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View Full Version : Can you see the edge of the universe?



mutant
2004-Mar-09, 11:42 PM
Ok, I know this is a dumb question, but that never stopped me before so:

I have read that the latest guestimate of the age of the universe is 13.7 billion years. I just saw the latest Hubble image that shows galaxies out to 13 billion light years. That means to me that the edge of the universe is only .7 billion light years farther out.

If we improve our instruments and our techniques will we eventually be able to see out to the edge of the universe?

No, I don't expect to see a wall or a do not enter sign. What I would expect to see is nothing, just a void.

Does anyone else think this may be possible and if it is what would you expect to see, or are my assumptions incorrect to the point where it might be best if I was committed. I have great difficulty dealing with these huge distances and the mysteries and many theories on how the universe may have begun.

Brendan
2004-Mar-10, 01:04 AM
Ok, I know this is a dumb question, but that never stopped me before so:

I have read that the latest guestimate of the age of the universe is 13.7 billion years. I just saw the latest Hubble image that shows galaxies out to 13 billion light years. That means to me that the edge of the universe is only .7 light years farther out.

You mean .7 billion light years?

We can't see much of any patterns further back than the time the background radiation was made. It's the surface of last scattering because before atoms formed, the light was scattered by charged particles. After those charged particles formed atoms, the radiation and matter didn't interact as much so the photons could continue traveling through the universe. The radiation is dated at 379000 years after the big bang. The bottom of this page gives a nice comparsion to looking at the bottom of a cloud.
http://map.gsfc.nasa.gov/m_uni/uni_101bbtest3.html

Brendan

mutant
2004-Mar-10, 01:21 AM
Brendan posted:

You mean .7 billion light years?

Opps. Thanks for pointing that out. I corrected it.

tracer
2004-Mar-10, 02:31 AM
Even if you had some magical telescope that could "see" objects at infinite speeds (instead of looking at the radiation given off by objects, which only travels at the speed of light), you still wouldn't be able to see the "edge" of the universe.

Because the universe has no edge.

The universe isn't shaped like a 3-dimesional ball. It's curved back on itself in four dimensions. It's like we're all living on the surface of an inflating balloon, except one dimension higher.

Cougar
2004-Mar-10, 02:49 AM
I have read that the latest guestimate of the age of the universe is 13.7 billion years. I just saw the latest Hubble image that shows galaxies out to 13 billion light years. That means to me that the edge of the universe is only .7 billion light years farther out.... If we improve our instruments and our techniques will we eventually be able to see out to the edge of the universe?
Well, if we could see that last .7 billion lightyears, we wouldn't be seeing the edge - that would be the beginning of the universe. Remember that the farther we look, the farther back in time that we see.

As for the leading edge of our light horizon, I don't know where that is, but if Alan Guth is correct (he came up with the original idea of inflationary cosmology), then the edge of our light horizon has a long way to go to get to the outer edge of the actual universe, which likely has this weird topological curvature as previously mentioned. One solution to Guth's equations has the universe 10^23 times larger than our visible universe, and all of that vast expanse of as yet unseen universe is likely just more of the same.

kenneth rodman
2004-Mar-10, 08:39 AM
ok this question then comes to mind. couldn,t we someday look back to the big bang itself? I mean, it must have been one heck of an explosion, and if light was given off when this explosion occured, then shouldnt we be able to see it? or is thinking of the big bang as an explosion of sorts compleatly off base?

Kaptain K
2004-Mar-10, 01:13 PM
One of the big misconceptions is to think of the Big Bang as occuring somewhere in space. The Big bang was the creation of space (and time)!

Amadeus
2004-Mar-10, 01:39 PM
O.k heres my stupid question. As I understand it the universe is curved in on it's self right? if you go far enough in one direction you end up where you started from.

O.k take your "magic" telecope. If you look far enough could you not see the earth in the past?

Swift
2004-Mar-10, 01:56 PM
ok this question then comes to mind. couldn,t we someday look back to the big bang itself? I mean, it must have been one heck of an explosion, and if light was given off when this explosion occured, then shouldnt we be able to see it? or is thinking of the big bang as an explosion of sorts compleatly off base?
In a sense we can, but its so red-shifted that the radiation is in the microwaves. This is the 2.7K background radiation of the universe (actually if I remember correctly that is the "view" from when the universe become optically transparent, not all the way to the bang itself). We have satellites that are studying variations in it for data on the macro-structure of the universe.

Kaptain K
2004-Mar-10, 07:29 PM
O.k heres my stupid question. As I understand it the universe is curved in on it's self right? if you go far enough in one direction you end up where you started from.

O.k take your "magic" telecope. If you look far enough could you not see the earth in the past?
No! The Earth is less than 5 billion years old and we are already looking back 13+ billion years. :o

Nim
2004-Mar-11, 08:01 PM
O.k take your "magic" telecope. If you look far enough...

Keep in mind that telescopes don't see light that is far away, they see light that has traveled to it from far away. The light from Earth is traveling away from the telescope not towards it, so it will have to make a complete circle around the Universe to get back. The Universe is still expanding so I don't see that ever happening. And even if it did I think the light would be too spread out and too distorted by stuff that it ran into in outer space on its way back that we wouldn't be able to make out anything from it.