The existence of dark matter is induced from the behavior of faraway galaxies, which move in ways that can only be explained by a gravitational pull caused by more mass than can be seen. They estimate dark matter represents around 20 percent of the universe, with the other 75 percent made up of dark energy, a repulsive force that is causing the universe to expand at an ever-quickening pace.
Eduardo Abancens designed a prototype dark matter detector called a scintillating bolometer. It is a crystal so pure that it can conduct the energy ostensibly generated when a particle of dark matter strikes the nucleus of one of its atoms.
To prevent interference by cosmic rays, the bolometer is shielded in lead and kept half a mile underground. The challenge is to freeze the device to near-absolute zero, the temperature at which all motion stops. At the edge of absolute zero, it will possible to measure expected changes of a few millionths of a degree Fahrenheit.
Reference: “A BGO scintillating bolometer as dark matter detector prototype.” By N. Coron, E. García, J. Gironnet, J. Leblanc, P. de Marcillac, M. Martínez, Y. Ortigoza, A. Ortiz de Solórzano, C. Pobes, J. Puimedón, T. Redon, M.L. Sarsa, L. Torres and J.A. Villar. Optical Materials, Vol. 31 Issue 10, August 2009.
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