Our Solar System Author:Glen Phelan Our solar system consists of the sun and all the objects that revolve around it. these objects include the nine planets as well as millions of comets, asteroids, and meteoroids. The force of gravity pulls these objects into elliptical orbits around the sun. Even the distant planet Pluto cannot escape the pull of gravity because of the sun's ... more »massive size. One of the most interesting and most studied of our planet neighbors is Mars. Several American and Russian space probes have landed on the red planet since 1971. In January 2004, two rovers called Spirit and Opportunity explored a small portion of its surface. Over the next several years, other missions may explore the Mars polar ice caps and bring Martian rocks back to Earth.« less