Presets
Playback
Impactor material
Target world
Impactor
Model checks
The science
Energy
E = ½ m v2, m = (π/6) ρ d3One megaton of TNT is 4.184 x 1015 J. A 10 km stony body at 20 km/s carries about 7.5 x 107 Mt, the order of magnitude of the Chicxulub impact.
Crater scaling
The green curve is the published pi-group scaling of Collins, Melosh and Marcus (2005): the transient crater is Dtc = 1.161 (ρi/ρt)1/3 L0.78 v0.44 g−0.22 sin1/3θ (SI units, target density 2750 kg/m3). Small craters are simple bowls with Dfinal = 1.25 Dtc; above a gravity-dependent transition D* (3.2 km on Earth) they collapse into complex craters, Dfinal = 1.17 Dtc1.13 / D*0.13. The red curve is the simplified fit used by the 3D page; it is shown so you can see how far a quick formula can drift (it underestimates the reference by a factor of 3 to 4 for these cases).
Seismic magnitude
M = 0.67 log10 E − 5.87assuming 10−4 of the energy becomes seismic waves.
Honest simplifications
- No atmosphere: small bodies would break up or decelerate, and the Chelyabinsk-size preset would really airburst without a crater.
- The cross-section is a schematic of the excavation and collapse stages, drawn to scale in diameter; depths of complex craters use an approximate depth-diameter law.
- Impactors much larger than about 100 km exceed the validity range of the scaling; results there are indicative only.
- Ejecta are ballistic point particles; no melt sheet, ejecta blanket thickness or climate effects are computed. This is an educational model of planetary physics, not a hazard assessment.
What to try
- Load Meteor Crater and compare with the observed 1.2 km bowl.
- Raise the diameter past 1 km: the crater turns from a simple bowl into a shallow complex crater.
- Reduce the angle to 15 degrees: the crater shrinks only as sin1/3, so even grazing hits dig large craters.
- Switch to Mars: lower gravity makes the same impactor dig a larger crater.