<p>I'm not an expert in this, but I'll give it a try.</p>

<p>I think you've got the argument the other way round here. This was never discovered. It was assumed. But why?</p>

<ul>
<li>We know for the CMB being a redshifted blackbody-spectrum. This means the CMB consists of photons that were emitted in interaction with matter. </li>
<li>The CMB fluctuations inform us about the depths of gravity wells that those photons had to escape from (amongst other things). Thus we get a picture of the baryonic and dark matter density at the time of photon-matter decoupling.</li>
<li>This allows us to set up linear perturbation theory + simulations to look what happens to a uniform gas with the measured fluctuations on top. That's the rough idea.</li>
</ul>

<p>You could now of course ask "who was the first to implement this?".
The earliest theoretical work that I'm aware of <a href="http://adsabs.harvard.edu/abs/1965ApJ...142.1317P" rel="nofollow noreferrer">(Peebles 1965)</a> linking "a possible universal blackbody radiation" with the formation of galaxies came in the year of the discovery of background radiation by <a href="http://adsabs.harvard.edu/abs/1965ApJ...142..419P" rel="nofollow noreferrer">Penzias &amp; Wilson 1965</a>.</p>

CC BY-SA 4.0
2018-05-29T12:30:05.437Z
2018-05-29T12:30:05.437Z
AtmosphericPrisonEscape
<p>I haven't been able to find a reference to the first who showed that the small density fluctuations in the cosmic microwave background led to the formation of large scale structure as we know it.</p>

CC BY-SA 4.0
2018-05-29T08:00:56.013Z
I don't know too much about the details, but the initial studies of CMB indicated that it was remarkably uniform.  That uniformity was strong evidence for the expanding universe model and it dismissed a few other hypothetical models.  After observing the uniformity, the next logical step was to look more closely for any slight fluctuations.   Not sure if that helps.
userLTK
<cosmology><cosmic-microwave-background><early-universe><formation>
Who discovered the relation between CMB fluctuations and large-scale structure formation?
AlbertBranson
# Who discovered the relation between CMB fluctuations and large-scale structure formation?

(Asked by: username_0 on 2018-05-28)

I haven't been able to find a reference to the first who showed that the small density fluctuations in the cosmic microwave background led to the formation of large scale structure as we know it.

**Tags:** cosmology, cosmic-microwave-background, early-universe, formation

> **Comments:**
> **username_1**: I don't know too much about the details, but the initial studies of CMB indicated that it was remarkably uniform.  That uniformity was strong evidence for the expanding universe model and it dismissed a few other hypothetical models.  After observing the uniformity, the next logical step was to look more closely for any slight fluctuations.   Not sure if that helps.  

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## 1 answers

### Answer by username_2 on 2018-05-29. Score: 1 | Accepted answer

I'm not an expert in this, but I'll give it a try.

I think you've got the argument the other way round here. This was never discovered. It was assumed. But why?

* We know for the CMB being a redshifted blackbody-spectrum. This means the CMB consists of photons that were emitted in interaction with matter.
* The CMB fluctuations inform us about the depths of gravity wells that those photons had to escape from (amongst other things). Thus we get a picture of the baryonic and dark matter density at the time of photon-matter decoupling.
* This allows us to set up linear perturbation theory + simulations to look what happens to a uniform gas with the measured fluctuations on top. That's the rough idea.

You could now of course ask "who was the first to implement this?".
The earliest theoretical work that I'm aware of [(Peebles 1965)](http://adsabs.harvard.edu/abs/1965ApJ...142.1317P) linking "a possible universal blackbody radiation" with the formation of galaxies came in the year of the discovery of background radiation by [Penzias & Wilson 1965](http://adsabs.harvard.edu/abs/1965ApJ...142..419P).


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