Originally posted by jaywill
I have been trying to get my head around Big Bang cosmological concepts. Recently I imagined three scenarias which I think help me. But I would like some comments:
[b] 1.) You have a super fast space ship and you want to see what lies beyond the farthest possible galaxy. In the rear window of the space ship you see the last galaxy, the one farthest o mology and General Relativity ?
How would you correct any of these concepts? Thankyou.[/b]
#1 is not correct in that you would start to see galaxies from where you left, that were in back of you and now in front, as if you were on a giant globe and you are flying around the world, in that case if you had infinite fuel, you would just come back to the same place you started from and take the same trip over and over, but the gist of that is you would always see galaxies in front of you but going far enough, they would be the ones that were in back of you on the way out, so you just see an endless supply of galaxies but if you had a way to tag each one with an ID, you would find, OMG, I passed that sucker 14 billion light years ago. But you are always going in what seems to you to be a straight line because the universe itself is curved back on itself in a forth or fith dimensional way.
If I understand it right, #2 is not right either, as you approach c, you flatten out (get shorter) and widen out (get fatter). I think at c you would become a pancake of some order of infinite thinness the size of the universe but still going at c.
I think # 3 is the most correct, you can start out in any direction in a space ship and if you are extremely close to c you will eventually come back to where you started as I said in the first paragraph. All roads lead to Rome eventually.
Assuming you go in a straight (what appears to you to be a straight line) line from Earth and keep on in that same direction eventually you will find yourself at Earth, or at least where Earth was at the time you left. You would still miss Earth by millions of light years because the whole solar system is moving about 200 miles per second, in some direction or other, not sure which direction but if you go within a hairs breath of c you may think only a few weeks goes by on your onboard clock, but billions of years go by on Earth.
So when you get back to where you are, the movement of the stars in the heaven would put the solar system about 15 million light years away from where it was, plus the problem that the sun may go through its red giant stage and devolve to a white dwarf and the Earth and the rest of the planets would be cinders and/or gone completely.
In any event, you would not be able to use, say, a spectrometer to analyze the sun's spectrum because the sun would be an another stage of its existence and would not be even close to the nice yellow star we see now. You would in fact be at least 14 billion years in your own future and I calculated in 14 billion years at 200 miles per second the whole solar system could be 15 million light years from where it was when you left.
So you would not come back home, you would come back to a cinder world at best around a star that used to be the sun but now is a white dwarf or whatever it would evolve to in 14 billion years. They think the sun will begin going into its red giant phase in only 4 billion years or less so it would be around 10 billion years after that event you would come back to what you thought should be home.