heavy Bombardment about 4 billion years ago, the Oxygen Catastrophe roughly 2.5 billion years ago, and the Snowball Earth events about 850 million years ago. The details of these events --- and indeed, whether they even happened at all --- remain controversial. We shall present some widely accepted theories without dwelling on caveats or alternative scenarios. In every case, there is interesting physics involved in testing these theories."