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[Cthulhu]

hopy shit that stellar formation is HUUUUUUUUUUUUUUUGE :y

he probably wants a treat

[Heron TSG]

If this is what has come OUT of the center of the universe, imagine what it's like INSIDE of it.

This is coming out of the center of the galaxy, not the universe. And inside the center of the milky way is a supermassive black hole around which the whole galaxy orbits

Yes, but I think he's referring to the fact that galaxies came out of the center of the universe.

[MrWiggles]

However, there is no center to the universe.

[Bauglir]

-snip-

[Heron TSG]

Usually people refer to the location of the 'Big Bang' as the center of the universe. You know, the point equidistant from all the Cosmic Background Radiation.

[Bauglir]

-snip-

[Earthquake Damage]

Usually people refer to the location of the 'Big Bang' as the center of the universe. You know, the point equidistant from all the Cosmic Background Radiation.

I'm pretty sure the current presiding theory is that the universe has no central point.  Macroscopically, the structure of the universe is homogeneous, so there is no favored point of reference (e.g. a center).  The expansion of space is a three-dimensional analogue to the two-dimensional surface of an expanding balloon (that began expanding from a single point).  That surface has no center, though the three-dimensional balloon does.  Presumably, if time is our fourth dimension, then I suppose space-time has a central point of sorts.

This handily explains why the cosmic background radiation has no apparent source.  It's more or less omnidirectional.

[Euld]

That's another thing about the Big Bang that bothers me.  Apparently, our galaxy is going to collide with another in another who knows millions of years.  But if galaxies have been flying away from each other since the beginning, how are they changing directions?

[Aqizzar]

I'm pretty sure the current presiding theory is that the universe has no central point.  ...

This handily explains why the cosmic background radiation has no apparent source.  It's more or less omnidirectional.

I have never heard this theory anywhere.  Every treatise on background radiation I've ever heard said astronomers have a pretty good idea of which direction it's coming from, and that it's slowing down or something.  I mean, it wouldn't be the "Big Bang" theory if it didn't have an origin point, and I've certainly never heard a scientist suggest the universe popped into existence omnidirectionally.  Heck, everything I have heard is always spooky intimation about all the other visible galaxies (which are hardly homogeneously placed), are red-shifted, suggesting everything in the universe is drifting apart.

[Eugenitor]

Aqizzar, both are true- the universe had an origin point and the universe is mostly homogenous, with no central point, in three-dimensional space.

Where is the central point on the surface of a balloon, or on the surface of the Earth?

The problem is that the direction that space is expanding in, isn't a conventional spatial direction. Whatever direction we turn our instruments, we can't look at the center.

[Il Palazzo]

I'm pretty sure the current presiding theory is that the universe has no central point.  ...

This handily explains why the cosmic background radiation has no apparent source.  It's more or less omnidirectional.

I have never heard this theory anywhere.  Every treatise on background radiation I've ever heard said astronomers have a pretty good idea of which direction it's coming from, and that it's slowing down or something.

CBM radiation is coming from all directions, with small density fluctuations(pointing to the places where matter started collapsing to form clusters of galaxies etc.). It's this observation that seems to support Big Bang theory the most.

I mean, it wouldn't be the "Big Bang" theory if it didn't have an origin point, and I've certainly never heard a scientist suggest the universe popped into existence omnidirectionally.  Heck, everything I have heard is always spooky intimation about all the other visible galaxies (which are hardly homogeneously placed), are red-shifted, suggesting everything in the universe is drifting apart.

There is no center of the universe, and it's one of the base ideas of the Big Bang theory:

The Big Bang is often described as a tiny bit of matter, but that's an oversimplification. If the Big Bang occurred in a specific point in space, spewing galaxies in all directions, then we would expect our galaxy to be one of many galaxies sitting on an expanding shell of galaxies, with the center of that shell being the point of the "Bang." This, however, is not what we see, and not what the BB predicts.

If we were on a shell of galaxies, we would see many galaxies when we looked in directions along the shell, and few galaxies when we looked perpendicular to (up out of or down into) the shell. Moreover, distances and redshifts in such a scenario would depend on the direction we were looking. As we looked tangent to the shell, we would see many nearby galaxies with small redshifts. As we looked down into the shell, we would see more distant galaxies with higher redshifts. (Up out of the shell we would see only empty space.) This is not what we see. Galaxies, distant and nearby, are evenly distributed all around us. The number of galaxies and their redshifts are completely independant of which direction we look (we say that they are "homogeneous"), and that homogeneous distribution is also "isotropic," meaning that no matter where in the univerese you were, you would see exactly the same average distribution of galaxies and redshifts.

No, that little point of matter that was the Big Bang was not a little point of stuff inside an empty universe. It was, in fact, the entire observable universe. There was no "outside" of that point into which it could explode. In fact, the Big bang was not an explosion at all; it was simply the very hot state of the early universe. Distances between objects were much shorter back then, but the universe was still homogeneous and isotropic. Wherever you were in the early universe, you would see a homogeneous, even, distribution of matter and energy around you. There was no empty "space" outside of this point of matter into which it could expand, for all of space was already there, in that little "point." The expansion of the universe is manifested only in the stretching of space itself, perpetually increasing distances between distant objects, not in some "empty space" gradually getting filled as matter streams into it. These distances expand in all directions equally, and so cannot be traced back to a single point. If you try to do this, you find that the single point is your telescope, no matter where in the universe you observe from. After all, the "point" in question was all there was of space: the entire observable universe. The Big Bang happened everywhere. It happened right where you are sitting, where the Andreomeda galaxy is now, and in the most distant reaches of the universe. It's just that the reaches of the universe were not quite as distant those many billions of years ago.

One can imagine the universe as the expanding baloon(as EarthquakeDamage described), or expanding dough(space) with raisins(matter) embedded within, with Big Bang being the moment when the baloon(dough+raisins) "appeared" and begun expanding.

That's another thing about the Big Bang that bothers me.  Apparently, our galaxy is going to collide with another in another who knows millions of years.  But if galaxies have been flying away from each other since the beginning, how are they changing directions?

Homogenity of the universe is visible on a large(i.e.very large - larger than superclusters) scale.
On smaller scales, locally acting forces act to break it.
For example, it wasn't galaxies that begun "flying away" after Big Bang, but matter(energy). Yet, forces(gravity, strong and weak nuclear forces, electromagnetism) acted to create molecules, clusters of molecules, stars, galaxies, and so on, locally breaking the homogenity. Still, "looking" from far away enough, there are no parts of the universe that are more empty or more dense than the rest.
In the example provided in your question, the gravitational force is the most likely culprit for causing the galaxies to collide.


Astronomy explained:
http://curious.astro.cornell.edu/cosmology.php#questions

[Heron TSG]

Homogenity of the universe is visible on a large(i.e.very large - larger than superclusters) scale.

Have we ever actually seen a cluster of superclusters, or is this a theory?

[Il Palazzo]

Homogenity of the universe is visible on a large(i.e.very large - larger than superclusters) scale.

Have we ever actually seen a cluster of superclusters, or is this a theory?

Theory it certainly is, as is e.g. Big Bang and all the rest of scientific knowledge.
This theory, however, fits well with the observational data, that is: the background microwave radiation is nearly uniform in all directions, with the exception of previously mentioned fluctuations - areas where matter begun to gather, later to form large structures like superclusters.
Anyhow, homogenity means not that you can't, in principle, find any empty spaces between whatever structures you're considering at the moment - it's just that on average, the distribution of "emptiness" and "matter" is similar everywhere. So you can find filaments of superclusters stretching in all directions with equal probability.
This would not be true if e.g. the Big Bang was a true explosion of matter into preexisting space - this would create a shell of matter, with emptiness spreading inwards and outwards of (i.e.normal to) the shell.

[Zrk2]

That's another thing about the Big Bang that bothers me.  Apparently, our galaxy is going to collide with another in another who knows millions of years.  But if galaxies have been flying away from each other since the beginning, how are they changing directions?

Gravity from one pulling on the others and vice versa.

[Nivim]

 I just wanted to add (remind) that if one wishes to be less wrong, one probably shouldn't think about these things in the Cartesian system of three spatial dimensions and a fourth time dimension. The universe really doesn't care about what we think, or our systems of measurement, and thus will not conform to them.