{"id":39,"date":"2008-03-30T12:48:07","date_gmt":"2008-03-30T17:48:07","guid":{"rendered":"http:\/\/blog.richmond.edu\/physicsbunn\/2008\/03\/30\/will-physics-destroy-the-world\/"},"modified":"2008-03-30T12:48:07","modified_gmt":"2008-03-30T17:48:07","slug":"will-physics-destroy-the-world","status":"publish","type":"post","link":"https:\/\/blog.richmond.edu\/physicsbunn\/2008\/03\/30\/will-physics-destroy-the-world\/","title":{"rendered":"Will physics destroy the world?"},"content":{"rendered":"

Apparently a couple of guys are suing<\/a> to stop the Large Hadron Collider, the new particle accelerator being built at CERN.\u00a0 They’re worried about the possibility that the collisions will produce something like miniature black holes or other exotic objects that would then destroy the Earth.<\/p>\n

This sort of worry has come up a bunch of times before.\u00a0 Sometimes the worry is about the possibility that the state of matter that we know and love is only a metastable state, not the most stable state.\u00a0 The idea then would be that, if you produce a single nugget of the true stable state, everything else would collapse into that new state.\u00a0 It’d be like having a supersaturated sugar solution: as soon as you give it a nucleation point, everything crystallizes out.\u00a0 Think Vonnegut’s ice-nine.<\/p>\n

So should we be worried about the LHC destroying the world?\u00a0 The short answer is no.\u00a0 This sort of thing is logically possible, so it’s certainly worth considering the possibility, given the enormous downside of destroying the world.\u00a0 But people have considered it very carefully and have shown quite convincingly that there is no risk.\u00a0 There’s a short overview here<\/a>, with links to the technical reports.<\/p>\n

There’s one argument that dispenses with a lot of the various doomsday scenarios.\u00a0 The sorts of collisions that will happen in the LHC happen regularly in the Earth’s upper atmosphere, as ultra-high-energy cosmic rays strike the Earth.\u00a0 You can work out that, over the Earth’s 5-billion-year history, the number of times these events have occurred naturally is many times larger than the number of times they will occur at the LHC.\u00a0\u00a0 So the fact that the Earth is still around is very strong evidence that this sort of catastrophic scenario is impossible.<\/p>\n

As the NY Times article points out, there’s a loophole in this argument.\u00a0 The collisions in the upper atmosphere are fast-moving particles colliding with particles that are essentially at rest.\u00a0 Because of conservation of momentum, anything produced in such a collision would be moving at close to the speed of light, so it wouldn’t stick around long enough to do any damage.\u00a0 In contrast, the collisions in the collider will be of particles moving in opposite directions with essentially equal speeds, so the resulting detritus will be produced nearly at rest.\u00a0 There is a big difference between a micro-black hole whizzing through the Earth at nearly the speed of light, which would have essentially no effect, and one that’s moving slow enough to stick around. \u00a0 To see why you still shouldn’t worry, you have to read the technical reports.<\/p>\n","protected":false},"excerpt":{"rendered":"

Apparently a couple of guys are suing to stop the Large Hadron Collider, the new particle accelerator being built at CERN.\u00a0 They’re worried about the possibility that the collisions will produce something like miniature black holes or other exotic objects that would then destroy the Earth. This sort of worry has come up a bunch … Continue reading Will physics destroy the world?<\/span><\/a><\/p>\n","protected":false},"author":12,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-39","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/blog.richmond.edu\/physicsbunn\/wp-json\/wp\/v2\/posts\/39","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.richmond.edu\/physicsbunn\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.richmond.edu\/physicsbunn\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.richmond.edu\/physicsbunn\/wp-json\/wp\/v2\/users\/12"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.richmond.edu\/physicsbunn\/wp-json\/wp\/v2\/comments?post=39"}],"version-history":[{"count":0,"href":"https:\/\/blog.richmond.edu\/physicsbunn\/wp-json\/wp\/v2\/posts\/39\/revisions"}],"wp:attachment":[{"href":"https:\/\/blog.richmond.edu\/physicsbunn\/wp-json\/wp\/v2\/media?parent=39"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.richmond.edu\/physicsbunn\/wp-json\/wp\/v2\/categories?post=39"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.richmond.edu\/physicsbunn\/wp-json\/wp\/v2\/tags?post=39"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}