The 4th part of the PBS Nova Origins program explained the mapping of the early universe to show its clumpy, non-uniform nature, which led to the formation of galaxies and so on. The host said the entire mass and energy of the universe were contained within a space the size of a large pearl at the time of the Big Bang.
Would that indicate that it is possible to use the early map to determine the location in space of the big Bang? Would that be considered the center of the universe?
I had thought that the universe was considered to be everywhere expanding and did not really have a center or a point it was expanding from.
Standard logic would say that at least one of those views must be wrong, but when it comes to most things “universe”, standard logic may or may not apply.
So, does the universe have a center, and if so, do we know where it is?
The centre of the universe is is in a small town in Vermount, there’s a plaque there.
But more seriously there is no locatuion that can be considered the centre of the universe. The big bang happened everywhere, it was just at the time the (observable) universe was alot smaller (vanishingly small infact).
It’s too easy to imagine that as viewed from the outside, when in fact there would have been no ‘outside’ from which to view it; whether the universe is the size of a pearl, pumpkin, planet or… umm… something really big beginning with P, it’s still all there is of space.
Since we’re not well equipped to envision tesseracts, pentaracts, hyperspheres, and such, perhaps analogy will help.
I have a balloon; I blow it up. Its circumference and surface area are observably much larger. For our purposes, assume the balloon to be a perfect sphere. Clearly, it has a center.
Now, the question is, *where on that surface is the center of the balloon? * And the answer, of course, is nowhere – the center is in the middle of the three-dimensional volume which the surface of the ballon delimits.
Translate that into an expansion in four spatial dimensions, and what you’re asking about is the center of the three-dimensional representation we can observe – which is equidistant from every point in the universe in a direction that is not up, down, leftwards, rightwards, forwards, or backwards, but, to borrow C.S. Lewis’s term for a fourth-dimensional vector, andwards. And to ask its location in purely three-dimensional terms is equivalent to trying to find the center of the balloon on its surface.
I think you got that mixed up. The Universe is almost certainly unbounded, but it may or may not be infinite. Current evidence suggests that it is infinite, but this is by no means definite.
In the first few minuites after the Big Bang, the universe was only the size of the solar system. If you were around at that time and had a strong enough telescope, you could theoretically see all the way around the thre dimensional “surface” of the 4-d universe and see the back of your head! :eek:
Of course, at that time the universe was optically very very thick, so although the light-travel time might have permitted such a thing, no actual light would have been able to survive the trip.
Not to mention that the universe then was so hot and dense, it would instantly ionize you into a plasma.
And not to mention the fact that the curvature of the universe is not necessarily closed and that the rate at which the universe was expanding also fobids this. Even for a radiation-dominated universe, the time for a photon to traverse the universe is the same time for the universe to collapse into a big crunch.
No, if we forget trivial problems such stars, galaxies, planets in the way, etc, we can look in any direction, this is due to the fact that the universe is isotropic* and homogenous (obviosuly not totally).
Just about any part of the sky will do. The gases that condensed to form those galaxies was created ‘out there’ as space inflated. It did not come blasting out of a central explosion into a pre-existing space.
Obviously, I’m not as well read on C.S. Lewis as I thought. Where does he coin the term “andwards”? Doesn’t sound like it’d fit into a more purely theological text; the Space Trilogy, perhaps?
The universe was opaque to light until ~380,000 years after the Big Bang so you wouldn’t see a thing.
If the Universe expands at light speed (not counting Inflation very early on where it went faster) you would never see all the way around it regardless if the Universe was pea sized or billions of light years across.
While it is correct to say there is no “center” to our Universe (at least in three dimensions) in a manner of speaking you can say everywhere is the center. Meaning when you say to someone you are the center of the Universe you are in fact correct…at least as regards you personally.
Idea goes something like this…
The Universe may be much larger than the observable Universe. By “observable” I mean a radius from you to the edge that equals the time light can travel since the Big Bang (or ~13 billion light years to one “edge” [I use that term very loosely]). Even if there is more Universe beyond that it makes no difference to you as it can have no effect on you whatsoever. In essence it may as well not exist for all the impact it has on you. As such, the Universe is a bubble centered on whoever is observing it with a radius of ~13 billion light years. Naturally no two observers are in exactly the same place at the same time so each one has a Universe bubble slightly shifted from everyone else making each of them the center of their own Universe. Naturally for people on this planet the difference is so slight as to not be worth mentioning but this would be true no matter where you are in the Universe with radically shifted “bubbles”.
Do astronomers believe there is an “edge” to the universe where if you looked in one direction there would appear to be very little out there, but lots of stuff in the opposite direction? Would somebody there be able to say, arrrgghhh, the centre be that away cap’n?