"The Clean Room" is the seventh episode of the American documentary television series Cosmos: A Spacetime Odyssey. It premiered on April 20, 2014, on Fox and aired on April 21, 2014, on National Geographic Channel. The episode explores the methods and processes used to measure the age of the Earth. The episode also pays tribute to geochemist Clair Patterson (voiced by Richard Gere) in his quest to remove the neurotoxin, lead, from gasoline.