Exotic Particle: A kind of theoretical particle said to exist by some theories of modern physics, whose alleged properties are extremely unusual. Examples include tachyons (particles that always travels faster than the speed of light), WIMPs (weakly interacting massive particles which do not interact withelectromagnetism or the strong nuclear force), axions (particles with no electric charge, very smallmass and very low interaction with the strong and weak forces) and neutrinos (particles that travel close to the speed of light, lack an electric charge and are able to pass through ordinary matteralmost undisturbed).
A universe which is constantly growing in size and in which the constituent parts (galaxies, clusters, etc) are flying ever further away from each other. Although contrary to the static universewhich had been assumed throughout most of history, an expanding universe was confirmed by Edwin Hubble’s 1929 observations of the redshifts of distant Cepheid variable stars, and is consistent with most solutions to Albert Einstein’s general relativity field equations. It also suggests that, in the distant past, the universe was much smaller and ultimately had its beginning in aBig Bang type event.