Apollo 8 astronauts orbiting the Moon snapped the first picture of the Earth from space on Christmas Eve 1968. The so-called Earthrise photo became an instant icon for all of humanity. Cameras have since become more refined. NASA produced this composite from layers of satellite data.
We've learned much more about how the world works. Geologists are increasingly convinced human-induced change is so pervasive that a new epoch of the Earth's physical history has begun: the Anthropocene, or age of man.
An interdisciplinary team of scientists has begun to describe and debate what they call "planetary boundaries," limits beyond which we 7 billion people risk catastrophic disruptions. The study continues to foster debate about the approach and findings and is featured in the new book, The God Species, by Mark Lynas.
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