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Technology Page: Relativity |
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Imagine a world
where you:Well, guess what: All these things are true!!!(sort of)Welcome to the bazaar world of relativity.
The Theories of Relativity are 2 theories in physics that Einstein created in order to explain how Space-Time is distorted. These two theories are Special and General Relativity. Special Relativity, the first, was created to explain how space and time is distorted by the speed of an object. General Relativity was created to explain gravity as an effect of the Space-Time distortion caused by the presence of matter. The theory covered in this section is the special theory, and We will not cover General Relativity.
Space-time is a concept that Einstein developed in order to explain why certain properties of time are dependent on other properties of space. Instead of treating space and time separately, Einstein found that they naturally fit together to form a simpler equation. If space and time were not related, there could be no Theory of Relativity.
Special relatively is the theory of how many properties of an object are affected by its speed. For example, as an object its faster, several things happen:
- Time starts to move slower
- The object's mass increases
- The object's length decreases (in the direction of movement)
- The kinetic energy of the object increases.
The fact that so many properties of the object were related to its velocity was what made this theory very revolutionary. Also, this theory dictated that no objects could ever reach the speed of light, because if it did:
- Time would stop for that object
- The object's size would decrease to nothing
- The object's mass and kinetic energy would become infinite
And obviously, all these effects are either hard or impossible to do. Therefore, the only known things that can travel at the speed of light are photons, the particles that make up light. These laws, and there affects, are needed to show why the speed of light is constant, no matter how you are moving.
The speed of light does not depend on how fast or slow the person measuring it is going. For example, say there are two people, Jack and Jill, measuring the speed of a light beam.
- Jack is on a planet, emitting a laser beam and measuring its speed.
- Jill is on a space ship moving in the same direction as the light at half the speed of light.
- Common sense tells you that she should measure the speed of light as going half as fast as Jack measured it, right?
- Because of time dilation, time movers twice as slow for Jill as for Jack.
- Therefore, to Jill, everything outside her space ship (including the light beam) seems to move twice as fast!
- Therefore, both Jack and Jill measure the light as going at the same speed!
For any object experiencing
relativistic effects, its properties follow these equations:
Variables
Property |
At rest |
Relativistic |
| Length | l |
L |
| Time(1 sec.) | 1 |
T |
| Mass | m |
M |
| Energy | mc2 |
E |
| Speed of light | c |
c |
Example: If you support JavaScript, fill in info below and click "Calculate!"
Note: Use any units you want, and the answers will be in the same units. Only enter whole numbers or decimals!! For example, if I am 1.92 meters tall, I would enter 1.92, and not 1.92m!
If the Theory of Relativity was not true, then there would be no nuclear reactions, no atom bombs or stars, and thousands of experiments inside particle accelerators would not turn out the way they did. Inside particle accelerators, where they experiment with particles at velocities near the speed of light, they can measure the increase in mass of a particle. This increase is always exactly what relativity predicts. Another experiment which has helped prove relativity was where two atomic clocks were synchronized, and one was taken on several long jet rides. When the two clocks were compared, they were off each others time by a few billionths of a second - exactly what relativity had predicted!
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