Venus is one of the brightest objects in the Earth's sky. Known historically as both the morning and evening star, Venus' brightness is due to its proximity to the Sun and the Earth, and to its highly reflective clouds. 400 years ago the Italian astronomer Galileo was the first to look at Venus through a telescope and observe that this "star" displayed changing phases like Earth's Moon.

Venus has a very dense atmosphere and thick, yellowish-white clouds always conceal its surface. The harsh and bizarre world beneath the clouds was a mystery until just a few years ago.