We are time travelling right now?!

[Dean Mullen]

If Earth is spinning really fast, the earth is moving through space really fast, the sun is moving through the galaxy really fast and the milky way is moving really fast too, at as far as I know about 1,000,000 M/PH, does this mean that time for us is traveling much faster than it normally would? that being in a space were your true speed is 0 KM/PH, so if you left the galaxy and calculated how to use propulsion systems in the opposite directions of were your traveling to slow yourself down eventually you would be about 1 million km/ph slower than you usually are, hence time would travel a lot slower than usual, so you realize we are actually traveling through time pretty fast.

[IM Egdall]

There is no "true speed" of 0 miles per hour. Everything is moving with respect to everything else. There is no at rest frame of reference.

 

Consider two observers; one on Earth and an alien in outer space somewhere. (Assume neither are changing their speed or direction.) Say the Earth observer is moving at 1 million miles an hour relative to this alien observer in outer space.

 

Earth frame of reference: The observer on the Earth feels that she is standing still and the alien is moving. To the observer on Earth, time is running normally here. But she sees time running slower for the alien due to his motion.

 

Alien frame of reference: The alien observer feels that he is standing still and the Earth is moving. To the alien, time is running normally where he is. But he sees time for the observer on Earth running slower due to her motion.

 

So each sees the exact opposite effect. Who is correct? They both are. Time is relative.

 

And 1 million miles an hour is a small fraction of the speed of light (some 670 million miles an hour). So the time slowing factor involved is quite small. The formula is:

 

square root of (1 - v ^2) where v is the speed as a fraction of the speed of light.

Here v is 1 million miles an hour divided by 670 million miles an hour or 0.0015.

So the slowing factor is sqrt ( 1 - (0.0015)^2) = sqrt (1 - 0.0000022) = sqrt (0.999997) = 0.9999988

 

The relative velocity has to be some 100's of millions of miles per hour before the slowing of time is significant.

 

See my blog "It's Relative" for other examples.

Edited February 11, 2011 by I ME