Sixty-six million years ago a carbonaceous asteroid some fourteen kilometres across came down on the Yucatán platform at twenty kilometres a second, sixty degrees from the north-east, and the Cretaceous ended. This page digs it live in WebGL 2, in the browser, nothing to install: carbonate over crystalline basement, the ejecta curtain going up, and a ninety-kilometre transient bowl opening in about eighty seconds.
Two scales. The crater: presets from a one-kilometre rock to a thirty-kilometre one, with a readout of impact energy, ejecta, melt and seismic magnitude. The first day: the crater is a dot on the globe, but the plume outruns the atmosphere, arcs over half a world and is down everywhere within two hours — that, not the crater, is what ended the Cretaceous. Impactor size, speed and angle are knobs under advanced.
A contact model, not a shock code: no equation of state, no vaporization, no strength, and the first second is a scaling law (Collins 2005 and 2020, Housen & Holsapple 2011, Melosh 1989). The giant impact that made the Moon is the other page; source on GitHub, MIT.
Drag rotates · wheel zooms · space pauses · R restarts.