Astronomical Controversies

You expect controversy in politics. Every religious story comes served with intense debate. And you almost demand hullabaloo in sport. But controversy in science? Scientific controversies are actually quite common, and throughout history, within and outside the scientific community, battles have raged over many topics, from Galileo vs. the Catholic church over the motion of the planets, to Einstein not believing in quantum mechanics, and current debates over global warming, intelligent design and stem cell research. But the controversy that we are dealing with today is astronomical in size, yet deals with the runt of the litter. Whatever do we do with Pluto? A few months back, when we did a Mr Science show on Pluto, we all slept soundly in the knowledge that Pluto was a planet. But now things have changed, and Pluto has been demoted to a new class of heavenly body called a Dwarf Planet.