The morning star, commonly known as Venus, is the second planet from the Sun in our solar system. It is often visible in the early morning sky just before sunrise, which is how it earned its nickname. Venus is similar in size and composition to Earth, but it has a thick atmosphere filled with carbon dioxide and clouds of sulfuric acid, making it the hottest planet. Venus has a bright appearance due to its reflective clouds, which can make it one of the brightest objects in the sky after the Moon. It orbits the Sun every 225 Earth days and rotates on its axis very slowly, taking about 243 Earth days to complete one rotation.