Posted on 08/21/2006 6:13:30 PM PDT by vikingd00d
No it is not an ether.
(I'm gonna get clobbered for that one :) )
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If an inch represents the difference in the knowledge of Kepler and Galileo and todays observers, then a miles represents how much more knowledge there must be before we begin to explain it all. We may never travel that mile.
Why not? An invisible, odorless realm that affects gravity and light. Whys it not an ether?
Now back to the future?
In 1998 astronomers blew the lid off of the oscillating universe theory (first a big bang occurs, galaxies fly away from each other then slow down, slower and slower then gravity starts pulling them together again until they collide together and BOOM another big bang) because they discovered that the expanding galaxies were not slowing down, but actually accelerating aqwy from each other faster and faster.
Previous theories were tossed out, and new ones were needed.
One prominent theory suggested that there was additional matetr out there beyond the galaxies and the gravitation of that unseen matter is pulling the galaxies away faster and faster.
The frantic search for the elusive "dark matetr" began.
It has been one of the greatest hunts in the history of physics.
Now, apparently the hunt is over.
But.....
They really do not understand the nature of this exotic stuff. It is not like normal matter. Some theories suggest it is actually matter at the intersection of other dimensions, neither totally in our dimensions nor in the other dimensions.
Kinda like light which has properties of both matter and electromagnetic waves at the same time.
This is very big news.
I affect gravity and light but I am not an ether either.
Hmmmm... Light matter/energy vs. dark matter/energy...
The bigger question is why it is important to understand the world we live in.
Thanks for the ping.
BuMpiTy, BuMp, BuMp, ...BOOM!
Sorry. I'm just being obstinate.
It will be fascinating to find out where we fit dark matter/energy into our scientific worldview though. Not atoms/protons/neutrons/electrons/quarks or other normal matter constituents that would fit into the Periodic Table, then just what the he!! IS it?
It's sorta deflating to find out that we only know what a small fraction of everything is.
Godspeed
Very elegant--finding a spot where natural forces ought to separate the dark and luminous matter. It must have been a very cool moment when they first overlaid the IR chart with the lensing chart.
At a minimum, future work is going to have to explain gravitational centers that are completely separate from the IR centers. Dark matter seems like a pretty good way to do it. And, the dark matter theory obviously predicted this result in this oddball situation before the observations were made--they wouldn't have gotten 100 hours on the scope without a pretty compelling case that this was a way to test the dark matter theory. Sometimes science is just beautiful.
This result is, I think, almost as important as the confirmation of relativity by gravitational bending of light.
[Raising my hand ...] I have a question. As these clusters pass through each other, and the visible matter gets slowed down so that the dark matter sails through faster, the dark matter leaves the visible galaxies behind. Fine. Now then, I thought the first clue to the existence of dark matter was that galaxies were rotating as if there were lots more mass than we could detect. So, won't the rotation of these "naked" galaxies (stripped of their dark matter) cause them to fly apart? Is that going to be observed?
I'd need to have a better understanding of exactly what's going on to answer that; I'll have to punt until the heavy hitters show up.
The expansion of the universe is a large-scale effect; it doesn't affect the local motion of galaxies. Example: Andromeda is 2.2 million LY away from our galaxy, yet the two are moving towards each other.
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