The earth

Introductory text to the planet Earth

The Earth The Earth is the third planet in the solar system and at the same time the only celestial body on which life could be proven. As the fifth largest planet, the earth orbits the sun on an elliptical orbit in 365 days and six hours. One day lasts 23 hours, 56 minutes and 4 seconds. This corresponds to the time that the planet needs for a complete self-rotation, or in other words, to turn around on its own.

On Earth, temperatures range from -89 ° C to + 58 ° C, which are the absolute extremes. The mean air temperature is approx. + 15 ° C. This puts it in an optimal temperature range for the development of life. Because the axis of rotation of the earth is inclined by 23.5 °, solar rays reach the different latitudes at a different angle of incidence. The steeper the sun's rays hit the Earth's surface, the more radiant energy is released. The angle of inclination of the axis of rotation is responsible for the emergence of the seasons.

The moon

With the moon, the earth has a faithful companion. One speaks also of the Erdtrabanten (Trabant = companion). According to the now common theory, collided in the early phase of the solar system, a protoplanet with the earth. The enormous impact threw rock material into orbit, which formed the moon within a short time. Today, the moon is about a quarter of the Earth's mass.
The Moon - Loyal Companion of the Earth In addition to the solar and lunar eclipses, the moon is also responsible for the tides on Earth. While the Trabant revolves around the earth, its gravitational pull causes the mass of water to shift. Furthermore, the moon stabilizes by its gravity, the axis of rotation of the earth. Without the moon, the Earth's axis would fluctuate more, with the result that temperatures on Earth would become noticeably more extreme, both in the minus and plus ranges. For the development of life on earth, the moon should have played a not to be underestimated role.

The atmosphere of the earth

Compared to all other planets in the solar system, the Earth has an atmosphere of sufficient oxygen. About 21% of the earth's atmosphere is oxygen, while nitrogen accounts for the largest share of 78%. Originally, there was no oxygen in the Earth's atmosphere. Only photosynthesizing cyanobacteria and later also plants enriched the atmosphere with oxygen through their metabolism. The process of photosynthesis is about 3.8 billion years old and has enabled a life in its present form.

The atmosphere has another important role to play. Billions of small meteorites enter the Earth's atmosphere every day and burn up. Without atmosphere the earth resembled a permanent theater of war, as it would be exposed to the constant meteorite impacts. Only very large meteorites or asteroids reach the earth's surface without completely burning up. Most recently, an asteroid struck in 1908 in Siberia (Tunguska event) and destroyed an area of ​​2100sqm. The explosive energy exceeded that of the atomic bomb dropped by Hiroshima by more than a thousand times. Even in 7000km away Central Europe, the pressure wave was felt.