The two main forces that keep Earth in its orbit around the Sun are:

1. Gravity: The Sun's immense gravitational pull attracts Earth towards it. This is the primary force that keeps Earth from flying off into space.

2. Inertia: Earth's inertia, its tendency to move in a straight line, counteracts the Sun's gravitational pull. This means Earth wants to continue moving in a straight line, but the Sun's gravity bends that path into an ellipse.

These two forces are in balance, creating a delicate equilibrium that results in Earth's stable orbit around the Sun.