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Vanadium90

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**Different "Slices of Now" Observable from Earth?**

Brian Greene's excellent series continued last week on PBS with "The Illusion of Time" in which he showed with graphics how different "nows" occur depending on the motion of an observer. Using the example of a space alien 10 billion light years from earth, its "now" depends on whether the alien is stationary,moving toward, or moving away from the earth. If the alien had a powerful telescope, it can control its "now" by hopping on a bicycle and moving away from the Earth to look 200 years into our past, remain stationary and see our present, or move toward the Earth and see our future.(Remember the alien is looking at things 10 billion years old, it is not seeing things that didn't already happen on earth). Although the velocity of the alien is slow, the great distance causes an even small change in the angle of a slice of now to produce an effect of centuries in time of its "now".

My question is why don't we see this effect on Earth when we look at distant galaxies?

The observers on Earth are not all moving at the same velocity and this should produce the effect.

How so?

Example:Suppose a galaxy is 10 million light years from Earth on the same plane as the Earth's equator. A telescope on the equator is moving 1000 miles per hour (rotational speed of the Earth at the equator) toward the galaxy.

A telescope at 45 degrees N. Latitude and the same longitude is moving at 700 miles per hour toward the same galaxy(1000 mph x cos 45) for a difference of 300 miles per hour.

Calculation:

Using the formula in Fabric of the Cosmos p.540, the difference in "nows" due to the motion of an observer is :velocity x distance/c^2, where c is the speed of light.

In my example the distance is 10 million light years or 6 x 10^19 miles. The speed of light is 186,000 miles per second.

For velocity, actually a difference in velocity, (1000 mph-700 mph) = 300 miles per hour or 0.083 miles per second.

In other words the "slice of now" for the telescope on the equator is different(ahead in time) than the" slice of now" for the telescope at 45 degrees N. Latitude.

The result I get is: 0.083miles/sec x 6 x 10^19 miles/ (186,000)^2.= 4.4 years.

This answer does not seem correct: A telescope on the equator would see events(e.g. the start of a supernova) 4.4 years before the telescope at 45 degrees N. Latitude if the motion of the telescopes is toward the galaxy!

I know the motion of the Earth is more complicated than rotation on axis(to extend the analogy of Brian Greene,it would be similar to the difference of "nows" of two bugs walking with different speeds on the head of the cycling alien), but shouldn't the difference in velocities of the two scopes produce different "nows"? Could somebody help me with this?