1. Largest exoplanet: GQ Lupi b
Astronomers weren’t sure what to make of the mysterious GQ Lupi b when it was first discovered in 2005. Orbiting a young star around two and a half times farther than Pluto is from the sun, the companion object seemed to be either a planet or a brown dwarf, which is actually a type of small star. Subsequent observations have yet to clear up the confusion, but the best estimates suggest GQ Lupi b has a radius around 3.5 times that of Jupiter, meaning that if it is an exoplanet, it’s the largest ever found.