2007-06-14 06:05:04 · 6 answers · asked by Anonymous in Science & Mathematics ➔ Astronomy & Space
No one knows exactly what it is yet, but we DO know that it does not interact strongly via the electromagnetic force- light is the electromagnetic force carrier and hence this is why it's called "dark matter"... it neither absorbs, refracts, nor emits photons. The only reason we know with certainty that it exists at all is because it apparently DOES interact via the gravitational force and it is the effects of this interaction that we can observe on an astronomical scale.
2007-06-14 06:17:33 · answer #1 · answered by indiana_jones_andthelastcrusade 3 · 0⤊ 0⤋
Dark matter is supposed to explain the "missing mass" in galaxies. When looking at the motion of galaxies, every star revolves about the center at the same rate, even though they're at different distances from the center so if the closest star to the center makes one turn, the farthest star will also make one turn at the same time, in comparison the motion of our solar system follows the laws of physics, where planets closer to the sun revolve about it more often than planets farther from the sun. So to explain why this happens scientists have predicted that there should be a halo of dark matter around each galaxy, whose gravitational force affects the way the galaxy rotates. It does not interact with light.
There are also other theories as to why galaxies behave the way they do which do not require the existence of dark matter, one such theory is MOND.
2007-06-14 13:26:12 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Dark matter is something like the 80% of the mass of the universe that can not be directly observed. Despite the fact it cannot be directly observed, it does have a gravitational effect on the rest of the universe.
What does it do?
No one knows.
2007-06-14 13:15:48 · answer #3 · answered by jcurrieii 7 · 0⤊ 0⤋
A very large part of socalled 'dark matter' is liquid hydrogen, and something called 'liquid metallic hydrogen, much of which is STILL out there in interstellar and intergalactic space! And a good deal of these this strange, wild and weird states of hydrogen can be found in giant planets as in Jupiter, and Saturn and possible Uranus and Neptune in our own Solar System!!!
2007-06-14 13:55:58 · answer #4 · answered by Old Truth Traveler 3 · 0⤊ 2⤋
the short answer....no one really knows...the long answer dark matter is what is keeping the galaxies from flying apart...and it is made of an as of yet unknown type of matter
2007-06-14 13:10:00 · answer #5 · answered by Anonymous · 0⤊ 0⤋
This is a question I asked a little bit ago:
http://answers.yahoo.com/question/index;_ylt=AiPMV1L8atNOvwiB5H6iS9Xty6IX?qid=20070611121114AAnXhrf
2007-06-14 13:46:27 · answer #6 · answered by M&M 5 · 0⤊ 0⤋