Type Ia supernova occurs whenever a white dwarf star gains enough additional mass to pass above the Chandrasekhar limit, usually by stealing additional mass from a companion star. Since all Type Ia supernovae are believed to occur in essentially the same way, they form a standard candle whose intrinsic luminosity can be assumed to be approximately the same in all cases. By measuring the apparent luminosity of the explosion from Earth, researchers can then infer the distance to supernova. Comparing this inferred distance to the apparent redshift of the explosion allows the observer to measure both the distance and relative velocity of the supernova. The Supernova Cosmology Project concluded that these distant supernovae were receding more quickly than would be expected due to the Hubble expansion alone, and, by inference, the expansion of the universe must have been accelerated over the billions of years since the supernovae occurred. The High-z Team also came to a similar conclusion. The two teams' reports were published within weeks of each other, and their conclusions were readily accepted by the scientific community due to corroborating theories. This conclusion has subsequently been supported by other lines of evidence. These findings reinvigorated research into the nature of the universe, and especially into the role of dark energy. For this work Perlmutter was awarded the 2011 Nobel Prize in Physics, shared jointly with Riess and Schmidt. Perlmutter is also a lead investigator in the Supernova/Acceleration Probe project, which aims to build a satellite dedicated to finding and studying more supernovae in the distant universe. The goal is to more precisely determine the rate at which the universe has been accelerating. He is also a participant in the Berkeley Earth Surface Temperature project, which aims to increase our understanding of recent global warming through improved analyses of climate data. Perlmutter is a professor and currently teaches at UC Berkeley. Awards and recognition In 2002, Perlmutter won the Department of Energy's E. O. Lawrence Award in Physics. In 2003, he was awarded the California Scientist of the Year Award, and, in 2005, he won the John Scott Award and the Padua Prize. In 2006, he shared the Shaw Prize in Astronomy with Adam Riess and Brian P. Schmidt. The same year, Perlmutter won the Antonio Feltrinelli International Prize. Perlmutter and his team shared the 2007 Gruber Cosmology Prize (a $500,000 award) with Schmidt and the High-Z Team for discovering