THE EARTH & THE SOLAR SYSTEM

BASIC FACTS

• The full moon is seen only once in about a month’s time and the night called as Full moon night or Poornima. 

• A fortnight later is the New moon night or Amavasya which is the best night sky, provided it is a clear/cloudless night.

• We can’t able to see moon and all other bright tiny objects during day time because the very bright light of the sun does not allow us to see all these bright objects of the night sky.

• The various patterns formed by different groups of stars are called constellations. Ursa Major or Big Bear is one such constellation.

• One of the most easily recognisable constellation is the Saptarishi (Sapta-seven, rishi-sages). It is a group of seven stars that forms a part of Ursa Major Constellation. 

• In ancient times, people used to determine directions during the night with the help of North star/Pole Star which always remain in the same position in the sky indicates the north direction. 

THE SOLAR SYSTEM

• The sun, eight planets, satellites and some other celestial bodies known as asteroids and meteoroids form the solar system. 

• There are eight planets in our solar system. In order of their distance from the sun, they are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

• Jupiter, Saturn and Uranus have rings around them. These are belts of small debris. These rings may be seen from the earth with the help of powerful telescopes. 

• ‘Sol’ in Roman mythology is the ‘Sungod’. ‘Solar’ means ‘related to the sun’. The family of the sun is, therefore, called the solar system. 

• Aryabhatta was a famous astronomer of ancient India. 

• Neil Armstrong was the first man to step on the surface of the moon on 21 July 1969.

• Inner planets - very close to the sun. They are made up of rocks.

• Outer Planets - Very-very far from the sun and are huge planets made up of gases and liquids.

• Mercury is nearest Planet to the sun.

• Venus is considered as ‘Earth’s-twin’ because its size and shape are very much similar to that of the earth.

• The earth is the third nearest planet to the sun. In size, it is the fifth largest planet.

• From the outer space, the earth appears blue because its two-thirds surface is covered by water. It is, therefore, called a blue planet.

• The Moon is the only satellite of the earth having diameter only one-quarter that of the earth and is about 3,84,400 km away from us. The moon moves around the earth in about 27 days. 

• The Moon takes exactly the same time to complete one spin. As a result, only one side of the moon is visible to us on the earth.

• Till August 2006, Pluto was also considered a planet. However, in a meeting of the International Astronomical Union, a decision was taken that Pluto like other celestial objects (Ceres, 2003 UB313) discovered in recent past may be called ‘dwarf planets.”

Some useful Information about the Planets of Our Solar System

1. MERCURY One orbit around sun - 88 days, One spin on axis - 59 days.
2. VENUS - One orbit around sun - 255 days. One spin on axis - 243 days
3. EARTH - One orbit around sun - 365 days. One spin on axis - 1 day Number of moons - 1
4.  MARS - One orbit around sun - 687 days One spin on axis - 1 day, number of moons - 02
5. JUPITER - One orbit around sun - 11 years, 11 months about 12 years. One spin on axis - 9 hours, 56 minutes, number of moons - 16
6. SATURN - One orbit around sun - 29 years, 5 months. One spin on axis - 10 hours 40 minutes, number of moons - about 18.
7. URANUS - One orbit around sun - 84 years. One spin around axis - 17 hours 14 minutes, number of moons - about 17.
8. NEPTUNE - One orbit around sun - 164 years. One spin on axis-16 hours 7 minutes, number of moons - 8.

Asteroids

Apart from the stars, planets and satellites, there are numerous tiny bodies which also move around the sun. These bodies are called asteroids. They are found between the orbits of Mars and Jupiter . Scientists are of the view that asteroids are parts of a planet which exploded many years back.

Meteoroids

The small pieces of rocks which move around the sun are called meteoroids. Sometimes these meteoroids come near the earth and tend to drop upon it. During this process due to friction with the air they get heated up and burn. It causes a flash of light. Sometimes, a meteor without being completely burnt, falls on the earth and creates a hollow.

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