Quote:
Originally Posted by 12clicks
Yeah, I keep hearing that from guys unable to explain themselves.
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Here is an explanation:
The speed of sound can change, while the speed of light can never change. If you're driving in a car and you yell at someone in front of you, the sound waves are traveling at the speed your car is + the speed of sound. So relative to someone standing on the road as you go by, that sound is travelling at faster than the speed of sound.
The same doesn't apply to light, so when you're in a car and you turn on the lights, the light is still going the speed of light and not the speed of light + the speed of your car.
If I'm traveling towards sound, that sound is going to reach me going faster than it normally would be at rest. But if I'm travelling towards light, the light is reaching me at the same speed as it would if I were at rest.
So if I wanted to jump in a spaceship and travel towards a planet at faster than the speed of light, I'm going to arrive at the planet and see things that happened before I even left, since I'm travelling at faster than the speed of light.
Time travel happens more going the other way, future travel, where the closer to the speed of light you go the more time changes and five minutes for you might be hundreds of years for someone at rest relative to you.