How many planets have been explored?
Flexi Says: Scientists explore planets outside of Earth in many different ways, including with space craft, telescopes, and other remote sensing devices. So far, humans have only ever been to the Moon. However, scientists have landed remotely operated craft (e.g., rovers, landers) on the surfaces of Venus, Mars, Earth's Moon, Saturn's moon Titan, and several asteroids. These craft have collected and sent back data on surface and atmospheric conditions. Space craft have either orbited or performed close fly-bys of all of the planets in our solar system. Scientists also use powerful land and space telescopes to study the planets and other objects in our solar system. Planets outside our solar system are very difficult to explore, since they are so far away. However, a mission to send tiny probes to our nearest star system, Centauri, is in the early planning stages.
Learn more in the Satellites, Shuttles, and Space Stations lesson.