If time is relative to the speed of light, then how does that apply to slowed light?

Question

Scientists have been able to slow light down to speeds of less then 40 miles per hour, are there any applications of this regarding the theory of relativity? Would this cause the atoms to travel forward in time?

Sorry if my wording is a little ambiguous, I'm having trouble articulating the question.

Answer 1

You're right about scientists slowing down the speed of light. These very slow speeds have been achieved in just the past few years.

But this doesn't have any implications for the theory of relativity. The theory actually uses the universal constant "c" which is always 299792458 meters per second. This is commonly called "the speed of light" because it happens that light travels at speed "c" _if_ the light is traveling in a vacuum.

When light travels through a transparent medium, it slows down to a speed less than "c". For example, when traveling through water, light goes at only about 3/4 c. But since relativity is based on "c", not on the speed of light per se, the slowing of light in a dense medium has no implication for the theory of relativity.

Answer 2

The constant c, which is the speed of light in a "vacuum" is nearly 300,000,000 m/s. Think of this not as an instantaneous speed of light, but as the maxium speed in which an electromagnetic wave ( or anything else ) can travel. Light itself can only achieve this super high speed because it has no apparent mass, the amount of energy required to move a chunk of matter at that speed would be infinite. But back to your question, scientists have been able to slow light down by passing it through a super-dense medium chilled to near absolute zero, but this has not effect on the actual "speed of light", which you could think more or of as the "speed limit of light", that is used in relativity.

Answer 3

I do recall reading about the "slowed light" you refer to. It isn't actually a violation of the speed of light in a vacuum being a constant.

Even when we say that light goes slower in a medium like glass or water we're not really making light put on the brakes. Maybe an easy way to look at light traveling through a medium is as if its being absorbed and reemitted so there's something of a time delay added that makes it look like it's going slower.

And I think I remember wading through the complicated argument in classical E&M a while back that shows that what's really going on is a combination of many waves that leads to the amazingly simple result that looks as if the light is just slowing down.

Answer 4

Time is not relative to the speed of light - it is relative to the speed of the observer or the object being observed. The speed of light can be altered by passing it through a material other than a vacuum - that's how lenses work. But the speed of light in a vacuum is constant. I have heard that there has been some work accomplished on reducing light speed substantially - I had not heard the 40 mph number. I don't think that this is occurring in a vacuum, so I think the effect on time in general is insignificant. But inside the medium? hmmmm.

Answer 5

Yeah, I know of an experiment where they did slow it down below 40mph..and its quite famous in the physics community.

Time dialation is dependent on the speed of light in a vacuum. Slowing the light down is a cool thing but tthe theories of relativity wont be changed because it is based on light speed in a vacuum only. But, im sure new physics can be studied with slowed down light

Answer 6

atoms are always travelling forward in time...
time points in one direction, even though it can be dilated/contracted, it cannot be reversed (even by reversing the big bang, and having gravity crunch the universe back to where it started, that wouldnt turn back time, otherwise we would see broken mugs fixing themselves and rising up off the floor and putting themselves back on tables....
have scientists really been able to slow light down this much?
to do this in a vacuum would be more impressive however, you would need an artificial black hole for that though ,surely...
unless they are just using dense mediums to slow light through
and by 'slow' i do not mean slow...i mean refract....
the speed of light is a constant,
the speed of light through a medium depends on that mediums refractive index...(correct me if im wrong)

Answer 7

This is news to me!! The speed of light (in a vacuum) is, as I understand it, a natural constant at about 186,000 miles/sec. I think that it's more than improbable that 'scientists have been able to slow it down to less than 40 miles/hour!

The basis of your question is so extremely unlikely that it seems pointless to conjecture upon it.

Answer 8

Here is what Newton had: - the pace of sunshine used to be the identical for all observers, "almost limitless". - each observer agreed on their pace with recognize to an extra observer, even a thrid frame. Here is what Einstein confirmed: - the pace of sunshine used to be the identical for all observers, c. James Clerk Maxwell's equations required the identical regular for all inertial observers. - each observer agreed on their pace with recognize to an extra observer, simply now not for a 3rd frame with out exact math. "Einstein's concept of relativity states that point is relative on the grounds that house-time will also be bent" OK, that is the General Theory of relativity, the rough one. "however then how is pace of sunshine regular?" It is most effective regular *in the community*, now not over a direction that is going different locations with curved house (Shapiro time lengthen, gravitational lensing).