What is the closest planet to our solar system's sun?

The story behind the answer

Mercury is the correct answer because it’s the innermost planet, orbiting the Sun at about 58 million km (0.39 AU). It zips around the Sun in just 88 Earth days, much closer and faster than Earth (1 AU), Mars (1.52 AU), or Jupiter (5.2 AU).

Despite being closest, Mercury isn’t the hottest planet—Venus is hotter due to its thick greenhouse atmosphere. Mercury’s thin exosphere and slow rotation create extreme temperature swings and a heavily cratered, Moon-like surface. To remember the order from the Sun, try the classic mnemonic: “My Very Educated Mother Just Served Us Noodles”—Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.