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Light, Media and Different Time Speeds

06/25/2009 10:32 AM

Hello everyone; I have something wandering in my mind for some time, so I decided I'll ask it here and try to have some insight about it. It is actually more like a physics question (that has its feet a bit off the ground) than engineering; but I'm sure a good discussion will come out of here.

Here's the thing: I'm considering how light would behave upon passing from one medium to another which are in different time speeds.

Imagine there are two adjacent zones which perceive time in different speeds. We can say one has the time speed 1.00 while the other has (for example) 2.00. So, in Zone 2, time passes twice as fast as Zone 1. So if you went to Zone 2 from Zone 1 and stayed one hour there and then returned, Zone 1 would have experienced only half an hour (I guess I made the point).

In my problem, I assume Sun as the light source on the "universal" time frame, that is time speed coefficient 1.00. The sunlight is travelling to Earth, only to enter a zone which has a different time speed (slower or faster, not a specific speed). What would happen? Would anything happen? Would light behave differently or experience a change as it passes through the mediums?

Something that I had in my mind that the amount of light entering the new zone would change because the volume of photons entering the area per (the new area's) seconds would change and this would create a brighter (or dimmer) light for that area's perceivers. But then again, this is when you assume light behaves as a particle only.

Any ideas?

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#1

Re: A different type of change in medium...

06/25/2009 2:16 PM

I think that it would appear to move at the same speed. (Plank's constant is the same) because you, the observer, are in either one zone, or the other.

If you had a sensor that could straddle both zones, then maybe, but that is basically equivalent to having one portion of your sensor in the past or future, and one in the present. We don't have a visual on that. cool idea though.

A similar question would be to have light pass between two mediums moving at different near-c velocities, and measure any differences.

You have to ask Jorrie, or emc_c, et al, for a real answer.

Chris

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#2

Re: Light, Media and Different Time Speeds

06/25/2009 5:15 PM

Can you reframe your question a little. It is meaningless to talk about time speed. An object can move through time at different rates, that is, with a slower or faster clock, but time isn't moving through time.

We can talk about frames in which the clocks in one are seen to measure time half as fast as in the other. But, you have to say something about how you synchronized the clocks, who is measuring, how they're measuring, and so on.

There is no "universal" time frame that we know about. If there were, we could possibly ditch relativity.

Have you studied relativity yet?

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#3

Re: Light, Media and Different Time Speeds

06/25/2009 6:05 PM

Speed of light in different media?...it's why a stick looks bent when you dip the end of it into water.
It's dalled refraction isn't it? Or am I missing something...?
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#4

Re: Light, Media and Different Time Speeds

06/25/2009 6:07 PM

I've messed around thinking of light, and string theory, and multiple universes and am told some of my theories are impossible.

I did find out that in a universe with a slower constant for the speed of light, that there would be fewer, and more stable elements.

I figure in another universe the difference would be a different constant for the speed of light.

In Jorries Physics Thought Experiment concerning the Balloon model of a finite universe, I proffered a twisted hotdog balloon balanced on the weird connection of the two Universes where at the twist there was chaos.

The two halves of the balloon model are spinning around the void center of the infinity circle because of the imbalance of the competing universes with two different speeds of light as a constant.

So far this is the salient essence of my light theories, and as I said, I am sometimes told things I think of are impossible.

At anyrate you may well be interested in Jorries Physics Blog where now we are discussing a perfect balloon model of the finite universe.

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#5

Re: Light, Media and Different Time Speeds

06/26/2009 12:03 AM

Well, First, in Relativity there is no universal "clock." That is one of the major differences between Relatively theory and Quantum theory. In Relativity theory, every inertial frame in the Universe has its own clock running at a different rate. Therefore, I believe light would have the same speed as it passed from one inertial frame to another. Remember, if you are moving and you shoot a light beam out ahead of you, the speed of light does not become c + your speed. Instead, it remains c.

However, if you want a semi-practical example of light traveling at different speeds, you can investigate the speed of light in different mediums. For example, light travels slower in glass than it does in air. The boundary differences cause the refractive effect - light gets "bent" to a different angle. Further, the speed of light in certain materials can be lower than the speed of a particle passing through the same material. If this is the case, the particle creates an electromagnetic shockwave (much like the shockwave of a sonic boom). The shockwave causes the passage of the particle to emit light, known as Cerenkov Radiation.

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#13
In reply to #5

Re: Light, Media and Different Time Speeds

06/27/2009 12:04 PM

Remember, if you are moving and you shoot a light beam out ahead of you, the speed of light does not become c + your speed. Instead, it remains c.

Spock..."Fascinating!"

Scotty..."Aye, Captain, ye can't hold her at warp 1 much longer. Either turn off the navigation lights, drop back to impulse power, or go to warp 2 and scrub off all the photons that have accumulated on the forward shields. We have already harvested what we need to re-arm the photon torpedoes."

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#14
In reply to #13

Re: Light, Media and Different Time Speeds

06/27/2009 2:19 PM

Guest,

Please register so we can give you GAs that will accumulate.

-S

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#6

Re: Light, Media and Different Time Speeds

06/26/2009 3:25 AM

I'm not sure that I understood your question (...different time speeds???...meaning gravitational wells... ??? ... ) but here are two basic issues:

First: the speed of light is always c regardeless of the observers's inertial frame.

Second: the speed of light is always c regardeless of the material. It may looks that the light has a slower speed (v<c) as it's moving inside the (e.g.) glass (i.e. see refractive index) but, actually, the speed of the photons are, also, v=c inside the glass. The photons are simply absorbed and retransmitted by the atoms of the glass and this procedure produces a delay (i.e. the mean value of the speed of light is lower than c as it travels through the glass).

(Also, there isn't such a thing as a universal time frame.)

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#7
In reply to #6

Re: Light, Media and Different Time Speeds

06/26/2009 4:08 AM

The speed of light in water isn't 'C' .... and in a brick it's zero
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#10
In reply to #6

Re: Light, Media and Different Time Speeds

06/26/2009 2:13 PM

Yes, I know why the speed is slower in different mediums - I just didn't want to go that far. Also, Quantum physics depends entirely on the concept of a universal clock... It's something they're trying to find a way of doing without.

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#8

Re: Light, Media and Different Time Speeds

06/26/2009 7:02 AM

I haven't made a stupid post all day (well, it is only 7 am...), but there is such a thing as Universal time.

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#9

Re: Light, Media and Different Time Speeds

06/26/2009 2:10 PM

Here's an analogy for your question: Everyone's read or seen the screen version of HG Well's "Time Machine" - The hero sits in a fancy chair and pushes a lever. On screen, as he heads to the future, he sees the world move faster and faster and someone standing in the room sees him disappear.

Your question could also be reworded to ask what each guy actually sees.

Does the guy standing in the room see the hero sitting there, frozen, or would all light surrounding the hero freeze so he is just a dark sphere? Or would light be unaffected and keep bouncing off his temporally frozen form?

Wouldn't everything the hero sees become a blinding light?

Ponder away my friend. Only Michael Jackson knows now.

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#11

Re: Light, Media and Different Time Speeds

06/26/2009 7:51 PM

It's happening right now. Time is slowed in a gravity well. The spectral lines are red shifted in light emitted by a massive star.

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#12

Re: Light, Media and Different Time Speeds

06/26/2009 10:15 PM
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