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.It is radically different from Earth in other respects.It has the densest atmosphere of the four terrestrial planets, consisting of more than 96% carbon dioxide.he atmospheric pressure at the planet's surface is 92 times that of Earth's. With a mean surface temperature of 735 K (462 °C; 863 °F), Venus is by far the hottest planet in the Solar System, even though Mercury is closer to the Sun.