Mercury

Mercury

Introductory text to the planet Mercury

Mercury Mercury is the smallest planet in the solar system and at the same time the celestial body, with the shortest distance to the sun. As a rock planet, Mercury circles the sun in just 88 days. The temperatures are between -170 ° C and + 425 ° C. On no other planet in the solar system do temperatures fluctuate in such a wide range. And the planet also holds the record in terms of Bahnexzentrität. The orbit around the sun is highly elliptical. At its sunniest point, Mercury reaches the sun up to 45 million kilometers, at its most remote point there are 70 million kilometers between star and planet. This is a major reason for the strong temperature fluctuations.

Named after the messenger of the god Mercurius, the planet, as well as the other celestial bodies, owes its name to the Romans. No other planet orbits so fast around the sun, which is why the Roman naming is obvious. Incidentally, Mercurius is equivalent to Hermes in Greek mythology. But observing Mercury in the sky turns out to be extremely difficult. Only at dusk, or at a solar eclipse, can one recognize the planet. During the day, the sun prevents a view of the small planet.

Structure, atmosphere and surface

The surface of Mercury is quite similar to that of the Moon. Deep craters, with diameters of over 700km, testify to heavy impacts in the past.

The surface of Mercury

Unlike Earth, Mercury has no normal atmosphere that could possibly protect it from meteorites. There are two reasons for this: Gravity on Mercury is only 1/3 of Earth's gravity. This makes it easier for molecules to return to the exosphere. Furthermore, the strong solar winds prevent an atmosphere on Mercury from remaining long term.

In terms of structure, Mercury belongs to the earth-like planets. Inside the planet is a core of liquid iron and nickel. The surface mostly consists of silicates (see: silicon) and so Mercury, after the earth, is the planet with the highest density.

Mercury as a threat to the solar system?

Mercury's orbit is unstable and tends to become increasingly eccentric. This means that the orbit around the sun is getting bigger and bigger. Not only the sun exerts an influence on Mercury through its gravitational field. Each planet has a different strong gravitational field depending on its mass. The gas planet Jupiter, the most massive planet in the solar system, slowly pulls Mercury out of its orbit. In the long term, that could become a problem, namely, when Mercury crosses the orbit of the other planets. In the worst case, it comes to a collision. For the earth with dramatic consequences, especially when Mercury collides with our planet. It would also be conceivable that Mercury - instead of colliding with a neighboring planet - falls into the sun. In the best case, Mercury will slowly spin out of the solar system without hitting the sun or a planet. These scenarios are considered by astronomers to be very unlikely, if possible. For the moment, this can not be of any importance to humans, because before Mercury becomes a danger, 1 to 1.5 billion years pass.

Life on Mercury?

Size comparison: Earth vs. Mercury Although Mercury comes as close to the sun as any other celestial body, it is not the hottest planet. Venus reaches even higher temperatures. As already mentioned, Mercury has no atmosphere. Heat radiates comparatively quickly back into space. On Venus, an atmosphere of carbon dioxide not only provides better heat absorption but also a greenhouse effect.

Despite the temperatures of over 400 ° C, frozen water exists on the much cooler poles of Mercury. This suggests that microbial life may or may not have been possible there. Due to its proximity to the sun, this seems to be nothing more than an almost impossible hypothesis. The conditions on the planet are too extreme (temperature + high radiant energy) for microbes to survive for a long time. For humans, a manned mission would be deadly. So far, only two space probes have dared to make their way to Mercury.

Summary

Mercury is the smallest and sunniest planet in our solar system.

No other planet in the solar system has a larger temperature range (-170 ° C to 425 ° C).

In the distant future (> 1 billion years), Mercury could become a threat to the solar system. Its orbit increases, which inevitably crosses the orbits of other planets.