<blockquote>
  <ol>
  <li>The faster you move, the slower does time feel</li>
  </ol>
</blockquote>

<p>No.</p>

<p>The faster someone else you are <em>observing</em> moves <em>relative to you</em>, the more time (as observed by you in their frame) slows down relative to the passage of time in <em>your</em> local frame.</p>

<p>Put another way, your local time is the fastest rate at which time changes.  Any measurement you make of time passing in frames moving relative to your will be slower.</p>

<p>Locally <em>your</em> time never slows down as measured by you.</p>

<p>And, hard as it is to accept, this works in reverse to.  Other people see your time slowing down as they see you moving relative to themselves (where they see themselves as not moving).  This is not a contradiction or paradox - it is the only way the math works out in a self-consistent way.  Two people moving relative to each other <em>both</em> see the other persons time slow down relative to their own !</p>

<p>You have to use the mathematics of special relativity to understand why this works out that way, but it has been measured and we know it does.</p>

<blockquote>
  <p>So there MUST be an absolute definition of zero movement in the universe for statement 1. to be true.</p>
</blockquote>

<p>This is a reasonable deduction and you have proven (in effect) that (1) leads to a false conclusion so is itself false.  You might actually enjoy learning the details of special relativity using math.</p>

<p>Most apparent paradoxes in relativity come from trying to mix "everyday" common sense (which is basically non-relativistic mechanics) with relativity.  Do not mix and match these as it leads to confusion.  When using relativity you must apply it consistently.  That's the key to resolving these apparent paradoxes.</p>

<blockquote>
  <p>the very atoms that the person consists of will move around slower in relation to each other which will cause this “feel” of slowing time in the human brain.</p>
</blockquote>

<p>Do not confuse the idea of your personal sense of the passage of time with the formal definition of time in relativity (and physics).  Although relativity uses the notion of "observers" these are not human perceptions, but abstract measurements.  The formal definition of, for example, a second has nothing to do with a human sense of time.</p>

CC BY-SA 4.0
2020-06-04T22:58:45.357Z
Thanks for commenting. If both moving persons see the other person as moving slower, then the whole idea in lets say, the movie interception, where a person is moving really fast and then meets his family which are the much older than him - is not possible according to your explanation? In that case, I think I am convinced :) Thanks
Stephan Møller
CC BY-SA 4.0
2020-06-04T23:49:37.523Z
@StephanRyer This ones is tricky and you need to read about what is known as ["The Twin Paradox"](https://en.wikipedia.org/wiki/Twin_paradox).  You will fine a great deal of material on the [physics.se] site as confusion about how this works is quite normal.  I'm not familiar with the movie, but the fact that someone must accelerate and decelerate, accelerate again and decelerate again to return and meet complicates this.
StephenG - Help Ukraine
CC BY-SA 4.0
2020-06-05T00:57:48.090Z
@StephanRyer Are you talking about the movie [*Interstellar*](https://en.wikipedia.org/wiki/Interstellar_(film))?
PM 2Ring
CC BY-SA 4.0
2020-06-05T05:12:41.917Z
PM Ring2: Ohhhh, yes I meant interstellar. Thanks!
Stephan Møller
CC BY-SA 4.0
2020-06-05T05:28:27.947Z
StephanG: Thank you for pointing out that the statement 1. was where I missed it and referencing the twin paradox. I did not know of this until now.
Stephan Møller
CC BY-SA 4.0
2020-06-05T19:05:19.230Z
The time dilation in *Interstellar* is a bit different to the Twin Paradox of Special Relativity. In that movie, the time dilation on Miller's planet is due to a combination of the gravitational field of the huge spinning black hole, and the extreme orbital speed of the planet. There are several questions on this site related to this, eg https://astronomy.stackexchange.com/q/20210/16685 And also on the Physics site, eg https://physics.stackexchange.com/q/557123/123208
PM 2Ring
CC BY-SA 4.0
2020-06-04T22:45:22.613Z
2020-06-04T22:45:22.613Z
StephenG - Help Ukraine
<p>I have read multiple posts in here about the concept of an absolute zero speed definition in space. However, I have some arguments FOR absolute zero speed, which I would like to write here, and have people to comment on to see if I am missing something.</p>

<p>My theory:</p>

<p>There MUST be an absolute zero point - but not necessarily easy (nor possible) to measure.
Einstein said…
To explain why I think this must be true, I would like to list two statements that the public seems to agree on and of which I think are contradictory:</p>

<ol>
<li>The faster you move, the slower does time feel</li>
<li>There is no absolute zero point of speed - all movement is relative</li>
</ol>

<p>Statement 1 is discussed <a href="https://www.space.com/21675-time-travel.html#:~:text=Einstein&#39;s%20theory%20of%20special%20relativity,relativity%2C%20gravity%20can%20bend%20time" rel="nofollow noreferrer">here</a>.</p>

<p>The article states:</p>

<blockquote>
  <p>“…physicist Albert Einstein showed that time is an illusion; it is relative — it can vary for different observers depending on your speed through space.”</p>
</blockquote>

<p>So, this means: If two persons move at different speeds, the fastest moving person will observe time as passing by slower than the other person. Actually, the very atoms that the person consists of will move around slower in relation to each other which will cause this “feel” of slowing time in the human brain.</p>

<p>So say we remove all other objects in the world so we have a universe with just these two persons. If all movement is relative, there would have been no notion of different speeds of movements of the two persons. So there MUST be an absolute definition of zero movement in the universe for statement 1. to be true.</p>

<p>So, how do we measure this? I really don’t know. Maybe we will never be able to. Maybe knowing what the asbolute zero is will never be important as everything we can achieve can be done without ever knowing this. But it must exist.</p>

<p>What am I missing?
I am fully aware that lots of people actually work and study this area quite intensively. So, I would expect that an expert on this subject may be able to pin point what I might be missing. So this is my invite to join the discussion in the thread below.</p>

<p>I look forward to hearing your thoughts in the matter.</p>

CC BY-SA 4.0
2020-06-05T14:45:45.007Z
I’m voting to close this question because this is not a site for random speculative theories
Carl Witthoft
CC BY-SA 4.0
2020-06-05T15:26:25.180Z
No. Lorenz-transformation does not affect the result of any experiment, that is an essential part of Special Relativity. -> There is no SR way to have an absolute zero (velocity) point. However, there is a global intertial frame - the cosmic microwave background seem originating from a gas cloud moving in the direction of the Hercules constellation with 160 km/s . Note, this thing has changed in the science twice since Newton and Galilei, so don't take it prescribed for the eternity - but a next change would require something highly above what we now know.
peterh
CC BY-SA 4.0
2020-06-05T22:52:38.480Z
I’m voting to close this question because it is not about Astronomy as defined in the help center. I think 'here is what I think, where am I going wrong' is a legitimate method for learning physics and this might be taken up in Physics SE with some rewrites, but it's off-topic here.
uhoh
CC BY-SA 4.0
2020-06-06T19:41:56.573Z
Fair enough - just glad for the help in any case :)
Stephan Møller
<speed><special-relativity>
Absolute zero speed in space
Stephan Møller
# Absolute zero speed in space

(Asked by: username_0 on 2020-06-04)

I have read multiple posts in here about the concept of an absolute zero speed definition in space. However, I have some arguments FOR absolute zero speed, which I would like to write here, and have people to comment on to see if I am missing something.

My theory:

There MUST be an absolute zero point - but not necessarily easy (nor possible) to measure.
Einstein said…
To explain why I think this must be true, I would like to list two statements that the public seems to agree on and of which I think are contradictory:

1. The faster you move, the slower does time feel
2. There is no absolute zero point of speed - all movement is relative

Statement 1 is discussed [here](https://www.space.com/21675-time-travel.html#:~:text=Einstein's%20theory%20of%20special%20relativity,relativity%2C%20gravity%20can%20bend%20time).

The article states:

> “…physicist Albert Einstein showed that time is an illusion; it is relative — it can vary for different observers depending on your speed through space.”

So, this means: If two persons move at different speeds, the fastest moving person will observe time as passing by slower than the other person. Actually, the very atoms that the person consists of will move around slower in relation to each other which will cause this “feel” of slowing time in the human brain.

So say we remove all other objects in the world so we have a universe with just these two persons. If all movement is relative, there would have been no notion of different speeds of movements of the two persons. So there MUST be an absolute definition of zero movement in the universe for statement 1. to be true.

So, how do we measure this? I really don’t know. Maybe we will never be able to. Maybe knowing what the asbolute zero is will never be important as everything we can achieve can be done without ever knowing this. But it must exist.

What am I missing?
I am fully aware that lots of people actually work and study this area quite intensively. So, I would expect that an expert on this subject may be able to pin point what I might be missing. So this is my invite to join the discussion in the thread below.

I look forward to hearing your thoughts in the matter.

**Tags:** speed, special-relativity

> **Comments:**
> **username_1**: I’m voting to close this question because this is not a site for random speculative theories  
> **username_2**: No. Lorenz-transformation does not affect the result of any experiment, that is an essential part of Special Relativity. -> There is no SR way to have an absolute zero (velocity) point. However, there is a global intertial frame - the cosmic microwave background seem originating from a gas cloud moving in the direction of the Hercules constellation with 160 km/s . Note, this thing has changed in the science twice since Newton and Galilei, so don't take it prescribed for the eternity - but a next change would require something highly above what we now know.  
> **username_3**: I’m voting to close this question because it is not about Astronomy as defined in the help center. I think 'here is what I think, where am I going wrong' is a legitimate method for learning physics and this might be taken up in Physics SE with some rewrites, but it's off-topic here.  
> **username_0**: Fair enough - just glad for the help in any case :)  

---

## 1 answers

### Answer by username_4 on 2020-06-04. Score: 7 | Accepted answer

> 1. The faster you move, the slower does time feel

No.

The faster someone else you are *observing* moves *relative to you*, the more time (as observed by you in their frame) slows down relative to the passage of time in *your* local frame.

Put another way, your local time is the fastest rate at which time changes. Any measurement you make of time passing in frames moving relative to your will be slower.

Locally *your* time never slows down as measured by you.

And, hard as it is to accept, this works in reverse to. Other people see your time slowing down as they see you moving relative to themselves (where they see themselves as not moving). This is not a contradiction or paradox - it is the only way the math works out in a self-consistent way. Two people moving relative to each other *both* see the other persons time slow down relative to their own !

You have to use the mathematics of special relativity to understand why this works out that way, but it has been measured and we know it does.

> So there MUST be an absolute definition of zero movement in the universe for statement 1. to be true.

This is a reasonable deduction and you have proven (in effect) that (1) leads to a false conclusion so is itself false. You might actually enjoy learning the details of special relativity using math.

Most apparent paradoxes in relativity come from trying to mix "everyday" common sense (which is basically non-relativistic mechanics) with relativity. Do not mix and match these as it leads to confusion. When using relativity you must apply it consistently. That's the key to resolving these apparent paradoxes.

> the very atoms that the person consists of will move around slower in relation to each other which will cause this “feel” of slowing time in the human brain.

Do not confuse the idea of your personal sense of the passage of time with the formal definition of time in relativity (and physics). Although relativity uses the notion of "observers" these are not human perceptions, but abstract measurements. The formal definition of, for example, a second has nothing to do with a human sense of time.

> **Comments:**
> **username_0**: Thanks for commenting. If both moving persons see the other person as moving slower, then the whole idea in lets say, the movie interception, where a person is moving really fast and then meets his family which are the much older than him - is not possible according to your explanation? In that case, I think I am convinced :) Thanks  
> **username_4**: @StephanRyer This ones is tricky and you need to read about what is known as ["The Twin Paradox"](https://en.wikipedia.org/wiki/Twin_paradox).  You will fine a great deal of material on the [physics.se] site as confusion about how this works is quite normal.  I'm not familiar with the movie, but the fact that someone must accelerate and decelerate, accelerate again and decelerate again to return and meet complicates this.  
> **username_5**: @StephanRyer Are you talking about the movie [*Interstellar*](https://en.wikipedia.org/wiki/Interstellar_(film))?  
> **username_0**: PM Ring2: Ohhhh, yes I meant interstellar. Thanks!  
> **username_0**: StephanG: Thank you for pointing out that the statement 1. was where I missed it and referencing the twin paradox. I did not know of this until now.  
> **username_5**: The time dilation in *Interstellar* is a bit different to the Twin Paradox of Special Relativity. In that movie, the time dilation on Miller's planet is due to a combination of the gravitational field of the huge spinning black hole, and the extreme orbital speed of the planet. There are several questions on this site related to this, eg https://astronomy.stackexchange.com/q/20210/16685 And also on the Physics site, eg https://physics.stackexchange.com/q/557123/123208  

---

