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View Full Version : Ignorant Question: Size of the universe?

mbjvx
2004-Mar-03, 02:42 AM
Fogive the ignorance in advance please, but what is the approximte size of the universe? Say, the diameter from one end to another? I'm assuming twice the age the unverse in lightyears across?

Taibak
2004-Mar-03, 03:00 AM
Not exactly. You're right that the *observable* universe - essentially, everything we can see from Earth - is a sphere, centered on the Earth, with a diameter that's proportional to the age of the universe (Age of universe x 1 light year/year = Radius of observable universe).

However that's just what we can see. The *actual* universe is infinite. It has no center and it has no edge and wherever you go, you'll see a roughly equal amount of galaxies any way you look.

mbjvx
2004-Mar-03, 03:03 AM
Ok, but the mass of the universe doesn't change (?)- so regardless of the FINAL size (which we can imagine is infinte), there's still the same amount of stuff there?

Normandy6644
2004-Mar-03, 03:42 AM
Bigger than a breadbox... :lol:

mbjvx
2004-Mar-03, 03:48 AM
thats 21, you lose buddy.

:evil:

Density my friend, denisty, im asking about Mass here.

Ut
2004-Mar-03, 04:40 AM
Well... Where would it go?

Taibak
2004-Mar-03, 03:11 PM
Ok, but the mass of the universe doesn't change (?)- so regardless of the FINAL size (which we can imagine is infinte), there's still the same amount of stuff there?

Essentially, yes. However, you have to remember that mass and energy are the same thing and it is possible, in a few rare situations, to gain mass as long as you lose enough energy to balance it out.

You also have to remember that an infinite universe means an infinite amount of matter and energy.

hickboy
2004-Mar-03, 03:15 PM
If the universe is expanding, how can it be infinite? If it is infinite, wouldn't it already stretch forever? Or is it just the observable universe that is expanding?

mbjvx
2004-Mar-04, 12:11 AM
You also have to remember that an infinite universe means an infinite amount of matter and energy.

But where is that 'new' matter comming from? Is this additional matter fabricated AFTER the big bang?

Brendan
2004-Mar-04, 01:05 AM
If the universe is expanding, how can it be infinite? If it is infinite, wouldn't it already stretch forever? Or is it just the observable universe that is expanding?

The space between the clumps of matter is expanding, making the entire universe expand. The observable universe is also expanding because light from greater distances is reaching us as time goes by.

Brendan