# How much faster does time pass in space in comparison to that on Earth?

1. Jan 14, 2012

### Ralphonsicus

The title says it all really. Thanks.

Last edited: Jan 14, 2012
2. Jan 14, 2012

### Ralphonsicus

Re: How much faster does time travel in space in comparison to that on Earth?

Pass, could be a better term.

3. Jan 14, 2012

### elfmotat

If I'm interpreting your question correctly, you're asking how much slower clocks run on Earth due to gravitational time dilation?

An observer that's a very large distance away from any gravitational fields would measure the time interval between two events on Earth to be:

$$\Delta t=\frac{\Delta \tau }{\sqrt{1-2GM/rc^2}}$$

where $\Delta \tau$ is the time between the events as measured on Earth.

Using the appropriate numbers for M and r, we get that the distant observer's clock runs about 1.000000000696 times as fast as the clock on Earth.

4. Jan 14, 2012

### Ralphonsicus

Thanks, just what I was looking for.

5. Jan 15, 2012

### joan pendleto

WHERE in space would have to be determined. You could speak of a space ship beyond the gravitational field traveling at a constant speedwhile observed by a person standing on the earth looking up at the ship with a telescope. Or you could speak of a cosmic ray shooting by the same observer at a constant speed. Or you could speak of the planet Jupiter orbiting the sun at its' constant speed while the observer on earth orbits the sun too. These three are any three of an untold number of inertial frames of reference (movements in space) which can be compared to the observer on earth standing there in his own inertial frame of reference relativelyspeaking. So there will be an untold number of answers if you set up the problem this way. And according to the special theory of relativity there is no other way to set it up. Its' the old person on moving train versus person standing on tracks observing so to speak. with a light reflected between two mirrors on the train traveling straight up and down and yet traveling diagonally to reach wayside observer thereby causing to ensue all the relativity math with its' time dilation and spaceshortening. I hope this isn't a silly answer to a great question which opens the doorway to it all.

6. Jan 15, 2012

### joan pendleto

Sorry I didn't realize you were referring to the gravitational field situation only. My reply concerned just special relativity no consideration of the slowing effect of gravity just what's out there in space speed wise as compared to here on earth. Things will would always be slower in space from our standpoint and we'd be the slower ones from outer space's, standpoint. According to special relativity. How you reconcile this with the slowing effect of gravity on earth clocks as compared to space clocks I am too limited to imagine.

7. Jan 15, 2012

### alexg

Only true if there is a difference in the relative velocity between the object in space and the object on the earth.

If they are at rest with respect to each other, then there is no difference in the rate time passes, if we are only considering SR.