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Old 9th March 2012, 02:49 AM   #1
drgsrinivas
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The paranormal science of relativity

A layman and a scientist (www.debunkingrelativity.wordpress.com

Layman: In the light of the observations on cosmic ray muons, why don’t we believe that the muon had in fact travelled 16000meters in 2 microseconds?
Mod WarningBreach of rule 4 removed. Do not copy and paste large amounts of material from elsewhere.
Posted By:Cuddles

Last edited by Cuddles; 30th March 2012 at 04:23 AM.
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Old 9th March 2012, 02:58 AM   #2
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Originally Posted by drgsrinivas View Post
''So it is just rubbish all the way down, not even tortoises! The tortoise model of the universe is much better than relativity.''

Er....no.
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Old 9th March 2012, 03:00 AM   #3
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http://www.internationalskeptics.com...35#post7593935
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Old 9th March 2012, 03:10 AM   #4
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Originally Posted by drgsrinivas View Post
Layman: Why should we believe in time dilation which we can’t appreciate, and ignore what we actually appreciate?
Made it to this part before I wanted to shoot myself in the face.
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Old 9th March 2012, 09:05 AM   #5
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Originally Posted by drgsrinivas View Post
A layman and a scientist strawman
ftfy
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Old 9th March 2012, 10:36 AM   #6
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Layman and strawman approach to science: Write analogies and believe they say something profound. Done.

Scientist approach: Use analogies to describe hypotheses. Do possibly falsifying experiments, elevate your hypotheses to theory once a bunch of experiments have failed to falsifying them.

You're free to falsify relativity with an actual experiment, drgsrinivas.
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Old 9th March 2012, 10:45 AM   #7
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Drgsrinivas, the problem is that you're arguing with your own misunderstanding. No scientist wrote the "scientist" part of that "conversation", you wrote it, as a layman.
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Old 9th March 2012, 11:11 AM   #8
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Layman: on what grounds?

Scientist: From the law of constant speed of light
This is where the conversation starts to go off the rails. No scientist would say this. They'd say something along the lines of "A large number of experiments have shown that nothing can move faster than the speed of light, which agrees with a large amount of theoretical work." Most would add "Here are some examples", and cite a few papers.

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Obviously we canít appreciate this in our reference frame.
This is completely unlike any scientist I've met. By this point most have pulled out a pen and grabbed an envelope or notebook, and would be busy appreciating this in our reference frame.

Quote:
Layman: Pardon me sir; but muonís time dilation is a prediction or a proof of special relativity?

Scientist: The problem is you neither understand the mathematics nor the reference frames.
Yes, the first instinct of a scientist is to insult anyone who disagrees.

Quote:
Layman: Now I am getting the gist of relativity. Everything in relativity is counterintuitive, isnít it?

Scientist: Well, you are right but there is a lot more to go through before you can even dream of understanding relativity. Even I didnít believe in it initially, but having seen the vast support and evidence, I had no choice but to accept it. But over the course of time, as I thoroughly understood the theory and the maths, I got converted and became a believer of relativity.
This is just insane. No scientist says "I got converted"--even scientists who come to accept ideas they initially oppose never say this! It implies that science is a matter of faith, and that evidence is irrelevant. In actual fact, scientists are convinced by data (if they're honest, and in their role as a scientist), and "converts" can list the data that convinced them.

Quote:
Layman: Sorry sir, I didnít mean to dishonour science. I am just thinking that photons may be behaving just like horses and rail engines for the particles in the quantum world. If so, then we donít need the weird law of constant speed of light to explain the observations on neutral pion decay!

Scientist: But thatís not what special relativity (SR) predicts.
No, that's not what ACTUALLY HAPPENS. As in, we've measured it. Repeatedly. Arguing with this is akin to arguing that we can't sit in chairs--it requires us to ignore the evidence.

Whoever wrote this has little knowledge of how scientists act, and even less of relativity. I mean, I'm ignorant of the theory and *I* can see the flaws here.
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Old 9th March 2012, 11:13 AM   #9
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Time dilation is measurable from other experiments which don't depend on circular proof arguments, such as orbital satellite signal delay due to the speed of the satellite. Satnavs rely on the time dilation effect to be correct, and they are, very accurately.
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Old 9th March 2012, 12:01 PM   #10
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I'd just like to sit in on this thread since I listened yesterday to disc 2 of why e=Mcsquared' by Prof Brian cox and another author whose name I can't remember just at the moment, and I'm up to about Ch 9. I think the whole thing is really fascinating. Listened to 'the Elegant Universe' not so long ago. I do not try to get my head round it all but I think I've got a glimmering of it.
*settles down with slightly smug smile on face*
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Old 9th March 2012, 12:02 PM   #11
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The only way that is plausible is if the 'scientist' is a 'political scientist'
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Old 10th March 2012, 03:13 AM   #12
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Originally Posted by drgsrinivas View Post
Scientist: Special relativity (SR) prohibits speeds faster than light

Layman: on what grounds?

Scientist: From the law of constant speed of light
I have understood that it is only for convenience that we regard the speed of light as the fastest speed. What is really meant is the speed of a massless particle in vacuum, and since light is massless, it happens to be the speed of light.
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Old 10th March 2012, 04:41 AM   #13
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Man that guys theories on the debunkingrelativity site are not good.

the author of said sillyness Dr Srinivasa Rao Gonuguntla , claims to be an allopathic Dr specializing in homeopathic medicine.

In other words, he doesn't have any idea of what he is talking about.


I'm a laymen who has a special fascination with astrophysics (should've gone to school in it...sigh). Yet relativity is an easy concept to generalize but a very difficult concept to dig deep on. The very strange, illogical appearing things that it describes can seem confounding to the average person. We think of things like how we experience the world. To tell us that time and space are connected and that an emitted particle from a ray of light will not accelerate past the speed of light sounds...well , it sounds wrong! But, it's true.

If this guy has a problem with relativity I shudder to think what his comments on Quantum Mechanics would be!
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Old 10th March 2012, 04:50 AM   #14
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The math for special relativity is not all that hard. If you can do algebra and had a high school physics class, you can understand it.
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Old 10th March 2012, 05:08 AM   #15
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Originally Posted by drgsrinivas View Post
Layman: Well, the speed of an engine (photon) obviously doesnít depend upon the vehicle (pion) it was driving.

Scientist: What do you mean?

Layman: If the lone speed of a rail engine is 100kmph, this remains the same even when the engine gets detached from the moving train it was driving.
Imagine a horse which runs at 50kmph when free of load. Also imagine that this horse is pulling a cart at 40kmph. If the horse gets released from this moving cart, it will only run at its original speed of 50kmph and not at 50+40kmph.
So like SOL, the speed of a horse and the speed of a rail engine are also constant!

This is the bit that truly has me baffled. Is he trying to imply that until the pion decayed the photon was already there, pushing/pulling the pion along?
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Old 10th March 2012, 05:49 AM   #16
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Originally Posted by drgsrinivas View Post
Scientist: But thatís not the case with light photons. We know velocity of light is Ďcí. Neutral pions are fundamental particles with a high velocity and emit photons as they decay. If the neutral pionís velocity is Ďxí, we would expect the emitted photons to move at speed Ďc+xí. But the photons were noted to travel at just Ďcí in an experiment studying the decay of neutral pions. This proved beyond doubt that velocity of light is indeed constant and unaffected by that of the source.
Actually, that's not really correct. It the speed of light is affected by the speed of it's source. It just happens that for every reference frame the math of adding the speed of light and the speed of the source finds that the speed of light is c.

Originally Posted by Doubt View Post
The math for special relativity is not all that hard. If you can do algebra and had a high school physics class, you can understand it.
Except for deriving how speeds are added from only the Lorentz transformations. I used to be able to do that, but my maths has rusted heavily.
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Old 10th March 2012, 06:22 AM   #17
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Originally Posted by BNRT View Post
Actually, that's not really correct. It the speed of light is affected by the speed of it's source. It just happens that for every reference frame the math of adding the speed of light and the speed of the source finds that the speed of light is c.
Um, no. You get C without adding the speed of the source.

If you had device which simply measured the speed of light from the time it takes to pass a fixed distance, you'd get the same reading from every light source, no matter how fast the light source the moving relative to you.

You might be able to determine the speed of the source from the redshift/blueshift of a light-source with a known spectrum, but not from the speed of the light itself.
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Old 10th March 2012, 07:19 AM   #18
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Originally Posted by Brian-M View Post
Um, no. You get C without adding the speed of the source.

If you had device which simply measured the speed of light from the time it takes to pass a fixed distance, you'd get the same reading from every light source, no matter how fast the light source the moving relative to you.

You might be able to determine the speed of the source from the redshift/blueshift of a light-source with a known spectrum, but not from the speed of the light itself.
I may have worded it badly, but I think I was right. You can fire a photon from a moving train and the photon's speed (which is c) and the speed of the train are added. The addition of those speeds comes out as c.

Actually, I just tried this. Adding two velocities c and 0.5c using this equation gives us the composite velocity of c.
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Old 10th March 2012, 11:50 AM   #19
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Similarly Michelson-Morley experiment, which studied propagation of light in air medium (earth’s atmosphere), can’t enlighten us on how light travels in vacuum and can’t disprove the existence of ether.
Um so the MM experiement was not about the seasonal movement and rotation of the earth and the alleged etehr.

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Old 11th March 2012, 03:10 AM   #20
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Originally Posted by drgsrinivas View Post
Layman: I realise that we the lay people shouldnít try to understand Relativity but religiously believe in what the great scientists like you preach. Thank you sir.

www.debunkingrelativity.wordpress.com

Why is that last line suddenly fished straight out of thin air without making any sense?

Who ever said that people should not try to understand relativity?

If you want to understand relativity, beyond what is written in popular level books, then there is absolutely nothing to stop anyone from studying for a degree in theoretical physics Ö and from there you'll probably find you also need a PhD.
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Old 11th March 2012, 03:38 AM   #21
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Originally Posted by IanS View Post
Why is that last line suddenly fished straight out of thin air without making any sense?
It's so that the "Layman" can be an affronted martyr and show how unreasonable the "scientist" is.
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Old 11th March 2012, 08:29 AM   #22
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Originally Posted by IanS
If you want to understand relativity, beyond what is written in popular level books, then there is absolutely nothing to stop anyone from studying for a degree in theoretical physics Ö and from there you'll probably find you also need a PhD.
Therein lies the problem: science has a relatively high cost of entry. It takes years of hard work to get to the point where the theories make sense, and even more years of work until you can start making your own theories. That's fundamentally why scientists usually go for a Ph.D.--it's a systematic way to take that time. Doing it solo can be done, but takes a LOT more effort and usually a great deal more time. Most of the woo criticisms of science--anti-relativity, anti-vaccination, Creationism/ID, etc--simply don't want to put in that effort.
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Old 11th March 2012, 08:46 AM   #23
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Snail model of relativity

I do respect those who religiously believe in Relativity, but I just want to convey that my religion of snail relativity is equally good.

Your Light Relativity is based on the assumptions of

1) Speed of light is constant to all observers
2) Light is the fastest moving thing in the universe

According to the believers of this Relativity, if anything (like cosmic ray muon) is seen to travel faster than light, it must because of the time dilation and space contraction phenomena.

Similarly my Snail relativity is based upon the assumptions that

1) The speed of a snail is constant to all observers and
2) The snail is the fastest thing in our universe.

If anyone notices something else moving faster than the snail, that must be because of the phenomena of time dilation and space contraction.

Just by number and mass misinterpretation of data, one can't claim superiority over another.

www.debunkingrelativity.wordpress.com
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Old 11th March 2012, 08:50 AM   #24
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Muon's time dilation

High energy muons are produced at about 16000 meters above the ground as cosmic radiation collides with the atoms of the Earthís atmosphere. Significant number of them apparently survive to reach the ground level.

But from what scientists know about muonís life span (about 2 microseconds) and speed (about 0.9c), a muon can only travel about 600 meters before it decays. Then how could the muons, produced in the upper crust of the earthís atmosphere, are able to travel a distance of 16000 meters and reach the ground?

The only possible explanation for this scenario according to relativists is time dilation and length contraction! Letís explore this paranormal claim in depth.

The above figures of muonís life span and speed apparently come from the experiments on low energy muons produced in particle accelerators. But why do we think that the same figures must hold true for the high energy cosmic ray muons. In fact, in the light of the above findings on cosmic ray muons, why canít we propose that muons can travel faster or live longer than what we know of them?

Relativists propose time dilation for the muon as if our knowledge of its life span and speed is absolute and uninfringeable. Under certain conditions (energy state, composition of the surroundings etc) it shouldnít be impossible for a muon to travel faster or live longer.

The other question is- how do we know that the muons that reach the ground are all produced at a height of 16000meters? Is it impossible for the muons to get created at lower altitudes?

So there are better alternative explanations for the observations made of the cosmic ray muons though the relativists are obsessed and fascinated with only time dilation.

If moving particles experience time dilation,

1) Why not the muons produced in the laboratory experience the same time dilation and length contraction just like the cosmic ray muons if both of them travel with the same speed?

2) If a muon travelling at less than Ďcí (speed of light) could experience time dilation, why not a photon travelling at even faster speed experience the same? How come time dilation occurs only for the muon and not for the photon despite its faster speed?

Muonís time dilation is what we would propose in the given scenario if the theory of relativity is correct. (It is not an observed phenomenon to serve as a proof of time dilation and relativity)

Relativity is woven upon the weird assumption of constant speed of light which no experiment has confirmed. Of course scientists think that the theory of relativity and its weird predictions have been confirmed by many experiments. Muonís time dilation is one among them!!!

A weird theory supported by weird interpretation of experiments!
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Old 11th March 2012, 09:11 AM   #25
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Originally Posted by drgsrinivas View Post
Your Light Relativity is based on the assumptions of

1) Speed of light is constant to all observers
This is an assumption, but an assumption with empirical data backing it up.

Quote:
2) Light is the fastest moving thing in the universe
This is not an assumption, rather a consequence of the equations derived from the assumption that the speed of light is constant.

Quote:
According to the believers of this Relativity, if anything (like cosmic ray muon) is seen to travel faster than light, it must because of the time dilation and space contraction phenomena.
Muons have only appeared to move faster than light in one set of experiments. by far the most popular theory amongst physicists for why is experimental error.

Quote:
Similarly my Snail relativity is based upon the assumptions that

1) The speed of a snail is constant to all observers and
This is easily falsified in any number of ways, not the least of which being the snails don't move at one consistent speed.

Quote:
2) The snail is the fastest thing in our universe.
Please show the equations which lead you to this conclusion.

Quote:
Just by number and mass misinterpretation of data, one can't claim superiority over another.
By "just by number" do you mean "just by doing the actual physics"? Because, yes, you can. Relativity is seen as correct because the maths works. The maths isn't a fudge behind which someone's pet wish is obscured.
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Old 11th March 2012, 09:16 AM   #26
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Originally Posted by drgsrinivas View Post
2) If a muon travelling at less than Ďcí (speed of light) could experience time dilation, why not a photon travelling at even faster speed experience the same? How come time dilation occurs only for the muon and not for the photon despite its faster speed?
They do. Photons experience all parts of their journey simultaneously.

Quote:
Muonís time dilation is what we would propose in the given scenario if the theory of relativity is correct. (It is not an observed phenomenon to serve as a proof of time dilation and relativity)
Relativity is correct. If it weren't, your SatNav wouldn't work.

Quote:
Relativity is woven upon the weird assumption of constant speed of light which no experiment has confirmed.
It's been confirmed many a time. Every time anyone uses SatNav, for a start.

Does your snail theory have a better explanation for the effects SatNav depends upon?
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Old 11th March 2012, 09:37 AM   #27
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Originally Posted by drgsrinivas
Your Light Relativity is based on the assumptions of

1) Speed of light is constant to all observers
In science we don't call the results of experiments assumptions. We call them conclusions.

Quote:
2) Light is the fastest moving thing in the universe
Got any evidence to contradict this? After all, relativity is extremely well supported by astronomical observations (gravity lenses, black holes, etc).

Quote:
If anyone notices something else moving faster than the snail, that must be because of the phenomena of time dilation and space contraction.
Cool. Draw up the math. I'd love to see it. Honestly, it'd be cool to see. One of my favorite classification systems for rocks was developed based on smell and sound. Perfectly internally consistent, actually, we just haven't developed it very much so it's not useful. This has a better chance of being useful, as we do in fact know that anything moving is experiencing time dilation.

Originally Posted by Squeegee Beckenheim
Relativity is seen as correct because the maths works.
I'd disagree. The math made predictions, and observations confirmed them. Observations such as Mercury's orbit, gravitational lenses, black holes, etc. Relativity is seen as correct because it makes specific predictions, and those predictions have been shown to be correct.
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Old 11th March 2012, 10:34 AM   #28
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Scientist: speed of light is constant to all observers i.e light always travels at velocity ‘c’ with reference to all observers irrespective of their own motion. A ‘stationary’ observer, a fast moving electron or the cosmic ray muon, all ‘measure’ the same speed of light.
Wrong! Light does not always travel at velocity ‘c’ with reference to all observers

Light travels at 'c' relative to the entire universe itself. However, all observers do always "MEASURE" the speed of light as "c", and do so no matter what velocity it is that they are traveling at, relative to the light itself.

This is because the measurement instruments change as velocity changes.

See http://www.outersecrets.com/real/forum_againstum2.htm
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Old 11th March 2012, 11:06 AM   #29
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Haven't there been experiments that slowed light down, and trapped it? Or am I misremembering?
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Old 11th March 2012, 11:13 AM   #30
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Originally Posted by Dinwar View Post
Haven't there been experiments that slowed light down, and trapped it? Or am I misremembering?
I think Hawking proved that if you had a photon meter and stood on the outer rim of a black hole and measured the photons travelling just outside the event horizon, the gravitational pull would slow down the photons to below light speed due to the gravitation curving the light waves making it technically possible to move faster than THAT light, but not faster than true light speed.

Plus, it's already been proven that if you have enough gravity you can warp light right into a black hole
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Old 11th March 2012, 11:19 AM   #31
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Originally Posted by Dinwar View Post
I'd disagree. The math made predictions, and observations confirmed them. Observations such as Mercury's orbit, gravitational lenses, black holes, etc. Relativity is seen as correct because it makes specific predictions, and those predictions have been shown to be correct.
That's what I meant, but I phrased it very sloppily.
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Old 11th March 2012, 11:30 AM   #32
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Originally Posted by Dinwar View Post
Haven't there been experiments that slowed light down, and trapped it? Or am I misremembering?
There have definitely been experiments that slow light down to an amazingly slow speed. I forget what the speed was, but you can drive faster than it in a normal car.

I read about the stopped light in New Scientist and mentioned it to my dad. He's a laser research scientist and he said that it wasn't really stopped or trapped or anything and describing it as such was wrong. I can't remember the specifics of what he said actually happened (I'm not a scientist, it was a while ago and my memory's not the best-functioning programme on the face of the planet), but it was something like the light was sampled, the information about it was stored, and then an identical light beam was later emitted.

None of which really matters to relativity, as it's the speed of light in a vacuum that's the fastest speed, not just the speed of light. Light changes speed in all sorts of different media. It's different in water than it is in air, which is why you get the refraction effects you do when looking at things immersed in water.
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Old 11th March 2012, 12:31 PM   #33
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Originally Posted by Squeegee Beckenheim
I read about the stopped light in New Scientist and mentioned it to my dad. He's a laser research scientist and he said that it wasn't really stopped or trapped or anything and describing it as such was wrong. I can't remember the specifics of what he said actually happened (I'm not a scientist, it was a while ago and my memory's not the best-functioning programme on the face of the planet), but it was something like the light was sampled, the information about it was stored, and then an identical light beam was later emitted.
Ah. That sounds about right. I never discussed it with a physicist, just in some news articles about it, so it doesn't surprise me that my info is off. Thanks.

Quote:
None of which really matters to relativity, as it's the speed of light in a vacuum that's the fastest speed, not just the speed of light. Light changes speed in all sorts of different media. It's different in water than it is in air, which is why you get the refraction effects you do when looking at things immersed in water.
True. My point was that the OP doesn't understand light, so his entire argument is flawed. I mean, light doesn't go the speed of light, not always anyway.
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Old 11th March 2012, 01:27 PM   #34
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Originally Posted by Dinwar View Post
My point was that the OP doesn't understand light[...]
Amongst other things.

I'm sorry, BTW, if you thought that last paragraph was directed at you, as I assumed that you know enough about it not to need to be told about refraction. It was more for the aid of the OP and any lurkers who might not have ever learned such things.
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Old 11th March 2012, 01:39 PM   #35
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Oh, no worries. It's always good to be reminded of things, particularly in different contexts. I'm used to dealing with refraction in minerals, and hadn't actually thought about the implications for this conversation.
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Old 11th March 2012, 05:04 PM   #36
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Originally Posted by drgsrinivas View Post
I do respect those who religiously believe in Relativity, but I just want to convey that my religion of snail relativity is equally good.

Your Light Relativity is based on the assumptions of

1) Speed of light is constant to all observers
2) Light is the fastest moving thing in the universe

According to the believers of this Relativity, if anything (like cosmic ray muon) is seen to travel faster than light, it must because of the time dilation and space contraction phenomena.
Relativity isn't based on the assumption that light moves at a constant speed to all observers. That's just nonsense. The speed of light varies depending on the density of the medium through which it's passing.

Relativity assumes that the velocity of a massless particle in a vacuum, known as C, is the same relative to all observers. This commonly but inaccurately referred to as "the speed of light". (It'd be more accurate to refer to it as "the speed of light in a vacuum", because traveling through matter changes things.)

ETA: But others have already pointed that out.

This is why cosmic ray muons are observed to travel faster than light through the water in the detectors. They're traveling faster than light, which is allowed by relativity, but not traveling faster than faster than C, which isn't allowed by relativity.

The assumption that the speed of light C is the fastest speed possible is easily demonstrable by simple logic. The more kinetic energy you give an object, the faster it moves, right? So if you give an object infinite kinetic energy, it'd have to be traveling at the fastest possible speed. (Because if it were to travel faster, it'd have more kinetic energy. But you can't have more than infinite energy.)

From Newton's laws (which have been extensively tested) we know that V= √(Ke/(Ĺ m)). From this, it's clear that an object with zero mass and any amount of [kinetic] energy must logically have the same velocity as an object with mass and infinite kinetic energy.

So if an object with zero mass has the same speed (in a vacuum) as an object with infinite kinetic energy, and an object with infinite kinetic energy is traveling at the fastest speed possible, than an object with zero mass must also be traveling at the fastest speed possible.
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Old 11th March 2012, 05:36 PM   #37
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Originally Posted by Squeegee Beckenheim View Post
There have definitely been experiments that slow light down to an amazingly slow speed. I forget what the speed was, but you can drive faster than it in a normal car.

I read about the stopped light in New Scientist and mentioned it to my dad. He's a laser research scientist and he said that it wasn't really stopped or trapped or anything and describing it as such was wrong. I can't remember the specifics of what he said actually happened (I'm not a scientist, it was a while ago and my memory's not the best-functioning programme on the face of the planet), but it was something like the light was sampled, the information about it was stored, and then an identical light beam was later emitted.
The speed of light is only c in a vacuum. These guys used a sodium Bose-Einstein Condensate (many atoms in a single quantum state) at a very low temperature. The photons combine with the BEC atoms, so it's debatable whether it really 'counts' as slow light.
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Old 11th March 2012, 05:41 PM   #38
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Scientist: Understanding relativity is very complex, requires a lot of math and includes many things that seem non-intuitive to the casual observer, however it has been verified by numerous objective sources and much experimentation. If you want to understand it, you'll have to do a lot of studying.

Layman: I don't want to do that. If you can't make me understand using only the simplistic models I'm capable of fathoming, then it must be bunk. Look, I have a link to a website.
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Old 11th March 2012, 08:46 PM   #39
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Gravitational lensing reduces the velocity of light rays with respect to the velocity in vacuum. Considering a spherically symmetric object, an asymptotic observer would consider light passing through a gravitational field behaving as though it moved through a material with an effective index of refraction n(r)=1- 2 phi(r)/c^2 where phi(r) is the Newtonian potential. Since phi<0, n>1 always so the light appears to slow down when compared to it's velocity in free space (far from gravitational fields as r-> infinity phi(r)->0 so n->1). This result is easily derived from the weak field metric. A similar calculation can be done using Newtonian mechanics but then the factor of 2 within n(r) will be absent, which was one of the key points allowing initial observations (ie Eddington's eclipse observations of 1919 and 1922) to discriminate between GR and Newtonian gravity. The deflection angle of gravitational lensing can also be found for a spherically symmetric mass in this way. Close up to the mass it's a little more complicated since the weak field approximation no longer holds. Also note that unlike the index of refraction of a physical material, gravitational index of refraction is not wavelength dependent. In any case, any observer within the gravitational field is also affected by it of course so they will measure the usual speed of light, which jives with what MinisterOfTruth mentioned above.

Just throwing that out there.

For a nice discussion on the physics of gravitational lensing there's an classic overview by Narayan and Bartelmann here: http://arxiv.org/pdf/astro-ph/9606001v2.pdf

I would also like to apologize for my lack of LaTeX styles on the board - is it as simple as putting $$ around what I want to LaTeX up?
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Old 11th March 2012, 09:02 PM   #40
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Sorry, folks, but light always goes at c. The reason it takes longer to go through a medium than you think it would is because it interacts with the stuff in the medium (mostly electron shells).

This either takes more time (absorption and re-emission), or more distance (because the highest probability path has to go around the electrons), depending on which way you choose to think (depending on how you view/solve QED, but it doesn't really matter).

I use the latter with a lay audience. It's obvious that a fast skier who has to slalom is going to take more time to get to the finish line than if they had gone straight.

Of course, this is far from the whole story at the quantum level, but it's close enough to get a pretty good approximate idea.
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