Additional Data:

Diameter:

4.879 km

Average distance to the sun:

57.909.000 km

The mass of 1 kg weighs on Mercury:

344 g

One year on Mercury lasts vor:

88 days

One Mercury day lasts for:

58 days 15 hours

Temperature on the surface:

- 180°C bis 430°C

Orbital velocity:

47,7 km/s

Orbital inclination:

7,0049°

Orbital excentricity:

0,2056

Weight:

0,055 earth masses

Density:

5.427 kg/m³

Gravitational accelleration:

3,7 m/s²

Escape velocity:

4,3 km/s

Tilt of the rotaional axis:

0,034 °

Number of moos:

0

Number of rings:

0

 

Mercury is the smallest planet in the solar system, and he is also closest to the Sun. It can be observed with the naked eye, but because it orbits so close to the sun, it is often outshone by it during the day. Just before sunset or just before sunrise, you can make it out just above the horizon.

Mercury is so small that some moons of giant gas planets in the solar system are larger. It belongs to the group of rocky planets and has the highest average density next to Earth. Mercury has a liquid core, which is probably composed primarily of iron. This core occupies about 70% of the planet's diameter. It is believed that the planet lost much of its rocky mantle in a collision during its formation. The rock mantle around the core is 600 km thick. Mercury no longer shows any visible tectonic activity today. Because of its small volume, it continues to cool and its crust has contracted over the last 500 million years. The planet's crust, with its many overlapping impact craters, resembles the surface of the moon.

Mercury does not have a significant atmosphere. Traces of gases such as hydrogen, helium, oxygen, but also calcium, potassium, sodium and even water vapor are present. These substances come partly from the surface of Mercury, but also from the Sun. The solar wind has not only brought helium to the planet, but also contributed to the dark color of the surface. Recent research shows that, like the Moon, ice could also occur in craters on Mercury. These craters are usually located at the poles, where the ray of sunlight never falls. On Mercury there are no seasons in the earthly sense. The planet's axis of rotation is almost perpendicular, which means that solar radiation hardly changes over the course of its year. The eccentricity of its orbit has a much greater influence, which means that as the distance to the Sun changes, so does the amount of irradiation and therefore the temperature on the surface. On Earth, on the other hand, this effect is small.

Mercury has a magnetic field, but it only reaches one percent of the strength of the Earth's magnetic field. It is not known whether the magnetic field is created by currents of hot magma within the still-liquid iron core, or whether the planet's rock is still magnetized by an earlier magnetic field. Even according to the new definition, Mercury is still considered a planet, even though it is so small. Unlike the next class - the dwarf planets - Mercury does not have to share its orbit with any other celestial body of significant mass.

Mercury is always close to the Sun. If you want to observe it, you usually succeed after sunset. It is often found near the horizon and looks like a bright star that rises and falls rapidly over the course of a few nights. To get to Mercury, a spacecraft must decelerate almost as much as it would have to accelerate to Jupiter. Many probes only visit Mercury for a short time because it is very hot near the Sun and because they gain momentum there on their way to the outer solar system by flying by. So far, Mercury has not been approached by a manned spacecraft.

In the 3rd millennium BC, the Sumerian astronomers in Mesopotamia described the planet Mercury, which they then called Ubi-idim-gud-ud. Until the 6th century BC, two names were used for the planet Mercury. In the evening sky he was called "Hermes" after the Greek messenger of the gods and in the morning sky he was called "Apollo" after the Greek god of light and arts. The name "Mercury" goes back to the Roman messenger of the gods, Mercury. He was also the god of trade and thieves. The people of antiquity thought they recognized the god's speed in the rapid rise and fall of the planet.

In 1610, the Italian astronomer Galileo Galilei observed Mercury through a telescope for the first time.

In 1644, Johannes Hevelius discovered the phases of Mercury.

In 1915, Albert Einstein used his theory of relativity to predict the correct orbit of Mercury more accurately than was previously possible.

In 1984, NASA's Mariner 10 spacecraft photographed almost half of Mercury's surface during three flybys.

The European-Japanese space probe Bepi Colombo is currently on its way to Mercury. In 2025, it will enter orbit and deploy two research satellites.