Cosmologists had only been able to find half the matter that should exist in the universe. With the discovery of a new astronomical phenomenon and new telescopes, researchers just found the rest.
Maps of the long filaments of gas that hold the universe together may one day help us trace and unveil 'dark matter'.
A particle physicist explains just what this keystone theory includes. After 50 years, it's the best we've got to answer what everything in the universe is made of and how it all holds together.