More Matt Strassler: LHC hunts dark matter (Introduction)

by David Turell , Friday, June 19, 2015, 00:18 (3446 days ago) @ David Turell

Does it really exist? It is never seen but its mass explains the speed of galaxy rotation:-http://www.newscientist.com/article/mg22630263.000-chasing-shadows-how-long-can-we-keep-looking-for-dark-matter.html#.VYNV92DbK1t-"Perhaps we have simply been looking for the wrong thing. Perhaps dark matter particles are very massive, rather than fairly light, as many assume. The first experiments are now under way to detect any such "superheavy" dark matter that might have been created when the universe was just getting started.-"Or perhaps the true identity of dark matter is so unexpected that we haven't even thought to look for it, despite potential evidence lurking somewhere in the vast quantities of data from the LHC.-"Or perhaps we have embarked on one of those quixotic quests that mark the history of physics. At the beginnings of cosmology, Ptolemy devised a model of planetary motion that closely fitted observations. For more than a millennium, his successors adjusted these "epicycles" for new-found anomalies. Their laudable commitment and ingenuity was to increasingly little effect. In the end, Copernicus and Kepler blew the whole thing away - though it took a while for their model to be accepted.-"A more recent parallel comes from the search for luminiferous ether, the all-pervading substance once thought to be the medium for light. When Albert Michelson and Edward Morley failed to detect it in 1887, they didn't declare that the world needed a new theory for the propagation of light. Instead, they and others built a series of bigger and better instruments to find it. Eventually special relativity abolished the anomaly - but many etherists carried on looking regardless.-"Can we be sure we're not in their position, looking for something that isn't there? Well, there is no robust alternative to dark matter; plans to resolve the cosmic anomalies by other means, such as modified gravity are not well-attested."