Mercury formed approximately 4.6 billion years ago. The start of his life was tumultuous: asteroid impacts, intense volcanic activity, after which a slow cooling began. For about 3.5 billion years, Mercury has not developed — it seems immobile and stiffened. Yet it is one of the little-studied planets. From Earth, watching it is very difficult. This requires special apparatus, because Mercury is very close to the Sun and is not visible in its bright radiance.
On Mercury there is then intense heat, then extreme cold. In the hottest zones, temperatures can reach 430 OS due to proximity to the Sun. Here, solar radiation is 10 times stronger than on Earth. But at night or in the shade of uplands the temperature drops to -180 oC, because Mercury has no atmosphere, which keeps the heat. Because of this, there is no water on the surface and no wind blows.
Day and night on Mercury last long: the planet makes full turnover around its axis in 59 days, not for 24 hours like Earth. But the year is very short. Full turnover around the sun Mercury makes in just 88 days.
Since its formation, Mercury has been heavily bombarded by asteroids. The planet is covered with craters of various sizes. The diameter of the smallest one is a micrometer, and the largest one is several thousand kilometers. Unlike craters on Earth, they do not change on Mercury as there is no erosion.
There are not only craters on the planet, but huge cliffs ranging from 500 to 3000 m high. They formed when Mercury compressed, which occurred when cooled. Because of this, its radius decreased by 2 km.
Mercury has no natural satellites. In 2004, an American station, Messenger, was launched to it. It did not enter Mercury’s orbit until 2011. The station was the first man-made satellite of this planet.
The apparatus was equipped with powerful scientific instruments that allowed accurate observations. “Messenger” circled Mercury several times and took pictures of previously unknown areas of the planet. With it, a crater was also discovered, which was later named Rembrandt. The apparatus revealed a significant amount of lava flows around the crater, which swept under the weight, forming huge furrows.
Mercury’s artificial satellite completed its mission in 2015. A year earlier the machine used up all fuel, so it became impossible to adjust its work. It gradually approached Mercury’s surface until crashing against it.