The planet closest to Earth is Venus. Venus orbits the Sun between Mercury and Earth, making it the second planet in the solar system. Although it is often called Earth's "sister planet" due to their similar size and composition, Venus has a very different environment. Its thick atmosphere is composed mainly of carbon dioxide and has clouds of sulfuric acid, resulting in a strong greenhouse effect that makes it the hottest planet in the solar system, with surface temperatures reaching around 900°F (475°C). Venus has no moons and is often visible from Earth, shining brightly in the early morning or evening, earning it the nickname "Evening Star" or "Morning Star."