Moon Geology

What is Moon Geology?

The Moon is Earth's closest neighbor and one of the most studied worlds in the solar system — yet its surface looks almost nothing like our own. Instead of forests and oceans, the Moon is covered in craters, ancient lava plains, and jagged mountain ranges, all preserved in near-perfect condition for billions of years. Two main terrain types dominate: the dark, flat maria (from the Latin word for 'seas') are ancient lava flows that filled huge impact basins roughly 3 to 4 billion years ago. The bright, heavily cratered highlands are older, original crust that dates back to the Moon's early formation. Because the Moon has no atmosphere to burn up incoming space rocks and no water or plate tectonics to erode or recycle the surface, every impact leaves a mark that remains visible for billions of years. By studying crater shapes and sizes, scientists can estimate the age of different lunar regions and reconstruct the history of collisions throughout the inner solar system. This simulation lets you launch your own meteorites and explore how impact size, speed, and angle shape the craters left behind.

Parameters explained

Impact Size(km)

Impact Size controls the diameter assigned to new meteorite impacts in the simulation, from 1 km to 20 km. Raising the slider makes each triggered impact leave a larger crater and a more dramatic flash, so students can connect impactor scale with visible surface change. This is a simplified classroom control: it does not separately model velocity, angle, density, or target rock strength. Use it to compare small, medium, and large impacts on the same lunar surface, then ask students why real planetary scientists need more evidence than crater size alone.

Rotation Speed(x)

Rotation Speed changes how quickly the Moon turns in the 3D view, from a paused surface at 0x to a faster sweep at 3x. Slower rotation helps students inspect crater density, maria boundaries, and highland texture without losing their place. Faster rotation is useful when comparing the Full Moon view with focused presets because students can scan the surface and notice how features repeat or cluster. This control changes observation speed only; it does not imply that the Moon actually rotates this quickly in space.

Common misconceptions

• MisconceptionLunar craters were formed by ancient volcanoes, not meteorite impacts.

  CorrectEarly astronomers did debate this, but modern evidence overwhelmingly shows that the vast majority of lunar craters are impact craters. The circular shapes, raised rims, central peaks in large craters, and radiating ejecta rays all match what we see in impact physics experiments. The maria — the dark smooth regions — are from ancient volcanic lava flows that filled pre-existing impact basins.

• MisconceptionThe Moon has no geology because it is a dead, unchanging world.

  CorrectThe Moon has a rich geological history spanning about 4.5 billion years. It had active volcanoes that erupted lava for over a billion years. It experienced a period of intense bombardment called the Late Heavy Bombardment around 3.9 billion years ago. Even today, moonquakes occur and tiny micrometeorites continuously chip away at the surface. The Moon's story is still being written.

• MisconceptionLarger meteorites always make deeper craters.

  CorrectCrater depth often increases with impact energy, but the relationship between depth and diameter changes with crater size. Simple small craters are bowl-shaped and relatively deep, but complex large craters can develop flat floors, central peaks, and terraced walls — they are actually shallower relative to their diameter than simple craters because of the way the target rock briefly behaves like a fluid during the impact.

• MisconceptionThe Moon's far side is always dark because it never faces the Sun.

  CorrectThe far side of the Moon gets just as much sunlight as the near side — it is just never facing Earth. Because the Moon rotates at exactly the same rate it orbits Earth (a condition called tidal locking), the same hemisphere always faces us. During a new Moon, the far side is fully lit by the Sun. The phrase 'dark side of the Moon' refers to being unseen from Earth, not to being in permanent shadow.

How teachers use this lab

1. Start with the Full Moon preset and set Impact Size to 5 km, then trigger several impacts so students can record crater count and describe how new craters change the visible surface.
2. Move Impact Size from 1 km to 20 km while keeping Rotation Speed at 0x, then have students compare crater size categories and connect the observations to MS-ESS1-3 data analysis practices.
3. Use the Mare Imbrium Region preset, then switch to Ancient Highlands while Rotation Speed is slow — students compare basaltic plains with older highland crust and explain why terrain age affects crater density.
4. Set Rotation Speed to 3x for a quick scan, then reduce it to 0x or 0.5x for evidence collection — students discuss why observation rate matters when interpreting planetary surface data.
5. Have teams choose one preset, collect surface type, age range, crater count, and impact-size observations, then present a claim about how lunar regions preserve evidence of solar system history.