geometric center of the universe

Quasars are supposed to be the farthest objects in the universe…at the very edge of space.

If we assume that the universe is spherical in shape, and quasars populate the surface of that sphere, we should be able to calculate the rough geometric center of this sphere.

Is this the case, and if so, where are we in relation to this center?

As I understand it, it doesn’t work that way. Think of the universe as the outside of an inflating balloon. Quasars are as far from us as you can get in the universe, but if you go beyond them, you’re moving back towards us again. Therefore, no geometric center. Just like there’s no center on the surface of the earth. As I understand it.

I thought that it was impossible to calculate the center of the universe because we can only see a small part of it- the universe originally expanded much faster than light could return the signal due to the density of matter in primordial space, and that expansion remained in scale as the universe grew. also, quasars are the earliest thing we can see, but because of the light-bubble nature of the universe, we can’t see anything farther away.

the only thing we can really determine about the universe is that it is big and looks sorta like somone stuck a firecracker in a lump of gum and set it off.

I tell people that my watch always has the right time because I am the center of the universe and all time flows from me.
Most choose not to believe me and some even start quoting this Hawking fellow.

I think there may be a “center” to the Universe, but as my fellow astronomers have patiently tried to tell me, there isn’t a center in the traditional, three-dimensional sense.

We are at the center of the universe that we can see, in the same sense that a ship is at the center of its radar’s detection range. The ship is obviously not at the center of the Earth, and neither is the Earth at the center of the universe. There is assuredly more to the universe than we can see, however. The Hubble Space Telescope was pointed at the blackest part of space, and found that there were in fact hundreds of very faint and far away galaxies there. (I suppose Luke Skywalker lives there.) If the universe is finite in size, then we don’t have enough data to calculate the center. If it is infinite in size, then there is no center.

I’ve actually got a Staff Report in the queue that deals somewhat with this, but for now, I’ll just say that you can’t use the quasars to define the “edge of the Universe”, because they’re all over the place. Or, rather, they used to be. The quasars all died out billions of years ago, but there’s still some light en route from those that were far enough away, so we can still see the distant ones.

Quoth sturmhauke:

Even if it is finite, there’s still no reason to believe that there’s a center. Where’s the center of the surface of the Earth? Well, if you insist, you can say that it’s at the core, but that’s not on the surface. Similarly, if space is positively curved, then there is no center of the Universe anywhere within the Universe. If it’s not in the Universe, then that pretty much means that it doesn’t exist, so far as we’re concerned.

On the other hand, you can also pick any arbitrary point you choose, and call that the center. Your point won’t be any worse than any point anyone else might choose. So I hate to disappoint you, BobT, but you’re right.

My understanding is that most cosmologist model the universe to be both isotropic and homogeneous. That is, on a large enough scale, it looks the same in any direction (isotropic) and is uniform (homogeneous, no clumps, a nice shade of gray). Partly from Copernicus, any measurement that seems to indicate that the Earth is the center of the universe (that an observation looks the same in any direction) can only mean that it must be the same from any point in the universe (the isotropy again).

My understanding is there is no “geometric center” because, like Quadgop’s common analogy, there is no center on the surface of a balloon.

Similarly, there is no point that all celestrial objects are travelling away from; there’s no geometric point where the Big Bang started. Instead of fireworks, you should be thinking of that balloon. Every point is moving away from every other point as the balloon expands. Another way I like to think of it is an infinite sheet of 2D graph-paper. If you increase the size of all the squares on the graph paper, every intersection point will be moving away from every other. This is what Hubble observed about all galaxies, concluding an expanding universe. To model the Big Bang, shrink the size of the grid boxes until all the points are right on top of each other.

I guess I’m rambling a bit. Basically, only a static universe would have Euclidian geometry. If the universe is expanding or contracting, than space isn’t flat and will curve around, is infinite, etc. so its “center” has no meaning.

The observable universe is spherical and the center of the observable universe is right here. But the observable universe is only that part of the universe from which light has had time to reach us. The universe is much larger than the observable universe. The universe has no edge. If the universe if infinite, there is no center, and if it is finite, the center is outside the universe, which is the same as saying there is no center.

“If there’s a bright center of the universe, you’re on the planet that it’s farthest from.”