A Tenth Planet

This discovery is unbelievably cool. I have heard a little bit recently about the likelihood of there being objects of Pluto's scale in the Kuiper Belt. Although this is a little smaller than Pluto, you really have to say that if Pluto is a planet, so is this. And if this isn't, neither is Pluto. (Some people in recent years have been trying to argue that Pluto is not really a planet, but I doubt you will ever get the majority of people to let go of the idea that it is). Either way, the picture of the solar system we have had since 1930 - nine planets - now has to go. Psychologically, for me at least, this is a big deal. It's actually much less important than the discovery of the many planets orbiting other stars which we have seen over the last couple of decades, but this is so much closer to home.