We were very surprised to find out that Pluto is still geologically alive. It has upended our ideas of how planetary geophysics works. Alan Stern More Quotes by Alan Stern More Quotes From Alan Stern This is in a real sense the capstone of the initial missions to explore the planets. Pluto, its moons and this part of the solar system are such mysteries that New Horizons will rewrite all of the textbooks. Alan Stern new-horizons moon real It used to be said that Pluto is a misfit. But now we know Earth is the misfit. This is the most populous class of planet in our solar system and we have never sent a mission to this class. Alan Stern pluto earth class We're just learning that a lot of planets are small planets, and we didn't know that before, fact is, in planetary science, objects such as Pluto and the other dwarf planets in the Kuiper Belt are considered planets and called planets in everyday discourse in scientific meetings. Alan Stern dwarves everyday science Naming celestial objects is usually done by astronomers and professionals. Other people who are interested in space never get the opportunity to do that kind of thing. Alan Stern space opportunity people It's strictly coincidental that Pluto of course was named for the god of the underworld and we're describing these Halloween moons Alan Stern pluto halloween moon It'll be the fastest spacecraft ever to Jupiter...13 months after launch. We pass the Moon in just nine hours. Alan Stern jupiter moon nine To keep everyone invested in your vision, you have to back up a little bit and really analyze who the different stakeholders are and what they individually respond to. Alan Stern your back you vision There are lots of really interesting little planets out there in the Kuiper Belt, but Pluto's the only one that's got all the cool attributes. Alan Stern out only cool interesting Pluto is showing us a diversity of landforms and complexity of processes that rival anything we've seen in the solar system. Alan Stern us seen anything diversity Just because Pluto or comets aren't as big as Jupiter doesn't mean they are not scientifically important - indeed, just the reverse is often true. Sometimes, great things come in small packages. Alan Stern small great important sometimes We really just didn't realize the diversity of planetary types in our solar system. Pluto looked like a misfit because it was the only one we saw. And just as a Chihuahua is still a dog, these ice dwarfs are still planetary bodies. They're large enough to make themselves round by self gravity, and they surely pass the test of planethood. Alan Stern realize diversity self dog Just because Pluto orbits with many other dwarf planets doesn't change what it is, just as whether an object is a mountain or not doesn't depend on whether it's in a group or in isolation. Alan Stern depend group mountain change Of course Pluto is a planet: It's massive enough to have its shape controlled by gravity rather than material strength, which is the hallmark of planethood. Alan Stern planet gravity strength enough Pluto is as far across as Manhattan to Miami, but its atmosphere is bigger than the Earth's. Alan Stern far than miami earth As a planetary scientist, I don't know what else to call Pluto: It's big and round and thousands of miles wide. Alan Stern call big know miles The big lesson of planetary science is when you do a first reconnaissance of a new kind of object, you should expect the unexpected. Alan Stern new you unexpected science Pluto is still active four and a half billion years into its history. It was expected that small planets like Pluto would cool off long ago and not still be showing geological activity. Pluto is, in fact, showing numerous examples of geological activity on a massive scale across the planet. Alan Stern small cool long history Human beings have long wondered whether they are alone in the universe. Alan Stern human alone universe long Going to the Kuiper Belt is like an archaeological dig into the history of the solar system. Alan Stern solar going like history No one predicted Mercury would be a planetary core with the mantle stripped off. No one predicted volcanoes on the Jovian moons, or oceans on the inside of them. I can tell you, for every single planet, huge 'we never guessed that' things. Alan Stern never you single i-can