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☢ Io
Io Moon

Io: Radioactive volcano moon of Jupiter

Io is one of the 4 Galilean moons of the planet Jupiter. It is the hottest moon in the solar system, recording up to 2,600°F around its 400 volcanoes, hotter than Earth's volcanoes. Due to its proximity to Jupiter, it receives 3,600 rem of radiation a day (compared to 0.001 rem per day on Earth). This is 1,000 times stronger than needed to kill a human being.

Io, along with Callisto, Europa, and Ganymede, (the Galilean moons) were discovered by the Italian astronomer Galileo Galilei in 1610.

For a listing of all moons, see Moons of the Planets.

Io Facts
      1. Mass (kg)
      2. 8.94 x 1022
      1. Radius (km)
      2. 1,815
      1. Density (gm/cm3)
      2. 3.55
      1. Distance from planet (km)
      2. 421,600
      1. Rotational period (days)
      2. 1.769138
      1. Orbital period (days)
      2. 1.769138
      1. Orbital velocity (km/sec)
      2. 17.34
      1. Eccentricity of orbit
      2. 0.004
      1. Inclination of orbit (°)
      2. 0.040
      1. Albedo
      2. 0.61
      1. Magnitude (Vo)
      2. 5.02
      1. Atmosphere
      2. 90% sulfur dioxide


    Io Surface Map

    Io moon surface map