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Transcript of General Relativity
What is General Relativity?
Einstein concluded that massive objects, such as the sun, cause a distortion in space time, which is felt as gravity.
General Relativity applied...
If a body is set in the center of a trampoline, the body would press down and create a depression in the fabric. If a ball was rolled around the edge of the trampoline, it would be pulled in closer to the body. The same is true for rocks and meteors being sucked in by earth's gravitational pull.
1) Lejuwaan, Jordan. "Einstein’s Theory of Relativity: Explained." High Existence Site Wide Activity RSS. High Existence, n.d. Web. 14 Jan. 2014. <http://www.highexistence.com/einsteins-theory-of-relativity/>.
2) Redd, Nola T. "Fast-Spinning Star Tests Einstein's General Relativity Theory." Space.com. Space.com, 7 Jan. 2014. Web. 14 Jan. 2014. <http://www.space.com/24190-pulsar-gravity-einstein-general-relativity.html>.
3) Overduin, James. "Gravity Probe B." GP-B — Einstein's Spacetime. Standford University, Nov. 2007. Web. 12 Jan. 2014. <http://einstein.stanford.edu/SPACETIME/spacetime2.html>.
In 1905, Einstein completed his theory of special
relativity, bringing forth a new framework for all of
physics. The one factor of physics missing from his
special relativity theory was
worked for 10 years attempting to incorporate
acceleration into his theory. Finally, in 1915, Einstein
published his theory of General Relativity.
When Einstein was a young boy, his father showed him a pocket compass. Einstein was intrigued- he wanted to know how it worked. Following this event, he began building mechanical devices which showed his promising future as a mathematician. Einstein's brother befriended Max Talmud, a medical school student, who would bring Einstein literature on science and mathematics. These were early introductions to math and science for Einstein which led him to further study past grade school. Enrolled in a four year teaching diploma program at Zurich Polytechnic, 17 year old Einstein began falling in love with physics. A few years after graduating, Einstein became employed at the Swiss patent office where his job provoked thoughts that led him to conclusions about the fundamental connection between space and time. These thoughts contradicted Newton's laws of gravitation related to light which encouraged him to explore his conclusions more deeply.
4) Possel, Markus. "The Wave Nature of Simple Gravitational Waves." — Einstein Online. Max Planck Institute for Gravitational Physics (Albert Einstein Institute), 2006. Web. 15 Jan. 2014.
General Relativity Applied Cont.
Expanding on the trampoline analogy, picture our solar system. All of the planets revolve around the sun. Why? Because the sun is heavier than the individual planets. Therefore, the sun creates a dimple in the space fabric of our solar system causing the planets to be pulled inward towards and revolve around the sun.
Nearly every instance in which masses are accelerated causes a distortion. This distortion radiates away from the original site of disturbance at the speed of light in a wave-like pattern. The wave is a result of rhythmic shrinking and stretching of distances and is caused by the disturbance.
Gravitational waves have not yet been directly detected. There is hope that neutron stars orbiting each other, a black hole, or two black holes orbiting one another nearby might create a gravitational wave strong enough for us to detect.
5) Jones, Andrew Z., and Daniel Robbins. "Einstein's General Relativity Theory: Gravity as Geometry." Www.dummies.com. Wiley, n.d. Web. 15 Jan. 2014.
Gravity & Light
Light is deflected by gravity. Light traveling past a massive body is bent toward the mass. The closer the light is to the mass as it passes, the more it is bent. Because of this, the location of a star in the night sky as it appears to us is actually just the direction from which the star's light reaches us. Einstein's predictions about this deflection of light were verified by the results of two British expeditions during a solar eclipse in 1919 where nearby stars were photographed from two separate locations and compared.
Light can be deflected by masses in a way that causes us to see multiple copies of the same distant object.
One star that, instead, appears as four.
Mercury's orbit is unlike any other planets'. Every century its point of precession (the closest point to the sun) changes. It shifts by 5600 seconds of arc every century (about 1.5556 degrees).
6) Bobby's Dad - Kevin Coulter - Physicist
Newton calculated that the precession should be 5557 seconds of arc, that leaves an extra of 43 seconds of arc, not a huge amount but it was still not exact. He and other scientist tried multiples times of factoring different variables and possible dust around Mercury but none gave the correct answer.
When Einstein came up with the theory of general relativity, he calculated that newton's calculations were off by 43 seconds of arc per century, should his theories be correct .
The same is true of light that passes near black holes. Because black holes have such strong gravitational pull, the light rays of an approaching star can become trapped. Light that approaches from a greater distance is still warped, creating the illusion of two separate light sources.
More modern science has calculated that the shift is in fact 5600, proving Newton's theories incorrect and that Einstein's theory is correct, while also showing how precise general relativity can be.
In the photo above there are two galaxies that are in line with each other and the earth. The light for the the far galaxy is being bent by gravitational lensing of the close galaxy, this is what is creating the blue ring. This is also what is present in double stars around black holes.