Can one theoretically travel faster than light relativistically?

[tomh4040]

Pardel-Lux, I have never used a derisory name for relativists, and I do not call myself an absolutist. I did ignore the supposed mass increase because there is no mass increase, as that is what is supposed to restrict the attainment of light speed for any mass or particle. As SRT is fully symmetrical, why doesn’t the PA increase its mass (of course along with the Earth and the rest of the universe)? I could of course talk about time dilation to slightly change the subject. A moving object undergoes both time dilation and mass increase. All frames of reference are equal. Therefore the PA as well as the proton undergoes both time dilation and mass increase. As the proton is travelling along the PA, it undergoes time dilation ie its clock runs slow. As all frames are equal, the PA clock also runs slow. We now have a situation where the proton clock runs slower than the PA clock, and concurrently the PA clock runs slower than the proton clock. How, according to SRT, are we to tell which clock is running slower (or faster) than the other? One of Einstein’s “paradoxes” - for paradox read impossibility.

Tom Hollings

[tomh4040]

Mangetout, I am saying that a spaceship which carries its own fuel CAN accelerate to beyond light speed. The problems to be overcome are just plain engineering problems ( how does it carry enough fuel etc), nothing to do with relativity.

[naita]

@tomh4040

You have mixed up the basic premises, there is no laser in my original post, just starlight. You have also forgotten Newton’s second law of motion, “every action has an equal and opposite reaction”. The second ship would be slowed down by the reaction of the laser, and as these ships have to be light and flimsy to be pushed by the minuscule force of the light, that reverse force would not be negligible.

No I haven’t, I just didn’t include all the details. Sunlight or laser doesn’t matter, photons work the same. And the intermediate craft only needs to have a more powerful source of acceleration than the craft it accelerates and voila.

Your position is as ridiculous now as it was back in your previous stint posting here. There’s no real point in refuting all your flawed arguments again. If someone is curious they can just go back and read the old thread, or one of the many others we’ve had here picking physics-deniers arguments apart.
My Problems With Relativity

[RickJay]

@tomh4040

Mangetout, I am saying that a spaceship which carries its own fuel CAN accelerate to beyond light speed.

What you are failing to take into account is that as an object approaches C, the amount of force needed to accelerate it increases. At C, the amount is infinite. Since there is no such thing as infinite force, nothing can accelerate past C. That’s proven fact.

You have to understand, Tom, that this stuff isn’t just a hypothesis. The Special Theory is experimentally proven. To prove it wrong, you need to experimentally prove it wrong.

[wolfpup]

@Francis_Vaughan

@tomh4040

Of course information is transmitted. The arrival of the particle at the detector (or target or whatever) IS the information. Is the particle there or is it not there? - that is information.

You misunderstood how the accelerator works. The oscillator is not triggered by the particle, it is free running. It has been programmed to run long before the particle is ever set in motion.

ISTM that tomh4040 misunderstood your point even more fundamentally, as he seems to think you said that the proton does, in fact, exceed the speed of light. Whereas what you’re saying is the exact opposite. The oscillating electric fields constitute a waveform that appears to “move” faster than light, and should thus be capable of accelerating a particle faster than light. In actual fact, of course, it never can. As we build more and more energetic particle accelerators, we create correspondingly more energetic particles, which thus become correspondingly more massive, with no theoretical upper bound, but their speed simply approaches the speed of light asymptotically. And this empirical observation alone should end any further debate about special relativity.

I’ll also add this:

@Francis_Vaughan

I think it is important to realise that a lot of the above is basically a naive misunderstanding of what special relativity says. Sort of taking a pop science “lies to children” view of what it is and finding fault.

It isn’t about the speed of light. It is much more basic. What is at core is the speed of causality. It just tuns out that massless particles are constrained to travel at the speed of causality and so photons travel at this speed.

This is clear, accurate, and sums it up succinctly. If tomh4040 hasn’t been able to grasp this since at least 2012, he probably never will.

@tomh4040

We now have a situation where the proton clock runs slower than the PA clock, and concurrently the PA clock runs slower than the proton clock. How, according to SRT, are we to tell which clock is running slower (or faster) than the other? One of Einstein’s “paradoxes” - for paradox read impossibility.

What paradox? If both the proton clock and the PA clock are inertial frames of reference, then they are indeed equivalent, and each clock will see the other one running slower.

[Whack-a-Mole]

It has often been mentioned around here and elsewhere. The Oh My God Particle was a proton detected that hit earth’s atmosphere at an estimated speed of v = 0.9999999999999999999999951 c

Pretty fast.

They calculated the time dilation effect if you were riding along on the particle (this does not account for acceleration):

Object	                Distance[3] (light years)	     Perceived Travel Time

Alpha Centauri	        4.36                             0.43 milliseconds
Galactic nucleus	    32,000	                         3.2 seconds
Andromeda galaxy	    2,180,000                       3.5 minutes
Virgo cluster	        42,000,000	                    1.15 hours
Quasar 3C273	        2,500,000,000	                3 days
Edge of universe	    17,000,000,000	                19 days

(not sure if there is a better way to format the above…I did what I know)

[Exapno_Mapcase]

@tomh4040

Mangetout, I am saying that a spaceship which carries its own fuel CAN accelerate to beyond light speed.

I assume that a faster than light ship has some consequences. Can you give us the math to show what those are? Please do not explain in words. Write out the math and the people here will follow it.

[Mangetout]

Ah, OK. I think you had an accidental double negative in your post above, because you said you were arguing against there being no limit (i.e. arguing for there being a limit)

@tomh4040

I am arguing against there being no cosmic speed limit

Doesn’t really matter.

[Senegoid]

@Whack-a-Mole

It has often been mentioned around here and elsewhere. The Oh My God Particle was a proton detected that hit earth’s atmosphere at an estimated speed of v = 0.9999999999999999999999951 c

Pretty fast.

They calculated the time dilation effect if you were riding along on the particle (this does not account for acceleration):

[ . . . ]

(not sure if there is a better way to format the above…I did what I know)

@Whack-a-Mole – You can format the table like this. There are no tabs or other hidden characters in the source that I typed. What you see is what is there. Note, the first column is left-justified, the second column is right-justified, and the third column is centered.

Object Time	Distance[3] (light years)	Perceived Travel Time
Alpha Centauri	4.36	0.43 milliseconds
Galactic nucleus	32,000	3.2 seconds
Andromeda galaxy	2,180,000	3.5 minutes
Virgo cluster	42,000,000	1.15 hours
Quasar 3C273	2,500,000,000	3 days
Edge of universe	17,000,000,000	19 days

[PhillyGuy]

@Whack-a-Mole

It has often been mentioned around here and elsewhere. The Oh My God Particle was a proton detected that hit earth’s atmosphere at an estimated speed of v = 0.9999999999999999999999951 c

Pretty fast.

If I understand this correctly, were the particle self-aware and able to accelerate much closer to c, it would hit a speed point where said particle always perceived itself to get where it was going instantly. I’m thinking that you can’t get somewhere faster than instantly.

[Whack-a-Mole]

Yeah…pretty much.

If you achieve light speed time stops for you. If you press your lightspeed button you cannot ever push the stop button since there is no moment after you reach lightspeed to press the stop button.

Further, the universe has contracted in size to zero. There is no distance between two points anymore.

In a manner of speaking, you are everywhere at once.

So, you can never reach lightspeed. But, you can (in theory) get arbitrarily close to it and your clock will tick ever more slowly the closer you get compared to a clock on earth.

[tomh4040]

I cannot answer all replies individually, so I will just make this statement and show the maths involved (as requested). Then I will move on to pose another question.

There is no speed of light limit for a vehicle which carries its own propulsion device ie rocket motor.

Here is the maths :-

Assume that the exhaust velocity is 3,000 m/s and the mass of the rocket is 30,000 Kg (very similar to NASA’s Mercury-Redstone rockets). Now use the Lorentz transformation to find the mass (m). The velocity between exhaust and rocket is 3,000 m/s, so :-

m = m0 / sqrt( 1 - ( v / c )^2)
m = mass of rocket at velocity v as measured by the essential observer. Einstein’s observer, properly called the essential observer, is always (implicitly) at rest relative to the motive force. In this example the essential observer is in the same frame as the rocket exhaust.

m0 = 30,000 Kg - proper mass of rocket or rest mass when v = 0
v = 3,000 m/s - rocket’s velocity relative to the exhaust
c = 300,000,000 - m/s rounded up for simplification
m = 30000 / sqrt( 1 - (3000 / 3e8)^2) = 30,000.0000015 Kg

The increase in mass is therefore 0.0000015 Kg or 0.0015 gram which is simply not measurable compared to 30,000 kilograms. For all intents and purposes the mass increase is zero. Notice here that the mass increase is measured against the exhaust which is providing the motive force, and no matter what the velocity of the rocket when measured against its starting point (or anything else for that matter), the velocity between rocket and exhaust never changes, so the rocket mass is always 30,000.0000015 Kg (disregarding the loss of mass due to fuel used). In other words, the mass is fixed at 30,000.0000015 Kg for the values used above between rocket and exhaust, and the extra 0.0000015 Kg is an insignificant amount. As there is no significant mass increase with velocity, and certainly no accumulative mass increase, there is no theoretical upper limit to the velocity of the rocket.

Tom Hollings

[Great_Antibob]

There’s no actual increase in mass. This is a misunderstanding people make with relativity.

It comes down to the observer. An observer outside the rocket may “observe” that the rocket “appears” to be changing in mass based on their measurements but somebody on the rocket who measures the same will not get the same result.

Worse, this still ignores the real world - stable satellite orbits kind of rely pretty heavily on knowing relativistic effects. And all those experiments running atomic clocks for hours on end at altitude.

So, any examples (with math!) of how to explain those without a relativistic framework? And when we say “with math”, that means being able to explain those things that we already see with your proposed framework. Because those observations aren’t consistent with what you are currently proposing, unless you have some kind of math to show they are.

[tomh4040]

Does that make you half a relativist Great Antibob? There are many misunderstandings in relativity. If increase in mass is an illusion, then so is increase in length, and dilation of time. They are all derived from the same basaic formuta.

Tom Hollings

[tomh4040]

Now that I have got your interest, I will move on to a slightly different question, this one concerns time.

“Two exactly similar clocks, A and B, are in uniform relative motion. Einstein’s special relativity theory requires (1) that the motion is wholly relative, i.e. it belongs no more to one dock than to the other; (2) that the clocks work at different rates, i.e. one works faster than the other. My question is: what, consistently with the theory, determines which clock works the faster?

Suppose the relative velocity is 161,000 miles a second. Then, according to the theory, the time according to one clock (A, say) between the readings 1.0 and 2.0 o’clock of B is 2 hrs, so that A works twice as fast as B. This is a particular case of a general result obtained by Einstein in 1905 and universally accepted. But, similarly, the theory requires that the time according to B between the readings 1.0 and 2.0 o’clock of A is 2 hrs, so that B works twice as fast as A. (Einstein did not consider this case). These results are clearly contradictory.

My conclusion is that the theory must be false, since it demands that each of two clocks works faster than the other, which is impossible. Otherwise, something must determine which clock really works the faster. What is that something? ”

Science at the Crossroads page 55.

Please answer the question posed. Do not change it for a question of your own and answer that one (a favourite ploy of relativists).

Tom Hollings.

[wolfpup]

@tomh4040

Einstein’s observer, properly called the essential observer, is always (implicitly) at rest relative to the motive force. In this example the essential observer is in the same frame as the rocket exhaust.

That’s not just wrong, it’s incoherent.

Applying the Lorentz transformation to an inappropriate (i.e.- meaningless) reference frame is not “doing math”, it’s incoherent thinking. The rocket exhaust is moving along with the rocket so that reference frame is a constant, always 3000 m/s less than the rocket speed. So what? You may as well omit that complication and just consider the reference frame of the rocket itself. From that reference frame, and equally from the exhaust reference frame, there is of course no apparent limit to maximum speed. From that reference frame, due to time dilation, if you were traveling as fast as that super-fast proton mentioned above, you could make it to Alpha Centari in 0.43 milliseconds of proper time. But it would still take you more than 4.36 years to get there as measured from earth.

Assuming for the sake of argument that earth and Alpha Centari are not moving significantly relative to each other, this common reference frame is the only one that matters to observers on earth or observers on Alpha Centari when it concerns the observation of the spaceship’s speed. And applying the Lorentz factor to the spaceship as it approaches light speed, we find that the passage of time on the ship’s clock as observed from earth approaches zero, and its mass approaches infinity. Both of those factors are clearly observed in particle accelerators.

[Andy_L]

Both clocks appear fast to the other, as Einstein was well aware, and discussed often. This is no more a contradiction than the fact that if you place two rules at an angle to each other, the perpendicular line drawn from ruler A at its 6 inch mark intersects ruler B at its 7 inch mark, and (at the same time) the perpendicular line drawn from ruler B at its six inch mark intersects ruler A at its 7 inch mark. Do you understand now?

[wolfpup]

@tomh4040

“Two exactly similar clocks, A and B, are in uniform relative motion. Einstein’s special relativity theory requires (1) that the motion is wholly relative, i.e. it belongs no more to one dock than to the other; (2) that the clocks work at different rates, i.e. one works faster than the other. My question is: what, consistently with the theory, determines which clock works the faster?

I already answered that. If A and B are in uniform relative motion, they are in equivalent inertial frames of reference. Each will see the other clock running slower by precisely the same amount. It’s a perfect symmetry. There is no paradox here.

[Great_Antibob]

@tomh4040

Does that make you half a relativist Great Antibob? There are many misunderstandings in relativity.

Uh…no.

I mean you are misunderstanding relativity. Relativity itself uses equations so we have unambiguous answers and don’t have to work via analogy. There’s no single ‘formula’ from which it is derived. It’s a theory based on lots of observed phenomena and validated by predicting others.

The increase in mass is NOT an ‘illusion’. The issue is there is no such thing as a universally preferred observer.

The classic example is the Doppler effect. If there is a train whistle, what frequency you observe (hear) depends on whether the train is at rest (relative to you, the observer), coming towards you, or moving away from you.

Likewise, red shift/blue shift of observed light from stars. What is the spectra we see and how does that depend on the relative motion of the star from our position?

What is the ‘true’ frequency? They all are ‘true’ frequencies, dependent only on which point of view we accept.

So, we need to define the frame of reference to get a meaningful answer to that question.

From different frames of reference, we get different answers. And they are all equally valid!

Likewise, the measurement of mass (or length, or time) depends on the frame of reference from which you measure.

This is a very basic point not just for relativity but for basic physics. It was an assumption that was important going back to Archimedes, if not further back in time.

What you are missing is that you assume there must be a single, universal frame of reference from which all observations show the same thing. This is patently false, not just in relativity but even in a Newtonian framework.

Basically, you are not arguing relativity is wrong. You are arguing (without even realizing it) that the basis of all physics, including pre-Newtonian, is wrong.

[Great_Antibob]

@Great_Antibob

It’s a theory based on lots of observed phenomena and validated by predicting others.

Also, I want to re-emphasize this point.

We’re not just navel gazing here. Relativity is accepted, not only because the math works out but because it produces predictable results. Satellites have repeatedly come up in this thread.

The predicted orbits based on relativity are accurate to umpteen decimal places. If you have an alternate in mind, show how it can do something similar. Otherwise, it’s just thought experiments that have no analog to the real world.