(ORDO NEWS) — The sun has a huge gravitational force that holds the planets around it and forms a whole system with them.
They revolve around the Sun and have certain characteristics depending on their position.
Scientists are constantly exploring the solar system and are constantly making incredible discoveries that help to better understand the structure of the universe.
What is the solar system?
The solar system is a group of celestial bodies, consisting of the Sun and many other astronomical objects revolving around it. These include planets, satellites of planets, asteroids and other bodies.
The solar system is not unique: to date, thousands of other planetary systems have been discovered. The solar system is located in the Milky Way galaxy in a region known as the Orion Arm.
Scientists have determined that its age is approximately 4.57 billion years, and it was formed as a result of gravitational compression of a gas and dust cloud.
Structure and composition
The main body of the solar system is, of course, the Sun. It makes up 99.86% of the mass of the solar system. To date, eight planets are known to revolve around the Sun.
The nearest four of them are terrestrial planets, and the remaining four are gas giants.
Between these two groups is a belt of asteroids called the main belt, and beyond the orbit of Neptune, the last gas giant, is another group of asteroids – the Kuiper Belt.
Planets of the solar system
The plane in which the Earth‘s orbit lies is called the ecliptic.
With a high degree of accuracy, it can be argued that the orbits of all the other planets lie in the same plane, the maximum deviation of 7 ° is observed for Mercury.
At the same time, all the planets rotate in the same direction, which is indirect evidence that the solar system was once a single entity.
The motion of the planets is well described by Kepler’s laws.
Inner planets
A common characteristic of the terrestrial planets is the presence of a solid mantle, over which the atmosphere immediately begins to form. They are relatively small and have very few or no satellites.
Mercury
The planet closest to the Sun is Mercury, the average distance between two celestial bodies is 58 million kilometers. In addition, Mercury is the smallest and fastest planet. Mercury has no natural satellites.
Venus
The next planet from the Sun is Venus. Venus has no satellites, but there is a theory that Mercury was once one of them.
Earth
The third planet from the Sun is Earth, the home of humanity. The distance of the Earth from the Sun is from 147 to 152 million km.
The Earth is distinguished from the terrestrial planets by a very large satellite – the Moon, whose radius is 1737 km.
Mars
The last planet similar to Earth is Mars. The Red Planet has two moons, Phobos and Deimos, but they are very small compared to the Moon.
The largest of them, Phobos, has an irregular shape and dimensions of 26.8×22.4×18.4 km.
Outer planets
This group includes four gas giants, which are located at a greater distance from the Sun than other planets. Their huge size is due to the low density and large amount of gaseous matter in their composition.
Jupiter
The largest planet in the solar system. Jupiter also has 67 moons, some of which are quite similar in size to the planets. For example, Ganymede is 8% larger than Mercury, and Io has its own atmosphere.
Saturn
The sixth planet known for its icy rings and rocky meteoroids. It orbits Saturn behind Jupiter. There are 62 moons around Saturn.
Uranus
The third largest planet in the solar system. Neptune’s surface is mostly ice with small amounts of helium and hydrogen.
Neptune
The eighth planet from the Sun was discovered not by observation, but by mathematical calculations. Neptune has 14 moons, but only one of them, Triton, is the largest. Its radius is 1353 km.
Ninth planet
Is it possible that there are other planets in the solar system beyond the orbit of Neptune that astronomers have not yet discovered?
The existence of the ninth planet can only be confirmed by visual observation, but calculations do not help even approximately determine its position.
Oort cloud
The Oort cloud is a hypothesis about the existence of a whole cloud of asteroids on the very outskirts of the solar system.
So far, there is no indirect evidence of its existence, but the behavior of many comets approaching the Sun speaks of its existence.
The outer edge of the cloud is considered the edge of the solar system, since the Sun’s gravity ends at this distance.
That is why objects in the outer region of the cloud can be strongly influenced by passing stars, as well as our own galaxy. It is their gravity that “pulls” comets out of their orbits and launches them on their way to the Sun.
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