Dark matter

• Stars in galaxies do not reduce in orbital speed as the distance from the center of the galaxy increases, as do the planets in our solar system. This would imply that there is more matter in the galaxy than is visible. This is dark matter.
• Dark matter is not in the gravitation field of galaxies. Galaxies are suspended in the gravitational field of dark matter.
• Dark matter is required for the formation of galaxies. Clouds of gas are simply not dense enough to produce the required gravity. Computer simulations (cosmologist Carlos Frank) indicate that dark matter amounts around five times that of normal matter will satisfy simulation requirements for a galaxy creation.
• Einstein proposed that gravity is a bendable, malleable material that is influenced by gravity. Any object with mass can bend space, acting as a lens. Light bends in this 'gravitational lensing.' The estimated density of galaxies is not enough to account for the measured amount of bending. It is estimated that approximately 5 times the density of a galaxy, in dark matter, must be present to cause this.