Can Light travel faster than Light?

Did anybody watch the following program on NOVA?

The Fabric of the Cosmos

Acclaimed physicist Brian Greene reveals a mind-boggling reality beneath the surface of our everyday world.

http://www.pbs.org/wgbh/nova/physics/fabric-of-cosmos.html

If so what did you think of it? I think of all the all about the universe type programs, this is one of the best presentations.

 

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The speed of light is constant. (Even if they change

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).
To measure the speed of light, you need a standard meter and a standard second.

"The metre (or meter), symbol m, since 1983, it is defined as the length of the path travelled by light in vacuum in 1⁄299,792,458 of a second."

"Since 1967, the second has been defined to be the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom."


So first determine the length of the metre, according to the light.
Then measure the time it takes light to travel this metre and calculate the speed of light.

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Catch 22.

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....if a vacuum exists. That's the correction required. If the vacuum is a grain that changes size then you don't have a constant. The grain measured North and South are both different sizes.

 

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If this really seems to be a problem for you then measure the distance in feet or furlongs.

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IF this is true.... and IF this is true.... then it follows.

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IF pigs had wings and IF these pigs lived in your butt then it would probably be uncomfortable to sit down.

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Let's do this experiment theoretically:
We have the standard meter (length of the path travelled by light in vacuum in 1⁄299,792,458 of a second) and the standard second (the duration of 9,192,631,770 periods of the radiation...) and we measure the speed of light (in vacuum) as:299,792,458 m/s.

Suppose the speed of light (in vacuum) is changing due to certain conditions by 20%. (239.833.967 m/s)
But this, you can measure, only if you use the standards from the previous example.

But you must determine the new standard meter (length of the path travelled by light in vacuum in 1⁄299,792,458 of a second).
The new standard meter will be 20% lower than the old standard meter.
Now using this new standard meter will measure the speed of light as:299,792,458 m/s

So although in the second example, the speed of light is 20% lower than in the first example, we measure the speed of light the same, due to different standard meter. (The second standard meter is 20% lower than the first standard meter.)

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But space time as a grain is a theory that is sitting on the fence in science. So it has been scientifically validated, and measured. And North / South have been accurately measured as different sizes. So it's more a matter of when science adopts this theory rather than if.

 

But we don't live in both zones, so if we want to measure the distance to a planet in the North we have to adjust for the distance of a planet in the South. You can either adjust the speed of light, or you can adjust the distance, it doesn't really matter which.

 

I just watched it. It's one of those programs that makes me want to scream at the TV because they don't know anything. But after I calmed down, and decided to ignore the strange babbling I realised that the cosmological constant still has the valley missing in the middle of the outward forces. Inward forces travel through the valley, and outward forces collide in the middle, and that's the expansion of the universe that Einstein somehow missed. I posted this in 2004, I'm surprised it's still missing. Hawkins was on last night, he used my digging a hole example to explain nothing.. my igloo example. So something is getting through to people.

 

No problem the US would come to the rescue when someone measured the speed of light in feet.
Do you think anyone would notice that the length of the meter changed when it was mesured against other standards?
I wonder if anyone would notice that they suddenly got 20% taller?

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Best video yet to mediate between fringe and real physics.

 

With regard to your comment “that’s not the way light works, I offer the following for your consideration:

For the universal expansion at “slightly over the speed of light”, I calculate the distance from given point at the center between A and B to be approximately 7 billion light years as follows:

Using Hubble’s equation of D=V x H a Hubble constant of 80 km/s/mpc, and ½ the speed of light as 150,000 km/sec I calculate the distance to the center point as 2066 million parsecs. Converting to light years by using 3.26 x 1,000,000 I get 6,735,537,190 light years or about 7 billion light years, putting the points A and B about 14 billion years apart when the signal at the speed of light between A and B is sent.

Given our current universe age of 14 billion years and a diameter of about 84 billion light years due to expansion, it is clear that when the photons have traveled the first 14 billion years, say from point A to where point B was, B will no longer be there, but many times further away than when it started out from A.

If the above is correct, A and B will be over the cosmic horizon from each other and the light from one will never reach the other.
I realize that Hubble’s constant is not constant, and that the universe is accelerating, not expanding with uniform velocity, but these simplification are good enough for the point of the OP.

Correction in theory or math are always welcome.

 

The OP stated that A & B were moving each at a little over half the speed of light each. So when you add them together they would be moving away from each other at greater than the speed of light. So if A were stationary B would only be moving away at a little over half the speed of light (150,000 miles/second) sounds good.

All I am saying is as soon as a photon is emitted that point becomes fixed and from that fixed point B must be moving away at greater than 'c' before the light will never reach it.

 

Your point is well taken, my post concerning seperation distance was, to coin a phrase, "stupid".

But, my point now, which I hope isn't in the same vein, is that given the distances necessary to reach c/2 by expansion of the universe, point B will be over the horizon from where A was, and that the light will never reach B.

Thank you for correcting my poor post.

 

Okay I will admit that your scenario is possible. However I am not convinced that it is reality. I'd like to see less controversy on the red shift interpretations and absolute proof that there is a cosmic horizon. Which I'm expecting with the next generation of very large telescopes coming online this decade.

 

Defining the cosmic horizon as being the distance (radius) that due to the expansion of the universe the sepeartion speed exceeds the speed of light.

How could new telescopes provide any information on this? We have already observed most of the way to it and the Hubble constant (Which does not appear to be constant) predicts its existance.

Kind Regards,

Hardalee

 

Even the Wikipedia article (below) seems to make contradicting statements about what constitutes the cosmological horizon and how big the observable universe is. But I did get that we haven't observed it yet.

Observable universe