<story><title>First detection of the missing half of normal matter in our universe</title><url>https://www.newscientist.com/article/2149742-half-the-universes-missing-matter-has-just-been-finally-found/</url></story><parent_chain></parent_chain><comment><author>iheartmemcache</author><text>Dang I read the first paragraph of the article and immediately went searching for the real papers since I didn&amp;#x27;t expect any media outlet to include them at the bottom, but here they are for anyone who made the same mistake I did! &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;arxiv.org&amp;#x2F;abs&amp;#x2F;1709.05024&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;arxiv.org&amp;#x2F;abs&amp;#x2F;1709.05024&lt;/a&gt;
&lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;arxiv.org&amp;#x2F;abs&amp;#x2F;1709.10378&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;arxiv.org&amp;#x2F;abs&amp;#x2F;1709.10378&lt;/a&gt;&lt;p&gt;Not a cosmologist but here&amp;#x27;s my go at the de Graff paper. (Let&amp;#x27;s get this out of the way, the title is click-bait and the paper&amp;#x2F;researchers makes no such claims as to anything near 50%. New Scientist is trolling for hits with the word &amp;quot;half&amp;quot; or the journalist is fundamentally misunderstanding the work.) In de Graff, et al, they claim 30% of &amp;quot;90% of the missing baryonic matter [that composes the ~25% of our total universe observable from within our light cone]&amp;quot; has been found in the CMB structured as filaments between galaxies. They claim there&amp;#x27;s effectively a planar network layered on top of Minkowski space composed this baryonic matter. The temperature was at this &amp;quot;Goldilocks&amp;quot; midrange no one had previously analyzed (ranging from 10^5-10^7K). This wasn&amp;#x27;t previously found because people were searching &amp;quot;only the lower and higher temperature end of the warm-hot baryons, leaving the majority of the baryons still unobserved(9)&amp;quot;. [See &amp;quot;Warm-hot baryons comprise 5-10 percent of filaments in the cosmic web.&amp;quot;, &lt;i&gt;Nature&lt;/i&gt;, Eckert et al for more about baryons of this composition.]&lt;p&gt;Additionally, these baryons have 10x the density of what we observe (so this could potentially be evidence for the first stable baryonic matter composed of second generation quarks, or more likely the binding energies are different from our standard uud&amp;#x2F;udd nucleon quarks) permeating the universe, and where the roads in the network meet (&amp;quot;dark matter haloes&amp;quot;), you have embedded galaxies and galaxy clusters. They continue with their analytic methods of the CMASS data, and claim within the framework 30% of the total baryonic content (which, again, all analytical methods put this into no more than ~25%) is composed of this form of this matter.  I skimmed their methods and it seemed to at least logically hold -- they are using the appropriate data (SDSS 12) and didn&amp;#x27;t cherry-pick their galaxy pairs (so, no p-hacking here!).</text></comment>
<story><title>First detection of the missing half of normal matter in our universe</title><url>https://www.newscientist.com/article/2149742-half-the-universes-missing-matter-has-just-been-finally-found/</url></story><parent_chain></parent_chain><comment><author>lacksconfidence</author><text>&lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.reddit.com&amp;#x2F;r&amp;#x2F;space&amp;#x2F;comments&amp;#x2F;75944s&amp;#x2F;half_the_universes_missing_matter_has_just_been&amp;#x2F;do4mfjx&amp;#x2F;&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.reddit.com&amp;#x2F;r&amp;#x2F;space&amp;#x2F;comments&amp;#x2F;75944s&amp;#x2F;half_the_univ...&lt;/a&gt;&lt;p&gt;&amp;gt; The approximate distribution in the Universe is 5% regular matter, 25% Dark Matter, and 70% Dark Energy. Half of that 5% was missing, and now found.&lt;p&gt;&amp;gt; Regular matter makes stars and visible galaxies, so it is &amp;quot;bright&amp;quot;. Dark Matter is so named because it does not make things we can see with telescopes directly - it is &amp;quot;dark&amp;quot;. We can see the effects it makes with gravity, such as the rotation curves of galaxies, and gravitational lensing. So we know something is there, just not what it is made of. Dark Energy was invented to solve a couple of mysteries. One is the geometrical &amp;quot;flatness&amp;quot; of the Universe, and the other is the apparent acceleration of the Universe&amp;#x27;s expansion. Like Dark Matter, we don&amp;#x27;t yet know what it is. But something is causing the flatness and acceleration, so we gave it a name as a place-holder for theories.&lt;p&gt;&amp;gt; A similar situation happened a century ago, with the precession (shift) of Mercury&amp;#x27;s orbit with time. We thought it was caused by a planet inside of Mercury&amp;#x27;s orbit that we hadn&amp;#x27;t found yet. It was named Vulcan, after the Roman god of fire (not Spock&amp;#x27;s home planet). It turns out relativity was the right answer - the Suns gravity bends space near it, and causes the orbit to shift. Vulcan was just &amp;quot;a name we gave to whatever causes the observed effect&amp;quot;.&lt;p&gt;&amp;gt; Dark Matter and Dark Energy could turn out to be something entirely different than types of matter and energy, but in the mean time it gives them names we can attach theories about them to.</text></comment>