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A planet is a planet is a planet. Unless it\u2019s Pluto \u2013 then it\u2019s a dwarf planet. But even then it\u2019s a planet, according to experts. So what was behind the unpopular re-classification of Pluto by astronomers, and were they justified?\nAs the New Horizons spacecraft closes in on this small body, one planetary scientist says that this dwarf planet could be more typical of planets than Mars, Mercury, and Saturn. And that our solar system has not 8 or even 9 planets, but 900.\nAlso, meet a type of planet that\u2019s surprisingly commonplace, although we don\u2019t have one in our solar system: super Earths. Could they harbor life?\nAnd the DAWN mission continues its visit to the two most massive residents of the asteroid belt: Vesta and Ceres. Discover what these proto-planets may reveal to us about the early solar system.\nGuests:\n\n\nAlan Stern \u2013 Planetary scientist, Southwest Research Institute, Principal Investigator of the New Horizons mission\n\n\nMarc Rayman \u2013 DAWN Mission chief engineer and mission director\n\n\nDavid Stevenson \u2013 Professor of planetary science at CalTech\n\n\nRebekah Dawson \u2013 Astronomer, postdoctoral fellow at the University of California, Berkeley\n\n\nDavid Eicher \u2013 Editor-in-chief, Astronomy Magazine\n\nDescripci\xf3n en espa\xf1ol\nLearn more about your ad choices. Visit megaphone.fm/adchoices