KristenM

The theory of relativity explains that space and timeare relative because absolute motions is undetectable, the experiments with an electromagnetic wave that have been conducted, and there is no absolute rest frame and absolute velocity to tell you when you are moving and when you are at rest.

Background Info: The theory of relativity was created in the 20th century by Albert Einstien. His theory explained many of the problems in physics and astronomy of his day. The theory of relativity explained that space and time are relative because there is no way to tell when someone is moving and when they are standing still.

Due to the fact that there is no absolute rest frame and no absolute (constant) velocity there is no way to tell when something is moving and when it is at rest. He also states that "when two frames of reference are moving with a constant velocity that are realtive to each other they should have the exact same physical behavior." (Stern) Both frames can be chosen as a reference bench mark because everything is relative. In the 19th century the laws of electricity and magnetism were discovered. These suggested that light is an electromagnetic wave. With this they believed that electromagnetic forces would be able to distinguish if something was in motion or not. Due to subtle effects made this theory hard to distinguish. When his thoery was tested they confirmed taht ther is no way to tell wheter and object is in motion or not. Absolute motion at a costant velocity is undetectable no matter what process is used. There is no loopholes in this process. This is a picture taken by the Hubble Telescope of the galaxy cluster Abell 2218, which shows a demonstration of gravities ability to bend light, which was predicted by the theory of relativity. "The bright, massive galaxies in the cluster act like optical lenses, bending light from more distant galaxies into the faint arcs and rings visible in this picture." (Stern)

"Suppose you are in Ithaca, New York and want to travel to Rome, Italy, which is approximately due east of Ithaca and a quarter of the way around the globe. You might think the best way to get there is to start off heading east and keep going straight until you reach Rome, as shown in the red path on this map. In fact, though, if you start off heading east and continue to go straight, carefully putting one foot in front of the other, you will wind up taking the blue path; by the time you're as far east as Rome, you'll be somewhere in western Africa, near the equator! (If you don't believe this statement, try it out with a globe and a piece of string. Stretch the string tight so that it is forced to be straight, then place it east-west across New York. The rest of the string will pass through Africa and cross the equator, just like the blue path in the above map. What's going on here? Nothing too complicated, really. As we all know, the surface of the Earth is round, but when we try to represent it on a two-dimensional map we have to "flatten" it out. In the process of this flattening, it turns out, things get screwed up, and some lines which are actually straight (like the blue path) look curved, while some lines which are actually curved (like the red path) look straight. According to Einstein, the same thing happens near a massive object, only the curvature happens to something that has four dimensions (the space we live in plus one dimension of time) rather than two dimensions (the surface of the Earth). Space and time near a massive object are "curved," but we are unable to perceive this directly since we are limited to seeing things in three dimensions. Our brains therefore assume that space is flat, and in the process of making this assumption, things get screwed up. Objects which are actually moving along straight lines appear, in the "map" we construct inside our heads, to be traveling along curves and to be pulled by the massive object nearby." (Stern) "The Theory of Relativity." __Curious About Astronomy? Ask the Astronomer.__ 10 Feb 2009 .

Stern, David. "The Theory of Relativity." __From Starships to Stargazers__ 10 Feb 2009 .