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Universe 250+ Times Bigger Than What Is Observable
eldavojohn writes "The universe is only fourteen billion years old so we are unable to observe anything more than fourteen billion light years away. This makes it a bit difficult for us to measure how large the universe actually is. A number of methodologies have been devised to estimate the size of the universe including the universe's curvature, baryonic acoustic oscillations and the luminosity of distant type 1A supernovas. Now a team has combined all known methods into Bayesian model averaging to constrain the universe's size and their research is saying with confidence that the universe is at least 250 times larger than the observable universe."
It is, but oddly enough that does not bind the expansion. Space can be expanding faster than c and I believe the inflationary theory says just that.
The world's burning. Moped Jesus spotted on I50. Details at 11.
Can you show me the point where a circle ends?
The world's burning. Moped Jesus spotted on I50. Details at 11.
Supposedly matter cannot move faster than light. But the expansion of the universe following the Big Bang involves the dimensions of space-time. It's not the movement of matter, but the movement of existence itself in which that matter exists which can produce FTL expansion.
There's nothing "physical" about the edge of the observable universe. It's just the boundary between galaxies whose light has had time to reach us, and galaxies whose light is still on its way.
There's a wall and a telescope, where you can see into the alternate universe where everyone wears cowboy hats.
If you can't convince them, convict them.
The key idea is that of inflation: general relativity allows for the distance between points to increase faster than the speed of light. Alan Guth's theory for inflation proposes that this in fact occured in the early universe, and the theory is now backed up by observations of fluctuations in the microwave background radiation (among others), where microscopic fluctuations were "frozen in" due to the rapid expansion. The consequence of this inflation is that much of the current universe is not within our 14 Gyr lightcone.
As a side note, the big hub-bub about dark energy is that it appears (based on current observations) that our universe may be entering a second inflationary period. Fortunately, the timescale for this is on the order 100 Gyr, so it will be unlikely to effect our lives directly.
(640k)*4/3*pi ought to be big enough for anyone.
Some physicist is very welcome to fill in here, but I'm not sure it's correct to say that the universe "expands faster" than the speed of light. Locally, the expansion is slow, and objects aren't really "moving away" from each other -- rather more space is added in between them.
Think of it like blowing up a balloon with ants walking around on the surface. The distance between ants could increase faster than they can move, but none of the ants are moving relative to the space they occupy.
As a side note: One theory of the ultimate fate of the universe is that the expansion rate will increase past the point where the observable universe becomes smaller than atoms and other particles (a higher expansion rate means objects must be closer to each other for light travelling between them to overcome the expansion of the distance between them), essentially ripping all matter apart.
Beverly:
If there's nothing wrong with me...maybe there's something wrong with the universe!
Here's one you shouldn't be able to answer...
Computer, what is the nature of the universe?
Computer:
The universe is a spheroid region, 705 meters in diameter.
If telephones are outlawed, then only outlaws will have telephones.
I don't think he's referring to the edge of the "observable universe". The article states that the universe is 250x the size of the obserable universe. Hence, the universe itself, outside of being observable, has a limited size. That naturally leads to a question of "what happens a the end".
Numerous analogies have always been used to describe this. Most have already been brought up in this thread (circles, etc). The most famous is that of a balloon. To a 3d observer, a balloon's surface is of limited space. To the ant though, the surface of balloon is endless.
That observation never quite sat with me though. It works for an ant - incapable of reason, but swap out the situation for a PERSON sitting on another circular surface (like, say, a planet), and we have figured out quite readily that our surface is unending but finite - it's obvious - go in another direction and you end up circling back.
By the same token, you can't just easily dismiss a perceived infinity of the universe via analogy as a meaningless question. There must be a logical mechanic behind it. Either the universe literally ends with a wall (highly unlikely), it truly is infinite, or, there is some mechanism by which you "double back" and circle back to your previous position. Just personally, I've never seen a truly convincing mechanic for explaining just how the last one would work. The infinity mechanic makes more sense. Not that I'm saying that the universe is definitely infinite. I'm just saying that before I truly embrace that ideas I need a working model of how it would work as perceived infinity, outside of an analogy or "it just works that way".
"People who think they know everything are very annoying to those of us who do."-Mark Twain
For those of you who did not bother to read the whole article, there's a really important nugget that's lost in the 250+ times headline. The results show that the most likely curvature of the universe = 0. This means the universe, as near as our best minds can tell, is infinite. All the same dusting of galaxies in every direction, infinitely. Infinity is not a concept most people grasp easily. People ask things like "what's outside the universe?" but there is no outside, as "directionality" or "position" have no meaning outside the context of the universe. Likewise, there's no "before" the universe, as time has no meaning outside the context of the universe. My instinct says that we'll eventually come up with a nifty model of reality that includes a non-intuitive description of "position" that causes everything to make mathematical sense and has both quantum physics and relativity as predictable consequences.. but that is pure speculation. And it's a sure bet it'll be even harder to wrap our heads around than what we have now.
Not if you live in the one dimensional space curved in a 2nd dimension defined by the circle you can't.