The Search For Dark Matter in the Universe.

Essay by OmsamUniversity, Bachelor'sA+, December 2003

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Searching for Dark Matter

When Astronomers look at the Universe, they study the mysteries of the stars, dust clouds and other matter visible to radio, infrared, optical, ultraviolet, X-ray, or gamma-ray telescopes. What is not readily apparent through these mediums is even more mysterious. When Astronomers observe spiral galaxies like our Milky Way, they use Doppler shifts to determine the rotation speeds of stars and gas at various distances from the center of the galaxy. This allows them to calculate the mass of the galaxy. What they measure however is much larger than the mass of all the stars and gas that can be detected in the galaxy. Some calculate that at least 90% of the mass of our galaxy, other galaxies, and even the Universe cannot be seen. This can mean one of two things: our current theory of gravity is wrong; or there is a great deal of missing mass in the galaxy that we can't see, the so-called Dark Matter.


There actually is an alternative theory of gravity called MOND, for Modified Newtonian Dynamics. Mordecai Milgrom of the Weizmann Institute in Israel first proposed this theory in 1983. MOND does away with the need for dark matter by modifying our current theory in certain instances where the acceleration produced by gravity is very small, such as at the outskirts of galaxies. While there is much debate on this subject, most research is still centered on the search for Dark Matter. (MOND)

Scientists have been studying the problem of Dark Matter for many years and projects to identify and measure it are currently being conducted all over the world. The instrumentation for these projects is located in deep caverns and mines under the Earth and in orbiting satellites far up above our atmosphere. Scientists are considering a...