As I understand it, the faster I accelerate myself the slower time for
me moves as compared to an observer I left behind. Andromeda my be 2
million light years away but at higher and higher speeds accelerated to
I could get there in no time at all, but it would still be two million
years for the observer I left on earth. I also understand that if you
travel in a strait line eventually you will come back to where you
started. So given that, I could accelerate myself to some minute
fraction under the speed of light then coast and return to the place I
left in a few seconds. To the observer I left behind billions and
billions of years may have past making the universe to him that much
older but to me the universe would only be a few seconds older. How can
the universe be two different ages when I arrive back? Does
decelerating myself to the original speed I started at cause time to
speed up that much? Am I actually accelerating myself again to get back
to the speed of the original observer?

I know I may be making what you all may consider stupid mistakes, but I
am just an amateur trying to understand relativity a bit better. Any
answers would be greatly appreciated.

-Al

Albion wrote:
As I understand it, the faster I accelerate myself the slower time for
me moves as compared to an observer I left behind. Andromeda my be 2
million light years away but at higher and higher speeds accelerated to
I could get there in no time at all, but it would still be two million
years for the observer I left on earth. I also understand that if you
travel in a strait line eventually you will come back to where you
started. So given that, I could accelerate myself to some minute
fraction under the speed of light then coast and return to the place I
left in a few seconds. To the observer I left behind billions and
billions of years may have past making the universe to him that much
older but to me the universe would only be a few seconds older. How can
the universe be two different ages when I arrive back? Does
decelerating myself to the original speed I started at cause time to
speed up that much? Am I actually accelerating myself again to get back
to the speed of the original observer?

Both the "observer" and the universe at large will be equally older
when you finally return. The observer will have been dead for
millennia, many stars will have exhausted their nuclear fuel, galaxies
will have undergone whole rotations.

-Mark Martin

On 30 Aug 2005 20:20:03 -0700, "Albion" wrote:

As I understand it, the faster I accelerate myself the slower time for
me moves as compared to an observer I left behind.

Not precisely. The slower time moves compared to *any* non-moving
observer, whether at your momentary position or not. Time dilation is
a function of velocity, not of acceleration.

Andromeda my be 2
million light years away but at higher and higher speeds accelerated to
I could get there in no time at all, but it would still be two million
years for the observer I left on earth.

Actually somewhat more. It took time after all for you to attain your
final velocity.

I also understand that if you
travel in a strait line eventually you will come back to where you
started.

Nop.e - conjectured about, but not proven.

So given that, I could accelerate myself to some minute
fraction under the speed of light then coast and return to the place I
left in a few seconds. To the observer I left behind billions and
billions of years may have past making the universe to him that much
older but to me the universe would only be a few seconds older.

Yup.

How can the universe be two different ages when I arrive back?

It is not any more than it is now. You will whiz past your origin and
the origin will be more than two million years older. But you will
still be moving (faster than a speeding bullet)!

Does decelerating myself to the original speed I started at cause
time to speed up that much?

AHA! NOW you are decelerating yourself. And the answer is yup, sort
of. Actually time is a 'local' phenomenon. You have your time and your
original observer has his/her/its.Time is *not* Universal! (That's the
tricky part!) During deceleration (in this case) your time will catch
up with the elapsed time of your original observer.

Am I actually accelerating myself again to get back
to the speed of the original observer?

I rather hope so, or how else do you expect to match speeds with him
after all your acceleration?

I know I may be making what you all may consider stupid mistakes, but I
am just an amateur trying to understand relativity a bit better. Any
answers would be greatly appreciated.

You are assuming that time is universal. It isn't. It is a very common
error. If you can, find and read _Spacetime Physics_, by Taylor and
Wheeler. The math is not too bad, but the concepts are mind-blowers!


-Al

My are you gonna get a bunch of BS, kook-spawn, and troll-spawn
answers to this one!

HTH

the softrat
Sometimes I get so tired of the taste of my own toes.

--
If Barbie is so popular, why do you have to buy her friends? --
Steven Wright