When the Earth Had Two Moons

Cannibal Planets, Icy Giants, Dirty Comets, Dreadful Orbits, and the Origins of the Night Sky

By: Erik Asphaug

Narrated by: Adam Verner

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.

Supplemental enhancement PDF accompanies the audiobook.

PLEASE NOTE: When you purchase this title, the accompanying PDF will be available in your Audible Library along with the audio.

©2019 Erik Asphaug (P)2019 HarperAudio

slow start, but fantastic book

this is a fantastic book about the science of planetary formation. The intro and first chapter were more historical/philosophical, but then it got into the meat of the science and was fascinating. In most chapters the author does a neat job covering the original theories of planetary science quickly but at just the right depth, then goes over (the unexpectedly wide and uncertain) current state of the field.

Not sure how well this book would work if you aren't already interested in planetary science and how our solar system came to be (I could see it going either way), but for those of us already interested this is a fantastic listen.

it was interesting for sure

it was written casual like I'm speech to but I found it witty enough and entertaining.
it's not written in lineal terms exactly and there are several technical phases he could have explained more then once. but I really liked it. first book like this I've had. I thought the author was far very competent obviously and knew his stuff by was casual about and used lots of examples for comparison to what could be complicated info to many.
every work was cool. every matter he touched on was interesting and I am not beyond constantly backing my book up if I fall asleep when I listen at bed time. to much info to miss. highly re6

From an engineer.

Excellent book — content and reader. The author covered a lot more territory than just earth and moon. I heartily recommend it.

Interesting

A little hard to follow sometimes, but very interesting. Narration was well done. I would recommend it.

Latest planetary & astronomical science wellwrittn

Compares to the work of Bill Bryson & Stephen Hawking. Writing style is engaging, succinct, and accessible, especially for a book on astrophysics. But it's much more than that. Everything is contextualized to history, current events, personal anecdotes, etc. A great listen over a few days. I feel smarter for having listened.

great history

the story was just too short for me. two more chapters would have been nice.

I only made it halfway

The narrator had a voice that induces sleep. He also tended to sound like he was in love with what he was reading. I bought the book because I was looking for factual information. The title suggests that the author is writing about something that is true. While I understand that all science is based on theories, I expected the information to be based on some quantifiable data. The majority of the information I heard was a jumble of the author’s and other’s ideas. So it’s essentially science fiction. I enjoy science fiction, but this book isn’t written in an interesting style. It’s boring. One positive aspect of this is that it makes me want to go in search of what we actually know about these things. Preferably from sources that just give you the information without trying to make you listen to their boring thoughts about them.

Poorly written, poorly narrated

Disorganized writing is the hallmark of this author's style. The book is, for the most part, a series of weakly-related factoids. Why other people have praised this book is beyond me. Adding to my displeasure is the narrator's style and voice. He drones along in a semi-whisper I find quite annoying.