The Solar system

The Solar System

The Sun and the celestial bodies combining is known as the solar system. The sun is located at the centre, and all the planets revolve around it. There are eight planets in our solar system, along with a host of asteroids, comets, and meteors. The gravitational attraction between the sun and the celestial bodies maintains the revolving of these planets around the sun.

Like stars, planets are also celestial bodies; however, they are enlightened by the sun because they do not produce their own light. The solar system consists of eight planets. Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune are the planets in ascending order from the distance of the Sun.

Note: Pluto used to be counted as a planet till 2006. It was located at the farthest distance from the sun. Then in 2006, the International Astronomical Union (IAU) adopted a new definition of a planet in which Pluto does not fit. So, it is now eliminated from the solar family.

The Sun

It is a star that is nearest to us. It is the largest source of the emission of light and heat. Furthermore, it gives its light to all the planets revolving around it. It seems to rise in the east and set in the west as the earth rotates from the west to the east

The Planets

Planets look just like stars, but they do not have their own lights as the stars.  

• They continuously change their positions with respect to the stars
• A planet revolves around the sun in a definite path, which is known as orbit
• The time duration in which a planet completes its one revolution is known as the period of revolution. It increases as the distance of the planet increases from the Sun
• Besides revolving, the planets rotate on their axis too. The time duration in which a planet completes its one rotation is known as the period of rotation
• Some planets are known to have moons/satellites revolving around them. Any celestial body revolving around another celestial body is called its satellite. Usually, the term satellite is used for the bodies revolving around planets. e.g., the moon is a satellite of the Earth
• There are also artificial satellites revolving around the Earth. These are called artificial satellites.

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Planet Groups 

Planets can be divided into two groups:

• Inner Planets: It comprises the first four planets – Mercury, Venus, Earth, and Mars. These are much nearer the Sun than the other four planets. These have very few moons
• Outer Planets: It comprises planets outside the orbit of Mars – Jupiter, Saturn, Uranus, and Neptune. These are much farther off than the inner planets. They have many moons.

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Mercury (Budh)

• Mercury is the nearest planet to the Sun
• It is also the smallest planet in our solar system
• It is very close to the sun, which makes it invisible most of the time as it gets hidden in the glare of the sun. However, we can see it just before sunrise or just after sunset, near the horizon
• Mercury does not have any satellites

Venus (Shukra)

• Venus is located nearest to the Earth
• It is the brightest among all the planets
• It is also known as the morning and evening star because it can be seen in the morning, just before sunrise, and in the evening, just after the sunset
• It does not own any satellites
• Unlike the Earth, It rotates from East to West while the Earth rotates from West to East
• It appears in different phases, just like the moon.

The Earth (Prithvi)

The Earth is the only planet where life is known to exist. Some special environmental conditions are responsible for the existence and continuation of life on the Earth, such as distance from the Sun, moderate temperature range, the presence of water and suitable atmosphere, and a blanket of ozone.

• From space, the Earth appears blue-green as it is covered with 90% of its surface with water which reflects the light coming from the sun
• The Earth has only one satellite, i.e., the moon
• The earth is bent at both its poles, which is responsible for the change of seasons
• The plane of the Equator is called the equatorial plane, which is the plane of the equator and the orbital plane of the Earth that are inclined to each other at an angle of 23.5°. In this way, the Earth is inclined to its orbital plane at an angle of 66.5°

Mars (Mangal)

• The first planet outside the orbit of the earth, Mars.
• It is also known as the Red planet, as it is reddish
• It owns two small natural satellites

Indian Space Research Organization (ISRO) launched India’s first Mars orbiter mission – Mangalyaan, on November 5, 2013. It was successfully placed into the orbit of Mars on September 24, 2014. With this, India became the first country in the world to do so in its first attempt.

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Jupiter (Brihaspati)

• • It is the largest planet in the solar system. It is so large that about 1300 Earths can be placed inside this giant planet
  • It rotates rapidly on its axis

• Jupiter owns many satellites

• It is surrounded by faint rings

Saturn (Shani)

• • Saturn is the prettiest planet in our solar system, which appears yellowish
  • It is surrounded by four rings that are not visible with naked eyes
  • Saturn also owns many satellites

• Saturn is the least dense planet in our solar family. Its density is even lesser than the density of water.

Uranus (Arun) and Neptune (Varun)

• • These are located at the outermost orbits of the solar system
  • They can be seen only with the help of large telescopes

• Like Venus, Uranus also rotates from East to West

• The rotational axis of the Uranus is a highly tilted rotation axis. Due to its tilted rotation axis, it appears to roll on its side in its orbital motion.

Conclusion

You’ve probably heard that there are a number of artificial satellites orbiting the Earth. You may be wondering how artificial satellites differ from natural satellites. Artificial satellites are created by humans. They are launched from the Earth’s surface. They orbit the Earth much closer than the moon, the Earth’s natural satellite.

Several artificial satellites have been built and launched by India. The first Indian satellite was Aryabhata. Other Indian satellites include INSAT, IRS, Kalpana-1, EDU SAT, and others.

Artificial satellites have a wide range of applications. They are used for weather forecasting as well as transmitting television and radio signals. They are also used in communications and remote sensing.