Theory of relativity:Special Relativity and General Relativity

By: Tomas Bayas and Sebastian Naranjo

What Does it State

• The theory of relativity encompasses two theories within that are called the Special Relativity and General Relativity Theories. They both have different components that make up that Theory of Relativity as a whole.

• According to the theory everything can be relative with a few exceptions.

Discovery

• In the year 1687 Isaac Newton published a paper where determined his Theory of Gravitation.

• In it he stated that “The forces which keep the planets in their orbs must reciprocally be the squares of their distances from the centers about which they revolve”

• The theory worked quite well and even lead to the discovering of Neptune but there was a flaw.

• The theory couldn’t pinpoint accurately the orbit of Mercury and there were no explanations for this.

• Nearly 200 years later Einstein managed to discover what was wrong. Through his Theory of Relativity, which was published in 1905, he determined that the laws of motion determined by Newton were correct except when velocities reached the speed of light

• In his Theory of General Relativity, published in 1915, he determined that the Law of Gravitation proposed by Newton was also almost correct except that he determined that in the presence of strong gravitational fields, things changed, hence the orbit of Mercury couldn’t be determined before.

• Prior to Einstein discovery space and interactions that occurred in space where seen in a very different way and he provided a gateway to understanding interactions in space.

Description of General Relativity Theory

• This part of the theory addresses gravity• It considers gravity as a geometric property in

spacetime.• An object with mass can “curve” space and

create an orbit so nearby objects follow that path.

• According to Einstein gravity can curve space and time.

Description of Theory of Special Relativity

• This is a special case because it refers only to the possibility when two objects are moving at constant speeds relative to each other.

• The Special Relativity Theory states:– The laws of physics are the same for objects

moving at constant speed frames of reference.– Speed of light is constant in a vacuum regardless

of the motion or speed of the observers.

Spacetime

• We normally consider that there three dimensions in this world but Einstein’s work allowed to determine there is a fourth dimension which is spacetime; the combination of time and space into one interwoven continuum.

• Time cannot be separated from the dimensions of space because it depends on the velocity of an object and as already stated velocity (as well as other measurements) is relative.

Example of General Relativity

• Imagine you can set a large body in the middle of a trampoline. The body would press down and alter the surface causing a hole. If you place a marble on the edge of the trampoline it would approach the large body.

• This is similar to the force a planet can exert on a rock in space, bending the spacetime.

Impact on Society

• Even today the relativity theory plays its main role in the astronomical domain

• It helped to understand black holes, gravity waves and cosmic big bangs.

• Theorists have been using general relativity with other interactions, using concepts such as branes and string that are actually helping to prove the modern theories such as strings theory.

• Relativity plays a major role in a multi-billion dollars industry centered around Global Positioning system (GPS).

• Besides all the military uses, GPS is finding applications in airplane navigation, oil exploration, wilderness recreation, bridge construction, sailing and many more.

• To determine its location, the GPS receiver uses the time at which each signal from a satellite was emitted.

• This together with the speed of light the distance between the receiver and the satellites can be calculated.

• As the orbit of each satellite is known accurately, with this it is a simple geometry problem to compute the receiver’s location, both in space and time.

Bibliography

• Arora, Hans. "Helix Magazine." Einstein's Theory Of Relativity: Implications Beyond Science? N.p., 20 Oct. 2008. Web. 28 Feb. 2014. <http://helix.northwestern.edu/article/einsteins-theory-relativity-implications-beyond-science>.

• O’Connor, J J and Robertson, E F. "General Relativity." General Relativity. N.p., n.d. Web. 02 Mar. 2014. <http://www-groups.dcs.st-and.ac.uk/history/HistTopics/General_relativity.html>.

• Perkowitz, Sidney. "Relativity (physics)." Encyclopedia Britannica Online. Encyclopedia Britannica, n.d. Web. 02 Mar. 2014. <http://www.britannica.com/EBchecked/topic/496904/relativity>.

• Unknown. "The Equation That Changed The World | Quantum Science Philippines." The Equation That Changed The World | Quantum Science Philippines. N.p., n.d. Web. 02 Mar. 2014. <http://www.quantumsciencephilippines.com/69/the-equation-that-changed-the-world/>.

• Williams, Clifford M. "Einstein's Relativity and Everyday Life." Physics Central. N.p., n.d. Web. 02 Mar. 2014. <http://physicscentral.com/explore/writers/will.cfm >.

• Zimmerman Jones, Andrew and Robbins, Daniel. "Einstein's Special Relativity." - For Dummies. N.p., n.d. Web. 01 Mar. 2014. <http://www.dummies.com/how-to/content/einsteins-special-relativity.html>.

• Background pictures taken from Google Images, “Relativity-google search”. Web. 02. Mar. 2014. https://www.google.com/search?biw=1366&bih=667&noj=1&tbm=isch&oq=+relativity&gs_l=img.3..0l10.105340.106076.0.106517.8.4.0.0.0.1.175.409.2j2.4.0....0...1c.1.36.img..5.3.296.WjFFu-AilV8&q=relativity