<p>It's not possible to see photons from "beyond" the cosmic microwave background (CMB), because (assuming our cosmology is generally correct) the CMB is the result of recombination of electrons with protons in the early universe. Photons from before that era were absorbed in the plasma.</p>

<p>Essentially then, the earliest matter we can see (in photonic terms) is this glowing hot hydrogen, but massively red-shifted so it looks like hydrogen at 3K.</p>

<p>We see the CMB in every direction.</p>

CC BY-SA 3.0
2016-04-23T11:00:09.423Z
2016-04-23T11:00:09.423Z
adrianmcmenamin
<p>Regarding matter that has the highest redshifts, do we see such matter in every general direction we look (relative to Earth: up down left right front back)?</p>

CC BY-SA 3.0
2016-04-19T13:22:24.323Z
Yes we do, and it looks like [this](https://www.google.dk/search?q=cmb&biw=1505&bih=1045&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiFyb-s5ZrMAhUkL8AKHaqgAXMQ_AUIBigB).
pela
CC BY-SA 3.0
2016-04-19T13:25:40.843Z
That's CMB levels. I want redshifts.
Paul
CC BY-SA 3.0
2016-04-19T14:23:00.647Z
The CMB is all at the same redshift (~1100), to a relative precision within $10^{-5}$, no matter if you look up, down, left, or right. We haven't observed anything with higher redshifts.
pela
CC BY-SA 3.0
2016-04-19T15:21:25.273Z
So if the measured CMB peak wavelength is ~2mm, then the originating CMB was ~2mm/1100 (~2um)?
Paul
CC BY-SA 3.0
2016-04-20T09:07:09.967Z
More or less, yes. The answer depends a bit on whether you express intensity as a function of wavelength or frequency. I think 1 $\mu$m is considered the peak wavelength
pela
CC BY-SA 3.0
2016-04-24T06:44:20.280Z
Things closer to us appear bigger (duh), so most of what we see is the Milky way.  But if we ignore the close stuff, as I understand it, Matter is quite evenly spread out in every dimension, similar to CMB, which as adriancmenamin points out, came from matter.   The Universe appears quite uniform.  Very similar in every direction.
userLTK
<universe><redshift>
Locations of farthest matter
Paul
# Locations of farthest matter

(Asked by: username_0 on 2016-04-19)

Regarding matter that has the highest redshifts, do we see such matter in every general direction we look (relative to Earth: up down left right front back)?

**Tags:** universe, redshift
> **Comments:**
> **username_1**: Yes we do, and it looks like [this](https://www.google.dk/search?q=cmb&biw=1505&bih=1045&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiFyb-s5ZrMAhUkL8AKHaqgAXMQ_AUIBigB).  
> **username_0**: That's CMB levels. I want redshifts.  
> **username_1**: The CMB is all at the same redshift (~1100), to a relative precision within $10^{-5}$, no matter if you look up, down, left, or right. We haven't observed anything with higher redshifts.  
> **username_0**: So if the measured CMB peak wavelength is ~2mm, then the originating CMB was ~2mm/1100 (~2um)?  
> **username_1**: More or less, yes. The answer depends a bit on whether you express intensity as a function of wavelength or frequency. I think 1 $\mu$m is considered the peak wavelength  
> **username_2**: Things closer to us appear bigger (duh), so most of what we see is the Milky way.  But if we ignore the close stuff, as I understand it, Matter is quite evenly spread out in every dimension, similar to CMB, which as adriancmenamin points out, came from matter.   The Universe appears quite uniform.  Very similar in every direction.  

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## 1 answers

### Answer by username_3 on 2016-04-23. Score: 2

It's not possible to see photons from "beyond" the cosmic microwave background (CMB), because (assuming our cosmology is generally correct) the CMB is the result of recombination of electrons with protons in the early universe. Photons from before that era were absorbed in the plasma.

Essentially then, the earliest matter we can see (in photonic terms) is this glowing hot hydrogen, but massively red-shifted so it looks like hydrogen at 3K.

We see the CMB in every direction.


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