In the solar system there are four objects that are commonly called planets of the earth group: Mercury (the smallest), Venus and Mars, and the Earth (the largest). They are also called internal, solid-state, contrasting with external gas giant planets.
General characteristics
The facts about the terrestrial planets mainly concern their objective, visual characteristics, due to the fact that the physical presence of a person is possible so far only on one of these cosmic objects - the Earth.
It is known that these celestial bodies have a significant density, consist of iron and silicates, as well as oxygen, silicon, magnesium, aluminum. The facts we know about the terrestrial planets say that all these objects have a certain structure. In the center is a core containing iron and nickel. Then is the mantle, which includes silicates. It is covered with bark, also consisting of silicate rocks, but enriched with other elements. Mercury has no crust, which was, as scientists suggest, the result of meteorite bombardments of a space object. Earth and Mars have satellites. Mercury and Venus do not have them.
Earthy
Most scientists believe that the best conditions for the emergence of biological life exist precisely on the planets of this group. That is why the search and comprehensive study of these space objects attracts increased attention of scientists from all countries. An example of terrestrial planets is the so-called super-earth. According to 2012 data, more than fifty of them were discovered. On each of them, according to scientists, the emergence of life is theoretically possible.
Earth Planet Facts
But back to the solar system. Native Earth - the third in a row from the Sun. It is the largest of the solid-state planets in terms of density, diameter and mass. We learn a few facts about our planet:
- Today it is the only cosmic body known to man on which biological life is discovered.
- Earth formed a long time ago - over four and a half billion solar years ago. And life on our planet appeared, according to most scientists, about half a billion years after that.
- Together with the magnetic field, the ozone layer attenuates harmful solar radiation. This is one of the conditions for the possibility of life on the planet.
- The Earth's crust is made up of tectonic plates moving at a speed of several centimeters per year!
- Over 70 percent of the planet’s surface is water. Sushi accounts for less than 30 percent. Water is vital for all known living forms.
- The poles of the planet cover Arctic ice and the Antarctic shield from ice.
- According to some scientists, the Earth can maintain the living conditions of biological organisms for a rather long time: more than two billion years. Unless, of course, you try to artificially violate these conditions (as a result of the harmful and thoughtless activities of man and his impact on the biosphere).
- Our planet orbits the Sun in about 365.26 days, which is a sidereal year.
- The moon, the satellite of the Earth, causes the phenomenon of the tide, and also stabilizes the earth's axis, gradually slowing down the rotation of our planet.
- The fall of asteroids has repeatedly caused the extinction of various species of organisms, leading to significant changes in the biosphere. These and other facts about the terrestrial planets became known thanks to the activities of scientists who are constantly studying the processes occurring in the solar system.
Mars
- Everyone knows that they called the god of war. Another common name is Red Planet (due to the shade of the surface, which gives iron oxide).
- The atmosphere of Mars is rarefied. The surface has volcanoes, valleys, deserts. At the poles - ice caps.
- Two satellites of this planet of the earth group are known. Interesting facts related to Phobos and Deimos: that was the name of the sons of the god of war (translated as “fear” and “horror”). Their sizes in comparison, for example, with the Moon, are small. Both are irregular in shape.
- What other interesting facts about the terrestrial planets exist? The Egyptians called Mars - Red Mountains, in Babylon it was known as the Death Star, the Jews called the planet - the One who blushes. The cause in all cases was the bloody tint of this celestial body.
- The month of March is named after Mars.
- Interestingly, water cannot exist on this planet in liquid form due to the sparseness of the atmosphere. But it is present in the form of ice. This made it possible for scientists to suggest that life once existed on Mars.
- A person who entered Mars without a special spacesuit would die instantly, since at very low pressure all the oxygen in the blood would turn into bubbles.
- There is no ozone layer in the planet’s atmosphere. There is very strong radiation, fatal to humans.
- The wind speed in dust storms on the planet reaches 200 kilometers per hour.
- Some scientists believe that intersecting canyons on the surface of the planet are of man-made origin.
Venus
This celestial body also belongs to a class called the "Earth group planets." Interesting facts about studies of its composition and surface have attracted the attention of many scientists at all times. Consider the main ones:
- Venus is the brightest of the planets. On a clear moonless night, it is capable of casting a shadow on the earth's surface.
- Venus has no satellites, like Mercury. Its sphere is almost perfect, in contrast to the earthly, flattened.
- The Sun cannot be seen from the surface of Venus due to constant clouds. Also, there is no change of seasons as such.
- Scientists suggest that previously there were large reserves of water on Venus, but it has long evaporated as a result of increased solar radiation.
- Life on Venus is impossible because of the very high temperature.
- A day on the planet lasts a little less than an earthly year!
Mercury
Consider another 2-3 interesting facts about the planets of the earth group.
- Mercury is the smallest (according to 2006, when Pluto lost the status of a planet) and the planet closest to our main body, the solar system.
- This body is the least studied. So, scientists only in 2009 made complete maps of the surface of this celestial body.
- A day on the planet is twice as long as a year!
Here are another 2-3 interesting facts about the terrestrial planets:
- Deimos, the satellite of Mars, rises and sets twice a day.
- When Mars comes close to Earth, the largest number of UFO sightings is recorded.
This is how the planets of the earth group can be described. All the facts about space provided by scientists have recently attracted great interest among the general public. This is due to the possibility of biological life on other planets and the ever-increasing ability of mankind to comprehend the secrets of the universe.