text: Venus is known for being one of Earth's "twins". Venus is known for it's density and size that is quite similar to Earth's. "Astronomers are facinatedby Venus beacuse it may well once have been the most Earth-like planet in our solar system. Long ago, Venus was probaly covered largely with oceans and could have supported forms of life, just like Earth." (Paragraph 4, Challenges of Exploring Venus). Astromomers are saying that venus is very similar to Earth, by its size and that in the past Venus might have had life forms on it and that might be a good reason why it would be a good reason to explore Venus.