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cleanup

macrumors 68030
Original poster
Jun 26, 2005
2,643
10
Toronto
So I've never studied physics before, but my friend showed me the results from the Hafele-Keating Experiment. It states that a plane-bound clock flying eastbound (with the earth's rotation) experiences time dilation and thus returns to us slower than a ground-based clock (and thus loses time). I get that. But it also shows that a plane-bound clock flying WESTBOUND (against the earth's rotation) experiences time contraction and returns to us FASTER than a ground-based clock (and thus gains time).

I honestly have no idea why the westbound clock is different. Isn't it still moving relative to the ground-based clock, regardless of its direction of motion? Doesn't it experience time dilation all the same? Why is it different?

Any physics buffs have any idea? I'm really at wits end with this... been thinking about it all week.
 

lewis82

macrumors 68000
Aug 26, 2009
1,708
12
Totalitarian Republic of Northlandia
The ground based clock moves at a speed of roughly 530 km/h (at the equator, being closer to the poles actually reduces the linear speed but not the angular speed). The eastbound-flying, which flies at about 800 km/h, has a total speed of about 1330 km/h. The westbound-flying plane, on the other hand, goes at about 270 km/h.

The time dilatation can be easily calculated, and is proportionnal to the speed. So there you go ;)
 

CorvusCamenarum

macrumors 65816
Dec 16, 2004
1,231
2
Birmingham, AL
The ground based clock moves at a speed of roughly 530 km/h (at the equator, being closer to the poles actually reduces the linear speed but not the angular speed). The eastbound-flying, which flies at about 800 km/h, has a total speed of about 1330 km/h. The westbound-flying plane, on the other hand, goes at about 270 km/h.

The time dilatation can be easily calculated, and is proportionnal to the speed. So there you go ;)

Doesn't altitude have something to do with it as well? It's been a while, but I think I recall reading A Brief History of Time or some similar book where it was touched on, albeit briefly.
 

flopticalcube

macrumors G4

redAPPLE

macrumors 68030
May 7, 2002
2,677
5
2 Much Infinite Loops
this thread makes me think... somewhat interesting (for physics-type people)... but i find it boring. hey, maybe because i am not a physics-type person.

didn't a well known guy say 'time is relative'? in my dictionary, it means, time will have a different meaning for every person on this earth.
 

comictimes

macrumors 6502a
Jun 20, 2004
874
1
Berkeley, California
The ground based clock moves at a speed of roughly 530 km/h (at the equator, being closer to the poles actually reduces the linear speed but not the angular speed). The eastbound-flying, which flies at about 800 km/h, has a total speed of about 1330 km/h. The westbound-flying plane, on the other hand, goes at about 270 km/h.

The time dilatation can be easily calculated, and is proportionnal to the speed. So there you go ;)
True, but I should think that's basically inconsequential compared to the 66,660(ish) mph that both planes are moving at (due to the Earth going around the Sun). It's all relative to what point you consider fixed... after all, our entire galaxy is speeding away the point of the Big Bang at some even more crazy speed :p
 

Rodimus Prime

macrumors G4
Oct 9, 2006
10,136
4
Relativity is one of those things that I found fun to calculated but always confused the hell out of me.

I hate physic II.
 

lewis82

macrumors 68000
Aug 26, 2009
1,708
12
Totalitarian Republic of Northlandia
True, but I should think that's basically inconsequential compared to the 66,660(ish) mph that both planes are moving at (due to the Earth going around the Sun). It's all relative to what point you consider fixed... after all, our entire galaxy is speeding away the point of the Big Bang at some even more crazy speed :p

The time dilatation depends on the observer. If the observer also moves at 66,660ish mph, the time dilatation due to the earth's orbit is the same for both, and will not affect the calculations.

The formula is:
8e8943fcbf5e131710d8d04571f428e5.png


where v is the relative velocity between the observer and the object.
 

Melrose

Suspended
Dec 12, 2007
7,806
399
Jet lag is the body's way of preventing time travel. Imagine how sicker than hell you'd be if you travelled 100 years one way or another, rather than just a few hours? :p

I love physics.
 
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