About -- Forum -- Articles -- Tutorials -- Books -- Apparel -- Contact

You are not logged in.

Announcement

#1 2005-07-09 19:05:07

wkhays
New Member
Registered: 2005-07-09
Posts: 3

Question re: time dilation

Remember the experiment where ..
1) Two identical twins start at one reference point on earth.
2) Twin "1" gets on a rocket and travels very close to the speed of light.
3) Once reunited on earth, Twin "1" has not aged as much as Twin "2" who remained on earth.

When I hear this, I always wonder why the same story is not recounted like this ...
1) Two identical twins start at one reference point on earth.
2) Twin "1" sits stationary in his rocket.  Relative to his rocket, the earth blasts away and travels very close to the speed of light.
3) Once reunited on earth, Twin "2" has not aged as much as Twin "1" since relative to the rocket's frame of reference, Twin "2" traveled very fast.

I'm sure I'm thinking about this wrong, so any help will be appreciated.

Thanks!

-WKHays

Offline

 

#2 2005-07-09 20:42:33

love faith swing
Junior Member
Registered: 2005-07-05
Posts: 21
Website

Re: Question re: time dilation

It has to do with Acceleration. The rocket ship accelerates and then decellerates. The acceleration is why twin 1 is now younger then twin 2. When objects are accelerating, you have to apply the rules of general reletivity and not just special relativity. Thats not a very good answer. Somebody else explain it a bit better...


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
"Science is either physics or stamp collecting"
- Ernest Rutherford

Offline

 

#3 2005-07-10 06:06:08

wkhays
New Member
Registered: 2005-07-09
Posts: 3

Re: Question re: time dilation

Thanks ... But I would have thought that relative to the twin in the rocket cockpit, the earth did all of the acceleration and deceleration ... I'll look into your idea re: GR and figure this out.  Thanks again!

Offline

 

#4 2005-07-11 00:05:16

love faith swing
Junior Member
Registered: 2005-07-05
Posts: 21
Website

Re: Question re: time dilation

one more thing. It is the rocket that is turning around in order to come back. Imagine that from the rocket's pov.  It isn't as reverseable. That has something to do with it too, not just the accelerating/ decelerating.


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
"Science is either physics or stamp collecting"
- Ernest Rutherford

Offline

 

#5 2007-10-01 09:35:20

steve
Member
Registered: 2007-09-20
Posts: 75

Re: Question re: time dilation

Regarding this whole twin thought experiment.  If twin A is on Earth and twin B leaves in his rocket ship near the speed of light and leaves for a year long round trip.  It is supposed that the twin on Earth would have aged  much more that his twin on the ship, right? 

Well now lets suppose that there is another person in a stationary ship that is in a location where he can observe both Earth and the route of the moving spaceship with twin B in it.  This separate stationary person marks off on his calendar the day the spaceship left and when the spaceship arrived back on Earth, and found that the ship indeed did take one year.  So one year has passed for all involved.  Everybody is a year older.  There is no vast difference in ages because the time universally was the same everywhere.  No time warp, no slowing of time.

Any outside observer would have seen the whole thing and everything involved move at the same rate through time.  A year trip takes a year.  In reality it took a year.  When you start to get involved with what is relative to something else does not change what REALLY happened in the physical universe.  No matter the speed of a moving object, the universe sees everything age at the same rate.  This whole viewpoint thing of twin A and twin B is just  a viewpoint.  What APPEARS to be happening from the twins perspective is just their “take” on what is happening.  Not what REALLY happened.


Steve

Offline

 

#6 2007-10-04 18:00:13

mystand
New Member
Registered: 2004-11-15
Posts: 1

Re: Question re: time dilation

No, the rocket is still accelerating/ decelerating. Even from a 3rd viewpoint. The rocket goes away, slows down, turns around and comes back. This is what causes the twin to be younger.

Offline

 

#7 2007-10-16 16:35:25

steve
Member
Registered: 2007-09-20
Posts: 75

Re: Question re: time dilation

How does a rockets motion have an influence on a persons aging process?  Both the rocket and the twin are part of the same universal time line.


Steve

Offline

 

Board footer

Powered by PunBB
© Copyright 2002–2005 Rickard Andersson



Copyright © J. Christopher Moore Publishing, All Rights Reserved