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= The Theory of Relativity =



The theory of relatvity has lead to new research findings in black holes, gravitational waves, and cosmology.



The theory of relativity attempts to explain things that most people would not even consider thinking about. Thus, it is hard for one to comprehend some of the situations that Einstein presents in his theories. Einstein used some ideas invented by Galileo to produce his theory of relativity. Eintstein's special theory of relativity says that time does not flow at a fixed rate, but the speed of light does. Later he expanded his special theory of relativity and created the general theory of relativity stating that matter causes space to curve. He explained his theories through thought experiments.

= Black Holes =



Although Einstein's theory of relativity predicted that black holes existed he actually did not believe in their existence. He stated that they were a mathematical curiousity. Scientists have been conducting more experiments that are leading them to believe that black holes do in fact exist. A black hole is thought to form from collapsing stars that are no longer able to support themselves against their own weight. Because of Einstein's general relativity equations, J. Robert Oppenheimer and Hartland Snyder theoretically discovered that black holes could form from collapsed stars. This led to the finding of possibly the first black hole, Cygnus X-1, discovered in 1970. Since then over a dozen black hole candidates have been found (Lightman par. 8).

= Gravitational Waves =



Another thing predicted by Einstein's theory of relativity was gravitational waves. Gravitational waves are disturbances in the curvature of spacetime caused by the movement of matter. Most gravitational waves cause such miniscule distortions of spacetime that you cannot detect them ("Ripples in Spacetime" par. 1). But scientists have built facilities called the Laser Interferometer Gravitational-Wave Observatories which sense the gravitational waves on two metal tubes 2 and 1/2 miles long. When a gravitational wave passes through one of these rods their length is changed by a measurement smaller than an atomic nucleus which can be detected by a laser system (Dine par. 60). Obviously the research on gravitational waves has changed tremendously because millions of dollars are being put into projects like these to test their existence.

= Cosmology =

Eintstein's general theory of relativity helped Friedmann come up with the Big Bang Theory. He began with Einstein's general relativity equations and came to a conclusion that the universe began from a single cosmo (Lightman par. 9). This theory also states that the universe will keep expanding forever unless the inward gravity cannot sustain the outward gravity and the universe collapses. This was proved by Edwin Hubble thus proving that the universe was expanding ("The Ultimate Singularity" par. 2). Now new telescopes are being built to try to determine the density of matter versus the rate of the expansion of the universe to help get a better understanding of this theory. The status of this cosmological theory is virtually the same as it was when Eintstein first came up with it and more people are finding ways to prove it.

= Lasting Thought =

In conlcusion, new devleopments are being made through the theory of relativity pertaining to black holes, gravitational waves, and cosmology. The theory of relativity still stands today in the same stance it did when Einstein came up with it. More people are experimenting with what he said and since the technology is advancing they are being able to prove his theories. Black holes are not as skeptical as they were in the past and there seems to be a lot more evidence proving their existence. New facilities are proving the existence of gravitational waves by detecting their presence with highly sensitive lasers. Cosmology is also being proved by the equations Einstein created. Hopefully in the future we can conduct experiments that will fully prove or disprove his theory of relativity and put a stop to all the debates.

= Works Cited =

Lightman, Alan. "NOVA | Einstein's Big Idea | Relativity (Lightman Essay) | PBS." __PBS__. 3 Feb. 2009 http://www.pbs.org/wgbh/nova/einstein/relativity/.

This article is well put together and is made by a credible source, PBS. The article has great pictures so that you can see what they are talking about and they also have neat animations that let you see what is happenning with Einstein's thought experiments. It covers black holes, gravity, and even about the beginning of time. They also have a link that will take you to their webpage that is dedicated to Einstein and has tons of information about him.

"General Relativity." __NCSA Web archive bounce page__. 3 Feb. 2009 .

They can find a lot of information on the theory of relativity such as embedding diagrams, the flow of spacetime, and gravitational time dilation. There are also numerous pictures which illustrate these various subjects. There are also some links to things such as the special theory of relativity, modern cosmology, black holes, and gravitational waves. This site is credible because it is made by the university of illinois. They site all of their sources correctly and the information appears to be accurate.

Dine, Michael. "NASA - Relativity." __NASA - Home__. 3 Feb. 2009 .

This website has a vast amount of information on every aspect of the theory of relativity. The article is on NASA's website which is an extremely reliable source as they are a government agency. It is written by Michael Dine who has his Ph.D. and is a professor of physics at the University of California. The website covers information from as far back as Galileo to present day. It is a great source of information for anyone who wants to gain knowledge about the theory of relativity.