The modification of the surface of a planet or satellite by collision with a bolide. On Earth, tectonics and erosion obliterate most signs of such events, but they are a major process in fashioning the surface of other solar-system bodies, most notably the Moon. An impacting bolide travels at up to 150 000 km/h. As it penetrates the surface its kinetic energy is instantly converted to heat, causing an explosion that vaporizes the object and the material it strikes and producing a crater much larger than the size of the bolide might suggest. An impacting meteorite about 3 m across and weighing 50 t will make a lunar crater 150 m in diameter.