Re: Have aliens visited earth?
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id say its probable for other intelligent life to exist somewhere. getting here is highly unlikely.
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Actually, the conditions for life to exist are extremely rare. Life as we know it is extremely fragile and it appears, based on probabilistic arguments, that the conditions for life to exist are not that common in the universe. Microbes quite likely exist in abundance but complex life not. This argument was first set forth in the book Rare Earth: Why Complex Life is Uncommon in the Universe by Peter Ward, Donald Brownlee.
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even if its uncommon tho, the incredibly vast number of other stars/planets in the universe means its pretty likely its happened elsewhere.
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This doesn't make sense. If it's uncommon it's not likely to have happened. Moreover the probability of a planet supporting life can be so small that even given the vast number of planets in the universe the expected number of planets supporting life can still be small. Say for example there the probability that planet supports life is 10^-15 and there are 10^9 planets in the universe. It doesn't matter how close these numbers are to the actual numbers the point is this: the expected number of planets supporting life is 10^-15 * 10^9 = 10^-6 = 1/1000000.
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