<story><title>Spooky Alignment of Quasars Across Billions of Light-years</title><url>http://www.eso.org/public/news/eso1438/</url></story><parent_chain><item><author>madaxe_again</author><text>Conservation of angular momentum. I don&amp;#x27;t see this as all that shocking. If you consider that the universe is growing (or at least it appears to be and to the best of our knowledge), and that therefore at some point the matter that now comprises these quasars was quite probably part of a single coherent system, say, an earlier galaxy, which would have had angular momentum - all this is showing is the angular momentum of the structure which birthed the quasars. Which is neat.&lt;p&gt;Simple version: imagine you have a long pole which is spinning, fast. Then imagine a ninja comes in and slices the pole up, perpendicular to its axis, so you&amp;#x27;ve got 20 short poles. The 20 short poles continue to spin on the same axis as the original long pole. If those poles are in the vacuum of space with nothing slowing them down, they will continue to spin in the same way for a &lt;i&gt;very, very long time&lt;/i&gt;. They might wobble a bit (precession), which explains why the poles aren&amp;#x27;t  all perfectly aligned in this data.</text></item></parent_chain><comment><author>tjradcliffe</author><text>Our intuition does a very poor job of answering questions like this (well, almost any questions, really) and we can spend a lot of time fooling ourselves that the way the universe actually is &amp;quot;makes sense&amp;quot; in some intuitive way. It doesn&amp;#x27;t. If it did, we&amp;#x27;d have had correct physics in 1687 BCE instead of 1687 CE.&lt;p&gt;One way to test this is to ask yourself what your intuition tells you before you know the answer. You&amp;#x27;ll mostly get it wrong, unless you have formal training in the field. Intuitive &amp;quot;explanations&amp;quot; are only good after the fact, and even after the fact can be misleading and problematic, as the one you bring up here is.&lt;p&gt;The universe as a whole (very probably) has zero angular momentum. There are consequences on the large scale if this is not the case that we&amp;#x27;d probably have detected by now. So early star formation, including quasar formation, happened in a hot zero-momentum gas cloud that filled the expanding universe. That is the structure that birthed the quasars. That means that while there may well have been local eddies, there was not any overall rotation to the gas. So why would quasars that formed in distant parts of that gas have their axes aligned in the same direction?&lt;p&gt;Short version: your mental model of the early universe is not accurate, so your intuitive explanation doesn&amp;#x27;t actually explain the phenomenon under study. Simply because it &amp;quot;makes sense&amp;quot; of the data does not make it useful. In particular, you&amp;#x27;ve assumed a counter-factual.&lt;p&gt;The reason why cosmologists are surprised by these results is because they have a better understanding of the early universe, and know that there is no known mechanism to align the rotational axes of these objects. They are now wondering what that mechanism might be. Global angular momentum is one possibility, but it is far, far down on the list because it is contradicted by a lot of other data.</text></comment>
<story><title>Spooky Alignment of Quasars Across Billions of Light-years</title><url>http://www.eso.org/public/news/eso1438/</url></story><parent_chain><item><author>madaxe_again</author><text>Conservation of angular momentum. I don&amp;#x27;t see this as all that shocking. If you consider that the universe is growing (or at least it appears to be and to the best of our knowledge), and that therefore at some point the matter that now comprises these quasars was quite probably part of a single coherent system, say, an earlier galaxy, which would have had angular momentum - all this is showing is the angular momentum of the structure which birthed the quasars. Which is neat.&lt;p&gt;Simple version: imagine you have a long pole which is spinning, fast. Then imagine a ninja comes in and slices the pole up, perpendicular to its axis, so you&amp;#x27;ve got 20 short poles. The 20 short poles continue to spin on the same axis as the original long pole. If those poles are in the vacuum of space with nothing slowing them down, they will continue to spin in the same way for a &lt;i&gt;very, very long time&lt;/i&gt;. They might wobble a bit (precession), which explains why the poles aren&amp;#x27;t  all perfectly aligned in this data.</text></item></parent_chain><comment><author>kahirsch</author><text>&amp;gt; Then imagine a ninja comes in and slices the pole up, perpendicular to its axis, so you&amp;#x27;ve got 20 short poles.&lt;p&gt;Why would you expect the ninja to do this? Why would you expect large-scale structures of the universe to form parallel to the quasars&amp;#x27; axes?&lt;p&gt;As far as we can tell, the alignment of planetary systems in the Milky Way are random.[1]&lt;p&gt;[1] &lt;a href=&quot;http://astronomy.stackexchange.com/questions/546/why-is-our-solar-system-tipped-about-63%C2%B0-with-respect-to-the-plane-of-our-gala&quot; rel=&quot;nofollow&quot;&gt;http:&amp;#x2F;&amp;#x2F;astronomy.stackexchange.com&amp;#x2F;questions&amp;#x2F;546&amp;#x2F;why-is-our-...&lt;/a&gt;</text></comment>