Got me. Listening for answers!

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Well that is the basic gist of it. Problem is, if something is traveling x miles per hour, its perceived frequency will be off y percent at z distance. The problem is that doesn't tell you what the distance is. You can still have x miles per hour be off by y percent at any distance.

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There are 10 types of people in this world. Those that understand binary - and those that don't.

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I was reading the other day that supernovas were going to be used as a measurement for galactic distances.  the reasoning behind this is that supernovas explode almost identically so measuring one in a distant galaxy one can determine the size of the galaxy and by that the distance that galaxy is from us.

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Truth is after all a moving target Hairs to split, and pieces that don't fit How can anybody be enlightened? Truth is after all so poorly lit - Getty Lee

I had also asked in another far OT forum that actually yielded an answer I could almost accept. He pointed to the article on red-shift on Wikipedia. I started reading it but I really didn't know what the hell I was looking for.

Copied below for convenience....

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redshift is as u stated but simplified a bit so others can maybe better understand is when visible light....ie. the colors u see when light shines through a drop of water.... is either emitted or reflect by the object and is shifted toward the (less energetic) or "red" spectrum of light due to the Doplar effect. this redshift is caused by the wavelengths increasing.
blueshift is the exact opposite and thus wavelengths decrease
this also works and corresponds like u said for sound waves
another thing to clarify is speed vs. velocity
c speed is a scalar quantity and gives no direction when saying it
were as velocity is a vector quantity and tells u whether or not it is moving toward u or away from u
they do NOT use speed when determining redshift and in obtaining ur desired value distance. they use velocity.....and as u know velocity is change in distance/change in time in some direction
where they are getting redshift from is to understand the difference in wavelengths emitted by an object based upon some stationary point (which i belive the point is the point in the specturm of light that the wavelenght should appear in not its shifted or redshift point....c as the planet for exaple is moving away at some velocity the wavelength that was sent at time A is going to have a lesser value then the value of the wavelength sent at time B they use this relationship to get a redshift estimate.....yes technically it is only an estimate because they didnt actually measure it they calculated it
it has also been determined through matematical proofs and equalities that redshift is also equal to the velocity of the planet/the speed of light
so actually they find the redshift first using the first method i told u about with the wavelengths then work backwards to determine velocity....then using this they can....
determine distance.....
however to do this they also use a thing called hubbles constant(which is what you are missing)
distance to whatever is = velocity/hubbles constant
now hubbles constant is a whole nother story on its own, and you can just google it to find out how to find it cause i dont want to write a paper here, but essentially to find the distance they are using the velocity of the whatever you are looking at, hubbles constant, and the difference in wavelengths emitted by the whatever to find velocity to find distance.
i pry confused u more but you can probably google either redshift or hubbles constant to get a better answer
and some of this could be a bit off cause its coming off the top of my head and i didnt exactly try to memorize this stuff, but i think this will help.....maybe
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There are 10 types of people in this world. Those that understand binary - and those that don't.

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