One of the biggest “controversies” in recent astronomy history has been the “demotion” of Pluto from “planet” to “dwarf planet.” This has been a topic for a while, but got kicked up a notch in January 2005, when a team led by astronomer Mike Brown of California Institute of Technology discovered an object in the Kuiper Belt (a belt of objects beyond Neptune, of which Pluto is a part) that is larger than Pluto. This got a lot of attention from the public, in part because Pluto somehow intrigues people as the “little guy” in the solar system. To most scientists, this is mainly a matter of semantics. What we call the object doesn’t change what it is or where it is or the fact that it is an interesting thing to study (the New Horizons spacecraft recently gave us our first-ever close-up views of Pluto and its moons on July 14, 2015). Take a look at the articles below, then write a discussion board post about your own thoughts about this. Is it a useful discussion to have among scientists? Among the public? Does it help or hurt efforts to encourage interest in astronomy?

Video of Mike Brown

Pluto’s Honor. (Tyson, Neil. Natural History Magazine. February 1999.) Note that this was written before the discovery of Eris.)

Breaking News – Pluto Not a Planet (Plait, Phil. Bad Astronomy Blog. August 24, 2006.)