Mercury is the planet closest to the Sun. Conditions here could not be considered comfortable as temperatures vary between minus 180┬░ and plus 400┬░ Celsius, depending on the season. This great temperature range of almost 600┬░ Celsius is not found on any other planet.
Mercury was named after the Roman god of trade. It is a rocky planet, which can be compared to the Moon, as both have many craters. They are, however, thought to originate from different periods of the history of our universe.
Mercury has a diameter of 4880 kilometers. It is the second smallest planet of our solar system. Only Pluto is smaller than Mercury. Its mean distance from the Sun is 59 million kilometers. However, due to its extremely eccentric orbit, the actual distance is between 46 and 70 million kilometers.
As Mercury is closest to the Sun, it is exposed to the strong gravitational_forces of the Sun and orbits at a high velocity. Its average speed is 48 kilometers per second. It takes Mercury about 88 days to complete a full revolution about the Sun. Mercury circles the Sun in 88 days, while radar measurements have shown that one rotation on its own axis takes 58.7 days. While orbiting the Sun once it rotates one and a half times on its own axis.
As Mercury is never far from the light of the Sun, it can only be observed from Earth for a short time at dusk. Observations with a telescope are a disappointment for the viewer. The Mariner 10 space_probe passed the planet Mercury in 1974 and 1975. It transmitted the first image of the planet's surface to the Earth. It also provided data, which led to the discovery of Mercury's magnetic_field, which is one hundred times weaker than that of the Earth.
In 1991, powerful radio_telescopes were used for further exploration. Huge areas of ice were found at the poles of the planet.
