What is dark matter?

Answer 1

It is matter of (still) unknown composition. It doesn't interact with light, that's why it is called dark (no light absorption or emission; you can imagine it as something transparent in all wavelengths), however it exerts gravitational forces. The theory of dark matter was postulated in an attempt to explain the fact that the kinetic energy of galaxies seemed to be greater than the sum of the kinetic energies of the solar systems composing them. About 22% of the universe is believed to consist of it, while visible matter is only 4% (the rest being dark energy)!!

Answer 2

It has long been wondered why galaxies, spinning at enormous speeds, did not simply break apart...with the stellar systems flying out like so many water droplets off a shaking dog. Without anything concrete to go on, the physicists invented dark mass/energy; where the dark mass side of this duality provided the gravity to counter the centrifugal forces of a spinning galaxy.

In all, dark mass/energy makes up about 96% of the mass/energy in our known universe...according to proponents of the dark side. That's a lot of darkness.

Until most recently, there has been no physical evidence of the dark side. However, just late last year (2006), a Stanford group photographed a strange glow around two colliding galaxies. After much analyses, the group concluded that this was dark matter set to glowing by the collision. [See source.]

Answer 3

a theory to explain some weirdness - graviational force of galaxis seems much stronger than the visible stars in it should have. So the current guess is that there is some invisible (hence dark) matter that generates this gravitation.

Answer 4

I read an article recently announcing that the axion has finally been discovered. It is a leading candidate for dark matter. For you three folks out there that know what I'm talking about, all I can say is .... really!!!. Download article from link below.

Answer 5

Coal (carbon). That is for sure.
Dark matter in the universe can not be observed. It has been invented to explain the missing mass in the universe.

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Answer 6

Its is gaseous matter such as nub lea, that is not in the process of giving off light due to fusion or other processes

Answer 7

space is full of things but we dont see all of it. dark matter is that. we see all the stars and stuff but in the dark spaces between stars and stuff its more stuff. dark matter stuff like other planets and stars and stuff

Answer 8

matter that doesnt emit or reflect energy, like 'normal' energy. its theorized to account for a big chunk of the universe so that their model works (it needs a certain amount of matter and we can see theres not enough so that means there has to be more)

Answer 9

Material that does not give off photons but does exert gravitational forces.

Answer 10

It's the aether that Einstein said did not exist.