Mercury

The smallest planet in our Solar System and nearest to the Sun, Mercury is only slightly larger than Earth's Moon. From the surface of Mercury, the Sun would appear more than three times as large as it does when viewed from Earth, and the sunlight would be as much as seven times brighter. Mercury is the fastest planet in the Solar System, zipping around the Sun every 88 Earth days. However, despite its proximity to the Sun, Mercury is not the hottest planet in our Solar System. Because the planet is so close to the Sun, Mercury's surface temperature can reach up to 450°C. However, Mercury has no significant atmosphere to entrap any heat, therefore at night temperatures can plummet to minus 170°C. This temperature swing of more than 600°C is the greatest in the Solar System. One day on Mercury (the time it takes for Mercury to rotate or spin once with respect to the stars) takes 59 Earth days. One day-night cycle on Mercury takes 175.97 Earth days. Mercury is a rocky planet which has a solid, cratered surface, much like Earth's Moon. No evidence for life has been found on Mercury.