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b'Everyone knows that a big rock did in the dinosaurs, but smaller asteroids are millions of times more common and can also make a violent impact.\\xa0\\xa0Yet unlike the bigger asteroids, we\\u2019re not tracking them.\\xa0Find out what we\\u2019d need to keep an eye on the size of space rocks such as that which exploded over Chelyabinsk, Russia.\\xa0\\xa0And how an asteroid whizzed by Earth in late August 2016, only hours after it\\xa0had been spotted.\\nAsteroids are the one natural disaster we can defend against, but an economist explains why humans are reluctant to invest in protection against \\u201clow probability, high impact\\u201d threats.\\xa0\\nAlso, how to authenticate that chunk of asteroid that you found in a field and NASA\\u2019s first ever return mission to an asteroid.\\xa0It plans to bring some fresh samples back to Earth.\\xa0\\nGuests:\\n\\n\\nPeter Jenniskens\\xa0\\u2013\\xa0Senior Research Scientist, SETI Institute\\n\\n\\nDavid Morrison\\xa0\\u2013\\xa0Senior Scientist of the Solar System Exploration Research Virtual Institute, NASA Ames Research Center\\n\\n\\nAlex Tabarrok\\xa0\\u2013\\xa0Economist, George Mason University\\n\\n\\nSharon Cisneros\\xa0\\u2013\\xa0Mineralogical Research Company, San Jose, California\\n\\n\\nJ. L. Galache\\xa0\\u2013 Astronomer, Minor Planet Center, Harvard Center for Astrophysics\\n\\n\\nChristina Richey\\xa0\\u2013\\xa0NASA Planetary scientist, deputy program scientist, OSIRIS-Rex mission\\n\\n\\nLearn more about your ad choices. Visit megaphone.fm/adchoices'