My very easy method just speeds up naming planets.

Every physics classroom has a solar system line like this, or like this.

Sorry, Pluto.

Looking at the line, which planet is closest to Earth?

Venus or Mars.

To answer, you need first know that, like many things in school, the line is a lie.

Planets are not people, cueing for coffee, but rather, spheroids scattered in space, always

in motion, not in simple circles either, but in ellipses at untidy angles.

In the cold, dark expanse, this is the cosiest Venus gets to Earth, but only about once

a year and a half-ish.

Starting close, she orbits far, then comes back, needs some space on the other side of the Sun.

This means when Venus is away, Mars can be the closest to play. So because of orbits, there isn't one answer to who is the closest.

It's really who is mostly the closest, the mostest closest. When Mars and Venus are both on the other side of the Sun, it leaves Little Mercury the closest.

Each of Earth's inner three planet friends are, at one time the farthest, and the closest.

And Mercury, with his smallest orbit, makes him never that far from Earth, at least on planetary scales,

giving the little guy a uniquely close relationship with Terra.

In fact, watching the planet spin, because of his small orbit, Mercury, not Mars or Venus,

is the closest planet most of the time. Looking at the line, that seems impossible,

but nonetheless, in the way of actual orbits, if we keep measuring the distance to all the planets

as they spin,

Mercury is Earth's most-est-closest neighbor, which is delightfully unexpected.

But wait, if Mercury is the most as closest to Earth, he has to be the most as closest to Venus as well, right?

...