correct order of accretion of planetesimals is 1. Masses of matter form around dust grain 2.masses of matter collide 3.atoms and molecules are added to dust grain.
Conservation of angular momentum explains why the contracting solar nebula's rotation rate increased as it contracted.
The solar system contains the Sun, eight major bodies called planets, and at least thousands of smaller bodies and denser planets lie closer to the sun.
The masses of all the planets combined is about 1% of that of the Sun.
The planet's orbital period is the time it takes to return to the same location in the sky, relative to the Sun.
Asteroids are the densest form of interplanetary debris
