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Is it true that people who travel a lot on airplanes live longer than those who don't

  1. Nov 3, 2008 #1
    Since time goes slower for those who are moving at high speeds (on airplanes), does this not mean that people who travel a lot on planes constantly have a higher life expectancy of 8-10 years than those who don't?
     
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  3. Nov 3, 2008 #2
    Re: Is it true that people who travel a lot on airplanes live longer than those who d

    No. The speed of a plane in relation to the surface of the earth is not even close to lightspeed.

    If anything their lifes will be shorter on average due to radiation.
     
  4. Nov 3, 2008 #3
    Re: Is it true that people who travel a lot on airplanes live longer than those who d

    People who travel airplane speeds do experience every so slightly slower passage of time relative to earth's surface. But it's only a few billionths of a second over a lifetime.(That's an illustrative figure, not any kind calculated estimate.) That's because gravitational potential is a bit lower and speed higher relative to earth's surface.

    Offsetting such an "advantage" is the very low humidity typical in airplanes which may make the spread of germs easier, potential exposure to germs from lands foreign to your home country and additional exposure to cosmic radiation, high energy particles from space. And of course that awful person in the seat next to you is likely is drive your blood pressure sky high!

    So spending times in airplanes is not a good tactic to extend life. It's more likely to shorten life a bit. Maybe living on a mountaintop would be a compromise.
     
  5. Nov 3, 2008 #4

    D H

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    Re: Is it true that people who travel a lot on airplanes live longer than those who d

    No. The time dilation is small, much less than a microsecond for an eastward round the world flight. Moreover, you would have to fly eastward only. A person who flies westward gains time (but again less than a microsecond). It would take several million round-the-world flights to accumulate one second in time loss or gain.
     
  6. Nov 3, 2008 #5
    Re: Is it true that people who travel a lot on airplanes live longer than those who d

    From a GR view (assume the East vs West; increase vs decrease speeds cancel) only considering altitude: the higher levels have time running relatively faster.
    Thus to live “longer” you need to dig deeper down into the gravity well.
    Remember the few microseconds you would gain would not seem any different locally, you would just see a it more history pass by at higher levels.

    Actually I saw a play “Clockworks: Einstein Time” open at a Conference on Einstein a couple years back where they had a main character working to build his home higher and higher in order to live longer than others below.
    They had a Director/Playwright discussion after the show and I pointed out the error, the local Collage Physics professor that consulted was there and could only say “oops”.
     
  7. Nov 3, 2008 #6

    mgb_phys

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    Re: Is it true that people who travel a lot on airplanes live longer than those who d

    In a plane at a hight of 10km (ie 33,000ft) a clock will run about 1:1012 faster due to GR and about 1:1010 slower due to special relativity.

    For GPS satelites in orbit at a greater height but going faster the difference is the other way around, they run faster due to GR.
     
  8. Nov 3, 2008 #7
    Re: Is it true that people who travel a lot on airplanes live longer than those who d

    But don’t forget the point made by DH above
    Since on the surface we are already in motion due to earth rotation depending on direction of the plane it can be moving slower not faster than someone standing on the surface assuming they are near the equator or far from a pole .
    Then even SR causes the plane time to run faster.
     
  9. Nov 3, 2008 #8

    mathman

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    Re: Is it true that people who travel a lot on airplanes live longer than those who d

    I suspect the main reason people who fly a lot live longer is that they are in general healthier.
     
  10. Nov 3, 2008 #9

    mgb_phys

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    Re: Is it true that people who travel a lot on airplanes live longer than those who d

    But don't forget all that beneficial radiation.
    A transatlantic trip gives you about 0.05mSv, compared to a background of 2.5mSv/year and a legal limit of 5mSv/year.
     
  11. Jun 1, 2010 #10
    Re: Is it true that people who travel a lot on airplanes live longer than those who d


    I would not be surprise, for example in the UK they found richer people lived longer than poorer people by a fairly similar number of years.

    Basically if you travel a lot on aircraft you are likely to be wealthy and wealthy people in general tend to live longer than their poorer peers.

    Don't confuse cause and effect though I doubt poor sticking a poor person on an aeroplane would increase his life span much, all things being equal.
     
  12. Jun 1, 2010 #11
    Re: Is it true that people who travel a lot on airplanes live longer than those who d

    Well, if you are a fighter-bomber pilot who strafes and kills people on the ground or even in a slower moving helo gunship you are definitely going to live longer than those you kill - even if you buy the farm yourself because the kill ratio in favor of the airborne person will more than make up for the premature termination of the gunship shooter.

    In terms of flying alone the speeds generated will subtract only nanoseconds off the world line of the aircraft so there is no practical difference.
     
  13. Jun 1, 2010 #12
    Re: Is it true that people who travel a lot on airplanes live longer than those who d

    Well you are picking a rather contrived situation where you are by definition killing more people who are not flying.
    During the wars ie WW2 the life expectancy of a pilot was not very good.
    Indeed one source says it was 7 weeks, which is I imagine much shorter than for the Army and Navy personnel I think your estimate is based upon some selective examples such as Iraq or Afghanistan with may not be representative of the overall situation.

    In that particular situation it is because, as I said above, because they were wealthy, not because they were flying.
     
  14. Jun 1, 2010 #13
    Re: Is it true that people who travel a lot on airplanes live longer than those who d

    I think you would live longer because flying is much safer than driving a car.
     
  15. Jun 1, 2010 #14
    Re: Is it true that people who travel a lot on airplanes live longer than those who d

    Not on a per trip basis it isn't.

    Anyway the original question seem to relate to relativity, I arrived by a direct link.
     
  16. Jun 1, 2010 #15
    Re: Is it true that people who travel a lot on airplanes live longer than those who d

    The direction of travel has no basis on the dilation of time - you wouldn't "gain" time at all - you might gain less time going west vs. east due to the relative motion(earth's spin) to the observer(people on the ground) - but not gain.

    And besides all this - this is relativity. Nothing happens longer or shorter than it does for anyone else. Without an observer to tell you that you aged less, you wouldn't know. If you traveled near the speed of light for 20 years, you wouldn't notice any difference in the time it took if you spent 20 years on earth. You would still age the same, you would still have the same lifespan.

    Its only when an observer is put into the equation that you will notice the difference. However lifespan and experience would be the same. Let me explain. I'll use the twin example. A set of twins at the age of 20 are separated. One stays on earth while the other leaves earth traveling near the speed of light. During the time, they each get married - have kids, and spend their free time doing hobbies and spending time with their families. At the age of 40 they start to write a biography about their life in the last 20 years and they publish it. Say the twin that left earth at the speed of light returned at the age of 40 to publish his biography on earth. His brother would have aged quite alot more than him - 40 or more years maybe. However, if you were to compare their biographies -beside the different lifestyle of being on earth and being in space - they would have similarities and their experience would have been comparable. They would have had the same fulfillment in life at the age of 40(granted they were self motivated and similar minded twins.) The only difference is the earthbound brother would be very old by now - regardless of the age difference, his "younger" brother would still have to experence the 40+ years of similar life experience that his "older" brother has already had. There is no gain in lifespan. Think of it in the sense of forward time travel - because it is precisely that.
     
    Last edited: Jun 1, 2010
  17. Jun 2, 2010 #16

    Dale

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    And don't forget deep vein thrombosis and jet lag!

    In the end, you won't live longer, it will just feel that way.
     
  18. Jun 2, 2010 #17
    Re: Is it true that people who travel a lot on airplanes live longer than those who d

    Just pulling your chain...

    The real answer with relativity is that the time advantage is so-o-o small that it is negligible - and that's true if a baby were born on a jet and stayed on that jet throughout his/heer entire lifetime .
     
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