OT - Is the universe finite in size?
 

There has been news lately saying that the universe may not be infinite in size, but could be only about 70 billion light years across. Space wraps around so that light from a galaxy would eventually come back to where it started. Somehow they figured this out by observing the background microwave radiation of space, but I don't understand exactly what their reasoning is.

Anyway, it's very interesting that we may soon know whether the universe is finite or infinite in size. Here is an article about this:
http://www.newscientist.com/news/news.jsp?id=ns99994250

Re: OT - Is the universe finite in size?
 

so, if space wraps a millionth of a degree right, you simply keep turning a millionth of a degree left.

so it is infinite, wether it curves or not.

Re: OT - Is the universe finite in size?
 

<font size="2" face="sans-serif, arial, verdana">no
stuff going into a black hole is falling because space/time is folding (its called gravity).

Re: OT - Is the universe finite in size?
 

it's not folding. if it where folding, gravity would be 'random'. it's either stretched or squished, i'm not sure which. that is, if gravity is a function of space-time.

so, what specifically do you mean by curved? if you traverse an expanding series of circles in a straight line, to someone who's vision is defined by the circles, you curve. that's my point.

Re: OT - Is the universe finite in size?
 

Boy, we're really, getting the easy questions this week: What's the meaning of life? Is space truly infinite? Just how bad was "Contact"?

<font size="2" face="sans-serif, arial, verdana">only 70 billion light years? Is that all?

I have to say I'm not surprised- after all, if you believe in the big bang then a finite universe is kind of inevitable. I like the idea of it wrapping back round on itself, too. The way the combat area should in se4...

Re: OT - Is the universe finite in size?
 

Take things to 2-D for a moment, and consider a Flat universe (or planet)
goes straight along, and if there's no discontinuity, then its infinite in size.

Now have it curved around into a sphere.
Its finite in size, and if you're persistent enough to travel in a straight line you'll go all the way around and end up where you started.

You'll also notice that for large triangles, the angles DON'T add up to 180 degrees. Depending on the radius of the sphere and the size of the triangle, it will be somewhat greater than that.
(Take three points "almost" along the equator of your sphere - Three points form a triangle, but the internal angles are all "almost" 180 degrees!)
One point at the pole, and two others on the equator "east" and "west" will make 90+90+180 = 360 (!)

In practical situations of course, you only have a small triangle compared to the radius of the sphere, so you don't notice it very easily.

Re: OT - Is the universe finite in size?
 

Even if the universe is only 70 billion light years across, it will continue to expand. Approximately 66% of the universe is made up of the mysterious "dark energy", an anti-gravitational form of energy that is forcing the universe into a continual and accelerating expansion. When examining the spectral shifts in light from distant galaxies, astronomers find that nearly all are moving away from us at high speed, showing the expansion. Therefore, the universe really has no limits, as it will continually expand before we could hope to hit the edge.

Re: OT - Is the universe finite in size?
 

<font size="2" face="sans-serif, arial, verdana">95-98%.

Re: OT - Is the universe finite in size?
 

<font size="2" face="sans-serif, arial, verdana">only 70 billion light years? Is that all?

I have to say I'm not surprised- after all, if you believe in the big bang then a finite universe is kind of inevitable. I like the idea of it wrapping back round on itself, too. The way the combat area should in se4...</font><hr /></blockquote><font size="2" face="sans-serif, arial, verdana">If there was a big bang whose cigarette lighted the stuff up?

Re: OT - Is the universe finite in size?
 

<font size="2" face="sans-serif, arial, verdana">Dave Lister, using jump leads from Starbug (according to the brummie BTL attendant in "Back to Reality". =-)