It’s practically no secret to anyone that many celestial bodies revolve around the Sun, which, in addition to planets, also include their satellites, comets, asteroids and other particles. Modern scientists have managed not only to observe them through telescopes and other devices, but even to conduct research on their samples obtained through the use of probes. All this now allows us to confidently answer many questions about planets close to the Sun, their satellites and other celestial bodies.
General description of the planets of the solar system
In total, there are nine planets in our solar system. Each of them is distinguished by its astronomical and structural characteristics. Like the Earth, they all revolve not only around their own axis, but also around a common celestial body. The planets closest to the Sun are Mercury, Venus, Earth, and Mars. They are also commonly called "Earth group planets." Their common characteristics are relatively small size, the predominance of solid elements in the structure, the absence of rings, as well as a small number of satellites. After them come the planets of the Jupiter group, which includes Jupiter itself, as well as Saturn, Uranus and Neptune. They are characterized by a rather dense atmosphere, as well as light components surrounding the nucleus. Around each of them there are rings consisting of fragmented substances, and numerous satellites rotate. As for Pluto, it is constantly in the dark, and some of the scientists do not consider it a planet at all.
Mercury
Almost every student knows what is the closest planet to the sun. This is Mercury. In terms of size, of all representatives of the system, it is in eighth place. An interesting fact is that the satellites of Saturn and Jupiter (Titan and Ganymede, respectively) are larger in size. The diameter of Mercury is 4880 kilometers, and its orbit passes at a distance of almost 58 million kilometers from the Sun. Throughout history, only one ship flew to this planet (Mariner-10 in 1974-1975), so now there is information about only 45 percent of its surface. According to scientists, temperature fluctuations here are in the range from 90 to 700 about K.
The closest planet to the Sun is somewhat reminiscent of the Moon. The fact is that there is no tectonic plate in it , and on the surface there are a large number of craters and huge chasms. By such a parameter as density, Mercury in the system is in second place after the Earth. The magnetic field of this planet is weak. Its power in comparison with the Earth is one hundred times less. Mercury has no satellites, and you can even see it with the naked eye.
Venus
The second planet, judging by the distance from the Sun, is Venus. In the case when a criterion such as quantity is taken as the basis, it is in sixth place. Its diameter is more than 12 thousand kilometers, and the orbit passes 108 million kilometers from the Sun. The first spaceship that flew up to Venus was in 1962, the Mariner-2.
Compared to Earth, Venus rotates very slowly. Due to the synchronization of its orbit and the rotation period, only one side of this planet is always turned towards us. Very often, Venus is called the "sister of the Earth", due to their great similarity. Indeed, its diameter is 95% of our planet, and its mass is 80%. The density and chemical composition are also quite similar. At the same time, one cannot fail to note the fact that in many other parameters there are radical differences. There is every reason to believe that once upon a time there was a large amount of water on Venus, which boiled over time, so now it is completely dry. The planet does not have a magnetic field (due to slow rotation), as well as satellites. You can see it with the naked eye, because in our sky it is the brightest "star".
Earth
The third from the Sun is the Earth. Its diameter is 12,756.3 km, and the orbit passes at a distance of 149.6 million km from the heavenly body. Like other planets close to the Sun, it has a history of approximately 5.5 billion years. In the system, the Earth is considered the densest celestial body. Water covers 71% of its area. An interesting feature is that only here does it exist in liquid form on the surface. Scientists suggest that it is in this that the stability of temperature on our planet is largely connected. The only natural satellite of the Earth is the moon. In addition to her, many artificial bodies were launched into orbit.
Mars
In fourth place in terms of distance from the Sun and in seventh position in size is Mars. Its orbit is located at a distance of almost 228 million km from the celestial body, and its diameter is 6794 km. The first ship to fly to it was the Mariner-4 in 1965. Like other planets close to the Sun, Mars boasts a rather original and interesting terrain. There are many craters, ridges, planes and hills. The average temperature on Mars is about minus 55 degrees. It is possible to see it even with the naked eye. As for the satellites, this planet has two of them: Deimos and Phobos, which rotate near its surface.