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 Posted: Fri Mar 02, 2007 9:10 am
I recently came by a book that mentioned Dark Matter and Dark Energy. I am more interested in the Dark Energy topic. This is based on the belief that the universe is expanding at an accelerated rate. Of course, this violates what we know presently about physics, so the theory states that some energy is causing the universe to speed up. Any comments or ideas on where this energy comes from?
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Posted: Mon Mar 05, 2007 8:05 pm
It's hard to answer where it comes from. It's just one of those things that just is. We could try and discribe it's properties better, but to say where it comes from? It's like asking where any other energy in our universe comes from. It's hard to answer and the answer can be rather trivial.
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Posted: Sat Mar 24, 2007 11:09 am
I'm wondering if you'd rather know what it is rather than where it comes from? It comes from wherever the Universe comes from which deserves a whole topic of itself... and does if you look in the Theories forum.
If you want to know WHAT it is then...
http://en.wikipedia.org/wiki/Dark_matter#Dark_matter_composition
Have fun reading that... most of it is way out of my depth at the moment and I'm not in the mood for reading right now!
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Posted: Fri Mar 30, 2007 8:01 am
In retrospect, what it is would be simpler. However, you can't help but wonder about the possibilities. 4laugh
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Posted: Fri Apr 13, 2007 10:21 pm
Actually one thing that hass been bothering me since hearing the universal expansion is actually accelerating:
The evidence posed for this, is that the farther into space we look, the faster everything is moving away.
However, the farther into space we look is also looking back into the past. Something happening a billion lightyears away, also happened a billion years ago, while something a million lightyears away happened a great deal of time closer to the present than now.
So how do we know that this discrepency in time is negligible enough to be able to say it is not prrof the universal expansion is slowing?
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Posted: Mon Apr 23, 2007 4:24 pm
Duntada: That's not quite a complete picture of the evidence.
In models of the universe, there's several parameters, one of which governs the expansion.
You're right that, until relatively, the expansion of the universe has been slowing. However, the way it has been slowing fits with a model in which it's about to start speeding up as galaxies are pushed too far apart due to the expansion, to be able to override the unknown force that is dark energy.
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