Wednesday, June 29, 2011

Too Big for One Post

I've started watching The Big Bang Theory.  Being who and what I am, a guy with no antenna on his TV, I'm watching the seasons on DVD.  I do enjoy an absence of commercials.

The show opens with a small vignette, then goes into the theme song.  It's pretty cool that there are some shows that still have theme songs.  One line is "fourteen billion years ago expansion started.  Wait..."

Expansion started.  That's one way to put it.  According to a commercial for Discover magazine back in the 80s, in a few seconds the Big Bang had created a universe that was already hundreds of lightyears across.

So how does that work?  Light speed limit, hundreds of lightyears, something's got to give, right?  Well, it does and doesn't.  There's so much mass around, so much gravity altering the shape of space itself and even time that it's pretty hard to define such a thing as time and distance under those conditions.  A physicist could actually define it, but I'm no physicist.  I understand the topic enough to know that the rules bend under conditions like that.  They bend because the conditions themselves are bent.

So the expansion is happening at something less than lightspeed under the conditions - space itself is pretty tightly compacted, space itself is expanding as the Big Bang unfolds.  But I'm a little confused by a few things:

How do we know the Big Bang is even over?  Some researchers posit that the universe must keep expanding, but these same researchers will admit that gravity's range is essentially infinite.  Given enough time, all expansion will come to a stop and reverse direction.

Using gravity lens effects, astronomers can bring in pictures that show what appear to be entire clouds of galaxies in the distance.  They are not clouds but multiple images of the same galaxies.  The light is bent so that what appears to be two or more remarkably similar distant galaxies is in fact the same one.  If your telescope is good enough, how likely is it that eventually you see so far into the depths of the universe that you're looking at yourself, the light of your own image bent back after billions of years, eventually slowing down and falling back onto yourself?

Granted, you won't be able to do that today.  Like I said, billions of years.  The light's going to be traveling for quite some time.  If your telescope is good enough, you could maybe look far into the distance and see a tiny, faint image of a young Earth, still cooling from its formation.  If you want to catch a peek of yourself, you're going to have to take one whammy of a nap, and set an alarm to wake yourself later.  Much, much later.

Have to collect my thoughts.  More on this tomorrow.

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