Astronomical measurements indicate that luminous matter, such as our sun, makes up only a small percentage of the total matter in the universe. The missing mass that makes up the remainder is known as dark matter.

Matter that is too cool to emit sufficient detectable radiation.

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. Possible sources of dark matter include undetected clumps of interstellar dust and gas, stellar remnants such as white dwarfs and neutron stars, neutrinos that have mass, and some as yet unknown form of matter.

Matter that's thought to exist in the universe, but that emits no signals other than gravitational effects.

This is a term used to describe an abundant substance in the universe whose composition is unknown.

A form of matter which does not emit light. Its nature is still being investigated.

Matter that cannot be detected by current instruments, although its existence can be inferred by its gravitational interactions. For instance, by studying the speed at which the 'arms' in the spiral galaxies rotate, astronomers know that they must be more massive than what can be estimated based on the light that a telescope measures. It has been proposed that part of this matter might be in the form of non-baryonic matter.

Matter whose presence is inferred from dynamical measurements but which has no optical counterpart.

The name given by modern astrophysics to the as yet unidentified substance which makes up 90% of the mass of the universe. This substance does not interact with ordinary matter and therefore cannot yet be measured directly.

Unknown and theoretical substance in space whose present is detected by its gravitational effect on celestial objects.

A matter that are not made of the same materials we know of. Dark matter does not emit radiation, thererfore the existance of dark matter can only be verified by graviation.

A nonluminous gravitational component of the universe invoked to explain the internal motions of galaxies and the motions of galaxies within clusters of galaxies.

(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

see related section] nonluminous (not emitting light or visible) material that cannot be detected by observing the sky, but whose existence is suggested by certain theories.

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.

matter that cannot be detected with current technology. It is too cold and dark to see or measure; scientists believe it makes up about 90 percent of the universe.

Unseen matter that is detected only by its gravitational pull on visible matter. Most of the universe is evidently made of dark matter. Its nature is yet to be determined.

Nonluminous mass, whose presence can be inferred only because of its gravitational influence on luminous matter. Dark matter may constitute as much as 99 percent of all the mass in the universe. The composition of the dark matter is not known.

Mass whose existence is deduced from the analysis of galaxy rotation curves and other indirect evidence but which has so far escaped direct detection.

A type of matter which is found near other matter. It cannot be observed directly (it is "dark"), but can be noticed as a result of the pull of gravity from the dark matter. Astrophysicists believe that more than half of the Universe could be in the form of dark matter.

Observations reveal that vast halos of invisible matter surround galaxies and galaxy clusters. This dark matter adds up to many times the mass of the visible stars, gas, and dust seen in galaxies. The temperature of dark matter is a measure of how fast the particles in it are moving. Hot refers to particles moving near the speed of light, and cold refers to particles moving much slower than that. The future of our universe depends on how much dark matter exists. More dark matter means the universe will eventually collapse while less dark matter means an ever-expanding universe. Hot and cold dark matter play a crucial role in understanding how galaxies formed. If all dark matter in the early universe were cold, galaxies would form first and later congregate into clusters.

A form of matter that exerts gravitation force but does not emit any detectable light or radiation; dark matter comprises most of the mass of the universe but its exact nature remains unknown

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

A kind of matter that cannot be seen directly and its composition is unknown. However, its gravitational effect can be measured. It is estimated that up to 90% of the mass in our universe is made of dark matter.

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).

Unilluminated mass detectable only through its gravitational interaction with normal matter. Normal matter can account for only about 10% of all matter in the universe. The remaining 90%--unobserved thus far--is considered dark matter.

The undetected matter in the universe which is not luminous. We know of its existence because of how clusters of stars and galaxies rotate.

The name given to material whose existence is deduced from the analysis of galaxy rotation curves, but which until recently, has escaped all detection. There are many theories as to what dark matter could be, but the definitive answer remains elusive.

Unseen matter that may make up more than 30 % of the Universe. As the name implies, dark matter does not interact with light or other electromagnetic radiation, so it cannot be seen directly, but it can be detected by measuring its gravitational effects. It is believed that dark matter was instrumental in forming galaxies early in the Big Bang.

The visible stars and nebulae make up only a small fraction of all the matter in the universe. The rest is in a form that is not easy to detect, but clearly exists because of the effect it has on the motion of stars in galaxies and the motion of galaxies in clusters. Dark matter probably consists of various types of subatomic particles.

This refers to matter particles of unknown composition that neither emit or reflect enough electromagnetic radiation to be detected directly. However their presence can be inferred from gravitational effects on visible matter such as stars and galaxies.

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 on any electromagnetic wavelength. [More Info: Field Guide

A form of matter which has not been directly observed but whose existence has been deduced by it's gravitational effects.

a form of matter that does not emit light, absorb light, or scatter light. Its only interactions are gravitational.

A term used to describe matter in the universe that cannot be seen, but can be detected by its gravitational effects on other bodies.

Invisible material in the universe that may mean that the universe is sufficiently heavy that it will not expand forever.

Unseen matter that has a gravitational effect on the motions of galaxies within clusters of galaxies.

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.

Matter in the cosmos that is undetectable because it doesn't glow. Dark matter, some of it in the form of as-yet-undiscovered exotic particles, is thought to comprise most of the universe.

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material that does not emit any light (or not detected yet), but has a significant gravitational effect.

Name given to the amount of mass whose existence until now has escaped all detections but which is deduced from the analysis of galaxy rotation curves.

Matter that is too dim to be detected by telescopes. Astronomers infer its existence by measuring its gravitational influence. Dark matter makes up most of the total mass of the universe.

Dark matter is unknown matter that may constitute as much as 99 percent of the matter in the universe.

Dark Matter is a fictional character and recurring antagonist in the Kirby series of video games. To date, it has appeared in three games, Kirby's Dream Land 2, Kirby's Dream Land 3, and Kirby 64: The Crystal Shards. It is also seen in a group picture with King Dedede, Dark Mind, Marx, and Nightmare, which is found in one of the treasure chests in .