OK, world's fastest animal, world's fastest person -- these are all fine and good, but with a serious Earth-centric bent. Indeed, there are many things in our universe that make Earth seem like a poky planet. Considering that a year in our world consists of 365 interminable days, it might be nice to have Mercury's speedy 88-day year when you're looking forward to summer vacation. But we're probably better off than any friends we might have on Neptune, who have to wait more than 60,000 days between birthdays [source: Russell].
But what about a year that comes around every 8.5 hours? Astronomers have found what they think is the shortest orbital period (or year) on Kepler-78b, a small Earth-size planet that's so close to its star that scientists call it a "lava planet" [source: Howell]. But Kepler-78b might have a run for its money: KOI-1843.03 -- a planet candidate -- has an unconfirmed orbit of 4.25 hours, which could make it the fastest orbiting planet in the universe, if Kepler's laws of planetary motion hold true.