how big is venus compared to earth
It takes 243 Earth days to rotate once on its axis. The planetâs orbit around the Sun takes 225 Earth days, compared to the Earthâs 365. Venus is often called the Earthâs sister planet: The Earth and Venus are very similar in size with only a 638 km difference in diameter, Venus having 81.5% of the Earthâs mass.Both also have a central core, a molten mantle and a crust.enus is often called the Earthâs sister planet: The Earth and Venus are very similar in size with only a 638 km difference in diameter, Venus having 81.5% of the Earthâs mass. Both also have a central core, a molten mantle and a crust.