This composite of 30 images of asteroid 2014 JO25 was generated with radar data collected using NASA's Goldstone Solar System Radar in California's Mojave Desert. NASA/JPL-Caltech/GSSR hide caption

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NASA/JPL-Caltech/GSSR

A computer illustration of a large asteroid colliding with Earth. (Size may not be to scale.) Such an impact is believed to have led to the death of the dinosaurs some 66 million years ago. Mark Garlick /Getty Images/Science Photo Library RM hide caption

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Mark Garlick /Getty Images/Science Photo Library RM

The Geologic History of Earth. Note the timescales. We are currently in the Holocene, which has been warm and moist and a great time to grow human civilization. But the activity of civilization is now pushing the planet into a new epoch which scientists call the Anthropocene. Ray Troll/Troll Art hide caption

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Ray Troll/Troll Art

Paleontologist Kenneth Lacovara speaks at TED in 2016. Bret Hartman /TED hide caption

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Bret Hartman /TED

How Can Dinosaurs Help Us Understand Our Own Species?

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Paleontologist Peter Ward speaking on the TED stage. Andrew Heavens/TED hide caption

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Andrew Heavens/TED

Are We Headed Into Another Mass Extinction?

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Proxima Centauri lies in the constellation of Centaurus (The Centaur), just over four light-years from Earth. Although it looks bright through the eye of Hubble, Proxima Centauri is not visible to the naked eye. ESA/Hubble & NASA hide caption

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ESA/Hubble & NASA