[Nateman]

There a more interesting theory about the end of ice-ball Earth. The surface of Venus is about as old as when Earth changed out of the ice-ball. It is that two proto planets smashed into other making Venus. That in turned caused the Earth to change it's place in orbit warming it up.

[JimSEA]

That’s interesting, thanks. The immediate questions I’d have would concern the geologic evidence of something of that magnitude since we have pretty old rocks in the cratons, particularly in South Africa and Australia. Also, what effect would it have on the earth moon relationship and, if the plates were in fact forming as seems likely, what would it do to that.