Dr. Clowe is an observational cosmologist who proved the existence of dark matter, garnering recognition from Discovery News in 2010 as the eighth most important Discovery of the Decade. A member of Ohio University's Astrophysical Institute, Clowe studies massive clusters of galaxies.

The confirmation of dark matter's existence is a major development in astrophysics, though Clowe's research cannot yet explain what dark matter actually is. Prior to this finding, dark matter was only a theoretical concept based on the observation that galaxies had only one-fifth of the visible matter required to create the gravity needed to hold them together.

Clowe's confirmation of dark matter's existence discounted decades of debate and made a once-theoretical concept a reality. Matter in the universe is determined from the light it emits or from gravitational pull. Light-emitting matter is far less common than the amount of matter inferred from gravity - thus the presumption that most matter in the universe is dark.

Clowe's discovery both confirms dark matter's existence and conventional perceptions of gravity in astrophysics.

His research uses weak gravitational lensing to study galaxy clusters. One such cluster is where he made his most noted breakthrough. The Bullet Cluster is made up of two smaller groups of galaxies colliding. The impact has resulted in the hot gasses filtering to the center of two groups of stars and matter. Clowe was able to measure the mass of the matter by studying the gravitational bend of light around the stars.