Find the escape speed v = √(2 G M / R) from the surface of a spherical mass.
| Escape speed (m/s) | – |
Use this calculator for the speed needed to leave a spherical body from radius R and never fall back, ignoring atmosphere and rotation. G is 6.674×10⁻¹¹ N·m²/kg². From Earth’s surface (M ≈ 5.97×10²⁴ kg, R ≈ 6.371×10⁶ m) the result is about 11.2 km/s.
M is the planet or star mass and R is the starting distance from the centre, not the height above the ground. Air drag and planetary rotation are omitted; a real launch needs more than this vacuum figure.
Mass (kg): Central mass. Earth ≈ 5.97e24 kg.
Radius (m): Distance from the centre. Earth radius ≈ 6.371e6 m.
Escape speed (m/s): √(2 G M / R).
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