https://hackerpaper.kaipfister.de/p/hep-ph_0207125/Collected HN comments and submissions linking this paper.enMon, 02 Nov 2026 11:16:22 GMThttps://news.ycombinator.com/item?id=20584527urn:hackerpapers:mention:hep-ph_0207125:20584527Thu, 01 Aug 2019 15:16:32 GMT<p>The fifth dimension is theoretical, yes. It turns out that you can get classical electricity and magnetism out of the Einstein equations by adding a fifth, rotationally symmetric spatial dimension (https://en.wikipedia.org/wiki/Kaluza%E2%80%93Klein_theory). Some people had hopes that quantum mechanics could fall out of the einstein equations in a similar fashion and this hope sort of lead to string theory, which needs to add further dimensions beyond the rotationally symmetric U(1) group of Kaluza-Klein theory to support the SO(3) (I believe) group of the electro-weak force (so they add 4…</p><p><a href="https://hackerpaper.kaipfister.de/p/hep-ph_0207125/">Paper and discussion history</a>. A mention is not an endorsement.</p>hep-ph