Heh; achktually, things like "parasitoid wasps" and "dark energy" are stuff people have heard (and misunderstood) of. The hidden stuff are the tons of boring (from the outside) and obscure notions that are very hard to describe and non-trivially related to the fancy stuff; and that are often a prerequisite to getting the full context for the fancy stuff. So please, when arguing with a physicist or a mathematician about their topic of expertise, please, give them a break. No, sphere eversion [0] does not correspond to a physical material that can pass through itself; yes, sphere eversion is still an extremely important process.<p>[0]<a href="https://www.youtube.com/watch?v=sKqt6e7EcCs" rel="nofollow">https://www.youtube.com/watch?v=sKqt6e7EcCs</a>