What is Dark Matter?

Answer 1

dark matter is no more than four percent ordinary matter, but the rest is unknown. dark matter only interacts with ordinary matter thru gravitation. its existance was discovered by fritz zwicky in 1933.

look here:
http://en.wikipedia.org/wiki/Dark_matter

Answer 2

Dark Matter is the name given to mass that is missing (cannot be seen ) in our universe if our current theories on gravity and expansion of the universe are to be valid.
The visible mass within our universe cannot explain the gravity
holding it together therefore there must be some more matter out
there that we cannot see...It must be dark ? ie...Dark Matter...
I believe that this "Dark Matter" need not necessarily be dark/unseen matter within the visible universe...I believe this Dark Matter may reside in another dimension within our own universe and gravity is common to all dimensions in our universe which would explain both the increased gravity and the missing mass.
I have not read or heard this theory / explanation anywhere however I seriously doubt that I have come up with an original thought so I have no source...I presume you could find it somewhere if you looked...
Your question is probably better than my answer..

Answer 3

Three principal theoretical considerations suggest that dark matter exists. The first is based on the rotation rate of galaxies. Galaxies near the Milky Way appear to be rotating faster than would be expected from the amount of visible matter that appears to be in these galaxies. Many astronomers believe there is enough evidence to conclude that up to 90 per cent of the matter in a typical galaxy is invisible.

Answer 4

http://en.wikipedia.org/wiki/Dark_matter

In cosmology, dark matter refers to matter particles, of unknown composition, that do not emit or reflect enough electromagnetic radiation (light) 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.

Answer 5

Dark Matter or Negative Matter is simply matter from our parralell universe it is spat out of black holes and also exist inbetween particles occasionally. Dark Matter is the quite simply the complete and total opposite of Matter.

Answer 6

I saw this thing on tv once. they said that like 90% of space is unaccounted for and some german dude said that it was dark matter. supposedly it's all around us. It is invisible and is only dectectible because of the gravity it emits. it holds the universe together or someting. try google-ing define: dark matter

Answer 7

Anything that is not hot enough to glow like the sun.

Your body for instance.

I think that the term was first invented to account for galactic arms spinning slower than would be predicted by counting the stars in that galaxy. Possible explanations are black holes, neutrinos, etc.

Answer 8

Empty space. You know when you think out of space, you think theres nothing beyond? There is, and it's dark matter.

Answer 9

The stuff that is relieved from your bowels when taking a colon cleansing product! lol

Answer 10

This was featured in a recent issue of scientific american. I think around May of this year. :)