Saturday, January 11, 2014

Bad Neighborhoods

Life on this planet has had its vicissitudes, but has - so far - survived for 3.5 billion years or so - roughly 14 Galactic years. It's not clear that this could have happened if we hadn't been located in a relatively ideal galactic neighborhood. Many parts of our galaxy might be too metal poor to produce Earth like planets. Others are so crowded with stars that we might have been bombarded with comets. In some parts of the galaxy there are just too many big, short lived stars going supernova with disastrous local consequences.

What about other galaxies?

Some are a lot like ours, but others, especially those in galaxy clusters, are loaded up with hot gas producing a lot of X-rays.

My question is, what about one of those galaxy clusters that radiate 10^44 ergs/s in the X-ray? Could our planet survive there? We have some X-shielding capability, but is it enough? Anybody know how to do the arithmetic?