Thread: Let's talk about light!

Speed of light broken:

http://www.newscientist.com/article.ns?id=dn2796

Scientists slow down the speed of light:

http://abcnews.go.com/Technology/story?id=99111&page=1

Scientists explain how time travel is possible:

http://abcnews.go.com/Technology/Story?id=98062&page=3

DISCUSS.

Just to clarify for the less informed:

- Noone is actually making information or matter go faster than c in that first experiment. It's just the group velocity of a series of electrical pulses. This trick is sort of like shining a very powerful laser pointer at a wall a long way away, and flicking your wrist. The dot on the wall will appear to move faster than c, but you aren't transmitting information faster than c.

- When they say 'the speed of light' in the second article, they mean, literally, the speed of light in a particular substance (in this case, sodium). c stays the same, they just make the light itself travel at lower speeds. The atmosphere does this all the time, as light travels faster in a vacuum than through air.

-The last article is an opinion piece, and is highly speculative. However, it is true that under GR (or SR, for that matter), if you can get information to a point in spacetime ouside your light cone, under the right conditions, you can talk to the past (this breaks causality, obviously).

Time-travel theories are pretty extremely hypothetical as of now. So. Yeah. Little to say about that. It might in theory work in accordance with the laws of relativity. But hey. It might also not work. Singularities and worm-hole shit are a bitch.

As for speed of light. It is speed of light. It is awesome.

There is no real reason to think Einstein is wrong, at the moment. Besides that, light is awesome. Especially strobe-lights that make everything look funky.

Darkness is faster, light can never catch up!