A couple of Octobers ago, some physicists won a Nobel prize in physics for determining that the expansion of the Universe is still accelerating. 

In the "we don't know everything" department, this strikes me as a no-brainer.

Much of what we know about the Universe is speculation, much of that based on math we've made up, and math that works, I'll grant you. Sometimes the math works because we make assumptions or formulas that work with what we think and not with what things have. Still, it's based on theory, supposition, ideas, and math with "if" in it...and previous iterations of the same.

The Big Bang Theory (not the television show), simply stated, says that the Universe began when the nothing that was before it "exploded" and became what it is today. Most believe that at the end of the Universe, it will collapse under its own gravity, possibly to initiate another big bang; possibly what happened at the start of this one...

The Universe is everything we have, spatially speaking. If there's an "outside" the Universe (other dimensions notwithstanding), it's Nothing. If you could reach the edge of the Universe and move a little farther away, you'd be expanding the Universe, not leaving it into the Nothing. Right?

So from the beginning, there was very little Universe, and a whole lot of Nothing. The Universe started expanding, probably all energy and no matter. As it expanded, it grew and filled the Nothing. At this very early point, it's all accelerating, mostly away from the center. During this expansion, some conversion from energy to matter began, and atoms formed, and our elements began to form, and then molecules. The expansion continued, the conversion contined, and the matter started to acrete into the stuff that fills space; dust, rocks, planets, stars, galaxies.

By this time, the Universe had to be very big. There are very many galaxies filled with very many stars and probably very many planets and rocks and dust.

All of that stuff creates gravity. Theories of acretion say that's why the things got bigger and became stars and planets. It's why planets and rocks orbit stars, and why stars cluster into galaxies. It's why galaxies cluster and collide.

As those acretions occurred, and those gravities interacted, and those things formed, stuff slows down.

It's a big place, the Universe, and all of this has taken a very long time. Probably still longer than the dozen billion years or so that they say the oldest stars are. Or maybe the stars are that old, but it took longer for the stuff to form the star to form. And it took some time for the stuff to get from the center of the Universe to where it formed into a star.

Even though scientists base their estimations on how long it takes the light from very distant stars to reach us, there was time before the star provided any light at all. That doesn't seem to figure into age of the universe discussions.

Think about how big a star is. How much matter has to acrue to be big enough and dense enough to start fission? How fast could that happen when left to chance of things just getting close enough? How long could that take to happen in the beginning? Millions of years? Billions of years?

So if we see the light of a star that's 12 billion light years away, we can safely say the universe is at least 12 billion years old. To consider how old the universe is, if we're basing it on that far away star, we need to also add in the time it takes for the star to form.

And we might want to consider that might not be the first time that a star has been in the area, as there are novas going on all of the time now, and probably have been for a while, so it might be that the light from these stars 12 and 13 billion light years away aren't the original stars in the neighborhood.

When figuring how big the universe is, again using that star as a reference, we need to try to consider what has happened to that star in the 12 billion years since it was in the spot where we now see it. Has the star continued moving? Was it moving away from us? If it hasn't died yet, that means it might be another 12 billion years of distance away. I mean, we're seeing where it was 12 billion years ago, in the case of a 12 billion light-year distant star, which is a long time for it to have done something.

No, I'm not suggesting that many more more light years away; just that same amount of time spent at the speed the star was moving when it left the light we now see. Of course, that star may be slowing down, drawn toward the rest of the gravity in the universe.

Regardless, unless the farthest out stars have all slowed down so much that they have started moving toward the center of the universe, the universe must be expanding, right?

And if some of these way-out-there stars or galaxies on the edge of this expansion aren't feeling the effects of the gravity of the rest of the universe, because they're so far away, and since there's no other friction in space, at least some are probably still speeding from the bang, or some more recent nova or near miss or explosion of some kind...

I mean, good on 'em for continuing to study and trying to figure this stuff out, but "duh," the universe is bigger and older and still going more than we think.