Does negative mass explain dark matter?

Cosmologists claim that all the matter we can see in the universe really only accounts for 5% of everything that's out there - the other 95% is so-called "dark matter" and "dark energy." Figuring out exactly what these are has puzzled scientists for decades, and troubling results have popped up time after time. Now, an Oxford physicist claims one theory could end up resolving all the missing pieces in cosmology. Charlie brings in a paper that could change physics just by changing the sign. Read the paper and news articles here.