Erosional Activity on Mercury, Venus, and Moon

Erosion in Earth is mainly caused by water or moisture, wind, and other earthly activities. However, in other planets like Mercury and Venus, as well as our own satellite, which is the Moon, there is less erosion activity. Considering their distance from the Sun, the two mentioned planets are the closest ones to the Sun, and in case of Moon, it has the same distance as the Earth from the Sun which is 1 astronomical unit. We could say that in these heavenly bodies, the moisture is least to exist since they are prone to the intense heat of the Sun, considering that the Moon gets its light from the Sun.
Aside from that, the Sun has strong gravity that enables it self to pull the planets and other heavenly bodies in the Solar System. Considering that the Mercury and Venus are the planets considered closest to the sun, both planets have received also the strongest attraction of the gravitational pull. In this case, the materials of the planets are more intact that could prevent to be eroded.
In relation to the planetary size, it is correlated to the gravity such that the bigger the planet or the heavenly body, the greater of its gravitational pull. The Mercury, Venus, and Moon, which are relatively small bodies in Solar System, it has lesser gravity pull than the Earth. However, with the influence of the Earth’s gravity to the Moon, it prevents the moon from its orbiting and other erosional activity in the said satellite. Mercury and Venus, as it was mentioned before, both planets have been affected by the gravitational force of the Sun. The fallen heavenly bodies, such as meteor and asteroids, that also causes erosion in planets would be avoided by attraction of gravity pull of the Sun. Instead of collision with Mercury or Venus, it would be then collided with the Sun. In this case, there would be lesser erosional activity.

Reference:
July 1, 2007
July 1, 2007