Venus is a planet.
Venus is the second planet from the Sun , orbiting it every 224.7 Earth days . It has the longest rotation period ( 243 days ) of any planet in the Solar System and rotates in the opposite direction to most other planets . Venus is a terrestrial planet and is sometimes called Earth 's `` sister planet '' because of their similar size , mass , proximity to the Sun , and bulk composition . As the closest planet to Earth , Venus has been a prime target for early interplanetary exploration . It was the first planet beyond Earth visited by a spacecraft ( Mariner 2 in 1962 ) , and the first to be successfully landed on ( by Venera 7 in 1970 ) .