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A little knowledge. A more familiar sky.

Learn the night sky.

Recognise it. Remember it. Find it again.

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Your next small discovery2 min read

Jupiter’s moons

Meet Jupiter’s four large Galilean moons. Give each one a personality and the names become easier to remember.

Outwards from Jupiter
  1. IoVolcanoes
  2. EuropaIce
  3. GanymedeGiant
  4. CallistoCraters
Orbital order · not to scale or tonight’s positions

Io

The volcanic one. Closest to Jupiter of these four moons.

Europa

The icy one. Strong evidence points to an ocean beneath its ice.

Ganymede

The giant one. The largest moon in our Solar System.

Callisto

The cratered one. Outermost of the four Galilean moons.

Make it stick

I Eat Giant Cookies

Io → Europa → Ganymede → Callisto. From the closest orbit to the farthest.

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Sources & further reading