# Traveling to space aging more slowly is true?

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1. Aug 18, 2015

### praveena

Hai pf,
yesterday i asked a question to my friend that
"I had heared that people who were travelling to space may have a slight age difference is it true??? assume if i and my friend are of age 30. i got a chance to travel to space. and i was returning to earth after 5 years. then my friend who lived at earth has an age of 35 and i have an age of moreorless 32. is those lines were true?
who replied me the below mentioned answer
in your case. You travel from earth, you get older 2 year and your friend 5 year.
Let's say γ=52=2.5
How fast should you go?
What is V, so that √(11−v2)=2.5?
2.5∗√(1−v2)=1
√(1−v2)=0.4
1−v2=0.16
v2=1−0.16=0.84
v=√(0.84)
You have to travel at about 2,750,000 km per second.
here my question is does the travelling speed or velocity affects agening?

2. Aug 18, 2015

### phinds

speed IS velocity for this case. What causes differential aging is that you have taken different paths through spacetime. Your clock ticked at one second per second and his clock ticked at one second per second but they took different paths through space-time and so ticked a different number of times.

This is the "twin paradox" and you can find hundreds of discussions on the internet.

3. Aug 21, 2015

### |Glitch|

Special Relativity predicts clocks moving at faster relative speeds compared to a clock at rest will tick slower. Therefore, the faster you are moving relative to someone at rest, the slower you will age when compared to the person at rest. However, General Relativity also predicts that a clock closer to an extremely massive object will tick slower than a clock much further away from any gravitational influence.

In the real world this can be demonstrated in our GPS system. The GPS satellites are orbiting Earth at 4 km/s, causing their on-board clocks to tick 7 μs/day slower than the clocks on Earth due to Special Relativity. However, as a result of General Relativity, the clocks on Earth will tick 45.9 μs/day slower than the clocks on the GPS satellites. Which results in a time difference of 38.9 μs/day. The discrepancy may not seem like much of a difference, but if not compensated for over the span of a day it amounts to ~10 km.

4. Aug 21, 2015

### DaveC426913

Your numbers are off. You cannot travel as fast as, or faster than, 299,000 km per second under any circumstances.

5. Aug 22, 2015

### Armando Valle

Yes bro, this is called relativity and gravity affects your perception of time, maybe you should read about the airplane experiment and its nuclear clocks, its very interesting

6. Aug 22, 2015

### phinds

You misunderstand. It does NOT change your perception of time. To repeat what has already been said, your clock ticks at one second per second.

7. Aug 22, 2015

### Armando Valle

It can change your perception of time just like traveling at the speed of light, because nothing can be faster than that your particles have to slow down, you are contradicting yourself

8. Aug 22, 2015

### phinds

Again, you misunderstand. You cannot travel at the speed of light. If you travel just under the speed of light relative to me, your clock ticks at one second per second and so does mine. You see mine ticking much slower and I see yours ticking much slower, but neither of us has our perception of time changed.

9. Aug 22, 2015

### DaveC426913

Relativistic does not change your perception of time, it affects your observations of other frames of reference.

10. Aug 22, 2015

### phinds

Isn't that what I just said?

11. Aug 22, 2015

### DaveC426913

Yes. I didn't feel that a simple' +1' or 'DaveC426913 liked this post' was sufficient to convince the OP of the wisdom of your words.

12. Aug 23, 2015

### stevebd1

You'll probably find this web page of interest-

The relativistic Rocket
http://math.ucr.edu/home/baez/physics/Relativity/SR/rocket.html [Broken]

Last edited by a moderator: May 7, 2017