Regolith Gardening 2D: Lunar Artifact Depth Cross-Section

Time Controls

Simulated speed 10⁴ yr/s

Micrometeorite flux 1.0×

Site Status

Elapsed time

0 yr

Gardening depth

0.0 mm

Impacts recorded

Artifacts intact

5 / 5

Apollo 11 Artifacts

How it works

Every year, roughly 10⁴–10⁶ micrometeorites strike each square metre of the airless lunar surface. Each impact excavates a tiny crater and flings regolith grains sideways, so over time the top layer gets churned — "gardened" — like soil turned by worms. This simulator uses a simplified power-law fit to the classic gardening-depth trend from Gault et al. (1974) and Quaide & Oberbeck (1975):

d(t) ≈ A · (F·t)^0.4   [cm]
A ≈ 0.025, F = flux multiplier, t = years

≈ 0.6 mm churned in ~10 years
≈ 1 cm churned in ~10,000 years
≈ 1 m churned in ~10^9 years

An artifact survives only as long as the gardening depth stays shallower than the artifact's own burial depth. A footprint (≈1 cm deep) is the first thing erased; the LM descent-stage debris field (≈20 cm) and a buried core-tube sample (≈50 cm) outlast it by orders of magnitude — which is exactly why deeper hardware, not surface footprints, is what a real space-archaeology survey expects to still find intact.

Simulated speed — how many years of gardening pass per real second (log scale, 10⁰–10⁸).
Micrometeorite flux — scales the effective impact rate relative to the Moon's measured value; higher flux reaches a given depth sooner.
Bottom chart — drag left/right anywhere on the depth-vs-time graph to scrub through geological time directly (the model is a closed-form function of time, so scrubbing recomputes every panel instantly, paused or not).

Regolith patch Intact artifact Erased by gardening

Top: overhead crater map. Middle: depth cross-section (log scale) with the five real artifacts. Bottom: drag to scrub the log-log depth-vs-time curve.