What is "Dark Matter?"  
     
 


 
 

DEFINITION:

In astrophysics and cosmology, dark matter is matter of unknown composition that does not emit or reflect enough electromagnetic radiation to be observed directly, but whose presence can be inferred from gravitational effects on visible matter.

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 metre 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 (Wikipedia, 2007).


VIDEO: "Hubble-Cast: Dark Matter Found"
---->




THE PROBLEM:


Though most (if not all) scientists agree that Dark Matter does indeed, exists, no one can seem to determine what, exactly it is, or where it came from.



VIDEO: "What is Dark Matter?: Interview " ---->