How does red shift affect distance?

Question

If red shift indicates that all galaxies in the universe are moving away from us at close to the speed of light, why has the distance to them remained unchanged in my lifetime?

Answer 1

Actually the distance to those galaxies has changed, it's just that it's not practical for astronomers to continuously update the distances.

Here's an example --
This year the distance to some galaxy has been determined to be 3-billion light years. By computation that means that this galaxy is moving away from us at 1.4^14 mph! That means that in another year its distance from us will be more than an additional 427,673.7 light years.

Answer 2

1) Very few objects in the universe are moving anywhere close to the speed of light relative to the objects around them (including us). For example, the arms of the Milky Way galaxy revolve around the galaxy's center at a rate of about 40,000 mph, which is a teeny, tiny fraction of the speed of light. (.00006 C)

So please don't worry about things flying off at C. It doesn't happen. A few of the most distant objects obtain a velocity of .00010 C relative to us.

Star Trek was just a sitcom, anyway. I don’t see how human technology can ever devise a means of going much faster than the .0000375 C that we can do now. There is just no practical way to get to the stars. Even at .01 C you would run into relativistic problems that woulg grunf tubrex yr unrequignizable and kip kawtchin up w/yoorown faeces. Disgusting, I hop lune.

*Whew!* glad to get this thing slowed back down.

2) How long is your liftetime? If you are 60, some of the more distant objects will have moved measurable distances since you were born. But the distances involved are teeny, tiny compared to the vast distances that separate us from those objects. We are talking about things moving a few light-minutes in 60 years, while the objects are millions of light-years away from where we are. So the distances have changed, but not very much.

3) In regard to your title question: It's the other way around. Distance affects red shift; red shift does not affect distance. George Ellery Hale and Edwin Hubble working at Mt. Wilson in the 1920s mapped the red shift of many stellar objects as part of a study of the distribution of the stars. In general, the further away from us a star is, the more its light will be shifted toward the red end of the spectrum, because the faster it will be moving relative to us.

As with all astronomical measurements, it is a tiny shift, and very very sensitive instruments are required to detect any differences. Astronomy may be called the science of detecting vast realities by making infinitesimal measurements.

Answer 3

They are not the same distance from you. But in your life the change in their position is imperceptible. They are too big and too far away for that change in position to be noticed.
Suppose you are 30 years old. Suppose that a galaxy was moving exactly away from us at .9 the speed of light. In 30 years that galaxy would have moved 1.75971E+14 Miles. That is a lot.
But what you see is what you get. How big is a galaxy?
Our galaxy is 5.8657E+17 miles across. The change in motion as a percent would be movement/size. That is, 0.03% this is NOT 3 percent. It is .03 percent. This change in position is too small to be noticed.

;-D Galaxies are big and the distances are huge.

In most cases light that was emitted from them since you were born has not arrived here and will not arrive here for thousands or millions or billions of years.

Answer 4

The distance has changed. The red shift is the stretching of light that is caused by the galaxies moving away form us.

Answer 5

the red shift is simply a way to measure which direction the object is moving. they haven't moved in your life time because it takes light so long to get here that they are already moved from where the light originated. also they are moving so fast that it takes so long for the light to reach us that by the time its movement is visible you are dead.