: 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

It’s closest to Earth *on average*. It is also closest to every other planet *on average*. This is because its closest to the sun and has both the smallest orbit, and as a direct consequence, the fastest one. This means it doesn’t move very far away even if it’s on the other side of the sun, and it comes back around multiple times while the Earth completes one. Meanwhile planets like Mars and Jupiter will be on the opposite side of the sun for six months every year, even if their orbital ring is closer (Jupiter’s isn’t).