next, simon tries a material that is much more like the composition of an asteroid like dimorphos.. whoa! we've got ejecta — stuff thrown up. you can see this is bouncing much more this time than it did with the sand. yeah. when the ball hits the gravel, ejecta is thrown away from the surface. physics says that the more ejecta there is, the more the target is pushed in the other direction. this is called momentum enhancement. that amount of momentum carried by the ejecta has to be balanced by extra momentum in the asteroid moving in the other direction. so, it'sjust like how a rocket works. you throw stuff out one way and the rocket goes up. exactly. and that's called the momentum enhancement, this magic beta factor that everybody wants to know. right, and that's what we saw with dart? yes. when dart hit dimorphos, the energy from the impact led to a crater being formed, and material from the asteroid was blasted out into space. this caused momentum enhancement, also known as the beta factor, and helped to propel the target further. it's the reason that a light spacecraft, weighing