This simulation shows what happens when momentum is not ignored, an approach that is allowed with modern supercomputers and codes. The same asteroid is now moving through the atmosphere at a typical impact velocity (20 km/s). For illustration purposes, extra energy is deposited into the asteroid when it reaches 5 km, for a total of 5 megatons. Momentum carries the hot fireball down to the surface, which enhances heat and wind effects on the ground.