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  The Theory of Relativity  **__Why should anyone care about the Theory of Relativity?__**     Albert Einstein's Theory of Relativity affects all people, even though so  me of them may not realize it. It applies to eve  ry object in the entire universe. The Theory of Relativity has led the way for more work and research in physics since it was released to the  public. This idea changed the way people think about objects. For many years b  ef  <span style="font-family: Tahoma,Geneva,sans-serif;">ore Einstein's theory, people a <span style="font-family: Tahoma,Geneva,sans-serif;"> <span style="font-family: Tahoma,Geneva,sans-serif;">greed with Isaac N <span style="font-family: Tahoma,Geneva,sans-serif;"> <span style="font-family: Tahoma,Geneva,sans-serif;">e <span style="font-family: Tahoma,Geneva,sans-serif;"> <span style="font-family: Tahoma,Geneva,sans-serif;">w <span style="font-family: Tahoma,Geneva,sans-serif;"> <span style="font-family: Tahoma,Geneva,sans-serif;">t <span style="font-family: Tahoma,Geneva,sans-serif;"> <span style="font-family: Tahoma,Geneva,sans-serif;">on's theories, thinking that everything in the universe was the same; all clocks ran the s <span style="font-family: Tahoma,Geneva,sans-serif;"> <span style="font-family: Tahoma,Geneva,sans-serif;">ame way regardless of their location in the univ <span style="font-family: Tahoma,Geneva,sans-serif;"> <span style="font-family: Tahoma,Geneva,sans-serif;">e <span style="font-family: Tahoma,Geneva,sans-serif;"> <span style="font-family: Tahoma,Geneva,sans-serif;">rse and all similar objects, like a yardstick, were a uniform length wherever they happe <span style="font-family: Tahoma,Geneva,sans-serif;"> <span style="font-family: Tahoma,Geneva,sans-serif;">ned to be. However, Einstein changed the way everyone t <span style="font-family: Tahoma,Geneva,sans-serif;"> <span style="font-family: Tahoma,Geneva,sans-serif;">hought when he talked about time dilation and length contraction. He s <span style="font-family: Tahoma,Geneva,sans-serif;"> <span style="font-family: Tahoma,Geneva,sans-serif;">tated t <span style="font-family: Tahoma,Geneva,sans-serif;"> <span style="font-family: Tahoma,Geneva,sans-serif;">hat time dilation, which sa <span style="font-family: Tahoma,Geneva,sans-serif;"> <span style="font-family: Tahoma,Geneva,sans-serif;">ys that a clock ticking farther away <span style="font-family: Tahoma,Geneva,sans-serif;"> <span style="font-family: Tahoma,Geneva,sans-serif;">from the observe <span style="font-family: Tahoma,Geneva,sans-serif;"> <span style="font-family: Tahoma,Geneva,sans-serif;">r will seem to move slower than a clock closer to them and a moving clock will seem slower than a stationary clock, and length contraction, which says that the observer will see every other yard stick as shorter than <span style="font-family: Tahoma,Geneva,sans-serif;"> <span style="font-family: Tahoma,Geneva,sans-serif;">his own, existed and changed the way people did and do think about the universe. Overall, regardless of whether or not Einstein's Theory of Relativity is accepted or rejected by society, they are greatly affected by it.

**__What is the Theory of Relativity?__**  <span style="font-family: Tahoma,Geneva,sans-serif;"> <span style="font-family: Tahoma,Geneva,sans-serif;"> First, everyone must know what the Theory of Relativity is. Einstein first published his theory in 1918 and applied it to the entire universe. His theory can be summed up by two basic statements: that the speed of light is a constant value and that the laws of physics observed by moving viewer are the same as laws of physics seen by a non-moving viewer. Basically, general relativity states that "gravity, as well as motion, can affect the intervals of time and of space in one direction is equal to acceleration in the other direction" (Lightman). One major component of general relativity is the equivalence principle. This states that gravity pulling in one direction is equal to the acceleration in the other direction. To give examples of general relativity, demonstrating the equivalence principle, Alan Lightman, a physicist, novelist, and professor at MIT, says that "a car accelerating forwards feels just like sideways gravity pushing you back against your seat. An elevator accelerating upwards feels just like gravity pushing you into the floor."

J.L. Safko, who works for the Univ <span style="font-family: Tahoma,Geneva,sans-serif;"> <span style="font-family: Tahoma,Geneva,sans-serif;">ersity of South Carolina gives two examples that demonstrate separate instances of the existence of Einstein's special theory of r <span style="font-family: Tahoma,Geneva,sans-serif;"> <span style="font-family: Tahoma,Geneva,sans-serif;">elativity an <span style="font-family: Tahoma,Geneva,sans-serif;"> <span style="font-family: Tahoma,Geneva,sans-serif;">d also use the equivalence principle. Both examples involve elevators in different situations. The first example has a person in an elevator <span style="font-family: Tahoma,Geneva,sans-serif;"> <span style="font-family: Tahoma,Geneva,sans-serif;">with no windows. This person wants to find out where they are, so they decide to run a simple experiment. This person drops a coin, <span style="font-family: Tahoma,Geneva,sans-serif;"> <span style="font-family: Tahoma,Geneva,sans-serif;">which falls to the floor of the elevator as expected. Because of these results, the person believes they are on the Earth's surface. However, <span style="font-family: Tahoma,Geneva,sans-serif;"> <span style="font-family: Tahoma,Geneva,sans-serif;">t <span style="font-family: Tahoma,Geneva,sans-serif;"> <span style="font-family: Tahoma,Geneva,sans-serif;">hey could be accelerating far away from any other object, which would produce the same result. His second example also has a perso <span style="font-family: Tahoma,Geneva,sans-serif;"> <span style="font-family: Tahoma,Geneva,sans-serif;">n i <span style="font-family: Tahoma,Geneva,sans-serif;"> <span style="font-family: Tahoma,Geneva,sans-serif;">n an elevator. This time, the person is floating. The person <span style="font-family: Tahoma,Geneva,sans-serif;"> <span style="font-family: Tahoma,Geneva,sans-serif;">drops a coin just as before, except this time the coin floats. These results cause the person to think they are in space far away from any other object. Just as before, there is another explanation that involves relativity. The elevator could be free falling towards the Earth. These two examples may seem far fetched, but both show how relativity is applicable, even in simple situations. Everyone feels the effects of relativity, both in positive ways and in negative ways.

<span style="font-family: Tahoma,Geneva,sans-serif;"> __**How does it affect society?**__ <span style="font-family: Tahoma,Geneva,sans-serif;">

One way people are affected by relativity is through the infinitely expanding universe. The theory that the universe will continually expand would make the temperature gradually colder over time, greatly affecting all people. The idea that the universe will keep expanding came from the big bang theory. Alexander Friedmann thought of this theory in 1922 based on Einstein's general relativity equations. In this theory, Friedmann stated that the universe began as an extremely dense mass at a very high temperature. This will affect "the universe may keep expanding forever, if its inward gravity is not sufficiently strong to counterbalance the outward motion of galaxies, or it may reach a maximum point of expansion and then start collapsing, growing denser and denser, gradually disrupting galaxies, stars, planets, people, and eventually even individual atoms" (Lightman). Assuming this theory is true, a drop in temperature should be expected. Although the change may not be realized overnight, people will eventually notice this overall decrease in temperature, which will affect the lifestyles of many different people from a variety of cultures.

Einstein's theory of relativity also affects travel. The example used in the picture shows a person theoretically traveling from Ithaca, New York to Rome, Italy. The red arrow is their intended path and the blue arrow is the path they will take because of relativity. If this person were to travel walking with one foot directly in front of the other in a straight line from Ithaca intending to arrive in Rome, they would be surprised where they end up. They would arrive nowhere near their destination. This is due to relativity. The reason this occurs is because near huge objects, like the Earth, time and space are curved. Going straight on a map will cause this because it is making something that is three dimensional, the globe, into something that is two dimensional, which will create distortion. Using this idea, Einstein stated that gravity can bend light, which scientists have recently proven with newer technology. Scientists have also found that black holes may exist because of the way light bends due to relativity. Because these scientists have been able to discover that there is a possibility that black holes exist, they are using Einstein's theory to study cosmology and to try to find <span style="font-family: Tahoma,Geneva,sans-serif;">out more information about both the past and the future of the universe. <span style="font-family: Tahoma,Geneva,sans-serif;"> Another common device t <span style="font-family: Tahoma,Geneva,sans-serif;"><span style="font-family: Tahoma,Geneva,sans-serif;">hat is always affected by relativity is the Global Positioning System, commonly referred to as the GPS. Without relativity, the GPS would never function correctly. Global Positioning Systems use time dilation in order to show accurate time readings. Relativity affects time differences between the satellites in space and the GPS device that people have. The GPS is moving, though it is basically stationary since the Earth is so huge, so it will lag behind the satellite clock in space. Because of general relativity, a clock closer to a large object will be slower than a clock far away from the same object. Therefore, the GPS clock on Earth will be faster than the satellite clock in space. As the GPS moves along the Earth, it performs relativistic calculations in order to be as accurate as possible at all times. A GPS on its own without any relativity renders itself useless. The only reason it can give times and distances to any destination is because of Einstein and his relativity.

The infinitely expanding universe, curving of time and space, and Global Positioning Systems are all affected by some aspect of Einstein's theory of relativity, and all of these things have an affect on society. Relativity surrounds everyone, even though they may not actually realize it. It impacts many different aspects of life, including common objects that people use each day. People may not accept or reject the theory of relativity because they do not understand how it works, but it still affects them. Although relativity seems credible, there is still no proof it exists since it is only a theory. Even the big bang theory uses Einstein's principles, but there is not even definitive proof that that is how the universe began. There is not any proof that it does not exist, but it will be interesting to see if anyone can find out more about the theory of relativity or more information to verify its credibility. Until proven otherwise, Einstein's famous theory will continue to live on.<span style="font-family: Tahoma,Geneva,sans-serif;"><span style="font-family: Tahoma,Geneva,sans-serif;">

<span style="font-family: Tahoma,Geneva,sans-serif;"> Works Cited <span style="font-family: Tahoma,Geneva,sans-serif;"> <span style="font-family: Tahoma,Geneva,sans-serif;">  "Curious About Astronomy? The Theory of Relativity." __Curious About Astronomy? Ask an Astronomer__. 25 Sept. 2002. 26 Jan. 2009 <http://curious.astro.cornell.edu/relativity.php>.

The intention of this website is to inform someone on the aspect of Einstein's Theory of Relativity that relates more to cosmology. It gives a summary of relativity and gives some practical applications of it. It also gives a good example of relativity in relation to travel with a picture that really helps in understanding what relativity does. The site has not been updated since 2002, but the information still seems to be credible. Cornell University maintains this site and an astronomer helped write the information.

"General Relativity." __NCSA Web archive bounce page__. 1995. 27 Jan. 2009 <http://archive.ncsa.uiuc.edu/Cyberia/NumRel/GenRelativity.html>.

This website is intended to inform one on Einstein's Theory of Relativity. It is an in depth site that includes information about the Theory of Relativity and, under the Exhibit Map link at the bottom, gives information about Albert Einstein and a time line of Numerical Relativity. Although it has not been updated recently, much of the information is still credible and the links to other sections of the site work well. The NCSA (National Center for Supercomputing Applications), which is used by scientists and engineers throughout the United States, along with the University of Illinois, maintain this site.

Lightman, Alan. "NOVA | Einstein's Big Idea | Relativity (Lightman Essay) |." __PBS__. June 2005. 26 Jan. 2009 <http://www.pbs.org/wgbh/nova/einstein/relativity/>.

The intentions of this site are to inform students about what the theory of relativity is as well as the history of it and how society perceived the universe before this theory. It is a well written site that gives more information than solely what the theory is and how it works. This site is relatively recent, updated in 2005. This information was written previously on another PBS website. This information is on the PBS website and is written by Alan Lightman, a physicist, novelist, and professor at MIT.

"NOVA | Einstein's Big Idea | Genius Among Geniuses |." __PBS__. June 2005. 27 Jan. 2009 <http://www.pbs.org/wgbh/nova/einstein/genius/>.

The site provided the picture above that includes Isaac Newton and Albert Einstein together.

Safko, John L. "Unit 56." __University of South Carolina Astronomy Center__. 1 Jan. 1999. 27 Jan. 2009 <http://astro.physics.sc.edu/selfpacedunits/Unit56.html>.

This site is intended to be used to self teach about the theory of relativity. It is a very detailed site and includes tons of information. However, some parts are slightly confusing because it is inferred that the reader already knows information about Einstein's theory. The has only been updated in 1999, but the information seems to be credible. J.L. Safko, who works for the University of South Carolina, wrote the information on the site. The site gives good examples of relativity in action.

"Theory: Special Relativity (SLAC VVC)." __SLAC Public Website Server__. 31 Oct. 2008. 25 Jan. 2009 <http://www2.slac.stanford.edu/vvc/theory/relativity.html>.

This website's purpose is to inform students and teachers about Einstein's Theory of Relativity. It summarizes the important points of the theory and explains how momentum and energy help make up the equation e=mc². This site was recently updated and the information seems to be accurate. Stanford University as well as the SLAC National Accelerator Laboratory maintain this site. SLAC researches many different aspects of physics, so their information should be very accurate.