# The Naked Scientists Forum

### Author Topic: Could we slow down an object relative to us and see if time speeds up?  (Read 1018 times)

#### thedoc

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##### Could we slow down an object relative to us and see if time speeds up?
« on: 25/09/2015 14:50:01 »
sowden ian  asked the Naked Scientists:

I was thinking about relativity (as one does) and this question came to me: Has there ever been an experiment which has tried slowing down an object relative to us to see if time speeds up? I then kept thinking and came up with more questions. I am not sure if they are stupid or just the ideas that come to drunk teenagers or am I using circular logic? I am very interested in the answers. If you can't find time to answer them quickly, could you point to a source for the answers. Supplementary 1 Is there a theoretical location (may be between galaxies) where an object could be slowed to be absolutely stationary where time is infinitely fast? Supplementary 2 I have always thought of time as just a something which measures a number of changes comparatively. e.g. a year is a rotation of the sun by the earth, or a day is a rotation of the earth (approximately) That means in these cases it is also a measure of distance like a light year. A second is a day/86400 so it the period for this rotation but it is also the period that a atom vibrates x times or the period it takes an element to warm up h degrees under the effect of t units of heat. Does this mean that travelling at the speed of light will stop all change, chemical, physical, electrical? Or is time something else? Supplementary 3 Following from 2: chemical change, physical change etc all require energy. Does that mean that there is an absolute limit to the amount of energy that can be expended in a period. i.e. at the speed of light is all the energy is being used moving? Supplementary 4 Following Supplementary 3 would that make a mathematical relationship between energy and time or have I just come back to y=mc 2? Supplementary 5 From 3: Does time stop in a black hole? Supplementary 5 Following from 2. If space is just a change in location and this takes time surely it is not surprising that space and time are related. Is this circular thinking?

Supplementary 6 Would it be possible to speed up a computer by sending into space and is this viable? I think that is enough to be going on with. I hope you can help: it really is keeping me awake at night. (It was listening to an old episode of the BBC program "In Our Time" that started me thinking this way). (I am 56,“ not a teenager) Regards, Hopefully, Relatively Ian

What do you think?
« Last Edit: 25/09/2015 14:50:01 by _system »

#### Colin2B

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##### Re: Could we slow down an object relative to us and see if time speeds up?
« Reply #1 on: 25/09/2015 15:12:22 »
Ian
Consider yourself stationary, you have an accurate clock which measures the  passage of time.
Someone else is in a spaceship with a similar clock, they travel close to the speed of light (relative to you), to them their clock moves at the same rate it always did. After the clock has counted a year, they have eaten a year's worth of food and aged a year. However, if you measure the time passing for them you measure it to be passing at a different rate - a year may pass for them, 100 years for you.
So to answer your question, if the spaceship slows down relative to you, you will measure their time as coming closer to the time measurement of your own, but both of you will still perceive you own time as normal.
I think it would be useful if you read up some of the articles on the net eg Wiki to understand the basic concept and then you will be better able to understand the answers to your other questions.
I'll leave it at that for the moment as I have to sign off soon, but I'm sure others will be able to post answers to your other questions.

#### Thebox

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##### Re: Could we slow down an object relative to us and see if time speeds up?
« Reply #2 on: 25/09/2015 15:14:31 »
sowden ian  asked the Naked Scientists:

I was thinking about relativity (as one does) and this question came to me: Has there ever been an experiment which has tried slowing down an object relative to us to see if time speeds up? I then kept thinking and came up with more questions. I am not sure if they are stupid or just the ideas that come to drunk teenagers or am I using circular logic? I am very interested in the answers. If you can't find time to answer them quickly, could you point to a source for the answers. Supplementary 1 Is there a theoretical location (may be between galaxies) where an object could be slowed to be absolutely stationary where time is infinitely fast? Supplementary 2 I have always thought of time as just a something which measures a number of changes comparatively. e.g. a year is a rotation of the sun by the earth, or a day is a rotation of the earth (approximately) That means in these cases it is also a measure of distance like a light year. A second is a day/86400 so it the period for this rotation but it is also the period that a atom vibrates x times or the period it takes an element to warm up h degrees under the effect of t units of heat. Does this mean that travelling at the speed of light will stop all change, chemical, physical, electrical? Or is time something else? Supplementary 3 Following from 2: chemical change, physical change etc all require energy. Does that mean that there is an absolute limit to the amount of energy that can be expended in a period. i.e. at the speed of light is all the energy is being used moving? Supplementary 4 Following Supplementary 3 would that make a mathematical relationship between energy and time or have I just come back to y=mc 2? Supplementary 5 From 3: Does time stop in a black hole? Supplementary 5 Following from 2. If space is just a change in location and this takes time surely it is not surprising that space and time are related. Is this circular thinking?

Supplementary 6 Would it be possible to speed up a computer by sending into space and is this viable? I think that is enough to be going on with. I hope you can help: it really is keeping me awake at night. (It was listening to an old episode of the BBC program "In Our Time" that started me thinking this way). (I am 56,“ not a teenager) Regards, Hopefully, Relatively Ian

What do you think?

https://en.wikipedia.org/wiki/Hafele%E2%80%93Keating_experiment

#### PmbPhy

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##### Re: Could we slow down an object relative to us and see if time speeds up?
« Reply #3 on: 25/09/2015 15:24:24 »
Quote from: thedoc

I was thinking about relativity (as one does) and this question came to me: Has there ever been an experiment which has tried slowing down an object relative to us to see if time speeds up?
At one time an atomic clock was placed on a plane in order to measure the time dilation effects. The moving clock was running slow compared to the a clock of the same construction which was at rest. When the plane lander the clock went back to "ticking" at the same rate as clocks which are at rest. You're really asking whether clocks at rest run faster than clocks in motion. Since clocks in motion run slower than clocks at rest, it directly follows that clocks at rest run faster than clocks in motion. Simple, huh?

Quote from: thedoc
Is there a theoretical location (may be between galaxies) where an object could be slowed to be absolutely stationary where time is infinitely fast?
No. In essence what you're looking for is a clock that runs infinitely faster than clocks at rest in an inertial frame in flat spacetime where clocks run at their normal rate. If a clock is placed in a gravitational field at a higher gravitational potential than the zero level then that's the only way known to get a clock to run faster. To have it run infinitely faster the gravitational field would have to be infinitely strong and there is no such field where that's possible.

Quote from: thedoc
I have always thought of time as just a something which measures a number of changes comparatively.
Essentially that's about right. For a full treatment on time pleas see http://users.wfu.edu/brehme/time.htm

Quote from: thedoc
e.g. a year is a rotation of the sun by the earth, or a day is a rotation of the earth (approximately) That means in these cases it is also a measure of distance like a light year. A second is a day/86400 so it the period for this rotation but it is also the period that a atom vibrates x times or the period it takes an element to warm up h degrees under the effect of t units of heat. Does this mean that travelling at the speed of light will stop all change, chemical, physical, electrical?
Questions like that need to be asked with a reference frame in mind since velocity is a relative concept. And a frame of reference does not exist in which instruments can be placed at rest in which travels at the speed of light.

Quote from: thedoc
Following from 2: chemical change, physical change etc all require energy. Does that mean that there is an absolute limit to the amount of energy that can be expended in a period.
The rate at which energy is used is called power and measured in units called Watts. There is no known practical limit to the how fast energy can be used.

Quote from: thedoc
Following Supplementary 3 would that make a mathematical relationship between energy and time or have I just come back to y=mc 2?
I'm sorry but I don't understand your question.

Quote from: thedoc
From 3: Does time stop in a black hole?
If you're talking about what happens in a frame of reference which falls into a black hole then at the origin of that frame of reference time runs at the normal rate.

Quote from: thedoc
Following from 2. If space is just a change in location and this takes time surely it is not surprising that space and time are related. Is this circular thinking?
No. But it's not correct. Space is not defined as a change in location. See http://users.wfu.edu/brehme/space.htm

Quote from: thedoc
Would it be possible to speed up a computer by sending into space and is this viable?
In space the gravitational potential is a tad bit smaller than it is on the surface of the ground. That implies that time runs tiny bit faster far from the Earth.

Quote from: thedoc
it really is keeping me awake at night.
Good man. I know the feeling. Been there, done that. :)

#### Craig W. Thomson

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##### Re: Could we slow down an object relative to us and see if time speeds up?
« Reply #4 on: 25/09/2015 17:12:21 »
Here, scientists have slowed down some photons:

#### mathew_orman

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##### Re: Could we slow down an object relative to us and see if time speeds up?
« Reply #5 on: 27/09/2015 10:02:52 »
You cannot see a photon unless it ends up in your eye...
Photon cannot be slowed, sped  up, stopped and or redirected...
It can only be re-emitted or absorbed...
Refraction, reflection and scintillation describe re-emitting of photons...

#### The Naked Scientists Forum

##### Re: Could we slow down an object relative to us and see if time speeds up?
« Reply #5 on: 27/09/2015 10:02:52 »