Many people theorize that most of the Universe is made up of "dark matter." What exactly is "dark matter?"

Answer 1

Nothing but a theory to explain the unexplainable. All known matter relfects light, radiation, energy.

Answer 2

Dark matter is used to describe a problem we have and are trying to solve. the speed at which galaxies rotate is related to the mass. near the center we can see the mass and it rotates according to what theory predicts. However the outer parts of galaxies rotate at a speed that says there should be alot of mass out there, far more than is in the center of the galaxy. The problem is that we see very few stars out near the outer parts of the galaxy. So theory says there should be alot of "Dark" matter, matter which is there but we cannot see (hence the name dark)
At first we thought it was mostly dust clouds and brown dwarf stars. Both of which are hard to see.

In the last few years however we have don calculations which show that even an enormous number of brown dwarfs and dust clouds could not compensate for the amount of mass that should be there.

This leads us to think that either there is some exotic form of matter that we don't really know about, or that our equations for gravity are missing something, and need to be revised.

Currently there is alot of work done, trying to test new theories and discover this "missing matter"

Answer 3

Dark matter is a fudge factor.
Cosmological Theories predict a certain amount of stuff in the universe.
Experimetnal Astrophysics observations only account for a small fraction of this.
The difference (and it is a huge difference- i.e. most of the universe) is called dark matter.
It is called "dark" according to theoreticians because the experimentalists can't find it or account for it. A lot of experimentalists would prefer to call it doesn't matter or dim matter. "Doesn't" matter because until a theory is experimentally demonstrated it doesn't matter, and "dim" matter due to the dim-witted view that it is more likely that such a large amount of matter is hiding out there than the possibility that the theorems could be wrong.

Answer 4

Its not a theory. Its more a statement of fact.

Observations on the movement of stars and galaxies show that these cannot be accounted for by the masses of the stars, galaxies and other stuff that is known.

This means there must be more mass out there that we cannot see. We can say what it does (eg it clumps) and where it might be, but we do not know what it is because it is not visible in any known way (that means including radio/gamma etc).

Dark matter is a bad name. It should be called "unknown matter".

Answer 5

it's just a term for something they can't quite explain.
They estimate the weight of galaxies by looking at all the stars in them. But when they look at how galaxies move, they find that galaxies must have much higher weight.

So the current hypothesis is that there is some "dark" (& hence invisible) matter in the galaxies that accounts for that difference in weight.
They do no really know what it is right now, but there will be probably more info as they observe more, build better telescopes, study the results.

Answer 6

One of the biggest conundrums in modern astronomy is the fact that over 90% of the Universe is invisible. This mysterious missing stuff is known as 'dark matter'.

Answer 7

In cosmology, dark matter refers to matter particles, of unknown composition, that do not emit or reflect enough electromagnetic radiation to be detected directly, but whose presence may be inferred from gravitational effects on visible matter such as stars and galaxies. Dark matter explains several anomalous astronomical observations, such as anomalies in the rotational speed of galaxies (the galaxy rotation problem). Estimates of the amount of matter present in galaxies, based on gravitational effects, consistently suggest that there is far more matter than is directly observable. The existence of dark matter also resolves a number of seeming inconsistencies in the Big Bang theory, and is crucial for structure formation.

The dark matter component has vastly more mass than the "visible" component of the universe [1]. 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. [2] Some hard-to-detect baryonic matter (see baryonic dark matter) makes a contribution to dark matter, but constitutes only a small portion [3] [4]. Determining the nature of this missing mass is one of the most important problems in modern cosmology and particle physics. Its urgency is underlined by David B. Cline in a 2003 article in Scientific American, in which he writes: "The terms . . . 'dark matter' and 'dark energy,' serve mainly as expressions of our ignorance", much as the marking of early maps with 'Terra Incognita'.

Answer 8

this is purely between the words given to a phenomena we haven't any reason behind. eg. darkish remember, darkish potential, the great attractor, a singularity, quantum entanglement, etc, etc, i don't think of all people extremely believes there is an vast volume of invisible textile spread by the universe. that is proper in our back backyard also, wreaking havoc on our community area. there is extra in all chance a mistake contained in the predicted variety of stars that are seen or another straight forward clarification.

Answer 9

It is matter that does not reflect light , but actually consumes it

Answer 10

If somebody knew, they'd get the nobel prize.