Speed of Light

Saiph · Jul 28, 2005

Correct, the balls rest mass remains unchanged, and this is the cause of gravity and is the "real mass". The "relativistic mass" is a misnomer, as it isn't mass that's changing, but the inertia (the stored energy basically) of the object. The faster you go, the more inertia you have (thus requiring more energy for each unit of speed). <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

daniko · Jul 29, 2005

High everyone ! About the suspicion of nexium- it's may be about the statement that: "... because there must be something absolute at which everything to be build on, he decided there is "absolute C" in vacuum". My reason to say so is the basic principle in mathematics. First you put some axioms, than stepping on them you prove everything else. That's the way geometry is made for example. In physics we have the same situation. To explain the observable reality, scientists first postulate some axiomatic facts that are taken for pure truth. Than they try to deduce everything that surrounds us. If the axioms of a given physics theory are well chosen, this theory makes good explanation of our world. What Einstein did was to collect the experimental experience of his time. Then he found that it's virtually impossible to measure different light speeds. So he decided that the "absolute C" is a good axiom for his theory. All the rest is just mathematics <img src="/images/icons/wink.gif" /> Speaking of which - the "Lorenz Transformations" are one mathematical product of the axiom of "absolute C" By the way the MBA_UIU'sclaim that "So to Tammy and I would see ... the light in your frame as moving at a fraction of C."is in direct conflict with the basic axiom of Einstein's relativity for the "absolute C". <img src="/images/icons/shocked.gif" />

Saiph · Jul 29, 2005

<blockquote>In reply to:<hr />he decided there is "absolute C" in vacuum<hr /></blockquote> DanIKo is right, it is a basis much like an axiom in mathematics. If that is taken to be true, you can base an entire, and logically valid system upon it. The difference between mathematics and physics is the applied nature of the math in this case. If we choose a bad axiom, then we do not get answers from the system that agree with what we see. Also, the axioms we choose are not merely "decided" upon, and held unassailable. The constancy of the speed of light in a vacuum is a very, very well observed phenomena, it's independence from an objects velocity (a bizzare non-classical result) is also very well documented. Our observations show us that the speed of light is constant in all frames. Einstein did use that observation as one of the primary foundations of his relativity theories. So MBA_UIU's clame that <blockquote>In reply to:<hr />"So to Tammy and I would see ... the light in your frame as moving at a fraction of C."<hr /></blockquote> is in conflict not just with an axiom, but an actual observational result. And if possibly true would undermine one of the most tested, and most successful theories of modern physics, especially since it's such a basic case and violation. Btw, DanIKo, didn't want to sound like I was re-iterating your statement, just elaborating and emphasizing some very good points. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

daniko · Jul 29, 2005

No problem <img src="/images/icons/smile.gif" /> I'm just trying to keep it short because I'm afraid of being boring

alkalin · Jul 29, 2005

I know that light is considered to have a constant value in regards to any local reference. That I accept. So if I measure the velocity of light in vacuum in my measuring device, I will measure c. And if I look at another person measuring the same thing in another reference, s/he will measure exactly the same value, regardless of the velocity of that other local reference in regards to me. But suppose that other device is moving relative to me at a high enough rate so that it’s velocity must be taken into account. Question? Do you still insist that c is constant everywhere, or am I able to find the other guy’s measured c is c but for me it is c + v, where v is the velocity the other reference is traveling relative to me?

Saiph · Jul 29, 2005

Actually steve, C can be calculated via Maxwell's equations. And it is now defined, as we use it for measurement standards. But it was measured first, then calculated, then measured more accurately, and then defined for use as a standard (due to the highly accurate and precise measurements possible). Alkaline: No experiment ever done has shown a velocity for light to be C+v. And many, many experiments show results that directly confirm the consequences of a "constant" C in all frames of reference. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

MBA_UIU · Jul 29, 2005

The speed of light is always constant to your frame of reference. This does not mean that the speed of light is always the speed of light in a vacuum. This is where my example becomes confusing. I should have said that my hyper speed example demonstrates that we are in a different medium, after all you cannot be at a hyper speed in earth’s gravity. Using my example, of Tammy and me in space and you and Tom on earth, Tammy and I would see the speed of light has 299,792,458 meters per second (it is traveling in a vacuum). You and Tom here on earth measure it slightly slower speed because you are thick (medium earth’s atmosphere). Also, because we are in space, we see time as being slightly slower then you and Tom (in other words earth’s gravity speeds up time by a fraction of second) this is called time dragging. So we can see that both speed and time are relative to our frame of reference. My mistake was to use the term hyper speed to explain that we were in space. One other thing that I should point out is that when I say the speed of light is always constant I mean that nothing with matter within your frame can exceed that speed. Say, for example, in water where the speed of light is roughly 1/3 of that in a vacuum you will not be able to build a ship that will go faster then the speed of light in that medium. Why, because light is still energy without matter and E=mc^2 still applies. We must remember that the speed of light is a mathematical constant which is defined as any well-defined real number which is significant interesting in some way; which is not meant to imply that the speed of light is a constant speed that disregards the medium for which it is traveling through. Just like the mass in E=mc^2 is not meant to mean the actual mass of an object but its mass like energy. <div class="Discussion_UserSignature"> <img id="268587ce-7170-4b41-a87b-8cd443f9351a" src="http://sitelife.space.com/ver1.0/Content/images/store/6/8/268587ce-7170-4b41-a87b-8cd443f9351a.Large.jpg" alt="blog post photo" /> </div>

Saiph · Jul 29, 2005

<blockquote>In reply to:<hr /> you will not be able to build a ship that will go faster then the speed of light in that medium<hr /></blockquote> Actually, you can. And things do exceed the local speed of light (the speed in a medium). the result is Cherenkov radiation. Nice blue glow due is created. <blockquote>In reply to:<hr />Why, because light is still energy without matter and E=mc^2 still applies<hr /></blockquote> First, you'd want the other equation, the kinetic energy equation. not the mass energy equivelance. Furthermore, they use "C" defined as the speed of light in a vacuum. This is invarient, and doesn't matter in what medium you do it it, you'll get the same answers. now, that said, you do make the good (and often overlooked) point that the speed of light does vary in a medium. It just doesn't vary in a vacuum. And if I had remembered to read all new posts, i'd have just agreed with tigerbiten on the cherenkov radiation. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

MBA_UIU · Jul 29, 2005

"Actually, you can. And things do exceed the local speed of light (the speed in a medium). the result is Cherenkov radiation. Nice blue glow due is created." If memory serves Cherenkov radiation is the effect seen when particles of energy exceed C. I do not believe that these particles have matter, but are pure energy, or electron like particles. As we all know, you cannot just create matter out of energy. Nothing made of matter, hence my reference to a ship, can be built that will surpass the speed of light no matter what medium the light is traveling in. <div class="Discussion_UserSignature"> <img id="268587ce-7170-4b41-a87b-8cd443f9351a" src="http://sitelife.space.com/ver1.0/Content/images/store/6/8/268587ce-7170-4b41-a87b-8cd443f9351a.Large.jpg" alt="blog post photo" /> </div>

Saiph · Jul 30, 2005

Well, an electron is made of matter, and so are many of the particles that create cherenkov radiation. Indeed, the only particle I know of that doesn't, or cannot, create cherenkov radiation is the photon (light) for obvious reasons. And we can create matter out of energy, it's just hard to concentrate that much energy in one spot. High energy gamma rays have been observed to split into matter anti-matter pairs, which both have mass and thus are matter. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

nexium · Jul 30, 2005

When high energy photons, such as ultraviolet light, are absorbed by certain materials, lower energy photons are created. ie neon colors and florescent tube. Are you sure gamma ray photons can't produce a blue glow in water? Neil

alkalin · Jul 30, 2005

Invariance is actually correct, but just remember that sophisticated math can not only bypass causality, but common sense too.

ehs40 · Jul 30, 2005

einstiens theroy say nothing can travel FASTER than light?? so that dosent mean we cant travel at the speed of light

alkalin · Jul 30, 2005

Relativity’s equations imply this, and are very good at describing local phenomenon. It is when they are applied in a blanket sense to the entire universe I see them break down. Travel at or above speed c is likely, as far as I am concerned. There are very serious problems in doing so, such as friction. Cherenkov radiation is a clue to it.

Saiph · Jul 30, 2005

actually, einstien's theories say you can travel slower than, at, or faster than the speed of light. You CANNOT switch between them however. So since we are at speeds less than C, we cannot go C, nor exceed C. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

alkalin · Jul 30, 2005

Seems to me a definite weakness in the relativity equations. I have seen Maxwell derivatives that would allow smooth transition in the speed of light region. Relativity equations, as you know, are another subset of Maxwell.

Saiph · Jul 31, 2005

I've seen no such thing from Maxwell. And they aren't weaknesses in Einsteins work, as they very, very accurately predict observed behavior. We see accelerated particles that react .999 C behave exactly as einstein predicts, that is an asymptotic rise in energy required for further velocity increases. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

daniko · Aug 1, 2005

Hi folks <img src="/images/icons/smile.gif" /> I see that the concept of the "absolute C" is chalenging to many. But in this conversation I see two little misunderstandings and they confuse many of you. First: The axiom about the "absolute C" IS NOT: "The Max Possible Speed of matter is 299'792'458 m/s" The axiom about the "absolute C" IS: "The Max Possible Speed of matter is the speed of light in vacuum" That way the exact value of C and it's measurement is not of importance !!! Second: The speed of light in medium (not vacuum) is NOT the speed the photons go through. There is no some kind of photon friction that slows them. The explanation is in the mechanics of light propagation through the medium. The photons are absorbet by the atoms of the medium and after a delay they are emitted in the oposite direction. That delay is the cause that light passes slowly through non vacuum spaces. In result the photons just jump like a swarm of grashoppers <img src="/images/icons/wink.gif" /> And some light on the "Cherenkov radiation": There is nothing misterious about it. It's the analog of the sound wave that the supersonic jets create when flying faster than the speed of sound in the air. All the best !

Saiph · Aug 1, 2005

well, just to nitpick: In a medium the values of permeability and permisivity (the two constants of the electric and magnetic forces) are different. Using these in the wave equations for light produce the correct speed. So when using the "wave version" of light, it does actually travel slower. DanIKO's photon bouncing and transmission is the correct way to reconcile this with the photon version of light. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

jatslo · Sep 5, 2005

kmarinas86 wrote: Rate of time is not constant. ime is constant. It varies depending where you are in the universe. ime is relevant to velocity, not space.

alkalin · Sep 5, 2005

Jatslo is correct. If I may, I will stick my neck out and say that time measures space, not the other way around. The time element measures our life, our world, our solar system, our galaxy, and our universe. Time in space is motion. Time does not have future, as motion of something does not exit in future, but can have prediction and therefore is virtual, and time does not have past, but may have history, and as such is again virtual.

jatslo · Sep 5, 2005

kmarinas86 · Sep 5, 2005

Actually. Where you are in space does matter. It's called Gravitational Time Dilation, the other type of time dilation is Velocity Time Dilation. Velocity Time Dilation = 1 / sqrt(1-v²/c²) Gravitational Time Dilation = 1 / sqrt(1-2GM/(c²r)) Time Dilation http://www.google.com/search?q=gravitational+time+dilation

jatslo · Sep 5, 2005

kmarinas86 quote and unquote: "Actually. Where you are in space does matter. Yes, time is relative to velocity of space-time in space. Time is constant; Space is constant; therefore we can conclude that Space-time is constant relative to the visible-speed-of-light (approximately 299,796 Km/s), which oddly enough is also constant. Who the HELL is Constantine anyway?

kmarinas86 · Sep 5, 2005

We can speak of time, such as the rate of time. But the definition of time itself never changes. In that sense, time is constant. The answer to your question: Constantime's Husband.

Speed of Light

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