On radio a couple weeks ago, I heard a story about four galaxies that are "racing" toward each other and preparing to collide. These galaxies are approximately 5 billion light years away.I have a few thoughts about this story -- or rather about the 5 billion light years:
- These galaxies have probably (almost undoubtedly) already collided and whatever happened to them after the collision probably completed itself a very long time ago.
- These galaxies are incomprehensibly far away -- the distance that light travels in a second is something like 172,000 miles; the distance that light travels in a year is 365 times 24 times 3600 times that; then, don't just multiply that by one billion, multiply that by 5 billion. That is one heck of a long way away.
- Finally, something that far in the distance it must take up an amazingly small amount of the night sky. Jostle the telescope (or whatever they use to sense the galaxies that far away) just a smidgen, and you would complete the miss all four galaxies.
- Space must be relatively haze-free for the light to be able to travel that far and not just die out.
1 comment:
Very thought provoking. During my middle of the night astronomy session with my daughter, I was pondering some of those questions. It is very hard to comprehend that what we see up there today actually happened millions of years ago. I wonder when we earthlings will be able to finally see what happened to those galaxies?
Thanks for your visit to my "Moon" post!
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