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Did you know that the Moon is a ball of rock? Its surface is mostly made up of a type of rock called basalt. Find out more in Moon, one of the titles in the Discovering Space series.
David Baker
David Baker is a history and science writer for SimonWhistler.com who holds the world's first PhD in Big History, studying under David Christian. He has delivered award-winning lectures at Macquarie University and the University of Amsterdam, is a visiting lecturer at the University of Paris-Sorbonne, and wrote the YouTube series Crash Course Big History, hosted by John and Hank Green in partnership with the Gates Big History Project. He is the author of The Shortest History of the World, and Sex.
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