“Life has been around on Earth for a bit over 3 billion years, maybe even 4 billion years. Physicists tell us that the Sun will eventually swell and turn into a red giant (it won’t explode in a supernova as it isn’t massive enough). But before it turns into that fat old sun in the sky and swallows up the Earth, it will have rendered life on Earth impossible by simply making the place too darn hot. That will happen in around 1 billion years. So if you reckon that the window of opportunity for life on Earth is around 4 or 5 billion years, that means life is around 75% or 80% of the way through our alloted span – on this planet at least. So, Life, looking back on things, what do you think the best bits were? What was your greatest achievement? And what do you hope to do in the years that remain? After all, you’re someway along the downhill slope now…”
— Matthew Cobb
(Source: whyevolutionistrue.wordpress.com)
