What is Dark Matter?
The Oxford dictionary defines dark matter as a non-luminous material which assumed to exist in space. But what does this mean? If dark matter is non luminous how do we know it’s there? How can we detect it? These are the kind of questions I will try to answer in this short article.
Discovery:
In the mid to late 19th century scientists observed that stars orbiting nearby galaxies were rotating faster than expected. The speed calculated indicated that the gravity created by them could not contain the matter within the stars. Therefore meaning that the stars should have been ripped apart from their own gravity. This indicated that there could be some other form of matter that is acting within the galaxy; which could have certain properties that explain the larger amount of gravity e.g. more massive matter.
Properties of Dark Matter:
Figure 1
Figure 1
Dark matter is hard to “get your head” around as scientists say that you can’t see it; then how can it exist? Dark matter is said to be “non-luminous”, therefore it does not absorb, give off or reflect light, which means we cannot observe the existence of Dark Matter (But we could detect it: See section on “Detection”).
Detection:
Although we cannot see Dark Matter it supposedly makes up 22% of the universe, compared to 4% of normal matter (See Figure 1).
The evidence of how dark matter could exist is from experiments held in particle accelerators, such as the Large Hadron Collider at CERN. As Dark Matter does not interact with electromagnetic forces, the detectors may not be able to detect dark matter in a collision of two or more particles in an experiment. However if the energy of the particles before the collision is not equal the energy of the products after the collision the energy could be lost to Dark matter that we cannot detect.
Dark matter often occurs in research and experimentation of physics such as extra dimensions and “supersymmetry”. If the existence of Dark Matter were to be proven true then it could yield promising indications to further topics of physics such as the ones previously mentioned.

Source Number: | Title/ Website Title: | Author: | Publisher/URL: | Date: | Contribution to report: | Assessment of Reliability of source and cross checking: | 1 | Dark Matter in the universe | Vera Rubin | file:///C:/Users/113074/Downloads/Rubin%20Dark-Matter.pdf | 9/02/2015 | In depth analogies of the topic that developed understanding of topic. | Corresponded with other sources. | 2 | Dark Matter | G.H.Rieke | http://ircamera.as.arizona.edu/NatSci102/NatSci102/lectures/darkmatter.htm | 9/02/2015 | Gave insight and general overview of the topic. | Corresponded with other sources. | 3 | Dark Matter | CERN | http://home.web.cern.ch/about/physics/dark-matter | 9/02/2015 | Gave General and slightly detailed info. on the topic. | Corresponded with other sources. | Figure 1 | % of Types of Matter in the universe | G.H.Rieke | http://ircamera.as.arizona.edu/NatSci102/NatSci102/images/darkenergy_pie.jpg | 9/02/2015 | Image of % of types of matter in the universe. | Corresponded to other sources. |