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The year is 1905. Over the past decades, both Isaac Newton and Aristotle have pretty much revolutionizedphysics, but...one man revolutionized it all over again. That man is the now-famous German scientist Albert Einstein. Although Einstein is remembered for a number of discoveries, his most well-known one may be the confusing but fascinating Theory of Relativity.

That fateful year, 1905, marked the moment when Albert Einstein proposed his theory. Back then, his statements stirred much controversy and discussion in the scientific world as they still do now. Today, however, through multiple experiments and examinations, Einstein's ground-breaking Theory of Relativity has been mostly accepted and plays an important role in science.

Now, before we jump in into how the Theory of Relativity has been proven, it would be nice to know a little about the theory.
 * Background Information **

In the late 19th century, Newton's theories were used predominantly. According to Newton, space and time are always the same regardless of location and position; thus a minute is a minute anywhere and a mile is a mile (Schonbert, James). However, in the 1890s, two scientists by the names of **Michelson and Morley** conducted an experiment (now known as the Michelson-Morley Experiment) in which they discovered that the speed of light is always the same (James). Because the speed of light was constant, this disproved Newton's previous theories (Choo, Debbie).

Although the Michelson-Morley Experiment did not follow Newtonian physics, Einstein proposed the Theory of Relativity which explained this phenomenon. The Theory of Relativity is usually broken into 2 parts: special relativity and general relativity. Special relativity deals with inertial frames of reference, while general relativity explains motion and gravity (James).

Einstein also brought forth a new idea in which time is the fourth dimension. A combination of the fourth dimension and the other 3 spacial dimensions is called the s**pace-time co****ntinuum** (James).

**The Precession of Perihelion **Mercury's orbit around the sun has been found to change over time. The precession of Mercury's orbit is supposed to be around 5600 seconds of arc per century; however, that figure is off by an additional 43 seconds of arc per century (Wudka, Jose). This extra time was accurately calculated by Einstein through his Theory of General Relativity (Wudka).     The equation used came from such characteristics of relativity like **time dilation** (as one gets closer and closer to the speed of light, time passes slower) and mass changes due to velocity (Forster, Malcom). Although Kepler's equations from Newton's theories are similar to Einstein's new relativistic equation, Einstein's was proved to be more accurate (Forster). <span style="font-family: 'Comic Sans MS', cursive;"><span style="color: rgb(26,107,20);"> <span style="color: rgb(26,107,20);"> <span style="font-size: 110%; font-family: Arial, Helvetica, sans-serif;"><span style="font-family: 'Comic Sans MS', cursive;"><span style="color: rgb(26,107,20);"> <span style="color: rgb(26,107,20);"> <span style="font-size: 110%; font-family: Arial, Helvetica, sans-serif;"><span style="font-family: 'Comic Sans MS', cursive;"><span style="color: rgb(26,107,20);">The Precession of Perihelion was recently demonstrated again in an experiment involving a **binary pulsar system** conducted by scientists from McGill University. In such a gravitational field, the orbiting pulsar would change its direction slightly according to Einstein's Theory of Relativity (Einstein was Right, Astrophysicists Say). After four years of research, the scientists from McGill concluded that Einstein, was indeed, correct  <span style="font-size: 110%; font-family: Arial, Helvetica, sans-serif;"><span style="color: rgb(26,107,20);">.<span class="Apple-style-span" style="font-size: 13px; color: rgb(0,0,0); line-height: 19px; font-family: arial;">
 * <span style="font-size: 190%; color: rgb(72,0,255); font-family: 'Courier New', Courier, monospace;">The Acceptance of Einstein's Theory of Relativity **

<span style="font-size: 110%; font-family: Arial, Helvetica, sans-serif;"><span style="color: rgb(26,107,20);"><span class="Apple-style-span" style="font-size: 13px; color: rgb(0,0,0); line-height: 19px; font-family: arial;"><span class="Apple-style-span" style="font-size: 14px; color: rgb(219,32,26); line-height: 21px; font-family: 'Arial Black', Gadget, sans-serif;">Pulsar Test from University of Manchester<span class="Apple-style-span" style="font-size: 13px; color: rgb(0,0,0); line-height: 19px; font-family: arial;"> <span style="font-size: 110%; font-family: Arial, Helvetica, sans-serif;"> <span class="Apple-style-span" style="font-size: 14px; line-height: 21px; font-family: 'Arial Black', Gadget, sans-serif;"> <span style="font-size: 110%; color: rgb(132,42,42); font-family: 'Palatino Linotype', 'Book Antiqua', Palatino, serif;">A 2006 research team observed a binary pulsar for three years to look at Einstein's Theory of General Relativity. They discovered three things which supported the theory: > <span style="font-size: 110%; color: rgb(132,42,42); font-family: 'Palatino Linotype', 'Book Antiqua', Palatino, serif;"> > <span style="font-size: 110%; color: rgb(132,42,42); font-family: 'Palatino Linotype', 'Book Antiqua', Palatino, serif;">
 * <span style="font-size: 110%; color: rgb(132,42,42); font-family: 'Palatino Linotype', 'Book Antiqua', Palatino, serif;"> **Gravity Redshift:** time dilation caused the pulse rate of one pulsar to slow when close to the other (thus proving that time does not have to remain constant). When a pulsar is closer to its companion pulsar's gravitational field, the pulsar clock (pulsing) slows, which Einstein observed ("General Relativity Survives Grueling Pulsar Test: Einstein At Least 99.95 Percent Right").
 * <span style="font-size: 110%; color: rgb(132,42,42); font-family: 'Palatino Linotype', 'Book Antiqua', Palatino, serif;"> **Shapiro Delay:** "The pulses from one pulsar when passing close to the other are delayed by the curvature [as discussed by Einstein] of space-time" ("General Relativity Survives...").

<span class="Apple-style-span" style="font-size: 14px; color: rgb(105,118,236); line-height: 11px; font-family: 'Arial Black', Gadget, sans-serif;">
 * <span style="font-size: 110%; color: rgb(132,42,42); font-family: 'Palatino Linotype', 'Book Antiqua', Palatino, serif;"> **Gravitational Radiation and Orbital Decay:** Because of the radiation from gravity, the two pulsars lost energy.

<span style="font-size: 110%; color: rgb(27,25,215); font-family: 'Arial Black', Gadget, sans-serif;">Gravitational Lensing <span style="font-size: 110%; color: rgb(27,25,215); font-family: 'Arial Black', Gadget, sans-serif;"> <span style="color: #ffffff; font-family: Tahoma, Geneva, sans-serif;"> s Gravitational lensing describes the bending of light due to gravity warping space (usually found near a massive object with a gravitational field). The light then follows this "curving of space-time ("Bending Light").  <span style="color: #ffffff; font-family: Tahoma, Geneva, sans-serif;"> <span style="color: #181098; font-family: Arial, Helvetica, sans-serif;"> <span style="color: #181098; font-family: Arial, Helvetica, sans-serif;">An example of bending light would be a black hole, in which gravity is so strong that not even light can escape - the gravity of the black hole pulls light toward it (Reiter, Austin). A black hole would support Einstein's Theory of Relativity, specifically the space-time continuum because time appears to slow down near a black hole. <span style="color: #181098; font-family: Arial, Helvetica, sans-serif;"> <span style="color: #181098; font-family: Arial, Helvetica, sans-serif;"> <span style="color: #181098; font-family: Arial, Helvetica, sans-serif;">Gravitational lensing also explains how gravity can behave like a lens, distorting and magnifying deep sky objects ("Einstein's Lens"). <span style="color: #181098; font-family: Arial, Helvetica, sans-serif;"> <span style="color: #181098; font-family: Arial, Helvetica, sans-serif;"> <span style="color: #0c2ba1; font-family: Arial, Helvetica, sans-serif;"><span style="font-size: 120%; color: #290ca6; font-family: Georgia, serif;"><span style="font-size: 110%; color: #080ba0; font-family: 'Lucida Console', Monaco, monospace;"><span style="color: #1017b1; font-family: Arial, Helvetica, sans-serif;">    Scientists can use clusters of galaxies which pull light in as a sort of lens to see those galaxies that (without the light) could not otherwise be detected ("A Gravitational Lens..."). <span style="color: #0c2ba1; font-family: Arial, Helvetica, sans-serif;"><span style="font-size: 120%; color: #290ca6; font-family: Georgia, serif;"><span style="font-size: 110%; color: #080ba0; font-family: 'Lucida Console', Monaco, monospace;"><span style="color: #1017b1; font-family: Arial, Helvetica, sans-serif;">

Based on later observations of Einstein's Theory of Relativity, such as the Precession of Perihelion, the pulsar experiments conducted at the University of Manchester, and gravitational lens, this confusing but fascinating theory has become accepted by much of the scientific world. In the future, researchers will be sure to use Einstein's theories in exploring a plethora of "the unknown," from the minuteness of a photon to the deep outer reaches of space.
 * <span style="font-size: 120%; color: rgb(235,145,36);">In Closing... **

WORKS CITED Choo, Debbie. "Michelson-Morley Experiment." University of Victoria. 4 Feb. 2009 <[|http://visav.phys.uvic.ca/~babul/ASTRO/DebbieC/mme.html]>. <span style="color: rgb(29,105,27); font-family: Arial, Helvetica, sans-serif;"> <span style="color: rgb(29,98,48); font-family: Arial, Helvetica, sans-serif;">This site provided a quick and easy explanation of the Michelson-Morley Experiment, complete with a flash demonstration and diagrams. It explained in easy terms how it applied to Einstein's Theory of Relativity. It was also a very credible site because it came from the University of Victoria, and the goal of the site (as a whole) is to educate students. "Einstein's Lens." Harvard University. 3 Feb. 2009 <http://www.cfa.harvard.edu/seuforum/einstein/resource_lensing.htm>. <span style="color: rgb(12,106,24); font-family: Arial, Helvetica, sans-serif;">Run by the Harvard-Smithsonian Center for Astrophysics, the website provides a lot of information on findings, particularly in astronomy and physics (of course). This short explanation on the above web page provided an easy to understand look at gravitational lensing. It described in simple terms how scientists can use this concept to identify deep sky objects and how it applies to cosmology today, from extra-solar planets to the amazing concept of dark matter. "General Relativity Survives Grueling Pulsar Test: Einstein At Least 99.95 Percent Right." Science Daily. 2 Feb. 2009 <http://www.sciencedaily.com/releases/2006/09/060914094623.htm>. <span style="color: rgb(13,119,17); font-family: Arial, Helvetica, sans-serif;">The site's goal is to publish scientific findings online and provide access to the public. This article provided by ScienceDaily offered much information on the binary pulsar system experiments and observations and provided detailed explanations of what the results mean for physics and the rest of the scientific world. Reiter, Austin. "Gravitational Lensing and Dark Matter." American Museum and Natural History. 4 Feb. 2009 <http://www.haydenplanetarium.org/resources/avaa/tags/universe>. <span style="color: rgb(20,107,32); font-family: Arial, Helvetica, sans-serif;">The site is operated mainly by the Hayden Planetarium and provides a lot of information on gravitational lensing. The page is sprinkled with videos and is organized neatly into different sections. The text explains the videos and also discusses black holes and how gravitational lensing works in giving scientists more information. Richmond, Michael. "Gravitational Lensing Theory." Rochester Institute of Technology. 3 Feb. 2009 <http://spiff.rit.edu/classes/phys240/lectures/grav_lens/grav_lens.html>. <span style="color: rgb(22,96,27); font-family: Arial, Helvetica, sans-serif;">This website provides many links to other websites and also explains gravitational lensing with many simple diagrams and how gravity can change the path of light. It also tells how galaxies can act as lenses and how that concept can change the way we view space. Schonbert, James. "Relativity." University of Oregon. 2 Feb. 2009 <http://abyss.uoregon.edu/~js/21st_century_science/lectures/lec06.html>. <span style="color: rgb(17,111,22); font-family: Arial, Helvetica, sans-serif;"> <span style="color: rgb(17,111,22); font-family: Arial, Helvetica, sans-serif;">This site provides a treasure trove of easy to understand images, diagrams, and explanations, including time dilation and twin paradox diagrams. The site is run by Prof. Schombert, a professor and astronomer at the University of Oregon. On his homepage, links to his research and other lectures are provided. This site is credible because it gives facts, not opinions and is written by a professor at a credible institution. It also gives information on other viewpoints/experiments, including Newton's observations and the Michaelson-Morley experiments. <span style="font-family: Arial, Helvetica, sans-serif;"><span style="color: rgb(14,18,205); font-family: 'Comic Sans MS', cursive;">Wudka, Jose. "Precession of the Perihelion of Mercury." University of California, Riverside. 4 Feb. 2009 <  <span style="font-family: Arial, Helvetica, sans-serif;"><span style="color: rgb(14,18,205); font-family: 'Comic Sans MS', cursive;">http://physics.ucr.edu/~wudka/Physics7/Notes_www/node98.html>. <span class="Apple-style-span" style="color: rgb(0,15,255); font-family: 'Comic Sans MS';"> <span class="Apple-style-span" style="color: rgb(16,132,45); font-family: Arial, Helvetica, sans-serif;">This site explains the Precession of Perihelion of Mercury and provides statistics, a picture, and an explanation of how Einstein's theory plays into the changing orbit. It also explains how something was missing from Newton's equations until Einstein came along and provided a more accurate value with his new formulas. Wudka is a professor at the University of California, Riverside.