Space is hostile to living beings. It is too cold or too hot, there is no air in it, it is empty and lifeless. Therefore, the appearance of the Earth, which became the home of humanity and an unimaginable number of other biological life forms, looks like a real miracle. Many favorable factors converged that allowed life to arise: the optimal distance to the Sun, the appearance of a magnetic field, the atmosphere, oceans and continents.
Currently, most of the area of the planet Earth is covered with land and water suitable for life, only some areas with a harsh climate resemble desert space, however, even there there are animals. It is difficult to imagine that the Earth was once a hot cloud of indefinite shape, consisting of cosmic particles and gas.
Birth of the World
According to the accepted theory, about 13.7 billion years ago there was a colossal explosion that scattered across space an unthinkable amount of energy and matter. This is how the universe was born. At first, it was a completeraging fire and was heated to a billion degrees. The particles of matter had too high energy and repelled each other. But gradually the Universe cooled down, atoms of helium, hydrogen and star dust began to appear, accumulating in nebulae, which became the foremothers of future stars and planets.
Earth
Planet Earth appeared in the same way as all celestial bodies, from a gaseous nebula, which began to shrink about 4.5 - 5 billion years ago. What caused the compression, it is impossible to say for sure. A popular version is that the Earth was helped by a powerful shock wave from a supernova that erupted a few light years away. The mass and area of the planet Earth increased due to the gravitational attraction of comic particles and gases, which fell at great speed. The birthing planet was a ball with a red-hot gut.
The appearance of water and land
Bubbling gases along with lava burst out, a primary atmosphere appeared. The whole Earth was covered with volcanoes and shrouded in gas clouds with a high content of water, which condensed and fell as rain, but evaporated again, touching the lava and the hot surface. The active volcanic period lasted two billion years and subsided approximately three billion years ago.
The planet was gradually cooling down. Solidified lava formed its land, and water vapor from the atmosphere and melted ice that fell intoto the surface, along with asteroids and comets, turned into liquid. The area of the planet Earth in those days was already commensurate with the current one, but the first oceans were much smaller than modern ones. Volcanoes still erupted for a billion years, but not so violently. The period of geological formation of the Earth began. The planet was literally leveled by water and winds. Extinct volcanoes disappeared, plains appeared.
Supercontinents Time of the Titans
According to authoritative scientists, the continents do not stand still, but are constantly drifting. Moreover, every 500 years they converge into a single supercontinent. The last of these supercontinents existed 200-250 million years ago. He was given the name Pangea, which means "all-earth" in Greek, its shores were washed by a single ocean Panthalassa. The total areas of Panthalassa and Pangea were equal to the total area of the planet Earth.
Children of Pangea
Approximately 170 - 200 million years ago, Pangea, for reasons that are not entirely clear, split into two parts, which, in turn, broke up into several tectonic plates. Continents and oceans were born in geological pains, the area of the entire land of planet Earth was redrawn. Evidence and eloquent traces of these grandiose processes are island arcs, rearing mountain ranges, and oceanic depressions. The continents continue to move closer, but the speed of their movement is negligible compared to their size - only a few centimeters per year. It is estimated that they will converge again into a supercontinent in 250 million years.
Solar system
But the presence of an atmosphere, a water shell, a sufficient amount of light and moderate temperatures is primarily due to the location of the Earth relative to the Sun. After all, life is possible only on one of the eight planets of the solar system. Depending on the structure, all the planets are divided into two groups and distributed as follows according to the distance to the Sun.
Terrestrial planets:
- Mercury is 58 million kilometers from the Sun. The smallest planet in the system has a very rarefied atmosphere, which causes incredible temperature fluctuations on the surface, which range from +430 ° C to -190 ° C.
- Venus - 108 million kilometers. The density of the atmosphere of this planet is ninety times greater than that of the earth. Venus is a real greenhouse, the temperature of its surface heats up to 460 ° C, so water cannot remain in a liquid state, therefore life is impossible.
- Earth - 149.5 million kilometers. Ideal conditions for life. The mass and surface area of planet Earth is greater than each of the terrestrial planets.
- Mars - 228 million kilometers. The carbon dioxide atmosphere of Mars is 500 - 800 times less dense than the Earth's atmosphere. The Martian surface is not able to maintain the temperature regime necessary for life. Mars is a very cold planet, at night frost reigns on its surface down to -100 ° С.
Gas giant planets:
- Jupiter - 778 million kilometers. The largest planet in the solarsystems. Its mass is two and a half times the total mass of the other seven planets, and its area is almost 122 times the area of the planet Earth. Jupiter is predominantly made up of helium and hydrogen.
- Saturn - 1.43 billion kilometers. The density of this planet, which is known for its amazing rings, is less than the density of water.
- Uranus - 2.88 billion kilometers. The coldest planet in the system, the temperature on the surface of Uranus drops to -224 ° C.
- Neptune - 4.5 billion kilometers. The planet farthest from the Sun has an atmosphere composed mainly of hydrogen and helium with a dash of methane. Neptune, like Uranus, is very cold, the temperature on it drops below 200 ° C.
Analyzing this information, one can once again be amazed at the coincidence of circumstances that made life on Earth possible. For a long time, scientists and science fiction writers assumed alien life on Venus and Mars, but research in recent decades has shown that this is unlikely. On the neighbors of the Blue Planet, the climate is too harsh, the density of the atmosphere is not suitable. There is no ocean that gave rise to the biosphere on Earth, and there is no powerful enough magnetic field to protect living beings from the deadly radiation of the Sun.
Earth: important numbers
They are:
- Diameter (average) - 6371 km.
- Equatorial circumference - 40,076 km.
- Volume - 1.081012 km3.
- Density (average) - 5518 kg/m3.
- Weight - 5.971021 tons.
- The speed of rotation around its own axis is 1675 km/h.
- The speed of rotation around the Sun is 107,000 km/h.
- Complete rotation around its axis - 23 hours and 56 minutes
- Revolution around the Sun - 365 days and 6 hours
What is the area of the planet Earth: the distribution of water and land
The distribution of water and land on Earth has developed clearly in favor of water. Rivers, oceans, lakes and reservoirs cover 70.8% of the planet. However, the remaining land is enough for the lives of billions of people. In exact numbers it looks like this:
- Total area of planet Earth (km2) - 510,000,000 km2.
- Land area - 149,000,000 km2.
- Land area respectively in the northern and southern hemispheres - 100,000,000 km2 and 49,000,000 km2.
- The average height of land above sea level is 860 m.
- The total area of water on planet Earth is 361,000,000 km2.
- The area of water, respectively, in the northern and southern hemispheres is 155,000,000 km2 and 206,000,000 km2.
- The average depth of the world's oceans is 3.7 km.
Interesting facts
In fact, humanity lives on a poorly studied planet, because the ocean occupies more than 70% of its area, but the ocean depths have been studied by barely 5%.
Scientists have calculated that the approximate mass of water on Earth is more than 1.31018 tons, but the share of fresh water is only 3% of this huge mass, and about 90% of it is in the state of ice.
About 90% of the world's ice and 80% of fresh water is stored in the Antarctic ice cap. This continentis the highest, its average height is 2.2 kilometers, which is two and a half times the average height of Eurasia.
The area of Eurasia is about 55,000,000 km2, that is, 37% of the land area, but over 5 billion people live in the Eurasian states, which is 71% of the world's population.
The area of the Pacific Ocean is larger than the total area of all continents and islands and is 35% of the area of planet Earth.
Almost a third of the earth's surface is covered by deserts.
Despite the high mountains and deep depressions, the surface of the Earth is very flat compared to its area. If the planet could be reduced to the size of a tennis ball, then the earth's surface would be perceived by the palm as perfectly flat.
