1. Gravity: This is the primary force. The Sun's massive size creates a strong gravitational pull that attracts the planets towards it. This pull is what keeps the planets from flying off into space.
2. Inertia: This is the tendency of an object to resist changes in its motion. Planets, due to their initial velocity, want to move in a straight line. However, the Sun's gravity pulls them towards it, causing their path to curve into an orbit.
Think of it like this: Imagine you are swinging a ball on a string. The string represents gravity, and the ball's inertia wants it to fly off in a straight line. However, the string keeps pulling it back towards you, creating a circular path.
