Smallest planet

Since the demotion of Pluto as a planet, Mercury is now the smallest major planet in the Solar System. At 4,879 km (3,031 miles) across, it is less than one and a half times the diameter of Earth's Moon. Being the closest planet to the Sun, it also orbits the fastest, at 48.87 km (30.36 miles) per second. It also has the greatest temperature range of any planet, from 427°C (800.6°F) under the scorching Sun, down to -173°C (-279.4°F) during the Mercurian night.