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Re: Do you think other life exists?
Some years ago, Issac Asimov published a rough estimation.
Generally, this galaxy has 100 billion stars. Some stars will not have planets.
Some will have gas giant outer planets (like Jupiter and Saturn) which are thought to be essential in allowing the formation of rocky innner planets (like Mercury, Venus, Earth and Mars).
Some of these rocky planets will be at the correct distance for liquid water to exist and be large enough to hold onto it (unlike Mars).
Based on a very conservative estimate, Mr Asimov concluded that there are 100,000 planets just like Earth.
Given that our Earth has had life on it for approx. 80% of the time since its formation it may be reasonable to conclude that there are 80,000 planets with life on them.
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