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Going FTL ... because the light is not going at c

F

Fritz_Brown

Super Moderator
Well, here is an interesting article about slowing down light. Essentially, with a holey waveguide, they have gotten light to slow to .003c :eek: . They can supposedly slow it more by applying an electric field.

What happens (relativistically speaking) when you slow light? Does it make it easier to achieve c, or does your limit just get lower? If you can crack the lower limit, does it change anything above that? Anyway, discuss amongst yourselves quietly.... :D
 
IIRC the speed limit just gets lower too. C is unpassable in Einsteinian physics ... it is THE limit, no matter hos fast or slow that is.
 
As I understand it, technically speaking you would. They are just so small as to be unnoticeable. Wasn't there an experiment done with two synchronised atomic clocks and a supersonic jet that proved the relativistic effects of travelling at high speed?
 
Cherenkov radiation.

Cherenkov radiation occurs when an object is travelling faster then light. Note that this is not travelling faster then C, just faster then light.

C is the speed of light in a vacuum. The speed of light through other materials is often slower. C is the limit.

See http://en.wikipedia.org/wiki/Cherenkov_effect

So if we were to travel in that tank at 30mph we would experience relativistic effects?
Click to expand...
You experience relativistic effects constantly already. Mostly the effects are too small to measure though. Decent time-dilation and curvature twisting generally only happen >> 0.1 C
 
In terms of the original question: FTL should really be FTC -- relativistic effects occur based on velocity relative to C, not velocity relative to light.
 
A couple of days ago the local TV had a BBC special on a similar issue (speed of light and time travel).

I think the synopsis is here: http://www.bbc.co.uk/science/horizon/2003/timetripqa.shtml

If you can find it it is worth checking out. Specifically the material on how to travel faster then C, and more importantly why this is a bad idea.

Of course travelling faster then C requires bending the universe more then normally allowed.
 
High School physics time.

Light changes speed all the time as it passes through different densities of material - this is what gives rise to refraction.

c is a universal constant, it does not change. It is defined as the speed of light in a vacuum.

A beam of light, wavefront, photon, call it what you will, can be slowed down from c as it moves througha much denser medium, and then it can speed up on entering a less dense medium. It can not ever travel faster than c.

Relativistic effects arise as your speed approaches a significant fraction of c, not a significant fraction of the local speed of light through whatever medium.
I'm sure that I read an article that said scientists somewhere have managed to "freeze" a photon - stop it moving.
 
Hehe ... well, one Aussie scientist reckons he can show Einstein is wrong about relativity, as mentione din this
News.com.au article.
In 2002, Professor Cahill started to question what he thought were anomalies in Einstein's theory that time and space are relative.

"They all agreed with one another and they were all indicating a huge speed difference in different directions," he said. "When you find out the speed of light differs, the whole Einstein theory starts collapsing."
Click to expand...
Any thoughts on that one? The science they mention is beyond me, for example what does "We know now the speed of light at approximately 300,000km per second is relative to space itself - before it was always relative to the observer." mean?
 
Relative speed.

If you are travelling at 0.5 C, light is still travelling past you at C. From your frame of reference the light is still going at C in all directions, and therefore (on paper) is travelling at 1.5 C in one direction and 0.5 C in the other.

From a stationary observer the light is also travelling at C, just as you are travelling at 0.5C.

If you can wrap your head around this (don't worry the headaches are normal) and really like high end math then theoretical physics has a chair waiting for you.

In other words C is the fastest you can observe something. It is also the fastest you can go. The speed of light is dependent on the observer.

Relativity is wrong. That is an easy enough statement, there are places where it breaks down, and these have been observed. Currently we don't have anything better to replace it with.
 
Which is like replacing a good steel knife with a stone axe.

Eventually we will find a diamond edged scalpel.
 
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