<blockquote>
  <p>If a human average life span is 60-80 years on earth, on mars will the average life span of a human be 62-82 years of earth years? Or will it be 60-80 years of Mars years?</p>
</blockquote>

<p>Relativity is about the relative state of the thing observing and the thing they observe.</p>

<p>Locally (e.g. on Mars) things do not go slower for <em>you</em>, but someone observing (e.g. from Earth) sees time passing more slowly for you.</p>

<p>Locally your life on Mars is not lengthened.  Measured from Earth, more time will pass on Earth (as measured by someone local to Earth) than passes on Mars (as measured by someone on Earth observing Mars).</p>

<p>This is more complicated than it might seem at first glance because <em>it works both ways</em>.  You (on Mars) see <em>me</em> (on Earth) moving, so from your point of view you <em>also</em> see my time frame slow down relative to yours.  From an everyday human point of view that seems like a paradox, as we would not expect <em>both</em> of us to see the other's person's time pass more slowly than ours, but relativity does work that way.</p>

<p>There's a question (or two) on Physics SE dealing with the "why" that happens and why it's not a mistake or a fault with the theory.  <a href="https://physics.stackexchange.com/questions/210794/question-doubt-about-time-dilation-symmetry-in-special-relativity">Here is one</a>.</p>

<p>It's even more complex when you have planets in orbits around a star, because that uses General Relativity and there are even more subtleties and additional effects on the rate of time we each measure for the other.  Gravitational time dilation does <em>not</em> work both ways - that depends on the strength of the gravitational field (from everything) so it's different for each observer.  <a href="https://en.wikipedia.org/wiki/Time_dilation" rel="noreferrer">Wikipedia's Time Dilation page</a> is a reasonable place to start reading from, I think.  Note that general relativity is considerably more complex mathematically than special relativity.</p>

<p>We have measured these effects - they are real, but very small in human experience of them.</p>

CC BY-SA 4.0
2020-05-31T19:34:29.277Z
I think that part of the OP's confusion stems from the fact that a Mars day ([sol](https://en.m.wikipedia.org/wiki/Sol_(day_on_Mars))) is slightly longer than an Earth day. Eg, 500 sols is almost 513.75 mean Earth solar days of 24 hours.
PM 2Ring
CC BY-SA 4.0
2020-05-31T19:36:40.637Z
@PM2Ring That's not my impression, however an answer from you relating to that would do no harm.
StephenG - Help Ukraine
CC BY-SA 4.0
2020-06-01T15:46:30.150Z
But it would be fun to calculate the magnitude of observed change in lifetime  from Earth -- Mars or reverse.  Your gonna need a lot of zeros to the right of the decimal point.
Carl Witthoft
CC BY-SA 4.0
2020-06-01T15:53:40.187Z
@CarlWitthoft We have different ideas of fun. :-)
StephenG - Help Ukraine
CC BY-SA 4.0
2020-06-02T07:50:16.743Z
@StephenG: Thanks for the explanation. That really clarifies my doubt. As you said `Locally your life on Mars is not lengthened`, so anyone in space would age normally like that of on earth.
Ashish Srivastava
CC BY-SA 4.0
2020-05-31T19:06:42.733Z
2020-05-31T19:06:42.733Z
StephenG - Help Ukraine
<p>I came across few  videos which says <code>Astronauts in ISS will have 0.07 seconds extra life</code>. </p>

<p>So if life is possible on mars, than what is the time period of life for us humans? Is it the same as that of earth or different?</p>

<p><strong>For example</strong>, if I spend 500 days on mars, that will be equal to spending around 515 days on earth. So is it that I'm gaining 15 days of life? I mean, can a human life span increase? </p>

<p>If a human average life span is 60-80 years on earth, on mars will the average life span of a human be 62-82 years of earth years? Or will it be 60-80 years of Mars years?</p>

<p>I don't know how much this makes sense but as a new learner just got a thought on space time. </p>

CC BY-SA 4.0
2020-05-31T21:28:23.313Z
Related in Space Exploration SE: [Which astronaut has experienced the largest relativistic shift in time (relative to Earth's surface)?](https://space.stackexchange.com/q/30342/12102) and [Astronauts and Time Dilation](https://space.stackexchange.com/q/41186/12102)
uhoh
CC BY-SA 4.0
2020-05-31T21:50:17.070Z
I’m voting to close this question because a question about the health effects of space travel is not about Astronomy as defined in the health center. However the question is certainly on-topic in Space Exploration SE
uhoh
CC BY-SA 4.0
2020-06-01T12:42:59.037Z
@uhoh Kind of a gray area. The question is about relativity, and astrophysics is generally on topic here.
usernumber
CC BY-SA 4.0
2020-06-01T13:45:20.940Z
@usernumber there is zero astronomy or astrophysics in this question; I only see relativity and a bit of human spaceflight.
uhoh
CC BY-SA 4.0
2020-06-01T15:44:19.557Z
@uhoh This isn't a health question!   It's a question of  **rate** of aging, which brings us to  SR and GR  explanations.
Carl Witthoft
CC BY-SA 4.0
2020-06-02T07:45:00.150Z
@antispinwards: Not exactly! But partially it does.
Ashish Srivastava
<space-time>
Will I age slower in space or on other planets?
Ashish Srivastava
# Will I age slower in space or on other planets?

(Asked by: username_0 on 2020-05-31)

I came across few videos which says `Astronauts in ISS will have 0.07 seconds extra life`.

So if life is possible on mars, than what is the time period of life for us humans? Is it the same as that of earth or different?

**For example**, if I spend 500 days on mars, that will be equal to spending around 515 days on earth. So is it that I'm gaining 15 days of life? I mean, can a human life span increase?

If a human average life span is 60-80 years on earth, on mars will the average life span of a human be 62-82 years of earth years? Or will it be 60-80 years of Mars years?

I don't know how much this makes sense but as a new learner just got a thought on space time.

**Tags:** space-time
> **Comments:**
> **username_1**: Related in Space Exploration SE: [Which astronaut has experienced the largest relativistic shift in time (relative to Earth's surface)?](https://space.stackexchange.com/q/30342/12102) and [Astronauts and Time Dilation](https://space.stackexchange.com/q/41186/12102)  
> **username_1**: I’m voting to close this question because a question about the health effects of space travel is not about Astronomy as defined in the health center. However the question is certainly on-topic in Space Exploration SE  
> **username_2**: @uhoh Kind of a gray area. The question is about relativity, and astrophysics is generally on topic here.  
> **username_1**: @usernumber there is zero astronomy or astrophysics in this question; I only see relativity and a bit of human spaceflight.  
> **username_3**: @uhoh This isn't a health question!   It's a question of  **rate** of aging, which brings us to  SR and GR  explanations.  
> **username_0**: @antispinwards: Not exactly! But partially it does.  

---

## 1 answers

### Answer by username_4 on 2020-05-31. Score: 7 | Accepted answer

> If a human average life span is 60-80 years on earth, on mars will the average life span of a human be 62-82 years of earth years? Or will it be 60-80 years of Mars years?

Relativity is about the relative state of the thing observing and the thing they observe.

Locally (e.g. on Mars) things do not go slower for *you*, but someone observing (e.g. from Earth) sees time passing more slowly for you.

Locally your life on Mars is not lengthened. Measured from Earth, more time will pass on Earth (as measured by someone local to Earth) than passes on Mars (as measured by someone on Earth observing Mars).

This is more complicated than it might seem at first glance because *it works both ways*. You (on Mars) see *me* (on Earth) moving, so from your point of view you *also* see my time frame slow down relative to yours. From an everyday human point of view that seems like a paradox, as we would not expect *both* of us to see the other's person's time pass more slowly than ours, but relativity does work that way.

There's a question (or two) on Physics SE dealing with the "why" that happens and why it's not a mistake or a fault with the theory. [Here is one](https://physics.stackexchange.com/questions/210794/question-doubt-about-time-dilation-symmetry-in-special-relativity).

It's even more complex when you have planets in orbits around a star, because that uses General Relativity and there are even more subtleties and additional effects on the rate of time we each measure for the other. Gravitational time dilation does *not* work both ways - that depends on the strength of the gravitational field (from everything) so it's different for each observer. [Wikipedia's Time Dilation page](https://en.wikipedia.org/wiki/Time_dilation) is a reasonable place to start reading from, I think. Note that general relativity is considerably more complex mathematically than special relativity.

We have measured these effects - they are real, but very small in human experience of them.

> **Comments:**
> **username_5**: I think that part of the OP's confusion stems from the fact that a Mars day ([sol](https://en.m.wikipedia.org/wiki/Sol_(day_on_Mars))) is slightly longer than an Earth day. Eg, 500 sols is almost 513.75 mean Earth solar days of 24 hours.  
> **username_4**: @PM2Ring That's not my impression, however an answer from you relating to that would do no harm.  
> **username_3**: But it would be fun to calculate the magnitude of observed change in lifetime  from Earth -- Mars or reverse.  Your gonna need a lot of zeros to the right of the decimal point.  
> **username_4**: @CarlWitthoft We have different ideas of fun. :-)  
> **username_0**: @StephenG: Thanks for the explanation. That really clarifies my doubt. As you said `Locally your life on Mars is not lengthened`, so anyone in space would age normally like that of on earth.  

---

