In message <3F1C81FE.8090909@ix.netcom.com>, Robert Casey <wa2ise@ix.netcom.com> writes

Jonathan Silverlight wrote:

In his story "Wrong Way Street" Larry Niven wrote that the Moon helped  there, by stripping off most of the Earth's atmosphere. Was that ever  a serious theory? I'd guess it's been discarded in favour of the idea  that Venus has a thick atmosphere because it's closer to the Sun and  hence hotter.
And would the Earth still have a thick atmosphere if it hadn't been blown off by the collision that formed the Moon?

I had heard that the difference is that the Earth has oceans of water that ate most of the
carbon dioxide out of the atmosphere.  Making limestone out of it. Venus either never had,
or lost most of its water, thus this didn't happen there.

The sad thing is that Venus probably had oceans in the beginning, but it was too hot to keep them. Perhaps even life - extremophiles are quite happy living in boiling water, but when it's all gone so are they.