## why don't i age while the earth stays young?

Discussion of theories involving time as a dimension, time travel, relativity, branes, and so on, usually applying to the "real" universe which we live in.

### why don't i age while the earth stays young?

if i shoot myself into a magic rocket that can go near the speed of light, without screwing around with our mass or anything, into space away from earth, why is it that I stay young while hundreds of years have passed on earth? wtf happened to relative motion? if im moving away from the earth near the speed of light, isn't the earth moving away from me at the speed of light as if im sitting still too? shouldn't I get old and die while they stay young? what am i missing here?

<----------- c ------(earth)---- =(Me in my rocket)>
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batmanmg
Trionian

Posts: 201
Joined: Sun Aug 20, 2006 10:21 pm

### Re: why don't i age while the earth stays young?

Ur not missing anything.Its just that u messed up by considering more than one reference frame at a time.

Pont 1: if u go off on a rocket, then who said that u dont age ie. stay young?? With respect to you ie taking you as the reference frame you do not age or atleast do not "relativistically" age.But for a person seeing you, you definitely age.

Pont 2: Seeing the other way, if u see them then they age and u dont appear to age.If this does not clarify then see this example:

A hunter (who knows some physics) wants to catch a lion.He sees a lion standing 100m away from him.He thinks too much and this is what he does.He runs directly away from the lion.Now wrt to him, the lion is running away.SO he thinks that it must eventually get tired, lose its kinetic energy and stop after a while which will make him easy to catch the lion.But what happens is that he runs => he loses his kinetic energy and stops..so to him it appears that the lion loses its kinetic energy and stops.But he got it wrong in the last part.Now the lion must come of its own accord to him and be caught, because in the last part: " will make him easy to catch the lion" he changes reference frame to that of lion.But in essence wrt to him he is still so it must be the lion which must come to him.
zizigmondy
Nullonian

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### Re: why don't i age while the earth stays young?

im not sure you really answered me there. you used too many conflicting negatives and positives in your answers.

"Pont 1: if u go off on a rocket, then who said that u dont age ie. stay young?? With respect to you ie taking you as the reference frame you do not age or atleast do not "relativistically" age.But for a person seeing you, you definitely age.

Pont 2: Seeing the other way, if u see them then they age and u dont appear to age.If this does not clarify then see this example:"

I understand what your saying, but it isn't very clear, and the tiger hunter example only enforced the idea of frames of reference, but didn't really answer what i asked to my understanding.

ok let me simplyfy this, me and my friend are the same exact age standing next to eachother and facing eachother and holding clocks on an endless plane which we can call space and ignore. My friend is super strong and he throws me backwards at the speed of light. Assuming we can still see each other and Im still flying through space, what do I see, and what does my friend see in terms of the clocks second hand moving faster or slower?

at a certain point I land on a trampoline that catapults me back toward my friend at the same speed and I land at his feet. Will my clock be ahead of his, or behind, or will they be the same time?
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batmanmg
Trionian

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Joined: Sun Aug 20, 2006 10:21 pm

### Re: why don't i age while the earth stays young?

If you move at close to the speed of light your clock will be behind everyone else's when you return to Earth. You will see his clock moving faster than yours and he will see your clock moving slower than his when you move close to the speed of light but your friend stays back on Earth.

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anderscolingustafson
Tetronian

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### Re: why don't i age while the earth stays young?

You will see his clock moving faster than yours and he will see your clock moving slower than his

Actually both sides will see the other clock moving slower than their own. Because of the symmetry of the situation.

if im moving away from the earth near the speed of light, isn't the earth moving away from me at the speed of light as if im sitting still too?

The problem with the twin paradox is that you've got one person accelerating and decelerating while the other person isn't. When you solve the equations (which involves differentiating some things and getting an expression for relative acceleration), you find that the twin on the spaceship ages less.

PWrong
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