>Yes, but would other planets have the very life friendly atmosphere, climate and other thing estential for life as we know it?
You know that the only requisite is electricity, which is everywhere in the Universe.
The oxygenation of the atmosphere was a result of life (plants, specifically), and not a pre-requisite for it.
Its not like life appeared as an ecosystem at somepoint in the past. The ecosystem has evolved as a result of life.
http://www.palaeos.com/Earth/Atmosphere/oxygen.htmThat's the beauty of evolution.
You see it in technology.
Someone had an idea for computation. The solution was some primitive hardware and primitive software.
The hardware and the software evolved a little independently, which lead to them evolving considerablly jointly.
Think of the Earth and biological life as the same system evolving together.
This is why I am a Universal Darwinist. The existence of star systems, the existence of human expression, all of it is shaped by evolution. If you've seen "A Beautiful Mind" you might know a little about game theory. Game theory is the underlying notion behind natural selection, and there is no aspect of the Universe that doesn't obey it. Its not just about monkeys and men.