Last week saw Neptune Day, the first anniversary - in Neptune years - of the planet's discovery on September 23, 1846. That got us thinking: what are the "birthdays" for all the other planets? Here's a handy, mildly insane guide.
Vesta is the asteroid belt's second largest object, but figuring out what it is has driven astronomers crazy. Is it an asteroid? A planet, perhaps a protoplanet? Whatever the answer, Vesta might just be the solar system's most important object.