Monday, May 13, 2013

Cosmic mediocrity reconsidered

Recommended reading: "Goodbye Copernicus, Hello Universe," by Caleb Scharf, in Nautilus. Excerpt:
There is something very old, deep, and, yes, significant that might challenge the notion of our mediocrity.
It starts because you’re made of the cumulative stuff of the cosmos. A little more than 3.8 billion years ago some part of you came crashing to Earth. It might have been a handful of your carbon, oxygen, or nitrogen atoms, or some of the many hydrogen nuclei that now exist in your molecules. Primordial things are these, the remains of a hot Big Bang that took place 10 billion years earlier. Pieces of the one-in-a-billion tailings of a universe filled with annihilating matter and antimatter.

Your heavier elements passed through the digestive system of other stars. Cooked up by nuclear fusion in 10 million degree stellar cores. Hidden from sight under seething cloaks of plasma that could be millions of miles deep, these tiny clusters of matter were eventually dispersed to interstellar space in supernovae explosions that could momentarily outshine an entire galaxy. Cooling in the chill of space, they inhabited nebular clouds, eventually once again succumbing to gravity’s relentless embrace to fall inwards to the tumult of a youthful swirl of matter surrounding a growing baby star. Going through this process just once is enough to make a smattering of heavier elements if the star is sufficiently massive, but it takes multiple stellar generations to enrich the universe enough to build worlds like ours, and us. We are well down the family tree.
Too much to summarize but a lot of fascinating stuff about astrobiology, Bayesian reasoning, the anthropic principle(s) and more. Whole thing here.

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