The force that pulls planets into a curved path as they orbit the Sun is known as gravity. According to Newton's law of universal gravitation, all objects with mass exert an attractive force on each other. In the case of the solar system, the Sun, which has a much larger mass than the planets, exerts a strong gravitational pull on them. This gravitational force causes the planets to accelerate toward the Sun, resulting in a curved orbital path rather than a straight line.
Additionally, the combination of this gravitational pull and the planets' tangential velocity (their speed in a direction perpendicular to the force of gravity) results in the elliptical orbits described by Kepler's laws of planetary motion.