OT: Lost in the Galaxy? No wonder.

[Karibu]

EvilGenius4ABetterTomorro said:
So, I was just thinking; Dark Matter must be invisible because if there is so much of it, why doesn't it interfere with our observation of other stellar objects like other galaxies. You don't hear someone say "I was watching Mars last nite when suddently an orb of dark matter blocked my view"

Dark Matter, Anti-Matter,and little lambs eat ivy.

There's also this assumption, that dark matter in the galaxy is spread on far wider area than normal matter. Scientists call it the "dark matter halo" of galaxy. For example, the diameter of our galaxy is considered to be about 100 000 light years. The diameter of dark matter in our galaxy is assumpted to be around million light years. Which is effectively 10 times more than visible matter in our galaxy. Perhaps you know more of this, Renegade?

[Renegade 13]

Karibu said:
There's also this assumption, that dark matter in the galaxy is spread on far wider area than normal matter. Scientists call it the "dark matter halo" of galaxy. For example, the diameter of our galaxy is considered to be about 100 000 light years. The diameter of dark matter in our galaxy is assumpted to be around million light years. Which is effectively 10 times more than visible matter in our galaxy. Perhaps you know more of this, Renegade?

Nope, I don't really know more than that. Just that they call the hypothetical dark matter halo objects MACHO's (Massive Compact Halo Objects).

Oh, I just remembered something more. Some candidates for dark matter:

SIMP's (Strongly Interacting Massive Particles): They interact with normal matter strongly, but still are thought by some to form at least a part of dark matter. Hypothetical Particel! Not proven to exist yet. SIMP Link (not much info)

WIMP's (Weakly Interacting Massive Particles): Another hypothetical particle that only interacts with normal matter through the weak nuclear force and gravity. Since they (theoretically) don't interact through electromagnetism or the strong nuclear force, they can't be seen directly, or interact with atomic nuclei. NOTE: Most of the above paraphrased from Wikipedia. WIMP Info Link

Neither of the above have been proven to exist yet, to the best of my knowledge.

Don't you just love particle physics?

Anti-particles have the same spin, but opposite charge.

Thanks for correcting me Wolfman

[Wolfman77]

Renegade 13 said:
SIMP's (Strongly Interacting Massive Particles): They interact with normal matter strongly, but still are thought by some to form at least a part of dark matter. Hypothetical Particel! Not proven to exist yet. SIMP Link (not much info)

This one has more info on SIMP's.
http://www.news.uiuc.edu/scitips/02/0604darkmatter.html

Also taks a bit about WIMP's, and their interactions in the early universe.