TNPSC Geography Notes - 6th Standard - Earth and the Solar System

Geography - 6th Standard - 
The Earth and the Solar System

The Earth and the Solar System

Without the help of the telescope we can see the five planets namely Mercury, Venus, Mars, Jupiter, and Saturn. On the other hand Neptune and Uranus can be seen only through a telescope. Before Sunset or Sunrise we can see Mercury and Venus for a few hours. These two planets appear only on the horizon.

The Morning Star - Venus

Venus rises a few hours before sunrise and therefore it is nicknamed as the "Morning Star". 

The Solar System

Solar family consists of the Sun, its eight planets, the satellites like the moon that revolve around the planets, dwarf planets, thousands of asteroids, meteoroids and comets, this called Solar System.

The solar system has eight planets. All planets revolve around the Sun. The Earth also a planet. Different kinds of life including human beings are found on Earth because the Earth's atmosphere has Oxygen. 

The Eight Planets are classified into Solid and Gaseous planets. other the Earth there is no Oxygen and gases, life does not exit in these planets. The moon revolves around the Sun. Thus it appears that all the planets move with the stars as a backdrop.

Solid Planets

Mercury, Venus, Earth and Mars

Gaseous Planets

Jupiter, Saturn, Uranus and Neptune

Hot Planets

Mercury and Venus

Cold Planets

Mars, Jupiter, Saturn, Uranus, and Neptune

The Elliptical Path and Orbit

All planets appear to move in an anti-clockwise direction. The planets which revolve around the sun, do not deviate from their respective paths. All planets revolve around the Sun in an Elliptical Path, approximately at the same plane. The path that the planet takes to revolve around the Sun is called "Orbit"

The Sun

Sun is the head of the Solar family. It is a large gaseous ball of fire. The gravity of the sun holds the Solar system together. Sun is the source of heat and light for the entire Solar family. The Earth is approximately 150 million km away from the Sun. No planets have light of their own, they reflect the light of the Sun.

The Rings of the Saturn

The Rings of the Saturn, consists of small stones, dust and ice particles. Only the Saturn Rings are Magnificent. Jupiter, Uranus and Neptune also have Rings.

Dwarf Planets

The Dwarf Planets are very small in size, smaller than our moon. Pluto, Charon, Ceres, Eris were newly grouped as Dwarf Plants in the year 2006.


Thousands of asteroids are found between Mars and Jupiter. Asteroids are clusters of celestial bodies which include tiny stones and big rocks that measure about 300 to 400 km in diameter. 

Asteroids have Indian Names

Some asteroids have Indian Names, Vynu Paoou - The Astronomer, Sarabai - Father of Atomic Energy, and Ramanujam - Mathematician.

The Moon

The Moon is not a planet, it is natural satellite of the Earth. The moon does not revolve around the Sun, it revolves around the Earth. Hence it is called a satellite.  Moon revolves around the Earth approximately at a distance of 3,84,401 km. It takes 27.3 days for the moon to revolve around the Earth and 27.3 days for the Moon to rotate on its axis. 

The Meteoroids

The sudden streaks of light seen on a starry night is called Meteoroids.

The Comet

A comet is not a star. It is rock made of dust and ice. The long tail is seen because as the comets come near the sun, the ice melts and reflects the light of the Sun.

The Universe

Millions of constellations of stars seen in the sky is called a Galaxy. Thousands of galaxies form the Universe. The Universe is vast and ever expanding. 

Milky Way Galaxy

Milky Way galaxy is one among the many Galaxies. Millions of stars, including the Sun and other celestial bodies which can be viewed with our eyes belong to the Milky Way galaxy. Milky Way galaxy is a dense cluster of stars. 

Earth - The Living Planet 

The Earth is the third planet from the earth. Land, water, air, and heat are available in the optimum level only on the Earth. Earth is called a "Living Planet" because of life of found in abundance only on this planet.

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