In your book Death from the Skies, you mentioned that about 4 billion years ago the sun was like half as hot as it is now, and in 4 billion years it will be twice as hot as it is now (I hope I got that right).
Is it possible then that a few billion years ago when the sun was "cooler" Venus was a nicer place where life could actually exist? and then in a few billion years when the Earth gets hot from the increased brightness, Mars will be a better place for life to exist?
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In your book Death from the Skies, you mentioned that about 4 billion years ago the sun was like half as hot as it is now, and in 4 billion years it will be twice as hot as it is now (I hope I got that right). Is it possible then that a few billion years ago when the sun was "cooler" Venus was a nicer place where life could actually exist? and then in a few billion years when the Earth gets hot from the increased brightness, Mars will be a better place for life to exist?