Aug 21 2009, 10:59 PM
QUOTE(Mark_Renton @ Aug 20 2009, 01:17 PM)
according to einstein and hawking space is finite. but at the moment the edge of space is still expending after the big bang. there is no sign of the expension stopping yet. even if it suddenly contract it will take BILLIONS of year for the gravitational force to pull everything back to pre big bang
so dont worry people. the fable end of the world armageddon scenario often seen in religious books is at least a few billion years away! haha
actually, the universe is not just expanding, it's accelerating. means it's going faster and faster by the minute. there might not even be a mass collapse. however, assuming the big bang theory is true, then what keeps the universe accelerating? so dont worry people. the fable end of the world armageddon scenario often seen in religious books is at least a few billion years away! haha
ah, that's the question isnt it?
which is why everybody is trying to find out what is dark energy (not to be confused with dark matter
).QUOTE(nice.rider @ Aug 21 2009, 10:52 AM)
When dealing with infinite space of the universe, most of us could get confuses easily.
The curved surface of the Earth can be used as an analogy. The Earth's surface is finite in area, but unbounded (no boundary). A traveller will not meet any edge or boundary in whatever direction he goes.
Similarly space could be finite in volume, but without any edge or boundary. An astronaut could, in principle, pointing his rocket in one direction and would return to his starting point at the end.
The big bang theory suggests that all matters (planets, asteroids, galaxies) are moving apart from each others a.k.a expending universe.
While the matters are moving away from each others, so DOES the SPACES within them are expending (imagine the spaces are stretch in an expending universe). The matters is NOT expending in spaces that already there, but the SPACES are being stretch further when the matters expend.
Many of us often assume that universe space is infinite and the planets are moving away and filling up more spaces which is already there (like a boy moving two balls apart in a big room (where spaces already be there) which is NOT TRUE.
Universe is a hypersphere with finite volume without boundary. The volume (x, y,z, t) continues to expend (and one day may retract) as a result of the big bang explosion.
If you are interested to understand this more, please refer to Einstein's hyperspherical cosmos modeling.
Cheers.
i might disagree here. in most articles i read, it mentions specifically that the density of the universe is dropping as the result of the accelerating expansion. if as u said matter also expands, then there should be no way to measure the expansion because everything is relatively expanding, we might not even notice it! The curved surface of the Earth can be used as an analogy. The Earth's surface is finite in area, but unbounded (no boundary). A traveller will not meet any edge or boundary in whatever direction he goes.
Similarly space could be finite in volume, but without any edge or boundary. An astronaut could, in principle, pointing his rocket in one direction and would return to his starting point at the end.
The big bang theory suggests that all matters (planets, asteroids, galaxies) are moving apart from each others a.k.a expending universe.
While the matters are moving away from each others, so DOES the SPACES within them are expending (imagine the spaces are stretch in an expending universe). The matters is NOT expending in spaces that already there, but the SPACES are being stretch further when the matters expend.
Many of us often assume that universe space is infinite and the planets are moving away and filling up more spaces which is already there (like a boy moving two balls apart in a big room (where spaces already be there) which is NOT TRUE.
Universe is a hypersphere with finite volume without boundary. The volume (x, y,z, t) continues to expend (and one day may retract) as a result of the big bang explosion.
If you are interested to understand this more, please refer to Einstein's hyperspherical cosmos modeling.
Cheers.
space expands. matters dont. which is why in a couple of billion years, there wont be any stars visible in the sky bcoz the distance is increasing faster than the light could reach us.
QUOTE(C-Note @ Aug 21 2009, 01:33 PM)
they are just THEORIES.
and until proven wrong, we accept it to be true.
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