# The slowing of time

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Does the time traveller move in slow motion as he approaches the near-speed of light?

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Does the time traveller move in slow motion as he approaches the near-speed of light?

As I understand it he doesn't but he might think you do. You don't but might think he does.

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As I understand it he doesn't but he might think you do. You don't but might think he does.

Lets say that there are two clocks , one on the ground and one on the spaceship and that they

were both synchronised before takeoff and that after the flight at the near speed of light the clock showed that it had lost x hours

because time had slowed down; where have the lost hours gone?

In order to balance books if one subtracts something it has to be added somewhere else.

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Lets say that there are two clocks , one on the ground and one on the spaceship and that they

were both synchronised before takeoff and that after the flight at the near speed of light the clock showed that it had lost x hours

because time had slowed down; where have the lost hours gone?

Nowhere, there are no "lost hours"

In order to balance books if one subtracts something it has to be added somewhere else.

There's nothing to balance.

Take the following example, two men start out at the same spot and walk to another spot. One takes a straight path and the other walks along a curved path. When they meet up again, one man has walked more step than the other. This does not mean that there are any "lost steps" we have to account for in order to "balance the books", only that the paths the men took were of different lengths.

With the fast traveling spaceship, we say that it took a different path through space-time than the other person, and this accounts for the difference in elapsed time for the two.

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Nowhere, there are no "lost hours"

There's nothing to balance.

Take the following example, two men start out at the same spot and walk to another spot. One takes a straight path and the other walks along a curved path. When they meet up again, one man has walked more step than the other. This does not mean that there are any "lost steps" we have to account for in order to "balance the books", only that the paths the men took were of different lengths.

With the fast traveling spaceship, we say that it took a different path through space-time than the other person, and this accounts for the difference in elapsed time for the two.

If the spaceship example involved twins, in order for one twin to end up younger than the twin on the ground the astronaught twin would have had to have spent his time in space in "slow motion" to account for difference in time between the clocks.

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If the spaceship example involved twins, in order for one twin to end up younger than the twin on the ground the astronaught twin would have had to have spent his time in space in "slow motion" to account for difference in time between the clocks.

That's one way of looking at it. You could also say that the twin on the ground spent his time in "fast motion".

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From to pov of the clock on the planet (or whichever is the stationary one), it will seem that the moving clock would have slower time, so yeah i think the person moving with the clock would seem to be in slo-mo. However, that same person wouldn't feel any different because to him, time is moving normally.

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Nowhere, there are no "lost hours"

There's nothing to balance.

Take the following example, two men start out at the same spot and walk to another spot. One takes a straight path and the other walks along a curved path. When they meet up again, one man has walked more step than the other. This does not mean that there are any "lost steps" we have to account for in order to "balance the books", only that the paths the men took were of different lengths.

With the fast traveling spaceship, we say that it took a different path through space-time than the other person, and this accounts for the difference in elapsed time for the two.

what then defines this "different path through space"? Don't tell me its the speed of the space ship as it approaches c. Does that mean that the speed of the spaceship maps out its own space-time? Hypothetically, if there were two spaceships, with spaceship1 moving at "almost the speed of light", and spaceship2 moving with about three-quarter of that speed, what then would be the time difference between both spaceships as observed from earth as an initial frame? Don't tell me it depends on their speed again, because that would not take into consideration the effect of "space" on speed. What are these "effects"?

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That's one way of looking at it. You could also say that the twin on the ground spent his time in "fast motion".

From an Earth frame of reference, does this mean that relativistic speed time travel has to be spent in slow motion? Is that possible?

Even if it were possible, wouldn't the time spent in slow motion cancel out the gain in time of the journey?

Wouldn't this suggest that significant time travel is impossible?

Edited by ronians1
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From an Earth frame of reference, does this mean that relativistic speed time travel has to be spent in slow motion? Is that possible?

Even if it were possible, wouldn't the time spent in slow motion cancel out the gain in time of the journey?

Wouldn't this suggest that significant time travel is impossible?

I think you are going to have to define 'time travel'. To me and my clock, I 'travel' forward in time at the rate of one second per second. Doesn't matter if I do it on earth or in a fast rocket. Time does not change for me. How you see me from your FOR has no impact on me, and you cannot consider one frame 'normal' and the other 'slow'.

You don't 'gain' time in the journey. As far as I can tell, relativistic speed has nothing to say about time travel.

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travelling at the speed of light,means that all the atoms.electrons and protons would be in suspended animation at absolute zero relative to each other,they cannot go faster than the speed of light,which they would already be doing in 1 direction,the direction of travel.

suspended animation produces zero passage of time.

Edited by derek w
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travelling at the speed of light,means that all the atoms.electrons and protons would be in suspended animation at absolute zero relative to each other,they cannot go faster than the speed of light,which they would already be doing in 1 direction,the direction of travel.

suspended animation produces zero passage of time.

Can I have a citation please? I've never heard of electrons, atoms and protons travelling at the speed of light.

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From to pov of the clock on the planet (or whichever is the stationary one), it will seem that the moving clock would have slower time, so yeah i think the person moving with the clock would seem to be in slo-mo. However, that same person wouldn't feel any different because to him, time is moving normally.

If the astronaught was travelling at the near speed of light(when everything comes to almost a standstill in the spaceship)

how can he think time was moving normally? Can biological systems even survive the near speed of light?

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Yes sorry that's the point I was trying to make ,mass cannot travel at the speed of light,only energy can be transmitted at the speed of light.

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If you are looking at a spaceship travelling by at relativistic uniform speed, you will see the cloocks and movements in/on the spaceship to be slowed down by the amount predicted by the Lorentz-Fitzgerald expression for time dilation.

The occupants of the spaceship will see you and your clock to be slowed by the same amount. Neither one sees their own time slowed or is in 'suspended animation' (?).

This is because there is no concensus on who is moving and who isn't, as all motion is relative. Hence the name of the theory RELATIVITY.

If there is an acceleration involved such as in the twin 'paradox', where one twin travels away, slows down reverses, and comes back, we know who moved at relativistic speed. The moving frame can now be discerned and there is an actual age difference between the twins.

Edited by MigL
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If the astronaught was travelling at the near speed of light(when everything comes to almost a standstill in the spaceship)

how can he think time was moving normally? Can biological systems even survive the near speed of light?

You can't tell that you're moving, if at constant velocity; as far as you can tell, you are at rest. So the question makes no sense in that regard — we are moving close to the speed of light relative to some cosmic rays.

Now, the question of whether we could survive an acceleration to a high speed with respect to something, is a different beast.

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Lets say we witness the twin paradox in real life without any knowledge of relativity. On Earth we see the astronaught twin climb out of his spacecraft considerably younger than his brother and both the clock on the ground and the one in the spaceship show different times.

With no knowledge of relativity at all - how does one explain what has happened to a group of laymen onlookers?

The only explanation I can think of is that (1) the astronaught has spent his time in space in slow motion

(2) the difference in clock times is due to time and reality slowing down on the spaceship.

This fact and reality surely - something that overrides everything else.!

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Lets say we witness the twin paradox in real life without any knowledge of relativity. On Earth we see the astronaught twin climb out of his spacecraft considerably younger than his brother and both the clock on the ground and the one in the spaceship show different times.

With no knowledge of relativity at all - how does one explain what has happened to a group of laymen onlookers?

The only explanation I can think of is that (1) the astronaught has spent his time in space in slow motion

(2) the difference in clock times is due to time and reality slowing down on the spaceship.

This fact and reality surely - something that overrides everything else.!

In the past, without relevant knowledge, explanations would likely be, its magic or god did it. Since Einstein has filled in some of the gaps in our collective knowledge, we don’t need to resort to falsehoods to explain away such things, we just need the appropriate metaphor.

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Lets say we witness the twin paradox in real life without any knowledge of relativity. On Earth we see the astronaught twin climb out of his spacecraft considerably younger than his brother and both the clock on the ground and the one in the spaceship show different times.

With no knowledge of relativity at all - how does one explain what has happened to a group of laymen onlookers?

The only explanation I can think of is that (1) the astronaught has spent his time in space in slow motion

(2) the difference in clock times is due to time and reality slowing down on the spaceship.

This fact and reality surely - something that overrides everything else.!

The astronaut would not agree. To him/her, aboard the craft, everything was normal.

What this looked like to lay onlookers is immaterial. We've studied the science, and understand what goes on.

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The astronaut would not agree. To him/her, aboard the craft, everything was normal.

What this looked like to lay onlookers is immaterial. We've studied the science, and understand what goes on.

Every trip we make we experience slow motion only the speeds we attain in life are so insignificant that it is not noticeable.

However at near-light speeds the slow motion experienced is literally "virtually frozen in time".

Why is it important in relativity that, aboard the craft during the journey, whilst travelling at the near speed of light everything has to appear normal to the astronaught?

Edited by ronians1
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Every trip we make we experience slow motion only the speeds we attain in life are so insignificant that it is not noticeable.

From whose perspective?

However at near-light speeds the slow motion experienced is literally "virtually frozen in time".

From whose perspective?

Why is it important in relativity that, aboard the craft during the journey, after travelling at the near speed of light everything has to appear normal to the astronaught?

It is important because without it the theory of Relativity would have been falsified.

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Every trip we make we experience slow motion only the speeds we attain in life are so insignificant that it is not noticeable.

However at near-light speeds the slow motion experienced is literally "virtually frozen in time".

Why is it important in relativity that, aboard the craft during the journey, whilst travelling at the near speed of light everything has to appear normal to the astronaught?

There are implications stemming from the idea that there is no preferred frame of reference.

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If you were moving uniformly at 99.9% of the speed of light in intergalactic space, ie. with no reference points such as stars or planets for your motion, you would not be able to tell that you are moving at all ( again motion is relative ).

So why would you NOT expect the normal passage of time, ronians 1 ????

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From whose perspective?

From whose perspective?

It is important because without it the theory of Relativity would have been falsified.

From the perspective an observer at rest on Earth or theoretical observer at rest on any near- obbject in space which, although may be moving, whose movement would be insignificant in relation to the near-speed of light.r

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"Swansot".There are implications stemming from the idea that there is no preferred frame of reference.

Question.Does this mean that mass can move at the speed of light if the space it occupies is moving. For example if 2 areas of space are expanding away from each other?

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