Planets

Part of Hall of the Universe.

The Hall of the Universe in the Museum’s Rose Center for Earth and Space. AMNH/D. Finnin

The Sun, an unremarkable star, holds in orbit a system of planets.  If most Sun-like stars have planets, then there should be billions of planets in our Milky Way Galaxy. Numerous other planetary systems have already been detected, many with configurations quite different than that of our solar system.

In This Section

What is a Planet? In our solar system, planets are the major bodies orbiting the Sun. Other Planetary Systems Until the end of the 20th century, ours was the only planetary system known. Surfaces Many forces shape the solid surfaces of planets and moons. Greenhouse Effect Visible sunlight heats a planet’s surface, which re-radiates the energy as infrared light. Volcanism Volcanoes provide an efficient way for solid planets and moons to shed their internal heat. Atmospheric Storms Great atmospheric storms occur on all the gas giants. Rings All of the gas giant planets have rings. Orbits The Moon orbits Earth. Earth orbits the Sun. The Sun orbits the center of our galaxy. Gravity holds all in orbit. Deciphering Celestial Motions The ancients believed that Earth was the center of the universe. Formation of Our Solar System The Sun and the planets formed together, 4.6 billion years ago, from a cloud of gas and dust called the solar nebula. Planetary Impacts Impacts have played an important role throughout the history of the solar system. The Search For Life In The Universe In the search for life, we have barely scratched the surface of other planets in our solar system.