Io's Volcanism

JavaScript — Io physics

const M_IO = 8.93e22;
const R_IO = 1821.6e3;

// Io heat output
const heat_io_W = 1e14;  // 100 TW
console.log(`Io heat: ${(heat_io_W / 1e12).toFixed(0)} TW`);
console.log(`Earth heat: ~44 TW (geothermal + radioactive)`);
console.log(`Io flux per area: ${(heat_io_W / (4 * Math.PI * R_IO * R_IO)).toFixed(2)} W/m²`);

// Tidal heating estimate
function tidalHeating(R_moon, e_orbit, M_planet, n_freq) {
  // Very simplified
  // Q × |k_2/Q| × ... — proportional to flexing
  // For Io: Q ~ 100, k_2 ~ 0.04 (rocky body)
  return 1e14;  // placeholder
}

// Resonance check (Laplace 1:2:4)
const T_IO = 1.769;
const T_EUROPA = 3.551;
const T_GANYMEDE = 7.155;
console.log(`Io ratio Europa: ${(T_EUROPA/T_IO).toFixed(3)}`);  // 2.008
console.log(`Europa ratio Ganymede: ${(T_GANYMEDE/T_EUROPA).toFixed(3)}`);  // 2.015

// Active volcano count
console.log(`Io: ~400 active volcanoes`);
console.log(`Earth: ~50-80 active`);

// Plume height vs. gravity
function plumeHeight(initial_velocity, g) {
  return initial_velocity * initial_velocity / (2 * g);
}

const g_io = 1.796;
console.log(`Plume reaching 250 km needs v_init: ${Math.sqrt(2 * g_io * 250000).toFixed(0)} m/s`);
// ~950 m/s — faster than sound on Earth

Why Io matters

• Tidal heating extreme. Lab for understanding orbital resonance + heat.
• Volcanic processes. Active geology in alien conditions.
• Comparative geology. vs Earth, Mars, Venus volcanism.
• Magnetosphere physics. Io feeds Jupiter's plasma torus.
• Future missions. Direct observation possibilities; Europa Clipper passes Io en route.
• Sulfur chemistry. Distinct from Earth's silicate-dominated geology.
• Solar system tour. One of most photogenic worlds; pizza-faced surface.

Common misconceptions

• Io is dead and frozen. Most active body in solar system.
• Volcanism is silicate like Earth. Sulfur-dominated; very different chemistry.
• Volcanoes alternate. Many erupt simultaneously continuously.
• Surface is changing slowly. 1 cm/year resurfacing — geologically fast.
• Io has water. Water lost early; only trace.
• Active geology means life. Conditions too harsh for known life.