Wednesday, September 30, 2009

Quadrillions and Quadrillions of stars...

I find it perverse and extremely arrogant of religion to insist that the entire universe was solely created to entertain/support humanity. That is an understandable viewpoint based on the knowledge level 2500 years ago, when it was thought that the earth was the center of the universe, and the whole thing was no bigger than the solar system, and no older than a few thousand years.

But after the findings of the last 200 years in cosmology, geology and physics, such a view is extremely difficult to comprehend. Have you ever looked at the Hubble Ultra Deep Field Image? They pointed the telescope at a tiny section of the sky (less 1/12,000,0000th of the entire sky) and took a picture (OK, slightly more complicated than that, but you get the idea). What they found was, for lack of a better word, magical. Over 10,000 galaxies, streching out over 13 billion lightyears of history, each one host to several billion stars.

Think about that for a minute. This was not a particularly interesting part of the sky they pointed at -- it was, in fact, fairly devoid of any visible light or known stellar objects. For all practical purposes, it was a blank, black bit of nothing to raise any interest. And yet . . . and yet. . .

10,000 visible galaxies, each with several billion stars. That alone is a staggering tens of TRILLION stars in that one image. But that image was just a random bit out of over 12.7 million possible bits of sky they could have looked at. There's no reason to think that it wasn't representative of the rest of the sky. Nor does it mean that those 10,000 galaxies seen by the Hubble were all that's in that little sliver of the heavens.

Think about it -- 12 million pieces of sky times ten thousand galaxies times several hundred billion stars per galaxy... That's a heck of a lot of stars! In fact, it's well over 200 sextillion of them. It's pretty much mind-blowing.

Let that number sink in a little bit -- 200,000,000,000,000,000,000,000

If the possibility of a sunlike star with a planetary nebula around it is extremely remote (say, 1 star out of every 1,000,000 happens to be like our solar system), that means there are approximately 200,000,000,000,000,000 "solar systems' out there. And if only 1 out of every 1,000,000 of those happens to have a planet in the "habitable zone", then there are only 200,000,000,000 possible 'earths'.

200 billion earth-like planets. How many of those will possibly have life? I don't know. But I wouldn't bet against the possibility.

Oh, and here's a little reality check on those solar/planetary probabilities. As you can see, I seriously UNDER-estimated the probabilities:

# of stars in typical galaxy: between 10 billion (dwarf galaxy) and one trillion (giant galaxies) (reference)

% of sunlike stars: ~10-20% of all stars (at least in the Milky Way Galaxy) (reference)

% of sunlike stars with rocky planets: ~5% (reference)


Now, think about all that for a few minutes, and then consider how reasonable and rational it is to think that all of that was solely for the sake of us humans on our little planet, with our thin smudge of organic life sloshing around on it. What possibly reason could there be to have trillions of galaxies out there that aren't visible or reachable? Why would any deity who could possibly conjure up a universe as vast and awesome as this one spend any time at all demanding blind obedience and servitude from a few billion slightly evolved apes?