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Author Topic:   Speed of Light Barrier
RCS
Member (Idle past 2608 days)
Posts: 48
From: Delhi, Delhi, India
Joined: 07-04-2007


Message 85 of 178 (500904)
03-03-2009 5:32 AM
Reply to: Message 1 by JustinC
07-10-2005 1:15 PM


Why can't we exceed the speed of light? I've heard two explanations but I am not sure which one is right.
There could be a third explanation: Lack of engines to break the barrier. Remember, as long as jet propulsion was not there, speed of sound too was an unbreakeable barrier. As you move faster, more energy is required to maintain the acceleration. You might interpret it the Special Relativity way ie the mass increases or the one by the classical fluid mechanics ie piling up of the waves in front of you.
If light waves are piling up in front of you, you too would feel the same effect. But at relativistic speeds, energy can be perceived as converting into mass. Effect is the same.
But a powerful engine can break the sonic barrier. Could powerful engines break the light barrier?
Remember, velocity of light as the CEILING is not founded on solid theory, so speeds faster than c can be there.
The first explanation is that mass increases as matter approaches the speed of light, so it would take more and more force to further accelerate an object as it approaches the speed of light. This seems wrong to me for some reason. One's mass doesn't objectively (from all reference frames) increase, does it? Only from a second observers. So why would the fact that there is a second observer affect how I can accelerate?
Mass does not increase objectively. But then the mass of the rocket as it approches sonic barrier too does not increase.
The second is the reason I think is correct, but I'm having trouble articulating it. Basically, it's a fundamental property of space-time. Velocities aren't additive according to special relativity. In order to add velocities, you use the equation:
u= (v1 + v2)/(1+ v1v2/c^2)
So from your referece frame you may add 2000 m/s on to your original velocity, but the second observer won't see it add that way due to the above equation.
Piling of the light waves does explain a lot. But then it points to:
1. Speed of light maybe a crossable barrier.
2. Special Relativity rule of addition of velocities is defective.
3. Something called ether may still be there, notwithstanding the Michelson Morley experiment. If you apply Doppler effect, the results would be as M-M got.
Relativity, btw, does not rule out ether.
Einstein derived his equations, which can easily fit the sound wave relativity.
Edited by RCS, : No reason given.

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RCS
Member (Idle past 2608 days)
Posts: 48
From: Delhi, Delhi, India
Joined: 07-04-2007


Message 103 of 178 (501206)
03-05-2009 6:21 AM
Reply to: Message 88 by kuresu
03-03-2009 4:56 PM


Remember, as long as jet propulsion was not there, speed of sound too was an unbreakeable barrier.
Of course, there's an important difference between the speed of light and the so called sound barrier.
There are numerous examples of objects in the universe that break the speed of sound. The earth, for example. Asteroids and comets. Electromagnetic radiation.
Nothing, however, is observed to travel faster than light. There is, as far as I'm aware, no serious proposal for being able to travel faster than light.
Electro-magnetic radiation?
No object has been observed so far. Can it be ruled out?
In other words, the difference between the sound barrier and the speed of light (in terms of being able to exceed those speeds) is that the sound barrier was one of technological limitation, whereas the speed of light is physical limitation.
Our technology is severely limited.
What is mass of objects travelling at c? Like photons. ZERO. Why are not photons and such like particles impossibly massive?
It appears that relativity does not hold good at c.

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RCS
Member (Idle past 2608 days)
Posts: 48
From: Delhi, Delhi, India
Joined: 07-04-2007


Message 104 of 178 (501208)
03-05-2009 6:29 AM
Reply to: Message 91 by NosyNed
03-04-2009 1:24 AM


Re: FTL
Actually, the expansion of the universe itself can be said to be faster than light.
quote:
Not in the sense that is being discussed. To say so would be messing up definitions badly. Velocity is through space.
Let them be messed up, so at least the drawbacks are exposed and rectified.
But are they really messed up? Universe is expanding faster than light. It can happen only IFF objects at its boundary are moving faster than c.

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RCS
Member (Idle past 2608 days)
Posts: 48
From: Delhi, Delhi, India
Joined: 07-04-2007


Message 105 of 178 (501209)
03-05-2009 6:35 AM
Reply to: Message 93 by onifre
03-04-2009 9:12 AM


Actually, the expansion of the universe itself can be said to be faster than light.
quote:
There isn't any physical object that's actually moving faster than light speed in the expansion. Galaxies appear to excede light speed, but the galaxies themselves aren't actually moving very quickly through space, it's the space itself which is expanding away, and the galaxy is being carried along with it. As long as the galaxy doesn't try to move quickly through space, no physical laws are broken.
Whether you drive or are driven, it is the same thing: you move.
Unless space is a real, physical object how ccan it expand?
Lots of semantics to save relativity.

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RCS
Member (Idle past 2608 days)
Posts: 48
From: Delhi, Delhi, India
Joined: 07-04-2007


Message 158 of 178 (540340)
12-24-2009 1:45 AM
Reply to: Message 109 by Percy
03-05-2009 8:36 AM


Relativity theory is very mathematical. Physicists and cosmologists plug values into the relativity equations to make predictions, then they peer through telescopes or otherwise make measurements, and in this way they verify the predictions of relativity theory.
With any set of axioms, you can construct a perfectly beautiful mathematics. But then unless such a construct is related to reality, it remains a curiosity.
Einstein's solution of his own equations led to an expanding universe, which he refused to believe. Hence he added a "mathematical" term to make a static universe... and.. rued it.
Have you considered the possibility that you might be rejecting relativity prematurely? That perhaps a bit more study might be appropriate before drawing conclusions?
I am not rejecting relativity lock stock and barrel. Just as Newton's mechanics has not been rejected.
Light, like any wave [even longitudinal ones] travels at a speed limited by the medium. Sound to has a limit. Can you claim it be the absolute limit for all objects? If you do, then you cannot have a world view broader than that of a whale.
Mind you, if you use speed of sound in relativity equations, they will hold mathematical validity. In fact, Einstein used the analogy of sound in his original paper.

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RCS
Member (Idle past 2608 days)
Posts: 48
From: Delhi, Delhi, India
Joined: 07-04-2007


Message 160 of 178 (540353)
12-24-2009 5:36 AM
Reply to: Message 159 by cavediver
12-24-2009 4:38 AM


With any set of axioms, you can construct a perfectly beautiful mathematics. But then unless such a construct is related to reality, it remains a curiosity.
And given that SR is the most successfully tested theory EVER, I guess it is on fairly good ground
So is the case with Newton's mechanics, within its axioms. It took man to moon and brought him back safely and accurately.
Can you claim it be the absolute limit for all objects?
Yes, as the most successfull theory EVER demonstrates this, and EVERY particle accelerator experiment demonstrates this PERFECTLY.
Fully, within its axioms.
But it has not explained why the remotest galaxies are moving faster than light. Nor how 35 billion year old quasars(?) are there in 14 billion year old universe.
We accelerate protons at CERN to an energy of 7TeV. The Kinetic energy to reach c in Newtonian terms is 0.5GeV. And yet they refuse to go any faster than 99.9999991%c. Why is that? Bloody mindedness?
For long it was thought impossible to break the sound barrier. More powerful movers broke it. Different motors with even different fuels. Are you accelerating the protons with the "right" "motors"?
One would have a world view based upon both all available evidence and remarkably solid theory. But if you want to belive in fairies, no-one is stopping you
Whoa. Relativity is not fairy tale, sure, but it is still on shaky footings. Btw, whales too have a completely valid world view.
Mind you, if you use speed of sound in relativity equations, they will hold mathematical validity.
No, they won't. An analogy is NOT an equivalence.
Try it then. Use speed of sound and it turns out to insurmontable.
Speed of light is a barrier, because it was assumed to be so. Einstein had no sceintific reason to adopt it except that it was highest known speed.
Edited by RCS, : Spellings corrected

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