Current theories on the universe means that scientists are only able to account for 4% of the matter in the universe, so new theories of dark matter (unseen matter) have been developed to explain this.<ref>[http://www.msnbc.msn.com/id/20360059/ Where is the rest of the universe?]</ref> | Current theories on the universe means that scientists are only able to account for 4% of the matter in the universe, so new theories of dark matter (unseen matter) have been developed to explain this.<ref>[http://www.msnbc.msn.com/id/20360059/ Where is the rest of the universe?]</ref> |