There are a very large number of planets suitable for life
Summary
Quotes
« It has been estimated that there are between one and thirty billion planets in our galaxy, and around one hundred billion galaxies in the universe. Removing a few zeros just to be on the safe side, a reasonable estimate of the number of planets available in the universe is one billion billion. Now, suppose that the beginning of life, the spontaneous appearance of a DNA equivalent, really was a completely staggering improbable event; so improbable that it only happened on one planet in a billion. A funding agency would burst out laughing if a chemist told them that the chances of their research succeeding were only one in a hundred. But here, we're talking about a one-in-a-billion chance. And yet... even with such an absurdly small chance, life will nonetheless have appeared on a billion planets, including Earth, of course. This conclusion is so astonishing that I repeat it. If the chances of life appearing spontaneously on a planet were one in a billion, even so, this staggeringly improbable event would occur on a billion planets. »
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