: I just learned that mercury is in fact the closest planet to the earth. What is this madness and since when?

Question

: I just learned that mercury is in fact the closest planet to the earth. What is this madness and since when?

In: 3690

Answer 1

Mercury is the closest planet, on average, to *all* the other planets, because, half the time, any given planet is on the other side of the sun from you, and the one with the smallest orbit will suffer (in terms of being close to any given planet) least from that. And the distance-to-the-planet-when-it’s-on-the-other-side-of-the-sun always outweighs a brief, temporary, distance-to-the-planet-when-it’s-passing-nearby.