Relativity
Re-thinking the Cosmos
In 1904, Einstein was reading one of James C. Maxwell's journals, when he noticed a disagreement with Isaac Newton about light. Maxwell deemed that light was an electromagnetic wave traveling at a fixed speed. Newton, however, deemed that light’s speed is not fixed, but fluid like accelerating and decelerating often. Einstein loathed disagreement in science. He believed that physics should be a set of laws that were simplistically explained with perfect correspondence. Einstein would work until his very last days if he had to solve this vision dispute.
For many months, Einstein worked to sort Newton and Maxwell out. Finally, through (shown left) a thought experiment, he figures it out. Einstein realizes that time simply means to be simultaneous to the clock. If he ate lunch at 12:30 that simply meant that when the clock struck 12:30, he ate lunch. The flow of time is different for a moving observer compared to a stationary one, he deems. A man is standing on a train platform, Einstein thinks, suddenly, two lightning bolts strike, each six feet apart and parallel to the man. Since the man is standing directly between them, the light from each bolt reaches his eyes at the same time- simultaneously. However, to the women standing on the train to the left of the man, the light from the leftmost lightning bolt reaches her eyes before the light from the rightmost- sequential. This would imply that the passing of time is entirely relative. No definite position in space or time can be the same to all onlookers.
Not believing it himself, Einstein tries another thought experiment. He imagines a photon clock (shown top right), counting time as a factor of every time a photon (or beam of light), trapped between two mirrors, hits the top mirror. The clock now begins to move, forcing the photon to take a longer, diagonal path between the mirrors making the clock tick slower. If an observer was sitting on one of the mirrors, it would appear to be moving slower because, since it's moving away, it takes more time for photons to reach our eyes. The observer would also see us and our stationary clock=as moving slower as well for the same reason.
Using his results, in 1905, Einstein published an article explaining his new theory. It was vigorously ignored and the few people who read it ridiculed Einstein. Finally, in 1907, a man named John Stark took notice. He planned to have Einstein to his house to refine and go over the theory. Einstein was overjoyed. Immediately he picked up his pen started looking over the theory once again. It was then that he added acceleration and things began to piece together. He imagines an unmoving man is floating in a box in zero gravity. Suddenly he falls to the floor. What happened? It could be that the box came into the orbit of a planet and gravity is pulling him down. Or it could be that a superhuman had attached a string to the top of the box and is pulling (accelerating) the box upward, the floor rising to him instead of him falling to the floor. Even if he had all the scientific instruments in the world, the man can not know what caused him to fall. Acceleration and gravity are the same things.
Special Relativity
Special Relativity essentially states that the faster you travel, the slower time space and time are for you. If you were traveling 300,000 km/second (light speed) in a super fast rocket ship, time and space would change around you. For all onlookers, you'd be frozen unmoving in time with an infinitely condensed length. When an object with mass travels celeritas (the speed of light), time and space slow to a stop for that person. One would not reach their destination until the universe condensed beyond them, not moving an inch until the end of space and time itself. However, oddly the person would not feel the time distance, blasting off and in a matter of seconds, they would reach their destination. These the speed and its corresponding time dilation can be represented with the equation time dilation = stationary time over the square root of one minus velocity squared over celeritas squared and
is graphed to the left. The length contraction of an object with motion can be represented with the equation length = the length when not moving root of the inverse of the velocity squared over celeritas squared. Rockets moving different speeds (as a factor of celeritas) and their associated contractions are shown right.
General Relativity
General Relativity is slightly different from Special Relativity as General Relativity add another factor: spacetime. General Relativity states that without matter, no time would pass and there would be no space- a nothingness, but when matter exists, spacetime must also exist, warping around the mass in what many call gravity. Imagine a rubber sheet (shown left) in which a person drops a ball onto. Now another ball is dropped onto the object. Now, this sheet is doubled upside down, pulling on the second ball both ways.
The ball now begins to orbit this is Einsteinium gravity, still governed by Newtonian laws, but a bit different. and that is what creates General Relativity.
At the time Einstein was teaching as a professor of analytical physics and thermodynamics at the Swiss Federal Institute of Technology in Zurich (ETH Zurich) but was still struggling to piece together his theory. And that was when he learns about spacetime, a highly skeptical concept suggested by philosopher, Eugène Minkowski. Einstein thought of spacetime in the following thought experiment.
A camera is filming a pair of dice capturing each moment (as in every possible division of time) as a single time frame. Now, the camera man takes out the reel and stacks each separate image on top of each other, compiling them into one big 3D picture that shows both space and time elapsed into a fluid- the spacetime continuum. With this in mind, Einstein realized that spacetime is the very atmosphere that his theory should take place in.
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Now Einstein had decided that he needed to simplify his theory into one, basic equation. He visited his friend Marcel Grossman, the chairman of the math department at ETH. After hours of speaking with Marcel Grossmann, Einstein realized that to ever explain spacetime to the general public, he’d need to give it a shape, a built they could relate to. Einstein realizes something through another simple thought experiment (shown right): The universe is flat and empty. No time passes and there is no space. Then, two objects appear, a planet and a moon. The smaller moon falls into the planets spacetime warp and begins to orbit. This shows, Einstein realized, that the curved motion between spacetime gravity. Which, in the science world, would mean there is nothing actually pulling matter down, but that spacetime offers a path downward, and, being that the matter is real, it is forced to take it. The only thing that can stop it is another object. Spacetime, Einstein realized, is shaped by matter.
Einstein goes to famous mathematician, David Hilbert to review progress, but then Hilbert decides to steal Einstein’s theory and
finish it on his own and a race to the finish begins. Meanwhile, on four days during the November of 1915, Einstein is scheduled to present his theory. This he would do in a manner that was precisely his style, coming back each week, telling what was wrong in the last lecture, and then beginning on that week's findings. Twas, Nov. 24, the night before the fourth and last presentation, that Einstein finally found his mark. In just one night, Einstein compiled 15 years of work into one simple equation: G=8GC4T. G for Gravity, the shape of spacetime, and T for the energy distribution. Both of which were fairly simple. Perhaps the most amazing part of this equation was the simple = that combined the two worlds. Yes, worlds. The left side full of geometry and mathematics, while the right side full of matter, physics, and movement. This link creates spacetime, matter (the right side) telling spacetime to bend towards it, while spacetime (the left side) telling matter to move, to orbit. Einstein told this to the attendees of the final presentation and it had a very controversial effect. Some agreed with awe, while others protesting in disgust. But Albert Einstein had one way to prove his 15 years of work. If the theory was correct, light from distant stars would bend around the sun, due to its large mass, and hit Earth. On May 29, 1919, there would be a total solar eclipse over parts of Brazil and southern Africa. Coincidentally, the incredibly bright Hyades Star Cluster would be passing directly behind the sun that same day. Einstein predicted the light would be warped all the way around the sun and hit Earth, making it appear that the cluster was to the side of the side as shown left.
Thus, on May 22, 1919, English astronomer, Arthur Eddington, with a crew of about 50 other astronomers traveled to Principe, an island in Africa, to view the theory during the solar eclipse that was to occur. On May 29th, the team of astronomers took photos of stars during a solar eclipse when the sun's effects would be most visible. They compared them with photos taken by Eddington in the previous months. The results were detrimental. The stars had shifted significantly (as shown below). On November 16, the astronomer published the results and Einstein became known as one of the greatest physicist of all time.