Cosmos A Spacetime Odyssey: The Clean Room

The seventh episode of Cosmos: A Spacetime Odyssey, titled "The Clean Room," airs tonight on Fox. In "The Clean Room," To determine the true age of the Earth, geochemist Clair Patterson (guest voice Richard Gere) developed the uranium-lead dating method to make an unprecedented discovery – calculating Earth's age of 4.5 billion years. But Patterson's groundbreaking discoveries were just beginning. Patterson made it his mission to draw public attention to the detrimental effects of lead in the environment and dedicated his career to fighting against the petroleum and chemical industry, eventually achieving public health's biggest victory of the 20th century. Neil deGrasse Tyson hosts. Featuring guest voice star Richard Gere as Clair Patterson. Cosmos: A Spacetime Odyssey, "The Clean Room," airs Sunday, April 20 at 9:00 p.m. ET on Fox.