# Speed of light and Time Travel

1. Mar 3, 2004

Well, We all know about Einstein Theory of Relativity.

The speed of light is constant.
And if someone travels close to the speed of light; time goes slower than someone walking on earth etc.

Ok, this is my question. (Involves Pilots)

Ok, since pilots travel at amazing speeds of 1,000 - 3,000 miles or higher in Military Jet planes and commercial planes and they experience 3-6 times the G force of earth. Let's say a pilot is flying around the world for 24 Hours straight let's assume.

So, in those 24 hours traveling at those fast speeds. Does the pilot age a bit slower than normal human aging during that 24 hour period?

Explain.

2. Mar 3, 2004

### Wooh

I believe that the answer is yes, but only very very very very very very slightly. I mean, how does 3000 compare to 300000000? And then, in many cases, 90000000000000000? Not much at all.

3. Mar 3, 2004

The pilots i seen so young and they are very old.

Specially this 79 year old men looking like in his 40's year old.

But, the others around 50's

He must of pulled a lot of G's in his flights. ;)

hehe.

4. Mar 3, 2004

### franznietzsche

$$t = \tau\gamma$$

$$\gamma = \frac{1}{\sqrt{1-\frac{v^2}{c^2}}}$$

$$v = 14432 \frac{meters}{sec}$$

$$t = \frac{\tau}{\sqrt{1-\frac{14432^2}{299792456^2}}} = \frac{\tau}{\sqrt{1-2.317x10^{-9}}}$$

$$= \frac{\tau}{0.99999999884127} = 1.0000000011587\tau$$

given that the g forces are only experienced during acceleration and never exceed ten gs (for medical reasons) we can calculate:

$$ds^2 = 1-\frac{\frac{2GM}{c^2}}{R}dt^2$$

$$ds = \sqrt{1-\frac{8.86112x10^{-3}}{6x10^24}}dt$$

$$ds = \sqrt{1-1.47685x10^{-27}}dt$$

that is for 1 g, which the coefficient is obviously insinificant. If we make the earth ten times more massive(10 g basically) we get:

$$ds^2 = 1-\frac{\frac{2GM}{c^2}}{R}dt^2$$

$$ds = \sqrt{1-\frac{8.86112x10^{-2}}{6x10^24}}dt$$

$$ds = \sqrt{1-1.47685x10^{-26}}dt$$

Which remains insignificant. Any added g forces will have essentially nil effect, the special relativisitc effects of the high velocity however are measurable by atomic clocks, but not significant in terms of a human lifetime or any amount of time recognizable by humans. For example if you lived a hundred years by your watch at that velocity some remote observer would measure 100.00000011587 years, which amounts to a net difference of 3 seconds over 100 years. Not much.

Last edited: Mar 3, 2004
5. Mar 3, 2004

HEY franznietzsche!

I did not typed that second post.

I was away from the computer and my little immature brother sat down and post that.. i think he deleted some of my files..

kids.. bah...

6. Mar 3, 2004

### franznietzsche

meh, either way, was good excersize for me.

But yeah the pilot does age more slowly, just not much. Its very insignificant as the numers show.

7. Mar 4, 2004

### HallsofIvy

Staff Emeritus
Hey! I'm going to use that the next time I suddenly realize that I had just said something stupid!

8. Mar 4, 2004

### ZapperZ

Staff Emeritus
Hehe... GREAT idea! I'll use that too, except I'll blame it on my evil twin Skippy! :)

Zz.

9. Mar 4, 2004

hmm..

HallsofENVY you think you're some kind of physic?

Ook , ms cleooo^^^

10. Mar 4, 2004

### pallidin

Damn. So, one would have to travel at a velocity 10.5 million times that of a jet for 100 years to "gain" a single year due to time dilation? That's if I even have my math right.
In any event, I can see that we don't fly jets for longevity.

11. Jul 8, 2010

### dave_baksh

From Franz's post above - am I right in thinking that the centrapeital force experienced from loop de looping in a plane (or in any other way) contributes towards time dilation in the same fashion as being in a gravitational field?

Because I've never heard that before (my knowledge of special relativity is reasonable and of general, minimal.)

12. Sep 7, 2010

### SANDU

Sir
if we travel around earth in opposite motion for 20 yrs then could we can go to past

13. Sep 7, 2010

### HallsofIvy

Staff Emeritus
A very strange assertion. Do you have any evidence to support it?

14. Sep 7, 2010