There’s a kind of tradition in theoretical physics of wacky “what if” papers. The whole “wormhole” thing is an example of this in action– somebody noticed that the structure of General Relativity would allow you to make tunnel-like structures between points in space, and then asked what you would need to make such a structure. The answer turns out to include “a negative energy density,” which is impossible, as far as we know, but that hasn’t stopped people from creating an entire cottage industry around papers about wormholes.<\/p>\n
(I don’t know if other sciences do this– are there biologists who make a career out of speculative papers on what life would be like if it were based on silicon rather than carbon?)<\/p>\n
As a fan of SF, I’m all right with this sort of speculative stuff, but it continues to strike me as odd when I run across these ideas being taken seriously. For example, there’s the Dyson sphere search<\/a> mentioned at Cosmic Variance the other day. Dyson spheres are another fanciful construct, based on the idea that a sufficiently powerful civilization might decide to harness solar energy more effectively by completely enclosing their star with a shell of matter. If you used the mass of Jupiter, and a radius twice that of the Earth’s orbit, you’d get a shell a few meters thick.<\/p>\n Far-fetched as this sounds, people are actually looking for these things. If you work through the consequences of making a Dyson sphere, it turns out that the whole thing ought to radiate in the infrared, so a group at Fermilab<\/a> is poring over infrared telescope data, looking for objects with the appropriate signature. They haven’t found any<\/a>, but they are looking.<\/p>\n There are times, though, when “what-if” papers tip over into annoying me.<\/p>\n <\/p>\n More precisely, it’s not the papers themselves that annoy me, it’s the coverage of them. Take, for example, this Physics Buzz item<\/a> on a scheme that would allow eavesdropping on quantum cryptography<\/a>.<\/p>\n Quantum cryptography is a technique that uses entangled particles to generate an encryption key that is shared by two people (traditionally, Alice and Bob) who want to exchange secret information. The security of the key is guaranteed by quantum mechanics– there is no way for an eavesdropper (“Eve,” a deplorable bit of twee nomenclature) to intercept the key without being detected, thanks to the way quantum measurement works. A scheme to break this would involve some sort of major revision to our understanding of quantum physics.<\/p>\n So, the paper being reported at Physics Buzz is big news, right? Well, not so much. There is a scheme being presented that would let Eve intercept messages undetectably, that much is true. However, it requires her to travel back in time, through a wormhole.<\/p>\n This isn’t remotely a practical scheme, it’s “what if” cubed. If you could make a wormhole, you could travel back in time, and if you could travel back in time, you could potentially eavesdrop on quantum cryptography. And if I had quickness and jumping ability, I’d be in the NBA.<\/p>\n Now, to their credit, the folks at Physics Buzz do report this with the appropriate qualifiers, even in the headline. The Science News<\/cite> piece<\/a> they based it on is a little less restrained (and also includes a really dopey explanation of cryptography involving birds). And I fully expect to see a New Scientist<\/cite> article proclaiming the end of quantum theory as we know it, based on taking the Science News<\/cite> piece and stripping out all the cautions and caveats.<\/p>\n “What if” papers are fun and all, but when they start getting taken too seriously, it rapidly becomes annoying.<\/p>\n","protected":false},"excerpt":{"rendered":" There’s a kind of tradition in theoretical physics of wacky “what if” papers. The whole “wormhole” thing is an example of this in action– somebody noticed that the structure of General Relativity would allow you to make tunnel-like structures between points in space, and then asked what you would need to make such a structure.… Continue reading If Wishes Were Horses We’d All Be Eatin’ Steak<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"1","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[],"class_list":["post-3198","post","type-post","status-publish","format-standard","hentry","category-physics","entry"],"_links":{"self":[{"href":"http:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/posts\/3198","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"http:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/comments?post=3198"}],"version-history":[{"count":0,"href":"http:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/posts\/3198\/revisions"}],"wp:attachment":[{"href":"http:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/media?parent=3198"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/categories?post=3198"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/tags?post=3198"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}