Physics is full of big, interesting questions about phenomenon such as black holes. This illustration shows the supermassive black hole at the heart of the active galaxy NGC 3783 in the southern constellation of Centaurus. M. Kornmesser/ESO hide caption

itoggle caption M. Kornmesser/ESO

The hunt for dark matter started with astronomer Fritz Zwicky's observations of the Coma galaxy cluster in the 1930s. This recent image of the Coma cluster combines optical and X-ray observations from the Chandra mission. J.Sanders et al/NASA/CXC/MPE/SDSS hide caption

itoggle caption J.Sanders et al/NASA/CXC/MPE/SDSS
itoggle caption Carlos H. Faham

Science has been working to shed light on the nature of the Universe for 400 years. Alberto Pomares/iStockphoto.com hide caption

itoggle caption Alberto Pomares/iStockphoto.com

This image of the galaxy cluster Abell 520 — 2.4 billion light-years away — may challenge some of our basic theories about Dark Matter. It is overlaid with false-color maps showing concentrations of starlight (orange), hot gas (green) and mass (blue). The mass is mostly Dark Matter. M.J. Jee and A. Mahdavi/NASA/ESA/CFHT/CXO hide caption

itoggle caption M.J. Jee and A. Mahdavi/NASA/ESA/CFHT/CXO