Earth Day 2015

On Earth Day, perhaps everyone ought to reflect on the emerging reality that our world, now 4.6 billion years old, more than 1/3 the age of the universe, and about 550 million years into the epoch of Complex life, is something REALLY rare in the Universe. Star Wars and Star Trek are nothing like reality, which is that the conditions that make for a world like Earth, with its robust and incredibly dynamic world-ecosystem, require a host of relatively unlikely conditions. In combination, the likelihood of a truly Earthlike world becomes very small; so small Earth may be one of only a handful of such planets in our entire Galaxy of 100 billion or more stars. If these facts don't impel us to develop a sense of responsibility for the stewardship of our precious planet, I don't know what could.
(Posted on Earthday to Facebook)