Dark Matter
Dark Matter is the name given to mass that emits no detectable radiation. ‘’Dark Matter accounts for the galaxies rotating about "local groups" in tighter orbits than we expect from our observations. Gravity is stronger than we can account for unless there is some matter we cannot see. We are much more certain what dark matter is not than we are of what it is” (Feild, Ann, 2013).
Scientists think dark matter is made of particles called WIMPS, "weakly interacting massive particles". When WIMPs get very close to other WIMPs, they should annihilate each other, because these particles are thought to be their own antiparticles, and when particles of matter and their antimatter counterparts meet, they destroy each other (Moskowitz, 2012).
For decades scientists have wondered whether a mysterious form of matter, simply known as “dark matter” because it does not interact directly with light, makes up the majority of the “stuff” in the Universe. A new study from an international collaboration of scientists has released new, compelling data that suggests that dark matter exists throughout our Universe (Millis, 2013).
It is believed that dark matter is in the galaxies because the .orbital speeds in the Milky Way remain high even very far from the center, indicating that a large amount of dark matter lies beyond our galaxy’s visible regions. It has also been found that orbital speeds in the outer regions of other spiral galaxies indicate that they too harbor lots of dark matter (Bennett, 2012).
The orbits of galaxies in clusters tell us that galaxy clusters contain huge amounts of dark matter. Temperature measurements of hot gas tell us the amount of dark matter in clusters, and give results that agree with those we infer from galaxy velocities. Gravity’s light-bending effects distort the images of galaxies lying behind a cluster, enabling us to measure the cluster’s mass without relying on Newton’s laws. These cluster
References: Bennett, D. S. (2012). The essential cosmic perspective, 6th edition. San Francesco: Addison-Wesley. Cain, F. (2008, SEPTEMBER 16). Universe today. Retrieved from universe today: http://www.universetoday.com/18256/where-is-the-sun/#ixzz2eAYLf8ED Field, Ann. (2013, December 2nd). DARK ENERGY, DARK MATTER. Retrieved from NASA Science: science.nasa.gov>Astrophysics>Focus Area Millis, J. P. (2013, April). Space news. Retrieved from redorbit.com: http:/www.redorbit.com/news/space/1112816010/dark-matter-and-antimatter-measured-in-space-040413/ Moskowitz, C. (2012, August 17th). Dark Matter Exposed. Retrieved from NBC News.com: http://www.nbcnews.com