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Old 08-03-2008, 04:04 PM
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Default Dark Matter

I have been following the efforts of scientists to detect dark matter (supposedly the vast vast majority of all the matter in the universe) with a detector placed deep underground in an abandoned mine shaft.
What they are looking for is WIMPS (weakly interacting massive particles) that are much larger than neutrons but that interact with ordinary matter so seldom that trillions upon trillions of them pass through us at any given moment.
Here's my problem: If the WIMPS are passing through the solar system right now, then the implication is that they are spread uniformly at least throughout the galaxy. However, if they are upwards of 90% of all the mass of the galaxy, this enormous amount of missing mass should be at work here in our own solar system. Yet, as far as I can tell, it is not. The planets orbit the sun, and the moons orbit the planets with no perturbations whatever from some gigantic amount of missing mass.
Now, it simply doesn't make sense (at least to me) that this one small corner of the galaxy should be free from material that allegedy just permeates the rest of the galaxy.
Could this be an argument in favor of MACHOS (massive objects such as brown dwarfs, planetesimals, etc.)? Those would certainly not be present in our solar system, having long ago been sucked into the sun and various planets, or simply ejected from the solar system by the giants and sent to drift in interstellar space.
These objects, most of them not very large, could exist in the trillions and trillions in interstellar space, yet they'd be virtually undetectable because their individual gravity wouldn't be large enough to cause the lensing effect predicted by general relativity, nor would thy interfere with the light from a star unless they passed directly in front of it. And even if that were to happen, what are the chances it would be detected and understood for what it was?
Just food for thought.
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Old 08-03-2008, 07:03 PM
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I have no idea, but love the sense of humour that astrophysics has. WIMPS and MACHOS. What other line of science would come up with names like that eh?
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Old 08-11-2008, 08:14 PM
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I find the whole dark matter subject hard to sallow. 95% of our universe made up of matter we can't see or touch. Give me a break.
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