Heliocodex

Learn / Outward from here

Moons

On the scale of light: 1.3 light seconds to our Moon. 4 lessons, in the order to read them.

  1. Start hereWhat a moon isAnything that orbits a planet is a moon. There are more than 400, from worlds bigger than Mercury to rocks a kilometre across.First look · How it works
  2. Moons with oceansSeveral icy moons hide seas of liquid water under their crusts, kept warm by tides. They are the likeliest places to look for life.First look · How it works
  3. Moons in stepSome moons keep time with each other, lapping their neighbours in exact whole numbers. That rhythm heats Io, carves gaps in rings and makes two moons swap places.First look · How it works
  4. The MoonOur nearest neighbour: a quarter as wide as the Earth, made from the wreckage of a collision, and the only other world people have stood on.First look · How it works

Outline Still to be written here

  1. The great moons of JupiterIo, Europa, Ganymede and Callisto, one by one.
  2. TitanThe moon with thick air, lakes and rain, and the probe that landed there.
  3. The far moonsTriton, the moons of Uranus, and Pluto and Charon.