Astronomers have wondered for ages about the existence of dark matter. The truth is astronomers aren't sure what dark matter is made of, but they think that it does exist in space. Dark matter is thought to exist as large black rings surrounding galaxies. The space between planets and stars isn't just nothing, it's probably matter of some sort. The consensus seems to be that it's made up of small subatomic particles called MACHOs (MAssive Compact Halo Objects) and WIMPs (Weakly Interacting Massive Particles). They aren't as big as atoms, but they're made of the same materials as atoms are. Astronomers think that WIMPs are between 10 to 100 times the size of protons, and that they may account for much of dark matter. So dark matter is full of WIMPs! .
The first evidence of dark matter was found in clusters of galaxies in 1933. Astronomer Fritz Zwicky discovered that the â€œmass of luminous material in a cluster of galaxies was much less than the total mass of the cluster implied by the velocities of the galaxies.â€.
Later in the 1970â€™s astronomer Vera Rubin conducted a study on the rotation of galaxies. The velocity of the stars in a galaxy was measured using a radio telescope. If you look at a spiral galaxy, some stars will be moving toward you and some will be moving away because of the rotation of the disk. By plotting the velocity in these stars he realized the stars near the edge of the galaxy were moving at the same speed as stars in the middle.
In the year 2000 using the NSF Cerro Tololo Inter-American Observatory in Chile and a method known as â€œweak gravitational lensingâ€, a group of scientists from Bell Labs, were the first to map the distribution of dark matter over large portions of the sky. The team analyzed the light from 145,000 very distant galaxies for evidence of distortions produced by the gravitational pull of dark matter that lay in their paths.