Solar System and Earth

Every day we see the Sun, the moon and stars in the sky. All these celestial bodies are a part of our huge universe.

The Sun, the Earth, the Moon and the planets form our solar system. The Sun is the star at the centre of the solar system, and it is a big ball of fire and gas. The Sun shines through its light.

Let us learn more in detail about the solar system and its planets.

Our Solar System and its Planets

Our solar system consists of eight planets. Their names are – Mercury, Venus, Earth, Mars, Jupiter, Saturn, Neptune and Uranus. The celestial bodies, which move around stars are called planets. The celestial bodies, which move around planets are called satellites. The moon is a satellite of the Earth. It moves around the Earth.

Natural and Artificial Satellites

The celestial bodies moving around the planets are known as satellites. There are two types of satellites: Natural and Artificial Satellites.

Natural Satellites

The satellites moving around the planets are known as natural satellites. The moon is a natural satellite of the Earth. The moon moves around the Earth.

The increasing and decreasing of the lit part of the moon is called the moon’s phases. The Indian calendar is prepared on the basis of the two phases of the moon. Each phase lasts for fifteen days. Based on the moon’s phases, horoscopes or cycles of zodiac signs are also prepared, dates are counted, and the Indian calendar is made.

  • The fortnight between Full Moon and New Moon is called Krishna Paksha.
  • The fortnight between New Moon and Full Moon is called Shukla Paksha.

Artificial Satellites

Artificial satellites are also called man-made satellites.

Man has made many satellites of the Earth. These satellites keep orbiting the Earth and taking images of the Earth. These artificial satellites are used for forecasting weather and other information related to forest fires. Some artificial satellites have also been sent into space, which helps transmit information from one corner of the world to another.

Our Planet Earth

Our Earth is the only planet to have life on it. This is possible because of the air and water on the Earth. Our Earth is spherical or geoid in shape and has two poles – the North and South Pole. These two poles revolve around the Sun in a fixed orbit path. The Earth moves on its axis.

  • A rotation causes day and night.
  • The spinning of the Earth around its axis is called rotation.
  • The Earth takes 24 hours to complete one rotation on its axis.
  • A revolution causes a year.
  • When the Earth moves around the Sun in orbit, its fixed path is called revolution.
  • The Earth takes 365 days and 6 hours to complete one revolution around the Sun.

Increasing and decreasing distances of the Earth from the Sun causes an increase and decrease in temperature. This also makes seasons.

  • When the Earth is close to the Sun, it is hot and is called perihelion. This occurs in January.
  • When the Earth is away from the Sun, it is cold and is called aphelion. This occurs in July.

The Earth is tilted on its axis. There is night for six months on both the poles and day for the next six months.

  • From 21st March to 23rd September, days are long, and nights are short in the Northern hemisphere.
  • From 23rd September to 21st March, the Sun remains for more time in the Southern hemisphere.

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