"How I Killed Pluto and Why It Had It Coming" made Mike Brown a lot of enemies

Never mind that he's a nice guy who spends his time studying the also-rans of the solar system, the little pieces of debris that get overshadowed by the big kahunas like Jupiter, Saturn and that big yellow thing in the sky. To those who have left him angry messages and emails, Cal Tech astronomer Mike Brown is a traitor to underdogs.

Why? Because he played a crucial role in Pluto's demotion from planethood. Five years ago, he made a discovery that raised questions about Pluto's status as the ninth planet. Pluto is now officially known as a "dwarf planet," disappointing hordes of kids – and those who are kids at heart – who feel a connection to the cold and lonely orb.

Some astronomers say he's wrong, but Brown is sticking to his guns. And how! His new book is called How I Killed Pluto and Why It Had It Coming.

I asked Brown about what makes a planet a planet and how his discovery changed the way that we see the solar system. And, of course, we talked about that other Pluto: the Disney cartoon dog, which is said to have been named after the planet. Er, make that ex-planet. (It got its name from the Roman god of the underworld.)

1 | 2

Next