Why are lunar maria darker than highlands?

Maria are filled with dark basaltic lava from ancient volcanic eruptions, while highlands are lighter-colored anorthosite (calcium-rich feldspar).

Why does the Moon have more visible craters than Earth?

No atmosphere (no erosion or burn-up), no plate tectonics (no recycling), and no water erosion to wear craters away.

Pro 🔒~20 min

Moon Geology

Lunar surface features, maria, highlands, and crater formation

How it works

The Moon's surface is divided into dark, flat maria (ancient lava plains) and bright, cratered highlands (older crust). Impact craters form when meteorites strike the surface at hypervelocity (10-70 km/s). Crater diameter depends on impactor size, velocity, angle, and target properties. Simple craters (<15 km) are bowl-shaped; complex craters have central peaks. The largest impacts created multi-ring basins. The Moon has no atmosphere or plate tectonics, so craters are preserved for billions of years. Lunar rock types include anorthosite (highlands), basalt (maria), and breccia (mixed impact debris).

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Step-by-step

Click on the lunar surface to create impact craters.
Adjust meteorite size, velocity, and angle to see how they affect crater dimensions.
Examine the cross-section view to see crater structure.

Key formulas

$D \approx 1.8 \rho_p^{0.11} \rho_t^{-1/3} d^{0.78} v^{0.44} g^{-0.22} (\sin\theta)^{1/3}$ Pi-scaling crater diameter formula relating projectile and target properties

Frequently asked questions

Why are lunar maria darker than highlands?: Maria are filled with dark basaltic lava from ancient volcanic eruptions, while highlands are lighter-colored anorthosite (calcium-rich feldspar).
Why does the Moon have more visible craters than Earth?: No atmosphere (no erosion or burn-up), no plate tectonics (no recycling), and no water erosion to wear craters away.