Time Dilation: When v = c

[EWright]

EWright: What justification do you have behind the claim that SR demands an infinite time dilation at v = c?

 

"Thus light does not get old; a photon that emerged from the big bang is the same age today as it was then. There is no passage of time at light speed."

 

Greene, Brian. The Elegant Universe p. 51. First Vintage Books Edition, 2000.

[adjective]

That is not justification. As Qfwfq pointed out, we have good evidence to suggest that light experiences infinite time dilation and the idea makes intuitive sense. That's not what I asked for. Neither did I ask for a quote from a popular science book--which will always be forced to grossly simplify things.

 

So, again, how does SR demand that a photon experiences infinite time dilation? Try again--perhaps with equations.

[EWright]

That is not justification. As Qfwfq pointed out, we have good evidence to suggest that light experiences infinite time dilation and the idea makes intuitive sense. That's not what I asked for. Neither did I ask for a quote from a popular science book--which will always be forced to grossly simplify things.

 

So, again, how does SR demand that a photon experiences infinite time dilation? Try again--perhaps with equations.

 

I didn't say I abide by the notion that a photon experiences no time. I am relaying what "they" say, in response to an inquiry. In my theory a photon does experience time, so I wouldn't waste my time on a formula to prove it, even if I knew how. I've also stated I do not have a physics background capable of working out such formulas. If popular science books can't get it right, what good are they? Perhaps all you physicists need to put your heads together and come to a general concenses on things. Greene's "Elegant Universe" is a highly acclaimed book. If it is full of falsities, perhaps someone needs to point that out to him and the rest of those of us who have an interest in the subject matter.

 

Additionally, are you saying that the nature of the universe is then only a subject that those who undertand the formulas are worthy of discussing? Being as you can't think outside of the box that Einstein has put you in, it seems that would be very counter productive, as no new ideas would then be allowed to be introduced into the thought processes of exploring new physics. Thus, answering the questions that current physics are unable to, would conceivably take that much longer to accomplish.

[Erasmus00]

Perhaps all you physicists need to put your heads together and come to a general concenses on things. Greene's "Elegant Universe" is a highly acclaimed book. If it is full of falsities, perhaps someone needs to point that out to him and the rest of those of us who have an interest in the subject matter.

 

The language of physics is math. Popular science books almost never delve into the math, they give only a qualitative description of the ideas. However, this treatment is bound to be imprecise, thats why it isn't a science text, but a popular science text.

 

Additionally, are you saying that the nature of the universe is then only a subject that those who undertand the formulas are worthy of discussing?

 

No, anyone is free to discuss the nature of the universe. However, the best descriptions we have to date are mathematical ones. Therefore, people who are really and truly interested in the subject learn the math. Those who don't have cut themselves off from a real understanding, and can develop a muddled, qualitative picture at best.

 

Being as you can't think outside of the box that Einstein has put you in, it seems that would be very counter productive, as no new ideas would then be allowed to be introduced into the thought processes of exploring new physics.

 

Not all scientists agree with Einstein. Many physicists have proposed other theories of gravity. To date, all experiment supports Einstein.

 

If you are referring to special relativity, I will say this: special relativity predicts that energy and mass are equivalent. The atomic bomb was a tremendous confimation of that prediction. If you replace SR, your theory better also be able to explain the equivalence of mass and energy.

-Will

[EWright]

I do not dispute that energy and mass are equivalent. SR predicts many things and it does so very precisely. I am saying that SR has some basic flaws, or rather, that there is a *more precise* or easier way to explain the same phenomena more accurately, simply, and in a way that corresponds better to our common perceptions of the universe around us. It's moreso a matter of which explanation is more "direct". You can take the side streets or the freeway to get to the same location and neither is 'wrong' but the side streets are arguably the less efficient way to get there (and less direct with more room for confusion... or the need to dodge more obstacles... along the way). Comprende?

[Boerseun]

I do not dispute that energy and mass are equivalent. SR predicts many things and it does so very precisely. I am saying that SR has some basic flaws, or rather, that there is a *more precise* or easier way to explain the same phenomena more accurately, simply, and in a way that corresponds better to our common perceptions of the universe around us. It's moreso a matter of which explanation is more "direct". You can take the side streets or the freeway to get to the same location and neither is 'wrong' but the side streets are arguably the less efficient way to get there (and less direct with more room for confusion... or the need to dodge more obstacles... along the way). Comprende?

Si, senor.

 

Einstein proposed relativity, and a host of others proposed a vast array of alternative theories over the years - and still do.

 

Fact is, we'll never know which theory is 100% right, but there might be an asymptotic approach to the truth. And all the evidence currently points to relativity having come closest. String theory et al is busy making inroads, and who knows - a couple of years down the line we might see some serious changes.

 

I think the most common issue for the layman is that relativity is counterintuitive, and they feel "locked-out" of the discussion to understand what the world that they inhabit is made of, and why things work the way they do. And the mass of evidence is such that any new theory to be proposed will need to overturn reams and reams of documented support for the theory that previously held sway.

 

But - if you have an alternative, let rip! You might just be the guy to show Einstein the door... (expect some serious critique, though...)

[Qfwfq]

So, again, how does SR demand that a photon experiences infinite time dilation? Try again--perhaps with equations.

lim v-->c 1/sqrt(1 - (v/c)^2) = inf

[quantum quack]

please correct me if I am wrong but I am very confident that SRT predicts that at v=c it takes an infinite amount of time to travel a zero amount of distance.

 

I am pretty sure this is the absolute outcome of the transforms.

 

I must admit it has always perplexed me how such a successful theory can involve such an impossible paradox of infinite time / zero distance, but of course this is just my POV.

It suggests to me that when v=c the universe and the massless object are in a state of suspended animation. a bit like 2 dimensional photo.

Which leads on to the conclusion that time is progressing forward at a rate of 'c' and that tne Now is 2 dimensional in that it has no time, thus the center of time [between the future and past] has zero duration universally which goes on to suggest that the NOW is as absoilute universally as the photons 'v' which contradicts SRT's abandonment of absolute time.....sheesh....!!! :xx:

[adjective]

lim v-->c 1/sqrt(1 - (v/c)^2) = inf

 

My previous response was that this was discontinuous, as per my initial post to this topic. However, having thought about the claim a bit more, I realize that lim v -> c- *does* tend toward infinity (I forgot about the property of right and left hand limits--it's been a while since I've had to use limits).

[Bobby]

Hi all,

 

I've been working my way through the math of special relativity to get a grasp on it and such.

 

Anyway, when I came across the time dilation equation (t' = t / sqrt(1 - v^2/c^2)) I wondered, given the nature of the subject, what happened to time when the velocity was the speed of light. Basically, I've come across two "interpretations." The first simply says that time stops, as observed by an outside frame. The other sort of glosses over the subject and doesn't mention what happens, instead leaving it to the reader to interpret (often they lead this interpretation by listing time dilation factors as v approaches c, leading the reader to think that time would cease).

 

The second approach is simply misleading in that it leads the reader into concluding something without actually stating so. The first bothers me on mathematical grounds.

 

If v = c, then v^2/c^2 = 1. If so, then the denominator is sqrt(1 - 1) = sqrt(0) = 0. So, the answer is undefined.

 

I tried taking the limit as v approached c, but I couldn't remove the discontinuity.

 

If anyone can shed any light on this--like if my algebraic skills are too weak to remove the discontinuity, or if there's a generally accepted interpretation on the subject--I would be extremely appreciative.

 

Thanks.

 

(Edit: Equation typo.)

 

 

To a large extent, Calculus is based on the concept of a LIMIT. A LIMIT is a statement such as "As A comes closer and closer to B then C comes closer and closer to D." In special relativity, as Velocity comes closer and closer to the speed of light, the relativistic effects become greater and greater.

 

In math, sometimes you have to replace the arithmetic with reason. Consider what happens to light as V approaches C. Any object moving away from you will be red shifted, meaning the wavelength becomes greater and greater. This also means that the light becomes dimmer and dimmer until the object simply fades away. This effect is also what you would see at a Black Hole.

 

Much of the confusion over Special Relativity comes from thinking that a physical thing like a spaceship is somehow different from light. It is OK for light to be "stretched" as it moves away from you, but it is not OK for a spaceship to be "stretched". However, the way you locate a spaceship is by looking at it. If the light is "stretched" then for all practical purposes the spaceship is "stretched".

 

We, the imperfect beings that we are, seem to think that something is "really" there or it is not "really" there. It appears to me, that if you believe in anything "really" being there, then as the velocity of a spaceship approaches the speed of light, then the spaceship "really" is stretched over space, and if V = C then the length of the spaceship would be the length of the universe.

 

This being my first post, I think I should end here. However, I could go on forever.