<p>The <a href="https://en.wikipedia.org/wiki/List_of_the_most_distant_astronomical_objects" rel="nofollow noreferrer">most distant objects</a> which can be seen with telescopes are around 13.39 ly away, with a redshift $z=11$. Telescopes see a roughly uniform Universe, although some very large structures were already <a href="https://en.wikipedia.org/wiki/List_of_largest_cosmic_structures" rel="nofollow noreferrer">identified</a>.</p>

<p>The <a href="https://www.cv.nrao.edu/course/astr534/CMB.html" rel="nofollow noreferrer">Cosmical Microwave Background</a> has a $z \approx 1000$.</p>

<p>It was measured for its possible minor anisotropies by the <a href="https://en.wikipedia.org/wiki/Cosmic_Background_Explorer" rel="nofollow noreferrer">COBE</a>, and the <a href="https://map.gsfc.nasa.gov/" rel="nofollow noreferrer">Wilkinson Microwave Anisotropy Probe (WMAP)</a> and <a href="https://en.wikipedia.org/wiki/Planck_(spacecraft)" rel="nofollow noreferrer">Planck</a> satellites.</p>

<p>It measured the temperature of the 2.7K Cosmical Microwave Background with $\approx 10^{-5} K$ precision. The technology was not easy.</p>

<p>There were two results:</p>

<p>First, there is a global dipole anisotropy showing that we are <a href="http://www.astro.ucla.edu/~wright/CMB-DT.html" rel="nofollow noreferrer">moving with</a> $\approx 368 \frac{km}{s}$ to the Hercules constellation. It is the nearest thing what could be seen, as if we had found an absolute reference frame.</p>

<p><a href="https://i.sstatic.net/4Ch2a.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/4Ch2a.png" alt="enter image description here"></a></p>

<p>Second, substracting this from the results, another, lesser anisotropy were found:</p>

<p><a href="https://i.sstatic.net/5KptA.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/5KptA.jpg" alt="enter image description here"></a></p>

<p>The distribution of the anisotropy, combined with the result of other experiments, helped to get</p>

<ul>
<li>the most precise measurement of the age of the Universe (13.7 Gy).</li>
<li>the most precise measurement of the curvature of the Universe (0, below measurement precision).</li>
<li>that the expansion of the Universe is accelerating.</li>
</ul>

<p>Also the polarity was measured, which has shown that the re-inozation happened earlier as it was previously believed.</p>

<p>This is the best result what we have until now.</p>

CC BY-SA 4.0
2018-08-15T12:49:25.140Z
The global dipole anisotropy isn't a surprising result. It is an expected result. CMB anisotropies were identified by COBE - much earlier than WMAP.
ProfRob
CC BY-SA 4.0
2018-08-15T19:02:20.857Z
Also, WMAP is not really the best results we have, as it has been succeeded by Planck.
pela
CC BY-SA 4.0
2018-08-16T06:36:21.227Z
Also, the dipole is much larger than the 160 km/s; on average it's 370 km/s.
pela
CC BY-SA 4.0
2018-08-16T06:58:09.673Z
@RobJeffries Maybe fixed.
peterh
CC BY-SA 4.0
2018-08-16T06:58:16.347Z
@pela Maybe fixed.
peterh
CC BY-SA 4.0
2018-08-16T10:38:44.333Z
Then while you're at it: You write that the CMB is measured with 1e-4 K, but later you write "tenths of Kelvins". Both are actually too high, as the CMB is measured with _less than_ 1e-5 K precision. :)
pela
CC BY-SA 4.0
2018-08-16T18:38:33.777Z
@pela No prob - fix done :-)
peterh
CC BY-SA 4.0
2018-08-15T00:17:32.197Z
2018-08-16T18:38:21.017Z
2018-08-16T18:38:21.017Z
peterh
<p>Have there been studies to compare structures that are 26 billion light years distant (i.e. from one side of the observable universe to the other) to search for faint differences?</p>

CC BY-SA 4.0
2018-08-14T22:10:20.997Z
Source of oldest info on isotropy is CMB https://astronomy.stackexchange.com/questions/475/what-is-the-mass-of-hotspots-in-the-cosmic-microwave-background-radiation?rq=1
Mithoron
<galaxy><cosmic-microwave-background><deep-sky-observing>
Studies of isotropy from different ends of the visible universe?
bandybabboon
# Studies of isotropy from different ends of the visible universe?

(Asked by: username_0 on 2018-08-14)

Have there been studies to compare structures that are 26 billion light years distant (i.e. from one side of the observable universe to the other) to search for faint differences?

**Tags:** galaxy, cosmic-microwave-background, deep-sky-observing

> **Comments:**
> **username_1**: Source of oldest info on isotropy is CMB https://astronomy.stackexchange.com/questions/475/what-is-the-mass-of-hotspots-in-the-cosmic-microwave-background-radiation?rq=1  

---

## 1 answers

### Answer by username_2 on 2018-08-15. Score: 2

The [most distant objects](https://en.wikipedia.org/wiki/List_of_the_most_distant_astronomical_objects) which can be seen with telescopes are around 13.39 ly away, with a redshift $z=11$. Telescopes see a roughly uniform Universe, although some very large structures were already [identified](https://en.wikipedia.org/wiki/List_of_largest_cosmic_structures).

The [Cosmical Microwave Background](https://www.cv.nrao.edu/course/astr534/CMB.html) has a $z \approx 1000$.

It was measured for its possible minor anisotropies by the [COBE](https://en.wikipedia.org/wiki/Cosmic_Background_Explorer), and the [Wilkinson Microwave Anisotropy Probe (WMAP)](https://map.gsfc.nasa.gov/) and [Planck](https://en.wikipedia.org/wiki/Planck_(spacecraft)) satellites.

It measured the temperature of the 2.7K Cosmical Microwave Background with $\approx 10^{-5} K$ precision. The technology was not easy.

There were two results:

First, there is a global dipole anisotropy showing that we are [moving with](http://www.astro.ucla.edu/~wright/CMB-DT.html) $\approx 368 \frac{km}{s}$ to the Hercules constellation. It is the nearest thing what could be seen, as if we had found an absolute reference frame.

[![enter image description here](https://i.sstatic.net/4Ch2a.png)](https://i.sstatic.net/4Ch2a.png)

Second, substracting this from the results, another, lesser anisotropy were found:

[![enter image description here](https://i.sstatic.net/5KptA.jpg)](https://i.sstatic.net/5KptA.jpg)

The distribution of the anisotropy, combined with the result of other experiments, helped to get

* the most precise measurement of the age of the Universe (13.7 Gy).
* the most precise measurement of the curvature of the Universe (0, below measurement precision).
* that the expansion of the Universe is accelerating.

Also the polarity was measured, which has shown that the re-inozation happened earlier as it was previously believed.

This is the best result what we have until now.

> **Comments:**
> **username_3**: The global dipole anisotropy isn't a surprising result. It is an expected result. CMB anisotropies were identified by COBE - much earlier than WMAP.  
> **username_4**: Also, WMAP is not really the best results we have, as it has been succeeded by Planck.  
> **username_4**: Also, the dipole is much larger than the 160 km/s; on average it's 370 km/s.  
> **username_2**: @RobJeffries Maybe fixed.  
> **username_2**: @username_4 Maybe fixed.  
> **username_4**: Then while you're at it: You write that the CMB is measured with 1e-4 K, but later you write "tenths of Kelvins". Both are actually too high, as the CMB is measured with _less than_ 1e-5 K precision. :)  
> **username_2**: @username_4 No prob - fix done :-)  

---

