New Horizons Mission
Alan - New Horizons is a NASA planetary mission that was just launched on the 19th January to make the first reconnaissance of Pluto and then hopefully on to Kuiper belt objects as well. The mission is the fastest space craft ever launched but because of the great distance will take about nine and a half years to reach Pluto before going on into the Kuiper Belt. So it's arrival will be in the summer of 2015. When it arrives, it'll be studying Pluto's system with cameras, spectrometers and other instruments to give us a very good view of what kind of a system this is. We'll look at how the different bodies are put together, what they're made of, their geology and study their atmospheres.
Chris - What does this actually add in addition to some interesting and intriguing findings of Pluto? What will it add to our understanding of that segment of our solar system?
Alan - I think most importantly we've discovered in the last decade something that was completely unexpected. That is that there's a whole new class of object out there. These are miniature planets or so-called 'ice dwarfs', which vastly outnumber the rocky terrestrial planets and the four gas giants. Instead of four of each of those, we think that there are hundreds of these ice dwarfs. Pluto was the first one discovered and is probably the best-known example. So this is going to give us our first handle on what this very populous class of body in our solar system is all about.
Chris - And is it just because they're so far away that they're so difficult to see, even with telescopes like Hubble? Do we need to send a raft there in order to look at them more closely?
Alan - That's exactly right. Pluto, the brightest of this population, is itself 50 000 times fainter than Mars and 100 times smaller in the sky. Even over 75 years, we've only been able to eke out a very small amount of information.
Chris - Do you think there are any surprises lurking out there?
Alan - It's an embarrassing but true statement that across the solar system as we've visited new types of bodies, we've typically found that our expectations way underestimated the richness of nature. So I expect very much to be surprised.