clipped from: fabiusmaximus.wordpress.com   

Of course bad things could happen.  Civilization, indeed human life itself, depends on Fate.  Super-bug pandemics, larger asteroid or comet impact, massive climate changes, eruption of a super-volcanoes, or supernova within 50 light years … the number of high impact - low probability scenarios is legion.  But we live our lives in defiance of these things, not in fear of them.