What is Dark Matter?

Answer 1

Back in the past, astronomers believed the universe to comprised only of properly developed structures. These included planets, asteriods, stars, nebulas, etc.

However, all these didn't add up to the total mass of the universe.There is still a lot of mass unaccounted for.

In the 80s, using radio telescopes, astronomers detected other material that exist in the universe. These include charged particles, mesons, sub atomic particles, etc. These material also don't emit radiation and are not detected by telescopes.

If these materiel can exist, astronomers speculate they may cover the entire universe and make up the lost mass.

Answer 2

No-one is exactly sure, but the universe should contain an awful lot more "stuff" than we can see. We were always told that space is a vacuum, but this may not be quite so.

The best analogy I've heard is to think of a room as the universe. If a normal person were asked what accounts for the most mass in the room, the obvious answer is the air, even though we can't see it. However, an observational astronomer would have to answer the lights, because they are the brightest things in the room.

Answer 3

Astronomers have calculated the mass of the universe by considering gravity, and have also worked out the total mass of all the objects they can see with their telescopes (including radio telescopes). The mass of the universe turns out to be much greater than the mass of the visible objects. So astronomers have concluded that there is a lot of "dark matter" in the universe - matter which has mass, but cannot be seen from the Earth, at least with current telescopes.

Answer 4

Dark matter is hypothetical matter that we can't observe(hence the name dark)that would account for the seemingly missing matter in the universe.Until recently,however,there was virtually no evidence for it's existance.

Answer 5

Dark matter is material that is believed to form a large part of the universe, but which has never been seen.

Answer 6

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.
pdg.web.cern.ch/pdg/cpep/glossary.html

Answer 7

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. It is believed to make up about 90% of the matter in the universe

Answer 8

Ya Sou , Yonnie ......In astrophysics, dark matter is 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.

Answer 9

Its what scientists use to explain the apparent lack of matter in our solar system.

Basically matter we can´t see.

Answer 10

It's in space, of all the matter up there, it makes up most of the matter, but is invisible to the eye.