# How much younger will I be?

• Beneer

#### Beneer

Hello all, hope you are well. A quick question. I'm employed as an airline pilot. If I fly for 20000 hours over my career at an average speed of 400 knots (roughly 200 m/s), how much younger would I be than my ground based colleagues upon retirement ? Kind regards, Ben

Hi Ben:

I calculate that you will be 64 microseconds (64 × 10-6 seconds) younger.

Regards,
Buzz

Last edited:
jackwhirl
As I recall, it depends on the direction you travel because traveling with the Earth's rotation is different than traveling against it. If you assume all trips are mirror images then you have to do 2 computations and add the results.

It is in any case, as Buzz has computed, an utterly trivial amount (even if he is off by a bit because of what I said)

Buzz Bloom
Gravity and velocity both play a role, don't they? And fight each other in this case, iirc.
Yeah: https://en.m.wikipedia.org/wiki/Time_dilation
I'm not sure which would win out at the crusing speed and altitude of commercial aircraft, but like above it is pretty trivial.

Gravity and velocity both play a role, don't they? And fight each other in this case, iirc.
They do, and that's a good point, although as you also note, that doesn't change the conclusion that in any case it is a trivial amount. What you've pointed out, in fact, makes it even more trivial.

Thanks everyone for your responses - thought it would be a trivial amount (didn't realize how trivial...) - warm regards, Ben