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When the Earth Had Two Moons

The Lost History of the Night Sky

Erik Asphaug



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26 February 2021
An astonishing exploration of planet formation and the origins of life by one of the world's most innovative planetary geologists.

In 1959, the Soviet probe Luna 3 took the first photos of the far side of the moon. Even in their poor resolution, the images stunned scientists: the far side is an enormous mountainous expanse, not the vast lava-plains seen from Earth. Subsequent missions have confirmed this in much greater detail.

How could this be, and what might it tell us about our own place in the universe As it turns out, quite a lot.

Fourteen billion years ago, the universe exploded into being, creating galaxies and stars. Planets formed out of the leftover dust and gas that coalesced into larger and larger bodies orbiting around each star. In a sort of heavenly survival of the fittest, planetary bodies smashed into each other until solar systems emerged. Curiously, instead of being relatively similar in terms of composition, the planets in our solar system, and the comets, asteroids, satellites and rings, are bewitchingly distinct. So, too, the halves of our moon.

In When the Earth Had Two Moons, esteemed planetary geologist Erik Asphaug takes us on an exhilarating tour through the farthest reaches of time and our galaxy to find out why. Beautifully written and provocatively argued, When the Earth Had Two Moons is not only a mind-blowing astronomical tour but a profound inquiry into the nature of life here-and billions of miles from home.
By:   Erik Asphaug
Imprint:   HARPER360
Country of Publication:   United States
Dimensions:   Height: 203mm,  Width: 135mm,  Spine: 21mm
Weight:   266g
ISBN:   9780062657930
ISBN 10:   0062657933
Pages:   368
Publication Date:   26 February 2021
Audience:   General/trade ,  ELT Advanced
Format:   Paperback
Publisher's Status:   Active

Erik Asphaug is a professor of planetary science at the University of Arizona, a member of the faculty of the world-renowned Lunar and Planetary Laboratory in Tucson, and was part of the team behind NASA's successful Galileo and LCROSS missions. A winner of the prestigious Harold C. Urey Prize from the American Astronomical Society, recognizing outstanding achievements by a young planetary scientist, his areas of expertise include the geology of comets and asteroids and the giant impacts that formed the planets and moons. He was also a professor at the University of California-Santa Cruz. He lives with his family in Arizona.

Reviews for When the Earth Had Two Moons: The Lost History of the Night Sky

[Asphaug's] writing is peppered with playful images... He is at his most charming when he is not just telling how scientists currently think about the chaotic formation of the solar system but relaying his own part in the story, as with the idea of that second moon. He perfectly captures the way that so many scientific insights occur: while sitting listening to something else and having your mind wander...embracing the chaos around us, as Mr. Asphaug does, ultimately makes the solar system an even weirder and more wonderful place than it seemed before. -- Wall Street Journal A gripping and endlessly fascinating account of how planets formed. -- Alan Stern, planetary scientist and leader of NASA's New Horizons mission to Pluto When the Earth Had Two Moons is a lyrical exploration of our solar system, introducing not just the facts of its formation and nature but the implications for all of us living on Earth. -- Amy Mainzer, visiting scientist at the Jet Propulsion Laboratory and professor of planetary science at the University of Arizona An enthusiast as well as a fine writer, Asphaug lays it out from the beginning. . . . An expert, entertaining review of what's known about the solar system. -- Kirkus Reviews Asphaug draws upon his years of research and expertise to provide the reader with a truly wondrous and surprising exploration of planet formation and the origins of life. A meticulous and expertly presented work of science, When the Earth Had Two Moons is unreservedly and enthusiastically recommended. -- Midwest Book Review An enthusiastic and erudite guide. -- Publishers Weekly

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