Answer: capture theory
Step-by-step explanation:
An asteroid is a rocky object which orbits sun having irregular shape and size.Asteroids are usually found in between the orbits of Mars and Jupiter in the asteroid belt.
Capture theory of moon suggests that moon was formed somewhere else in the solar system and was captured by Earth's gravity.
If the moon resembled an asteroid, it would have supported the capture theory i.e. an asteroid was captured by the gravitational pull and started orbiting around the Earth.