Final answer:
The size of an impact crater is largely determined by the kinetic energy of the impacting object, which is a function of both its mass and velocity. A smaller object with more mass, possessing the same kinetic energy as a larger, less massive object, would typically create a larger crater. Different materials, like those composing comets and asteroids, also influence the characteristics of the crater.
Step-by-step explanation:
The impact crater size is generally influenced by both the mass and the velocity of the impacting object. The energy of the impact, which determines the size of the crater, is a function of the kinetic energy, which is 0.5 × mass × velocity2. Therefore, if two objects have the same kinetic energy, the smaller but more massive object, which would have to be traveling at a lower speed to have the same kinetic energy as the larger, less massive object, would likely create a larger crater due to its greater momentum upon impact. A higher mass at the same velocity usually means more kinetic energy, leading to a larger crater.
When comparing impacts on astronomical bodies like the Moon, a comet, which is often composed of ice and dust, would tend to have a higher velocity but less mass compared to an asteroid, which is mostly rock and metal. This means that the crater from a comet impact could potentially be very different in terms of size, shape, and ejecta compared to a crater from an asteroid impact, which might be denser and move at slower velocities, leading to a different type of impact event.