Question

Use the nebular hypothesis to explain why the planets all orbit the Sun in the same direction.

Answer 1

It is from this orbiting matter that all the planets form, and of course, they are also spinning and orbiting in the same direction because of the conservation of angular momentum. There are two outliers in the solar system which seem to break the rules about conserving momentum — Uranus and Venus.

Answer 2

All the planets orbit the Sun in the same direction. Most of their moons also orbit in that direction, and the planets (and the Sun) rotate in the same direction. This would be expected if they all formed from a disk of debris around the proto-Sun.