Planet
Planets revolve around the Sun. They have their own long financial path. Which is called orbit. The movement around its axis is called rotation and the motion around the Sun is called parikrama. They have their own speed. Stars like planets, they have no light and heat of their own. These (stars) shine with the brightness of the Sun. Where there are no planets, the stars keep twinkling. The Greek word planet used for the planet is the Greek word plantes. It is composed of. Which means wanderer. Therefore, the planet is a symbol of constant movement or change in its position.
1. Inner Planets or Earth Planets
The inner planets include Mercury, Venus, Earth and Mars. The inner planets are relatively smaller and more dense. Of these, Earth is the largest and densest. All the inner planets are made of rocks and metals. They are also called terrestrial planets. Because it is similar to Earth. Under the inner planets, Mercury, Venus, Earth and Mars come.
(i) Mercury
It is the closest planet to the Sun. thhe smallest planet in the Solar System. It is slightly larger than the Earth’s satellite Moon. Mercury revolves around the Sun in 88 days and its axis in 59 days. There is no satellite.
Mercury has no atmosphere. The surface of Mercury is rocky and mountainous. One of its surfaces receives maximum light and heat from the Sun. And its other surface does not receive heat and light from the Sun. One part of Mercury is very hot and the other. The part is very cold. Its gravity is 3/8th that of the Earth.
Because Mercury is closest to the Sun. Therefore it is very difficult to observe. It remains hidden from the Sun’s glare for a long time. Therefore it is visible in the morning star in September and October before the Sun rises. After the sun is hidden in the region, as seen in the twilight star.
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(ii)Venus
Venus has no satellites of its own. It moves from east to west around its pole. Venus is like the moon in appearance. It is equal to Earth in size and weight. Venus’s mass is 4/5 times that of Earth. It takes 243 days to revolve around the Sun. CO2 is present in the atmosphere of Venus. Very little amount of oxygen and water vapor is found in Venus. 3/4 of the sunlight falls on the dim atmosphere of Venus. This is because the planet Venus appears brighter in the sky after the Sun and the Moon.Sometimes the planet Venus is visible in the eastern sky before the sun rises. And sometimes it appears in the western sky after the sun sets. Hence it is called morning and night star.
(iii) Earth
Our earth revolves around its pole from west to east at a speed of 1610 km/h. It takes 23 hours 56 minutes 4.09 seconds to make one revolution. Earth is tilted 23° 26’59” latitude from its axis. Day and night occur as a result of rotation at this pole of the earth. Our earth rotates from west to east. Our earth is more or less round. And it is slightly flattened from north to south. Because of its flattening, the shape of the earth is called sphere.The closest to Earth is the planet Venus. It is the 5th place in size. Earth is almost similar to Venus in size and composition. Earth appears blue green from space due to water and terrestrial grasses. That’s why it is also called blue planet.
Earth’s mass and density are 5.97 × 10²⁴ and 5.52 g/cm respectively. Earth takes 365 days, 48 minutes and 45.51 seconds to orbit the Sun. And it revolves around the Sun at a speed of 107160 km/h. It moves in its orbit in a long circular orbit around the Sun at a latitude of 661/2°. Internally, the Earth is composed of Sial (Silica + Aluminium), Sima (Silica + Magnesium), Nife (Nickel + Iron Eye) Its surface is covered with gases like a sheet, which is called air.Only Earth is such a planet. Where some special atmospheric conditions are responsible for keeping life continuously alive. It is in direct direction from the Sun. Hence this direct thermal boundary which crosses the ozone layer into water, soil, minerals, suitable atmosphere.
Our only natural satellite – Moon
The rotation of the smaller body around the larger body is called a satellite. The moon, when it revolves around the earth and is related to the sun, changes in day and night. As a result, the respective positions of the moon change daily. Like the moon appears different each night. The moon revolves around the earth on its axis in 27 days and 7 hours and in the same amount of time. So it has the same surface as seen from our earth. There is no atmosphere on the moon. There is no water on it. The diameter of the moon is 1/4 times that of the earth. The moon is about 384400 km away from the earth. Light converts from the moon and reaches us in only 1 or 1/4 second. Edwin Evdren ,Neil Armstrong and Colin reached the Moon for the first time on July 21, 1969. They found the Moon’s surface to be dusty and barren. There are many attars of various sizes. There are a large number of plateaus and high mountains on the Moon. These are the surface of the Moon. casts a shadow.
During a full moon day – the Earth is between the Moon and the Sun. That’s why we see the entire surface of the Moon.
On the day of the new moon – the moon is between the earth and the sun. Hence the light of the sun falls on the moon. Due to which we can see its other surface. And we cannot see the moon.
(iv) Mars
It is the base of the Earth in size. But its mass is only 1/10 times that of Earth. It revolves around the Sun for 687 days in its orbit and 1 day on its axis. Oxygen particles have also been found here. It is lighter. It appears red. That’s why it is called the Red Planet. Small satellites of Mars are Phobos and Deimos. Nix Olympia The largest volcano found on this planet is Olympus Mons. Channels have also been found. If it is in the opposite direction of the Sun in the sky relative to the Earth, then on such days it is very close to the Earth.
outer satellite or jovian planet It is present on the outer side of the orbit of Mars. Large and light dense planets like – Jupiter, Saturn, Aroon, Varun come in this category. They are composed of gases like helium, ammonia and methane. Due to their similarity to Jupiter, they are Also called Jovian planets. They have many satellites like the Moon.
(i) Jupiter It is the largest planet in the Solar System. It takes 11 years and 11 months to orbit the Sun and 9 hours and 56 minutes to orbit its axis. It has 16 satellites. Its identifying factor is a large one. It is a smudge. It has been speculated that its environment is very complex.Its mass is much higher than the combined mass of other planets. Jupiter is the second brightest planet in the sky after Mars and a thin atmosphere is found on Mars. It is found because it converts the sun’s rays. It is believed that helium and hydrogen exist in the form of gases in Jupiter. The outer surface of its cloud is of methane gas while ammonia is present on it in the form of crystals.
(ii) Saturn Apart from Jupiter, Saturn which appears yellow. Its specialty is that it has three beautiful rings around it in the solar system. It takes 29 years 5 months to revolve around the Sun and 10 hours to revolve around its pole. It takes 40 minutes. It has 18 satellites. Saturn is the least dense of all the planets. Its density is less than water. It is similar to Jupiter in size, mass and composition. It is colder than Jupiter.
(iii)Arun(uranus) This is the first planet that has been discovered with the help of a telescope. This planet was discovered by William Herschel in 1781. Hydrogen and methane gases are found in the atmosphere of Aroon. Except Venus and all other planets like Aroon and other planets rotate in the same direction. .Like Venus, Aroon rotates from east to west. Its distinctive feature is that its rotation is highly inclined. As a result, it spins like a wheel. It takes 17 hours 14 minutes to revolve around the Sun. is satellite.
(iv) Varun (neptune) It was discovered by Sir William Herschel. It is based on Newton’s law of gravitation. Which was given by Newton 180 years ago. It takes 164 to make one revolution around the Sun and 16 hours and 7 minutes to make one revolution on its axis. This is because in olden times only 6 satellites were observed. These are the two planets discovered after telescope. They are used in astronomy. They have 9 satellites.