The Universe Made Simple/The Solar System/Mercury
The first planet orbiting the sun travelling outwards is Mercury. Since it is the closest plant to the sun, Mercury orbits around the Sun at a faster pace than any other planet. It only takes 88 Earth days for Mercury to orbit the Sun. However one day on Mercury lasts 176 Earth days. During the day, the temperature on Mercury reaches 450° C but at night it drops down to negative 170° C. The sunlight that reaches the surface of Mercury is six times brighter and more intense than that on the Earth.
Mercury is the second densest major body in the solar system after the Earth. But an object that weighs 100 pounds on Earth would only way 38 pounds on Mercury. The interior of Mercury resembles that of the Earth and consists of a large iron core. The surface has cratered terrains, smooth plains, and is mostly made of rock and metal. There are many deep craters like those on the Moon’s surface. Scientists have proven that the floors of craters at the poles contain ice because they are permanently shielded from the Sun and thus never melt. Mercury’s atmosphere is dry, extremely hot, and almost airless. The gravity on Mercury is too weak to maintain a significant atmosphere for long periods of time and thus too weak to contain any moons in orbit. The magnetic field is about one percent as strong as that of the Earth.