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'Time-traveling' on an airplane: One of the cheapest tests of relativity

Forty years ago this October, physicist Joseph C. Hafele and astronomer Richard E. Keating bought tickets for themselves as well as four highly-precise Hewlett-Packard atomic clocks to take two commercial airplane trips around the world, one heading east and one heading west. Their mission? Test Einstein's theory. ( More...

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James Driskell 11
Time flies when you're having fun!
srobak 6
I still remember my first long-haul west. Departed ORD at 1330, took a semi-polar route to PVG and landed there 15 hours later. It was late November.

I watched the sun set, rise, set again and rise again in that period - and it was on it's way down when we touched down. In the span of 15 flight hours.

Jetlag or not - That will mess with your head. LOL

Then to really make things fun - we landed in LAX 1 clock hour after we departed PVG... lol.
s s 4
People who live in high rises are also time traveling as the taller the building, the faster it moves relative to the ground.

That's why penthouses are so expensive...
Silent Bob 10
I time travel every time I go to work. Flying the 737 instantly transports you to the 1960s!
ph gero 2
Very ecological !
sitting in one's chair, you are still traveling at the speed of light:
Time contraction occurs in many forms. This experiment took place in 1971 while Hafele was a prof and I was an undergrad at WUSTL. Somehow, 50 years has become "forty" ? I would gladly take back 10 yrs.
Skip the news article and instead follow his embedded link to [] or []
WhiteKnight77 2
Einstein might have been seen as wacko by some, but his theories have been borne out time and again.
OnTheAve 1
I think the definition could have better:

"The clocks that flew east – that is, with the Earth's rotation and with a slight difference in velocity relative to the clock on the ground – were 60 nanoseconds behind after the flight. The clocks on the flight traveling west – counter to the Earth's rotation and with a large difference in velocity relative to the clock on the ground – were a full 270 nanoseconds ahead of the clock in the laboratory.

What is the "difference in velocity?" Is it faster or slower? This should be explained if the author understood what he or she was writing about so the make the point clear to the reader.

I think the proper explanation is for the eastbound traveller would be to add the plane speed to the rotation of the earth, which means one is travelling faster compared to the person on the ground thus time moves slower.

For the westbound traveller, it's just the opposite. You subtract the speed of the plane from the earth's rotational speed, thus the traveller is moving slower compared to person on the ground thus time is faster.

Where's the damn editor?
chugheset 1
Reminds me of the old airline joke: A country bumpkin dropped off his friend at the airport in Charlotte and asked the agent what time the flight departed. "Six p.m." said the agent. "What time does it arrive in Nashville?" the bumpkin asked. The agent, calculating the time change in his head replied, "6 p.m., would you like to buy a ticket? "No" said the bumpkin, "but I'd like to stick around and watch that motherf****r take off!".
Chris B -3
I can’t see any airline or TSA agent testing for radioactivity in your luggage. Ever.

Atomic clocks aren't radioactive; in fact they have to use stable atoms so as to get the best stability.
srobak 1
they already do

Bill Butler 1
But, if you told them you had an atomic clock, they'd put you irons and scurry off looking for that meter!


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