Sentinels in the Sky

Since the launch of Sputnik in 1957, satellites have become the silent sentinels of our planet and the cosmos. Orbiting high above, they have changed the way we live, the way we think, and most profoundly, the way we see. In Sentinels in the Sky: How Satellites Have Revolutionized Our Understanding of Earth and Space, geologist and author James Lawrence Powell tells the remarkable story of how s...