There&#x27;s the reverse problem as well. If life develops by itself when it has (chemically) the chance ... then where is it ? Our sun is a third generation star (meaning some sun went nova, recoalesced into another sun, went nova, recoalesced in our sun and ignited, and that was 3+ billion years ago).<p>Our sun is not a particularly early third generation star. Given that it would take a civilization about a billion years to spread through the galaxy to all liveable planets ... some civilization should have done that up to 4-5 billion years ago.<p>If life can happen in 2nd generation stars as well, it should have happened 6-8 billion years ago.<p>Obviously this hasn&#x27;t happened.<p>I only see 3 reasonable explanations:<p>1) Drake equation is too optimistic. By a huge factor (2-300 million times too optimistic)<p>2) It&#x27;s not a problem, because civilizations kill themselves before doing interstellar travel and while we are on the way to doing that but not quite there yet.<p>3) There&#x27;s something we don&#x27;t know