What is the planet? Astrophysics
The Planets: Some luminaries influenced by the gravitation revolve around the sun in the space through certain orbits maintaining a particular duration are called planets. They have no light or heat of their own. The number of planets in the solar system is 8. They respectively stay from the sun in accordance with their distance, namely Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. Jupiter is the largest among the planets and the Mercury is the smallest planet in the solar system.
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| Our solar system |
Mercury: Mercury is the closest planet to the sun and the smallest planet in the solar system. Its diameter is 4,850 kilometers and its weight is equivalent to three-fiftieth of the earth. It orbits the sun once in about 88 earth-days. The average distance of it from the sun is 5.8 crore kilometers. It has no natural satellites. Its temperature is very high since it is the closest planet to the sun. Many holes and mountains with level ground have been noticed on the surface of Mercury. Mercury surface area is 74,800,000 square kilometers.
Venus: Venus is the closest to the Earth and its position is the second from the sun by distance. It is 10.8 crore km away from the sun and only 4.3 crore km from the Earth. We find it in the western sky as the evening star, and at dawn as vesper in the eastern sky. It orbits the sun once in 225 earth days. It has no natural satellites. Like earth, Venus has a substantial atmosphere but has no oxygen in it. The presence of carbon dioxide gas is about 96%. This planet orbits on its own axis very slowly. Therefore, the sun rises and sets twice a year in its sky. Acid rain showers due to the dense cloud of carbon dioxide in this planet. It is much drier than the earth, and the pressure of air is ninety times stronger in its atmosphere than that of the earth. Its surface area is 460,230,000 square kilometers and diameter is 12,104 kilometers.
The Earth: The Earth is the third closest planet to the sun. It has an area of 510,100,422 square kilometers. Its diameter measures 12,752 km in the East-West and 12,709 km in the North-South. The average distance of the earth from the sun is 150 million km. It orbits the sun once in 365 days 5 hours 48 minutes and 47 seconds. This planet has sufficient oxygen and nitrogen as well. The average temperature of the surface of the earth is 13.90°C. It has necessary water on its crust. Of all the planets, the Earth is the only planet which is ideal for living for the creatures and plants. It possesses one natural satellite, the moon, the only large satellite of a terrestrial planet in the solar system. The average distance of the Earth from the Moon is 381,500 km. It orbits the Earth once in 29 days and 12 hours. Holes, mountains, hills have been observed in the rear part of the Moon.
Mars: Mars, after the Earth, stands close to the Sun by distance. Its average distance from the sun is 22.8 crore km and 7.8 crore km from the Earth. Its diameter is 6,779 km and its weight is equivalent to one-tenth of the Earth. It has an area of 144,798,500 square kilometers. It takes 687 days to orbit the Sun, and it orbits once on its own axis in 24 hours and 37 minutes. It has two tiny natural satellites (Deimos and Phobos). Living is impossible here. It possesses an atmosphere containing 3% of nitrogen and 2% of argon gas. The amount of water is very scant here. It is colder than the Earth and its average temperature is below the freezing point. Its surface is peppered with gorges and vast volcanoes. Its red color comes from iron oxide (rust) in its soil.
Asteroids: Numerous small planets are orbiting together in between Mars and Jupiter. There is no other planet in this extent. A luminary with a diameter less than 1.6 km to 805 km is called 'asteroid'. They are called asteroids in a body.
Jupiter: Jupiter is the largest planet of the solar system. It stands fifth from the sun by distance. Its measure is equivalent to about 1300-fold of that of the Earth that is, it has an area of 61,419,000,000 square kilometers. Its diameter is 139,822 km. It is about 77.8 crore km away from the sun. Jupiter orbits the sun once in 12 years and on its own axis in 9 hours and 53 minutes. The sun rises and sets in this planet twice in one earth-day. It possesses a dense atmosphere. The up-level temperature of this planet's surface is very low and its internal temperature is very high. It has 67 satellites of which Ganymede, Callisto, Lo and Europa are the most important.
Saturn: Saturn is the second largest planet of the solar system. It has an area of 42,700,000,000 square kilometers and diameter of 116,464 km. It is 143 crore km away from the sun. It orbits the sun once in 29 years and 5 months and on its own axis once in 10 hours and 40 minutes. Saturn is larger than the Earth by 9-fold approximately, and it can be watched with open eyes. It possesses an atmosphere containing mixture of hydrogen and helium, methane and ammonia gases. Three bright belts have surrounded Saturn. It has 62 satellites of which Capitas, Tethis, Hua, Titan, Enceladus are to be mentioned.
Uranus: Uranus is the third largest planet. It is 287 crore km away from the sun. It orbits the sun once in 84 years. Its average diameter is about 49,000 km. Its volume is larger than Earth by 64-fold and its weight is heavier than that of the Earth by 15-fold only. Its atmosphere possesses a vast amount of methane gas. It has 27 satellites of which the largest ones are Miranda, Ariel, Oberon, Unbriel and Titania, etc. It is discovered that Uranus has belts like Saturn.
Neptune: Neptune's average diameter is 49,244 km. It is 450 crore km away from the sun. It has an area of 17,618,300,000 square kilometers. This planet is cold since it stays much far away from the sun. It is largely bluish to look at. It orbits the sun once in 165 years. It has 14 satellites -Triton and Nereid are its significant satellits. Neptune is accompanied in its orbit by a number of minor planets termed Neptune Trojans.
What is the largest planet in our solar system?
- Jupiter is the largest planet in our solar system.
What is the smallest planet?
- Mercury is the smallest planet in the solar system.
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