How Gravity Affects the Sun and the Earth

Earth

• Relative to the rest of the universe, the earth is quite small and is mostly subject to the gravity of other entities within the universe. It does, however, affect other heavenly bodies, the moon being the most affected. The earth, being much bigger than the moon, creates a gravitational pull upon the moon, which is what keeps it in orbit around the earth.

Sun

• The sun is the main heavenly body in the solar system, and thus the gravitational pull of the sun has a distinct effect upon the rest of the planets. Much as the moon orbits around the earth, caught in its gravitational pull, the planets all orbit around the sun. The sun, being far larger than any of the planets, exerts a stronger gravitational pull, and this is why the planets orbit around the sun and not any of the other heavenly bodies.

Galaxy

• Much as the planets of the solar system rotate around the sun, the many different solar systems that make up the Milky Way galaxy rotate around a central point, due to the pull of gravity. Scientists believe that at the center of the Milky Way galaxy, and many other galaxies, there is a massive black hole that exerts the gravitational force necessary to form a galaxy. Whatever is at the center of the galaxy, its gravitational pull causes the sun, the earth and the rest of the planets in the solar system to slowly rotate around the center of the galaxy.

Universe

• The Milky Way galaxy, relative to the scope of the entire universe, is minuscule, but even at the scale of the universe there are forces of gravity that are acting upon the sun, the earth and everything else in the solar system. Paradoxically, however, everything is moving away from everything else, rather than towards it. The reasons for this are not entirely clear, but there are theories, such as the existence of a force called "anti-gravity," that try to explain the expansion of the universe and everything it contains.