When people have questions about the end of the world — the predictions about the planet Nibiru's collision with Earth or the end of the Mayan calendar — they often turn to the Internet.
For years, NASA astrobiologist David Morrison has taken it upon himself to answer thousands of questions about the science of existential threats on NASA's Q&A site "Ask an Astrobiologist."
There, Morrison debunks and details the origins of popular apocalyptic scenarios and thoughtfully responds to questions like: "If the government knew about Nibiru, wouldn't they keep it a secret to avoid panic?"
He talks with NPR's Neal Conan about what he's learned from the process and whether he'll continue this part of his job in 2013.
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