quote:

Originally posted by occrider Actually I don't think the matter itself is expanding outwards. Sure matter moves in space but that movement is dictated by gravitational effects. However, there isn't a gravitational field coming from all directions that is pulling matter outwards (I think that would result in some heavily skewed elliptical orbits or something) rather I think that space itself is expanding and the matter is going along for the ride. Think of matter as 2 pen dots on a rubber band which is "space". As the rubber band stretches, the 2 dots do not move on the rubber band but rather "space" moves, contorts, whatever, and brings the dots along with them. Thus space is expanding ... which really cannot be classified as nothing despite the fact that there might not be matter in it.

I see what you're saying actually. I do not understand, though, the force that is pulling matter outwards. What keeps the matter from just staying where it is while space is expanding

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Originally posted by Sunsnail I see what you're saying actually. I do not understand, though, the force that is pulling matter outwards. What keeps the matter from just staying where it is while space is expanding

if i understood properly, it's the energy of the inital big bang, the continuation of movement, that force

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quote:

Originally posted by Psy-T if i understood properly, it's the energy of the inital big bang, the continuation of movement, that force

Well, that's what I originally thought with my first post. Then occrider says that it matter isn't actually moving, the space is.

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Originally posted by Sunsnail Well, that's what I originally thought with my first post. Then occrider says that it matter isn't actually moving, the space is.

oh sorry, i misread your question before

i dont have any problem envisioning it, especially with the help of the rubberband analogy, though i doubt i can explaing it any better, so i wont try

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People who own my ass: Citric Acid, Boomer187, Tribu, Sand Leaper,
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Psy-T - Down The Rabbit Hole (400minute long acid set)

I actually did a presentation once on this a long time ago. Stephen Hawking has done some work to support the theory that the universe either achieves a critical point and continues to expand indefinitely or it achieves a critical point where its internal gravity ultimately pulls everything back in and the universe eventually collapses back into a singularity (or something like that)--think rubber bands...

One thing in particular that I remember is that scientists have physically observed the Doppler Effect from other interstellar bodies, which proves that bodies are moving futher away, i.e. the universe is "expanding". Although, yeah, conceptually it doesn't seem logical that an "infinite" amount of space could somehow grow or shrink, since by defnition, infinite would already occupy all available space, all the time.

If you're really curious about some of this stuff and haven't already watched it, go check out Hawking's A Brief History of Time. I'd probably recommend the movie over the book. Neither are terribly exciting, but should at least give you some answers (even if they are only theoretical).

thanks everyone

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People who own my ass: Citric Acid, Boomer187, Tribu, Sand Leaper,
Jackson, venomX, jamie, Renegade, Konjin, Akridrot, Miss Bliss.
Psy-T - Down The Rabbit Hole (400minute long acid set)

Just want to add a few things:

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Originally posted by Sunsnail The big bang happened. All the matter in the universe expanded outward at a constant rate. It is still expanding now. Imagine a single point in space, the origin of the universe. Everything is moving away from that point...

This is incorrect in the sense that the Universe didn't expand from a single point. The Big Bang was like an explosion OF space, not an explosion IN space. Therefore it happened everywhere at the same time, there is no centre to the Universe.

quote:

Originally posted by Shakka One thing in particular that I remember is that scientists have physically observed the Doppler Effect from other interstellar bodies, which proves that bodies are moving futher away, i.e. the universe is "expanding".

Just nitpicking here. The redshifts that astronomers are not due to the Doppler Effect. The galaxies are not moving away from us (which would cause a Doppler shift) but rather it is the space between us that is expanding. The effect is pretty much the same though, but the implication is different. If the galaxies were moving away then that would imply that there is space to move into.

As for questions about matter being pulled apart, think of the expansion of the universe as being caused by a force (known as Dark Energy, the cause of which is still debated). In a galaxy, or a cluster of galaxies, the amount of mass causes enough gravitation to match the pressure of expansion and you get an equilibrium. Between clusters, the distances are too great for gravity to be able to overcome expansion.