A simple question for the Twittersphere ...

Which planet is closest to Earth? https://abs.twimg.com/emoji/v2/... draggable="false" alt="❓" title="Red question mark ornament" aria-label="Emoji: Red question mark ornament">https://abs.twimg.com/emoji/v2/... draggable="false" alt="🌍" title="Earth globe europe-africa" aria-label="Emoji: Earth globe europe-africa">

(No googling!)

#CelestialMechanicsQuiz

With 2,513 votes in, and many comments asking "when!?" we can confirm that:

Mercury is the closest planet to Earth on averagehttps://abs.twimg.com/emoji/v2/... draggable="false" alt="🤯" title="Exploding head" aria-label="Emoji: Exploding head">
(although Venus is closest at this very moment)

How could this be possible?

Remember that planets are always in motion, travelling in huge ellipses and getting closer and further from each other all the time

Mercury travels in the smallest orbit of all the planets, meaning it never gets as far away

Not only is Mercury the closest planet to Earth (most of the time), its also closest to Mars, Jupiter and, well, all the planets of the Solar System!

This video from @cgpgrey explains very well
https://abs.twimg.com/emoji/v2/... draggable="false" alt="👉" title="Right pointing backhand index" aria-label="Emoji: Right pointing backhand index"> https://www.youtube.com/watch?v=SumDHcnCRuU">https://www.youtube.com/watch...