|
Topics:
|
|
|---|---|
Words: |
509 |
Page:
|
1
This essay sample was donated by a student to help the academic community. Papers provided by EduBirdie writers usually outdo students' samples.
|
Cite this essay
Download
Dark Matter accounts for 84% of all the matter in the universe. The remaining 16% is ‘normal’ (also called baryonic) matter, comprised of every single planet, star and galaxy in the visible universe. Dark Matter earned its name because it does not interact at all with the Electromagnetic Force. This means it does not absorb, emit or reflect visible light, gamma rays, ultra-violet rays… etc. Since telescopes rely on some form of electromagnetic radiation to function (see graphic below), they can’t detect dark matter.
If dark matter is impossible to detect with our current instruments, then how was it discovered in the first place? Technically, dark matter has not yet been discovered. It is a ‘placeholder’ that reconciles Einstein’s Theory of Relativity (which is assumed to be correct at all scales in the universe) with astronomers’ observations of the universe, in the same way that variables such as ‘x’ or ‘y’ are placeholders in an algebraic equation. To form a stable orbit, there has to be a perfect balance between the speed that one object has in relation to the other, and the force of gravity pulling both objects together (this is influenced by how much mass the object being orbited has). If the object’s speed is too high, it may escape the orbit entirely, and if the gravitational force is too large, the two objects will collide. Observations of the rotation speeds of gas clouds orbiting in distant galaxies in the late 20th century revealed that they were very far from this balance. The gravitational force was calculated to be far too weak to keep the stars from flying off into deep space, but the stars kept orbiting in the galaxy, as if a much stronger gravitational force was acting on them. The calculation that stars needed a much stronger gravitational attraction between each other to behave as they were observed to led to the suggestion that there was ‘missing’ mass. This is because the magnitude of the force of gravity is influenced by the mass of the orbiting body (in this case the stars, solar systems and dust clouds) and the mass of the body being orbited (in this case the galaxies). This missing mass was given a name: dark matter.
In the search to learn more about dark matter, experiments have been carried out to study weakly interacting massive particles (WIMP). These are thought to be the sub-atomic particles that make up most dark matter (scientists currently predict that DM is formed of particles, but this assumption is based on the nature of baryonic matter). They are thought to be electromagnetically neutral, since they do not interact with light, and heavy and slow-moving, since otherwise they would not have clumped together into the density fluctuations that allowed galaxies to form. WIMPs are not predicted by the standard model of particle physics, but the theory of supersymmetry predicts certain elementary particles that In 1900, Lord Kelvin allegedly said “There is nothing new to be discovered in physics now. All that remains is more and more precise measurement.”
Get your paper done in as fast as 3 hours, 24/7.
Fair Use Policy
EduBirdie considers academic integrity to be the essential part of the learning process and does not support any violation of the academic standards. Should you have any questions regarding our Fair Use Policy or become aware of any violations, please do not hesitate to contact us via support@edubirdie.com.
Stuck on your essay?
