The universe is filled with a vast amount of galaxies of various shapes and sizes. A galaxy is defined as a system of millions or billions of stars with gas and dust held together by gravitational attraction. There are several types of galaxy types: elliptical, spiral and irregular. Spiral galaxies are galaxies which usually have a large mass in the middle with arms branching off of it containing stars and star systems (Swinburne University of Technology, n.d.). All of the objects orbiting the centre of the galaxy must maintain an orbital velocity, the velocity at which an object can orbit a mass without falling towards it. The formula to give the orbital velocity for a satellite is:
V=√(GM/r)
(Blackman, n.d.)
While the Law of Universal Gravitation …show more content…
The main opposing theory of orbital curves of a galaxy is the theory of the existence of dark matter. Dark matter is the given name for theorised matter that exists in the universe that cannot be visually observed but is rather inferred by other phenomenon that occurs such as gravitational lensing or gravitational rotation curves. As can be seen in calculation four in the appendix, the formula to find the amount of dark matter in a galaxy can be derived from the Law of Universal Gravitation.
For the rotational speed of all stars in the Andromeda Nebular to remain constant, the amount of dark matter present must increase proportionally to the radius. However, this is not the case. As seen in Graph One, the observational rotational velocities of stars in the Andromeda Nebular are scattered, loosely follow a decreasing linear trend. In order for dark matter to fit the observed information, it would have to be unevenly spread out throughout the galaxy to match the observed data. There is certainly proof towards both MOND and dark matter but there is also an argument about the probability of either being
V=√(GM/r)
(Blackman, n.d.)
While the Law of Universal Gravitation …show more content…
The main opposing theory of orbital curves of a galaxy is the theory of the existence of dark matter. Dark matter is the given name for theorised matter that exists in the universe that cannot be visually observed but is rather inferred by other phenomenon that occurs such as gravitational lensing or gravitational rotation curves. As can be seen in calculation four in the appendix, the formula to find the amount of dark matter in a galaxy can be derived from the Law of Universal Gravitation.
For the rotational speed of all stars in the Andromeda Nebular to remain constant, the amount of dark matter present must increase proportionally to the radius. However, this is not the case. As seen in Graph One, the observational rotational velocities of stars in the Andromeda Nebular are scattered, loosely follow a decreasing linear trend. In order for dark matter to fit the observed information, it would have to be unevenly spread out throughout the galaxy to match the observed data. There is certainly proof towards both MOND and dark matter but there is also an argument about the probability of either being