This is a great video describing the evidence for dark matter and darrk energy, courtesy of History Channel.
1st Evidence for dark matter -Astronomers expected stars near the center of galaxies should travel slower than stars near the outer areas. What astronomers noticed was quite different.
Astronomers noticed that velocities of matter in galaxies rotates at the same velocity, no matter where anything is located. There must be matter present exerting a force on all stars in the galaxies that keeps them travelling at the same speed.
2nd Evidence - gravitational lensing.
Astronomers noticed that light from distant galaxies is bent by the gravity of something with immense mass. The bending of light created lensed, duplicate images of those distant galaxies. Visible matter was calculated to be vastly insufficient to bend light of these distant galaxies. Therefore there must be an immense mass creating the distortion of light from distant galaxies. That something is dark matter.
Dark matter does not react with any type of light so it cannot be seen. We only know it is there because we can see the effects of its gravity.
It is estimated that 70% of the universe is composed of dark energy, 25% dark matter and only 5% is composed of everything we can see!
We will never completely understand our universe until we understand dark matter and dark energy.
Maddalena Environmental Inc.
P.S. If you're trying to make money online and have had limited success so far, you should check out THE EASIEST WAY TO MAKE MONEY ONLINE.
You can watch a FREE hangout here.