Saturday, December 10, 2011

Is Vesta the Smallest Terrestrial Planet?

What defines a planet, a decree by an "authority," or the data we learn about an object? The Dawn mission has revealed fascinating information about Vesta, all of which show it to be far more a planet than an asteroid. Here we have yet one more piece of evidence in support of a broad planet definition that encompasses the wide range of objects that both orbit stars and orbit planets, the satellites of stars.