Will Time Dilation at 100% c Speed Result in Eternal Life?

[PeterDonis]

Assuming the initial conditions given

You can't assume initial conditions that can't be realized.

at c, nothing would happen regarding an organism.

This doesn't follow. Photons move at c, and things happen regarding photons. The correct statement, as I said in an earlier post, is that the concept of "proper time" does not apply to photons. But proper time doesn't have to apply to photons for things to happen regarding them; that's obvious since we can run experiments involving photons in which things happen regarding them--they interact with other particles, are created and destroyed, etc.

It seems to me that if time did stop then you'd no longer be alive!

Time does not "stop" for photons. The concept of "proper time" does not even apply to photons, so it can't "stop" for them.

 

[DaveC426913]

It seems to me that if time did stop then you'd no longer be alive!

We're getting into philosophical woo-woo territory here, but I'll just add one observation: if time were "restarted", you'd still be alive - so I'd argue you did not stop living.

Peter's answer is correct: when you try to describe a frame of reference at c, you get silly results.

 

[PeroK]

We're getting into philosophical woo-woo territory here, but I'll just add one observation: if time were "restarted", you'd still be alive - so I'd argue you did not stop living.

Certainly it would be fair to say that you hadn't actually died!

 

[nucl34rgg]

The theory of special relativity doesn't really discuss what happens "at v=c". It discusses what happens as a massive object approaches v=c. I am pretty sure that we can't define a valid reference frame for photons since the photon can never be taken to be at rest. for example.

 

[PeterDonis]

The theory of special relativity doesn't really discuss what happens "at v=c".

It does for photons. It doesn't for objects with nonzero rest mass, as you point out; it just says that such objects can never reach c.

I am pretty sure that we can't define a valid reference frame for photons since the photon can never be taken to be at rest. for example.

You're correct, we can't. See our forum FAQ on this. But we don't need to define a "rest frame" for a photon to deal with photons using SR.

 

[ZapperZ]

I consider this question to be of the type "When did you stop beating your wife?"

One needs to FIRST establish that one CAN get to v=c. Only after that can one then consider the ramifications and consequences of such a scenario. In this case, it has NOT be established that one can get to v=c (i.e. you were beating your wife in the first place). This is a big deal, because this is a significant physics that must be described! We only know of massless entities that can attain such speed. Anything else reaching that speed will force a major revamp of our existing physics, so living "forever" will be the LEAST of our concern because there will be a whole zoo of consequences because of it!

If you wish to "learn", then learn it step by step. Be aware of what needs to be established FIRST. Make sure the branch you are hanging on is solid and well-established before you step out further onto it.

Zz.

 

[Sugdub]

So does it mean that a person in a rocket at c speed, will live forever?

Your wording “a person at c speed” does not mean anything. According to the principle of relativity of motion, only relative velocities make sense. Right now, there are plenty of physical objects in the universe which relative speed in respect to you is nearly equal to c. In the rest frame of such an object, your relative speed is nearly c (so there is no need to jump into a rocket)... and this does not entail any change in your living conditions: hence there is no rationale for anticipating that this representation of your body as being “in high-speed motion” could trigger any effect on your expected lifetime and neither on the behaviour of your biological clock. However many physicists claim that according to SR, the ticking rate of your biological clock in any such frame slows down, that your heart has nearly stopped ... on the one hand they claim you are nearly dead, on the other hand they also claim your lifetime expands nearly forever. Both options are wrong.

You must understand that SR does not predict any change in the actual behaviour of your heart, it does not tell anything about your expected lifetime, simply because it does not deal with changes in your living conditions. Its purpose lies elsewhere: it typically deals with changes in the formal representation of (e.g.) your unchanged living conditions.

Whether someone decides to represent your body in an inertial reference frame A where you are at rest or in an inertial reference frame B where it is in motion at nearly c does not affect your body at all and (fortunately!) does not affect in any way the behaviour of your heart. Let them do! But if the ticking rate of your heart is assigned a certain value when represented in frame A, SR tells us what must be the corresponding value of this ticking rate when your body gets represented in frame B. For the same living conditions and therefore the same behaviour of your heart (this is essential), the time interval between two consecutive ticks must be assigned different numerical values (using the same units) depending on the inertial reference frame in respect to which your body gets represented. One beat every second in frame A where your body is represented at rest might correspond to one beat every many seconds in frame B where your body gets represented in high-speed motion. But this large number of seconds simply belongs to a different description for the same behaviour, it does not mean that your biological clock has nearly stopped, it does not imply that you “will live forever”, whether in a rocket or not. Both descriptions are equivalent insofar any properly formulated physics theory will derive identical predictions irrespective of the selected description.

 

[ghwellsjr]

The OP asked about a slider app he made and the meaning of setting the speed at 100%, but if you look at his equation that his app solves, it requires a division by 0 under that condition which is forbidden.

His slider should therefore either not go all the way to 100% or should indicate an error or other meaningless answer rather than 0.

I don't know why there has to be all this discussion beyond that very simple point.

 

[Adam Rifai]

it requires a division by 0 under that condition which is forbidden

Good point, but at v=c , √ 0 = 0 and not forbidden , so the equation will look like
:

 

[Helakin]

I made a simple time dilation slider to experiment with the figs, i noticed at 100% c speed the time = 0
So does it mean that a person in a rocket at c speed, will live forever?www.timedilationcalc.blogspot.com.au

 

[PeterDonis]

at v=c , √ 0 = 0 and not forbidden

Yes, that's the equation that's in the table further down on the web page; but it's not the equation that's in the graphic ghwellsjr quoted in his post. That graphic needs to be fixed.

 

[Adam Rifai]

Yes, that's the equation that's in the table further down on the web page; but it's not the equation that's in the graphic ghwellsjr quoted in his post. That graphic needs to be fixed.

Yes, your are correct, i have tested v=c on other online TD calc and the output is t=0

If the universe will eventually recollapse to a Big Crunch, then you could, in theory, manage to live until the Crunch (but not beyond it, since the universe would end there and you with it).

This is also correct, since after the Big crunch, the the space in SPACETIME will be no more, and TIME will not exists without the SPACE

 

[ghwellsjr]

Good point, but at v=c , √ 0 = 0 and not forbidden , so the equation will look like
:View attachment 76689

And then, what calculation did you do to ask the question if a person would live forever?

Look, the Time Dilation factor, otherwise known as gamma, is undefined at v=c. That's what your slider should render if you want it to go all the way to 100%c.

 

[PeterDonis]

i have tested v=c on other online TD calc and the output is t=0

But, as ghwellsjr asked, how does t = 0 translate to "live forever"? t = 0 only tells you about one aspect of what happens at v = c; other aspects are described by the reciprocal of what you are calculating, which is undefined at v = c. So the overall answer, as has been said a number of times in this thread, is that an object with m > 0 cannot move at v = c; and for an object with m = 0, which only moves at v = c, gamma is undefined and so is proper time, so the concept of "living forever" does not even make sense for such an object.

the Time Dilation factor, otherwise known as gamma, is undefined at v=c

His slider isn't calculating gamma, it's calculating 1 / gamma. In other words, it's the factor by which you multiply coordinate time in a given frame to get proper time for an observer moving in that frame. So the slider is correctly giving 0 at v = c for that calculation. Some sources do indeed call this the "time dilation factor", not gamma. The real problem, as I said above, is that, even if this factor describes time dilation, that's only one aspect of what happens at v = c; he hasn't taken into account the other aspects.

 

[PeterDonis]

Since the OP's question has been answered repeatedly, this thread is closed.