Red-shift Definition and 16 Threads

Hi, I am not a cosmologist, but this question has been bugging me for some time. I am an engineer, and I own an aquarium, at least I owned an aquarium with an awesome LED light. Under certain conditions, I found that when the blue night light was on, organics in the water would fluoresce, green...

Does the relative density of the early universe contribute to the red-shift of distant galaxies? If so, by how much? How would this be calculated? Asked another way : Assuming both the early universe and the current universe are flat, could the relative difference of their space time metric...

Homework Statement [/B] I am stuck on the section of my lecture notes attached, where it says that equation 4.20 follows from 4.18 via an application of the fundamental theorem of calculus Homework Equations FoC: if ## f## is cts on ##[a,b]## then the function ...

The value for the red-shift of the CMB is 1090 according to the latest Plank study. How do they arrive at this number? You can look at how hydrogen lines of supernovae light are shifted, but how do you tell how far light is shifted when looking at the light from a primordial soup? Is there...

i know it sounds stupid, but i can't seem to find an answer to it where did the energy went? you can't just just destroy energy, but when you red shift a gamma CMB into a microwave CMB, the energy has go to go somewhere...? it's not like one gamma photo spitted into many microwave, cause that...

If you measure the red-shift of a star 10 million light years away, you measure the velocity of the star 10 million years ago when the stars were traveling faster (if we are willing to accept that the expansion of the universe is slowing down). This not such an outrageous idea since firstly it...

Is it theoretically/mathematically possible for light waves to be red-shifted so much that it's amplitude is equal to zero?

I accept that what I write below will be unpopular and argued with vehemently, however I think it should be considered with an open mind and recognised for the sense that it has. Originally the concept of an expanding universe (and therefore by extrapolation the concept of the Big Bang that...

So from a killing tensor the FRW metric is known to possess, for a massless particle we find the well known result that as the universe expands the frequency of the photons decreases . But , what does this do for gr ? Was this known to happen before gr ? Thanks a lot. (I know it is used to...

Homework Statement This is not a HW questions but from another thread. https://www.physicsforums.com/showthread.php?p=4495692&posted=1#post4495692 The statement I made was that if z increases for a source, then it is accelerating away. Or, it could that if z is constant then the sources...

I've recently read that red-shift is caused when a photon escapes a star and loses some of its energy, lowering its frequency and therefore making it appear redder. However, I've become very familiar with the fact that light will red-shift as it travels across the universe; I've been under the...

Could some one explain what red-shift really means when we're talking about the EH of a BH? Thank you.

This may seem elementary, however I have been unable to find a declarative statement that seems reliable. What is the equation for the red-shift z as a function of distance r to the best of our knowledge? That is z(r)=? Thanks in advance.

There appears to be three sources of red-shift: or are there only two, and two of the following are equivalent? (1) Classical Doppler shift (2) Relativistic Doppler shift (3) Red-shifting from the expansion of space Otherwise put, which ones are calculated for retreating galaxy clusters and...

Suppose that some time in the future a clever group of theorists and experimentalists finally devise a way to accurately determine the value of the Hubble Constant. Say by an interferometer connected to a quantum computer. Everything works fine in the lab and is checked and checked...

Hey, this is my first post. Just talking about an idea I had. A month ago I was pondering the effects gravity has on light. Specifically if there could be a “gravitational red-shift” of light coming from massive stars. I first started by thinking of gravity as simply causing an object...