what is Dark Matter? who proposed the theory of Dark Matter?

Answer 1

Dark matter is mass that does not interact electromagnetically, ergo it neither makes, absorbs or scatters EM waves (light), thus it is called "dark." We only know it is there from its gravitational effects on light emitting matter and from gravitational lensing. Because it is only detectable indirectly, learning its properties is difficult. Most studies involve proposing different forms for the dark matter (like sub-stellar masses of ordinary matter floating around) and then tests predictions made by the hypothesis. So far nothing.

Fritz Zwicky first proposed some non-luminous gravitating matter to explain some of the dynamical oddities observed in the motions of galaxies in the Coma cluster; not only was their not enough mass to explain the velocities of the galaxies within, but it was off by a factor of ~400! Even allowing for suitable error, the difference could not be reconciled. Since then we have learned that galaxies have sizable mass in the form of gas and dust, not just stars, thanks to observation in wavelengths that were not possible in the early 1930's. Still there is not nearly enough to explain what we see, and all alternate theories of gravity proposed to date (alternate to Newtonian/Einsteinian) proposed fail to describe empirical observations, so there appears to be some kind of mass out there that we can't see.

Answer 2

In astrophysics, dark matter refers to matter that does not emit or reflect enough electromagnetic radiation (such as light, X-rays and so on) to be detected directly, but whose presence may be inferred from its gravitational effects on visible matter. Among the observed phenomena consistent with the existence of dark matter are the rotational speeds of galaxies and orbital velocities of galaxies in clusters, gravitational lensing of background objects by galaxy clusters such as the Bullet cluster, and the temperature distribution of hot gas in galaxies and clusters of galaxies. Dark matter also plays a central role in structure formation and Big Bang nucleosynthesis, and has measurable effects on the anisotropy of the cosmic microwave background. All these lines of evidence suggest that galaxies, clusters of galaxies, and the universe as a whole contain far more matter than is directly observable, indicating that the remainder is dark.

IT was proposed by Swiss astrophysicist Fritz Zwicky, of the California Institute of Technology

Answer 3

I think I heard it from some Discovery Channel show. Dark Matter is a theory from scientists that the universe contains Dark Matter, and that these dark matters are the main sources of energy for the expansion of the universe. If anybody knows any more than this please post.

Answer 4

I t is proposed by Moti Milgrom in 1983 and backed up by Jacob Bekenstein in 2004.

In Astro physics, dark matter refers to matter that does not emit or reflect enough electromagnetic radiation (such as light, X-rays and so on) to be detected directly, but whose presence may be inferred from its gravitational effects on visible matter.

Among the observed phenomena consistent with the existence of dark matter are the rotational speeds of galaxies and orbital velocities of galaxies in clusters, gravitational lensing of background objects by galaxy clusters such as the Bullet cluster, and the temperature distribution of hot gas in galaxies and clusters of galaxies.
Dark matter also plays a central role in structure formation and Big Bang nucleosynthesis, and has measurable effects on the anisotropy of the cosmic microwave background.
All these lines of evidence suggest that galaxies, clusters of galaxies, and the universe as a whole contain far more matter than is directly observable, indicating that the remainder is dark.

The composition of dark matter is unknown, but may include new elementary particles such as WIMPs and axions, ordinary and heavy neutrinos, dwarf stars and planets collectively called MACHOs, and clouds of nonluminous gas.
Current evidence favors models in which the primary component of dark matter is new elementary particles, collectively called nonbaryonic dark matter.

Answer 5

The dark matter is also called 'Baryonic matter'.

Recently attempts are being made to find out the exact mass, temperature and other properties of it.

These are the matter particle spread all over the universe and responsible for many phenomena in the universe.

Answer 6

Did you watch Futurama last nite?


Oh and it is like the only matter in space that scientist haven't been able to put into a little box category like everything else. I guess that's because everything that goes near it disappears...

Answer 7

n astrophysics, dark matter refers to matter that does not emit or reflect enough electromagnetic radiation (such as light, X-rays and so on) to be detected directly, but whose presence may be inferred from its gravitational effects on visible matter. Among the observed phenomena consistent with the existence of dark matter are the rotational speeds of galaxies and orbital velocities of galaxies in clusters, gravitational lensing of background objects by galaxy clusters such as the Bullet cluster, and the temperature distribution of hot gas in galaxies and clusters of galaxies. Dark matter also plays a central role in structure formation and Big Bang nucleosynthesis, and has measurable effects on the anisotropy of the cosmic microwave background. All these lines of evidence suggest that galaxies, clusters of galaxies, and the universe as a whole contain far more matter than is directly observable, indicating that the remainder is dark.

The composition of dark matter is unknown, but may include new elementary particles such as WIMPs and axions, ordinary and heavy neutrinos, dwarf stars and planets collectively called MACHOs, and clouds of nonluminous gas. Current evidence favors models in which the primary component of dark matter is new elementary particles, collectively called nonbaryonic dark matter.

The dark matter component has vastly more mass than the "visible" component of the universe.At present, the density of ordinary baryons and radiation in the universe is estimated to be equivalent to about one hydrogen atom per cubic meter of space. Only about 4% of the total energy density in the universe (as inferred from gravitational effects) can be seen directly. About 22% is thought to be composed of dark matter. The remaining 74% is thought to consist of dark energy, an even stranger component, distributed diffusely in space.Some hard-to-detect baryonic matter (see baryonic dark matter) makes a contribution to dark matter, but constitutes only a small portionDetermining the nature of this missing mass is one of the most important problems in modern cosmology and particle physics. It has been noted that dark matter and dark energy serve mainly as expressions of our ignorance, much as the marking of early maps with terra incognita.

The first to provide evidence and infer the existence of a phenomenon that has come to be called "dark matter" was Swiss astrophysicist Fritz Zwicky, of the California Institute of Technology (Caltech) in 1933.

Although dark matter was detected via optical means in August 2006many aspects of dark matter remain speculative. The DAMA/NaI experiment has claimed to directly detect dark matter passing through the Earth, though most scientists remain skeptical since negative results of other experiments are (almost) incompatible with the DAMA results if dark matter consists of neutralinos.

Data from a number of lines of evidence, including galaxy rotation curves, gravitational lensing, structure formation, and the fraction of baryons in clusters and the cluster abundance combined with independent evidence for the baryon density, indicate that 85-90% of the mass in the universe does not interact with the electromagnetic force. This "dark matter" is evident through its gravitational effect. Several categories of dark matter have been postulated.

Answer 8

Nonluminous, so nonvisible in light telescopes, but has plenty of mass. (read gravity)