If only gravity were operating on Earth and there were no other forces acting, the planet would begin to move in a straight line towards the Sun. This would be because the Sun's gravitational pull would be the only force acting on Earth and it would cause Earth to accelerate towards it. However, Earth is also subject to other forces, such as the centrifugal force caused by its rotation on its axis, and the gravitational forces exerted by the Moon and other planets in the solar system. These forces all act together to keep Earth in a stable orbit around the Sun.

Without these other forces, Earth could potentially be pulled closer to the Sun and eventually collide with it. However, it is important to note that the Sun's gravitational pull weakens with distance, so as Earth moved closer to the Sun, the gravitational force would become weaker. This means that the rate of acceleration would decrease and it could take a long time for Earth to actually reach the Sun.