<p>Let us define this as the largest <em>observable</em> density of a stable object, in order to exclude black holes which may have  a very large (infinite) density at their centers or objects collapsing towards a black hole status.</p>

<p>If we restrict the definition in this way, then the answer should be the core of the most massive neutron star that we know about.</p>

<p>At present there are a couple of neutron stars with mass of about $2M_{\odot}$ (<a href="http://arxiv.org/abs/1010.5788">Demorest et al. 2010</a>; <a href="https://arxiv.org/abs/1304.6875">Antoniadis et al. 2013</a>. Depending on the exact composition and equation of state at their centres these should have densities of around $2 \times 10^{18}$ kg/m$^{3}$ at their centers and average densities of $\sim 10^{18}$ kg/m$^3$.</p>

<p>Note that these densities are around 3 times the density of a proton or neutron or 5-10 times the density of nuclei at zero pressure.</p>

<p>In principle, the density of a single electron is much higher.</p>

CC BY-SA 3.0
2016-05-18T14:17:02.467Z
Comments are not for extended discussion; this conversation has been [moved to chat](http://chat.stackexchange.com/rooms/39957/discussion-on-answer-by-rob-jeffries-what-is-the-most-dense-object-in-the-univer).
called2voyage
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2016-05-17T14:18:52.993Z
2016-05-17T16:41:07.223Z
2016-05-17T16:41:07.223Z
ProfRob
<p>Inspired by this answer to the question, <a href="https://astronomy.stackexchange.com/a/14891/11851">Why is the Sun's density less than the inner planets?</a>, what is the most dense object in the universe?</p>

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2016-05-17T14:52:34.510Z
Are you excluding singularities?
SE - stop firing the good guys
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2016-05-17T15:05:07.643Z
A singularity isn't observable and may or may not exist.
ProfRob
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2016-05-18T17:04:41.707Z
I'd say Trump would be in the top 3.
db9dreamer
<universe><density>
What is the most dense object in the universe?
8protons
# What is the most dense object in the universe?

(Asked by: username_0 on 2016-05-17)

Inspired by this answer to the question, [Why is the Sun's density less than the inner planets?](https://astronomy.stackexchange.com/a/14891/11851), what is the most dense object in the universe?

**Tags:** universe, density

> **Comments:**
> **username_1**: Are you excluding singularities?  
> **username_2**: A singularity isn't observable and may or may not exist.  
> **username_3**: I'd say Trump would be in the top 3.  

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## 1 answers

### Answer by username_2 on 2016-05-17. Score: 18 | Accepted answer

Let us define this as the largest *observable* density of a stable object, in order to exclude black holes which may have a very large (infinite) density at their centers or objects collapsing towards a black hole status.

If we restrict the definition in this way, then the answer should be the core of the most massive neutron star that we know about.

At present there are a couple of neutron stars with mass of about $2M\_{\odot}$ ([Demorest et al. 2010](http://arxiv.org/abs/1010.5788); [Antoniadis et al. 2013](https://arxiv.org/abs/1304.6875). Depending on the exact composition and equation of state at their centres these should have densities of around $2 \times 10^{18}$ kg/m$^{3}$ at their centers and average densities of $\sim 10^{18}$ kg/m$^3$.

Note that these densities are around 3 times the density of a proton or neutron or 5-10 times the density of nuclei at zero pressure.

In principle, the density of a single electron is much higher.

> **Comments:**
> **username_4**: Comments are not for extended discussion; this conversation has been [moved to chat](http://chat.stackexchange.com/rooms/39957/discussion-on-answer-by-rob-jeffries-what-is-the-most-dense-object-in-the-univer).  

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