<story><title>Every Black Hole Contains a New Universe</title><url>http://www.insidescience.org/?q=content/every-black-hole-contains-new-universe/566</url></story><parent_chain></parent_chain><comment><author>cft</author><text>In Einstein&apos;s theory of general relativity, Riemann tensor is assumed to be symmetric, due to great simplification of the theory compared to the one with non-symmetric Riemann tensor, and an absolute lack of experimental evidence to the contrary for 100 years since it was discoveried. Torsion, which is the cause of asymmetry of the Riemann tensor is set to zero. I do not know why this author is so excited about torsion tensor, the idea that torsion could be non-zero has been around for at least 90 years, but got zero traction. Disclaimer : I have a phd in string theory.</text></comment>
<story><title>Every Black Hole Contains a New Universe</title><url>http://www.insidescience.org/?q=content/every-black-hole-contains-new-universe/566</url></story><parent_chain></parent_chain><comment><author>taliesinb</author><text>Of course headlines have to be catchy, but this universe-in-a-black-hole concept is hardly a new one. Rather, the novel part here seems to be the idea that the connection in GR might might possess non-zero torsion, contrary to what is normally assumed.&lt;p&gt;In the whole black-holes-create-universes vein, last century the theoretical physicist Lee Smolin presented the quite delicious idea (described in his book The Life Of the Cosmos) that entire universes might be subject to the process of natural selection.&lt;p&gt;This would work if singularity formation involves the transmission of physical constants to the &apos;daughter&apos; universe with slight modification, quite a thing to suppose given we don&apos;t really know what physical constants &apos;mean&apos;.&lt;p&gt;If it occurred, this natural selection would optimize these constants for the production of black holes, which luckily for us co-incides with the production of life-bearing stars. Of course, all very unfalsifiable, but kinda epic.</text></comment>