A terrific thrill came over me. I switched the shutter back and forth, studying the images. Oh! I had better look at my watch and note the time. This would be a historic discovery.
Discovery is where the scientist touches Nature in its least predictable aspect. It discloses to us the regularities of Nature, but in itself, discovery is fickle, striking at the unexpected moment. This is the view that I must take after my serendipitous discovery of the moon of Pluto.
Things in the solar system can equally well be categorized in many different ways. Things with atmospheres. Things with moons. Things with life. Things with liquids. Things that are big. Things that are small. Things that are bright enough to see in the sky ... All of these are perfectly valid categories ... As with birds, your favorite solar system classification will depend on your interests.
The story of the discovery of Pluto has been told many times by its discoverer, historians, and the media, but in recent years has become all the more compelling because of the notorious reputation it has acquired following its perceived downgrading in 2006 to “dwarf planet” status. Seen in historical context over the last eight decades since its discovery, this rather small object in our solar system has assumed an outsized importance, precisely because it lies at the outer fringes of our solar system, at the borderline of normally assigned “classes” of objects in terms of its size and mass, and therefore at the border of normality in astronomy, where routine ends and creativity begins. Such borders are precisely what make Pluto interesting, and as such they illuminate in microcosm some of the many issues raised in this volume about the nature of discovery, interpretation, and classification in astronomy.