Meteorswarm wrote:It seems the most common topic we get repeated questions on is relativity, general and special. Seriously, this thread is stickied and has relativity right in the title. Now it's even in all caps and the first word. So please ask such questions here. Or maybe read some of this thread to see if your question has already been asked and answered. - gmalivuk
Since we seem to see a lot of repeated things in this forum, it might be a good thing to compile simple, fast answers here. If you have a simple "how does this work?" question, this is the place. It is NOT the place to answer questions at length; any question worthy of lengthy response deserves its own thread. If your question involves light, please see the relativity statement below. I'll get the list started with a few things:
Gravity travels at the speed of light, 299792458 meters/second. This has been closely validated with an experiment, but it mostly comes from theory since it isn't easy to measure.
The laws of thermodynamics are very, very true. You cannot get free energy, no matter how nice it would be, and no matter how much science fiction you read.
For everything we know about, including the matter you're made of, we cannot travel faster than, or even at the speed of light. The reason is that as you approach the speed of light, you gain kinetic energy at a much faster rate than you do at low speeds. This is why small particles going REALLY close to c, the speed of light, can pack a lot of energy.
Light does not have (rest) mass. Photons only travel at c through a vacuum.
Light acts as both a particle and a wave.
Incidentally, everything acts as both a particle and a wave. You, me, cars, George Bush.
The big bang was an expansion of space itself, not just stuff within space. This is often hard to visualize.
If your question involves traveling at the speed of light, a light source and an apparent paradox, please read about special relativity, or consider that the speed of light is constant to everybody and derive it yourself. Also, see Sir Elderberry's excellent post on the subject.
Please add your own! Also, if I'm wrong, correct me.
Edit 2008.12.03 added SR response
Edit 2009.04.10 beefed up SR response with the aid of Sir Elderberry, changed topic statement to reflect changed nature of thread - it is actually a place to ask questions you think have a short answer
Not only does matter not travel faster than light, neither does information. No matter how hard you spin those entangled photons.