1.33 explain that gravitational force

causes moons to orbit planets
causes the planets to orbit the sun
causes artificial satellites to orbit the Earth
causes comets to orbit the sun

Planets are held in orbit by the gravitional pull of the Sun. Similarly comets orbit the sun and moons and satellites orbit the planet. It is the gravitional attraction between this mass and each of the planets that holds the Solar System together and causes the planets to follow their curved paths.