Mercury is the closest planet to the Sun, so it is literally incandescent. The temperature on its surface can reach 400 degrees Celsius. Nevertheless, in 2012, the automatic interplanetary station Messenger, launched by NASA, noticed something amazing: chunks of water ice on the surface of Mercury.
Earlier radio telescopes detected something bright and reflective in the craters of Mercury, so the 2012 discovery confirmed the scientists’ guess. However, the question remained: how? How could there be ice on the hottest planet in the solar system? And where did it come from?
Recent research gives a very strange answer. Ice could appear not despite the heat, but thanks to it. In general, it is too hot on Mercury to have liquid water there, let alone frozen water.
But when such a massive object as the Sun is nearby, not only temperature, but also gravity plays an important role. On average, Mercury is 60% closer to the star than Earth. However, the difference between the attraction of the Sun at the smallest and largest distances is enormous.
In addition, the shape of Mercury is an imperfect sphere: it is slightly flattened, and its elongated parts act as handles for which the Sun pulls the planet towards itself when it is at the minimum distance to the star.