Tech WondersPlay

Space, GPS & MapsAstronomy

Why We Only See One Side of the Moon

The Moon spins exactly once per orbit

Every person who ever looked up has seen the same face of the Moon, never its back. So does the Moon even spin?

You'll find out

  • Does the Moon spin at all?
  • What put the brakes on its spin
  • Is the hidden side really dark?

Why it matters

The same tug that froze the Moon's face locks moons across the solar system and is slowly making your days longer.

About 3 min6 interactive slides · 5 questionsLesson 47 · Zone 6

Play this lesson

Free to play in your browser or on iPhone

More in this zone

  1. 46Digital PsychologyPhantom VibrationsMost phone users have felt a buzz that never happened
  2. 48CombinatoricsThe Pigeonhole TrickToo many pigeons for the holes guarantees a hidden match
  3. 49Online PrivacyIncognito Isn't InvisiblePrivate mode hides your history from your phone, not from the internet
  4. 50Online SafetyThe QR Sticker ScamA fake code taped over the parking meter sends your card to a thief
  5. 51Cryptographic HashingChange One Letter, Change EverythingA hash is a fingerprint that flips totally at the smallest change
  6. 52BinaryEverything Is BinarySongs, photos and this sentence are all just ons and offs
  7. 53Atomic PhysicsAtoms Are Mostly EmptyIf an atom were a stadium, the nucleus would be a marble
  8. 54Thermal EngineeringYour Fridge Doesn't Make ColdIt pumps heat out of the box and dumps it into your kitchen