I understand that we can measure the redshift of galaxies moving away from us. Can we do this with the CMBR, too? If we can't do it now, would be theoretically possible in the future?
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Nobody, including myself, can remember being taught about the CMB when learning about the big bang. I find this odd given its importance as evidence of the big bang. This is US education, might not be the same everywhere.
Note - I am not a student of physics, just someone curious. So I've been watching physics documentaries/youtube videos lately out of curiosity in an effort to better understand the universe. I've come across this idea of microwave background radiation, from what I have gathered it is the oldest light in the universe. I have a fair (although limited) understanding of what it is/how it came to be, but I can't wrap my head around how we're still able to detect it. Since it is photons that we are measuring, it seems to me that one of two scenarios explains why we can detect it today:
The light that we are seeing is from an infinite source - we will always measure this radiation because the source was never "turned off" and continually emits photons
Somehow, our location in space traveled faster than the speed of light to its current position where we are able to continue to measure the photons emitted from the source
Both of these thoughts seem naive and absurd, I simply ask: what is it that I'm missing, and why are these ideas wrong? I suspect that the expansion of space has something to do with this but I'm not sure. If my understanding is correct, this radiation existed everywhere in the universe as it cooled to the point where hydrogen could form and photons could travel without interference. But wouldn't the radiation eventually radiate out into the expanding universe, leaving matter traveling slower than the speed of light behind? Any insights from those more knowledgeable would be much appreciated :)
Slipping through stars, the sensitive see
The surface last scattering, shifting red sea
Of relic radiation.
Soaking all space, transparent apparent, searching
Hindsight and fore for homogeneous heat
And errors so errant.
Harness Heaven and Hell, harmoniously,
Small Pockets of Hot spin, whole atomically,
In my microwave.
Center still freezing, the outskirts outburst
In the first thirty seconds, space caved into thirst
And protons and
Parts of all size
My particle prize.
Focused like fulcrums, full crumbs fill
My mouth, making microwaved
Microwaves micro-meal stout.
I would think so because the early universe was almost pure hydrogen so I'd expect hydrogen lines to be taken out of it.
When we see light from the CMB, where is it coming from? What actually are we seeing?
I have trouble understanding what CMBR depicts.
Meaning, the light leaving it reaches our eyes almost instantly. Now, of course, if this were the case, the light leaving us would take near C/2 to get to the CMB.
And it's only near-instantaneous because it's so close to the edge of the universe (that means it's moving away from us very quickly (near the speed of light)).
Also, what if the opposite was true, what would that say about cosmology (what if it light traveling from the CMB was slowed down by a factor of almost 2)? What would these kinds of things say about the expansion of the universe and other cosmological models?
As I understand it, the cosmic background radiation leftover from the big bang is currently in the microwave spectrum, but is constantly redshifting as the universe expands; so logically that means eventually it will redshift enough to be in the visible spectrum. Does this mean that at some point in the distant future we will actually be able to see it with the naked eye, and what would this look like? (Assuming of course we survive that long as a species)
I know that there are theories that talk about how the Universe was 1 second/3 minutes/10 years/ etc... after the Big Bang. Did any of those theories predict the CMB? Was there ever any reason to expect anything like it before we discovered it?