Matter that's thought to exist in the universe, but that emits no signals other than gravitational effects
(cosmology) a hypothetical form of matter that is believed to make up 90 percent of the matter in the universe; it is invisible (does not absorb or emit light) and does not collide with atomic particles but exerts gravitational force
Matter that is in space but is not visible to us because it emits no radiation by which to observe it The motion of stars around the centers of their galaxies implies that about 90% of the matter in a typical galaxy is dark Physicists speculate that there is also dark matter between the galaxies but this is harder to verify
generally refers to undetected matter whose existence is needed to account for the motion of visible objects such as stars Dark matter may account for 90% of the mass of our universe
Dark matter is material that is believed to form a large part of the universe, but which has never been seen. Physical objects or particles that emit little or no detectable radiation of their own and are postulated to exist because of unexplained gravitational forces observed on other astronomical objects. Dark matter is believed to be part of the missing mass. Nonluminous matter not directly detectable by astronomers, hypothesized to exist because the mass of the visible matter in the universe cannot account for observed gravitational effects. Long believed to exist in large quantities, it enters into many theories of the origin of the universe and its present large-scale structure and into models of gravitation and other fundamental forces (see fundamental interaction) between particles. Numerous candidates for dark matter have been proposed over the years, but none has yet been confirmed
material that does not emit any light (or not detected yet), but has a significant gravitational effect
Any nonluminous astronomical object or particle that is detected only by its gravitational influence Examples include planets, black holes, white dwarfs (because they are low luminosity) and more exotic things like weakly interacting particles (WIMPs)
the "missing" mass of the Universe known to exist because more mass than can be observed is needed for a universe of ours' size and stability, possibly in the form of small black holes, particles currently thought to be massless, or mass exerting gravitational forces fourth-dimensionally
Theoretical non-luminous matter that has eluded detection by all present means, except through gravitational interaction with luminous objects Astronomers and astrophysicists calculate that dark matter comprises more than 90 percent of the universe Perhaps most of the universe exists as undetected clumps of interstellar dust and gas, plus cold dark stellar cores that collapsed billions of years ago Others have suggested an unknown form of matter, and a small mass for neutrinos Whatever the explanation, much of the universe has yet to be seen
Material that is believed to make up more than 90% of the mass of the universe, but is not readily visible because it neither emits nor reflects electromagnetic radiation, such as light or radio signals Its composition is unknown
Name given to the amount of mass whose existence is deduced from the analysis of galaxy rotation curves but which until now, has escaped all detections There are many theories on what dark matter could be Not one, at the moment is convincing enough and the question is still a mystery
The matter which is postulated to account for at least 90% of the mass of the Universe, but which has yet to be directly detected The evidence for its existence comes mainly from observations of the dynamics of stars in galaxies and of galaxies in clusters of galaxies, from gravitational lensing and from cosmological models Candidates for dark matter range from brown dwarfs and black holes to weakly-interacting elementary particles such as low-mass, fast-moving neutrinos or massive, slow-moving cold dark matter particles
Invisible "cosmic glue" that holds together rapidly spinning galaxies and controls the rate at which the universe expands It is observed by watching its gravitational affect on other objects
Matter in galaxies, clusters, and possibly between clusters, that can not be observed directly but can be detected by its gravitational effect As much as 90 percent of the mass of the universe may be in the form of dark matter
A nonluminous gravitational component of the universe invoked to explain the internal motions of galaxies and the motions of galaxies within clusters of galaxies
matter that we can't see, but we know must exist for various reasons, like spiral galaxies rotating so fast that, if the light matter was all that was there, the galaxy would fly apart Something must be holding it together, assuming gravity is still at galaxy-sized distances
Term used to describe the mass in galaxies and clusters whose existence we infer from rotation curves and other techniques, but which has not been confirmed by observations at any electromagnetic wavelength
Mass whose existence is deduced from the analysis of galaxy rotation curves and other indirect evidence but which has so far escaped direct detection