Constants library

Mass of Mars measured

M_{\mathrm{Mars}} = 6.4171 \times 10^{23}\ \text{kg}

kgMass of Mars, 6.417 × 10²³ kg — about 10.7 per cent of Earth's, small enough that the planet lost most of its atmosphere.

R_{\mathrm{Mars}} = 3,389,500\ \text{m}

mVolumetric mean radius of Mars, 3389.5 km; the equatorial radius is 3396.2 km and the polar 3376.2 km, a 20 km flattening.

g_{\mathrm{Mars}} = 3.71\ \text{m/s}^{2}

m/s²Equatorial surface gravity on Mars, 3.71 m/s² — 38 per cent of Earth's, the figure every Mars lander design is built around.

v_{\mathrm{esc},\mathrm{Mars}} = 5030\ \text{m/s}

m/sSpeed needed to escape Mars from the surface, about 5.03 km/s — less than half Earth's, which is why a return mission is even thinkable.

M_{\mathrm{Mercury}} = 3.3011 \times 10^{23}\ \text{kg}

kgMass of Mercury, 3.301 × 10²³ kg — the smallest planet, yet the second densest, with an iron core filling most of its volume.

M_{\mathrm{Venus}} = 4.8675 \times 10^{24}\ \text{kg}

kgMass of Venus, 4.8675 × 10²⁴ kg — 81.5 per cent of Earth's, making it our closest twin in bulk and nothing like it in climate.

M_{\mathrm{J}} = 1.8982 \times 10^{27}\ \text{kg}

kgMass of Jupiter, 1.898 × 10²⁷ kg — 318 Earths, and more than twice all the other planets combined; the unit for weighing exoplanets.

R_{\mathrm{J}} = 71,492,000\ \text{m}

mJupiter's equatorial radius at the 1-bar level, 71 492 km; the polar radius is 66 854 km, a 6.5 per cent flattening from fast rotation.

M_{\mathrm{Saturn}} = 5.6834 \times 10^{26}\ \text{kg}

kgMass of Saturn, 5.683 × 10²⁶ kg — 95 Earths spread so thinly that its mean density, 687 kg/m³, is less than that of water.

M_{\mathrm{Uranus}} = 8.681 \times 10^{25}\ \text{kg}

kgMass of Uranus, 8.681 × 10²⁵ kg — 14.5 Earths of hydrogen, helium and icy volatiles, tipped on its side at 98 degrees.

M_{\mathrm{Neptune}} = 1.02413 \times 10^{26}\ \text{kg}

kgMass of Neptune, 1.024 × 10²⁶ kg — 17.1 Earths, the densest of the giant planets and the one found with mathematics before a telescope.