Dark matter

[aniket]

Hey guys,
what is dark matter?what is it made up of and where is it?can any theory explain this?
can string theory explain this? so please frendz help me out of this.

[mathman]

The evidence for the existence of dark matter lies in various graviational effects on a large scale (galaxies and clusters of galaxies). What it is made of is still unknown. All that can be said is that most of it is NOT baryonic (ordinary) matter. There are several theories, but no evidence yet for any of them.

[BioBen]

What it is made of is still unknown.
I agree of course (your answer is the good one).
However, what i would just like to add is that i think that quite a lot of scientisit think that neutralinos (http://en.wikipedia.org/wiki/Neutralino) may be the mayor constituent of cold dark matter.

All that can be said is that most of it is NOT baryonic (ordinary) matter.
Baryonic dark matter is object like dwarf stars and other tiny "dark"(=shineless -but i dont know if that word exist) objects.
http://map.gsfc.nasa.gov/m_uni/uni_101matter.html
http://www.universetoday.com/am/publish/dark_matter_galaxy.html?2322005

Just to add : dark matter seems to make up around 23% of our universe mass-energy

can string theory explain this?
No idea ! Sorry :(

Benjamin

[Chronos]

Axions are still popular.

[EL]

Kaluza-Klein matter is also a suggestion.