Solar system
Cbse class 6, Social Studies
- Earth is the only planet which supported life
- Ozone protects us from the harmful rays of the sun.
- Origin of the universe has its root in Big Bang theory
- Universe is still expanding
- Solar system is present in the Milky way galaxy
- Planets evolved from Sun Debris
- Sun is a star formed 4.6 billion years ago
- Celestial bodies are all objects that exist in the sky
- Heavenly bodies are also called as Celestial bodies
- Celestial bodies include Sun, Moon, Asteroids, Meteors, Planets and Stars.
- Galaxy is an extremely large group of stars and planets; it extends over many billions of light year
- Distance travelled by light in one year is called as Light year
- It is used to measure the distance between celestial bodies in the universe
- Stars are made up of burning gases
- Star nearest to Earth is Sun
- The second nearest star is proxima centauri, which is 4.25 light years away from Earth
- Constellation is group of stars which form a pattern in the sky
- Some examples for constellation Orion, Ursaminor, Hydra, Canismajor
- The brightest star in the sky is pole star/ North star
- Sun is the main source of heat and light energy
- The light from the sun takes about 8 min 20 sec to reach the Earth`s surface
- Gravity keeps the planets in their orbits
- Sun energy drives weather and climate on Earth
- The word Planet is derived from a “planasthai” which means to wander
- Planets are not made up of burning gases
- Planets reflect the light they receive from the sun
- Planets move around the sun along the fixed path called as Orbit
- There are Eight planets that revolve around the sun
- Based on the distance from the sun, planets are divided into Inner and Outer Planets.
- Inner Planets are the one that are near the Sun. They are also called as Terrestrial planets
- Inner Planets are Mercury, Venus, Earth, Mars
- Outer planets are the one which are far away from the Sun
- Outer planets are Jupiter, Saturn, Uranus, Neptune
- Write a very short note Mercury?
· Mercury is very hot since it is very close to the Earth
· It has the shortest orbit
· It takes 88 days to complete one revolution
· Mercury has no atmosphere - Write a very short note on Venus?
· Venus is the brightest of all the planets.
· Venus is the Earth`s twin since it has same size of Earth
· Venus is also called as Morning star/ Evening Star - Write a very short note on Earth?
· Earth is also called as Blue planet/ Watery planet
· It is the fifth largest planet
· 70% Earth surface is covered with water, so Earth is called as Blue Planet
· Earth is neither too far nor too close to the sun.
· Atmosphere that surrounds the Earth contain gases such as Oxygen, Nitrogen, Carbon dioxide, Argon
· Sunlight – Plants use this sunlight to produce oxygen which is required by the living organisms to live - Write a short note on Mars?
· Mars is also called as Red Planet
· Red colour of the planet is due to the presence of Iron oxide on its surface
· Mars is close to the Earth
· Mars do not have atmosphere, It has 95% Carbon di oxide
· White polar caps are visible through the telescope which suggest that there is presence of water as ice - Write a short note on Jupiter?
· Jupiter is the largest planet of the solar system
· It has the gaseous surface of Helium and Hydrogen
· It has the Great Red spot. It has the rotating storm system lasted for more than 100 years - Write a short note on Saturn?
· Saturn is the second largest planet
· It has spectacular rings which are made up of ice and ice covered dust particles - Write a short note on Uranus?
· Uranus it rotates on its axis East to West.
· Atmosphere of Uranus consist of Hydrogen with traces of Helium, Ammonia, Methane
· It has ten thin uniform black rings made up of dust - Write a short note on Neptune?
· Neptune is the most distant gas planet
· Atmosphere consist of Hydrogen, Helium. It has three rings made up of dust. - Write a short note on Moon?
· Moon is the only natural satellite of the Earth
· Moon is also called as Luna
· Moon has no light on its own, it reflects the light from sun
· Moon has no air and no atmosphere
· Moon diameter is one fourth of Earth diameter
· Moon takes 29 days 8 hours to revolve around Earth. It is called as Lunar month
· In Moon nights are cold, days are hot
· Largest moon is Ganymede in Jupiter
· Second largest moon is Titan in Saturn - Write a short note on Satellites?
- · Satellite means Follower/ Attendant
- · Satellites are spherical bodies that move around the Earth
- · Satellite have no light on their own.
- · Satellite reflect the light from the Sun
- · All the planets have natural satellite except Mercury and Venus
- · Space satellites/ Artificial satellite are launched to study about the meterological information, Telecommunication and disaster warning
- · First Indian space satellite is Aryabhatta launched in 1975
44. Write a short note on Asteroids?
- · Asteroids are also called as Planetoids
- · Asteroids are made up of rock and metals that revolve around the sun between the orbit of Mars and Jupiter. It is called as Asteroid belt
- · Larger asteroids are spherical shape and smaller ones are elongated
- · Ex: Largest asteroids are Ceres, Pellas, Juno, Vesta
45. Write a short note on Meteors and Meteorites?
- · When celestial bodies collide, rocks break into small pieces and try to reach Earth. They are called as Meteors
- · Meteors are small, they burn before reaching Earth atmosphere
- · They emit light due to high friction and Velocity
- · When Meteors do not burn, they land on Earth surface known as Meteorites.
- · Group of Meteors create streaks of light as they reach the Earth atmosphere at high speed. These are called as Meteor showers.
- · Intense Meteor shower are also called as Meteor outburst.
- · Famous site of Meteor crater is in Arizona. It is 1.2 Km wide, 170 meters deep, caused the extinction of dinosaur
46. Write a short note on Comets?
- · Comet is a word derived from Latin word “ Stella cometa” means hairy star
- · Comets are luminous heavenly bodies
- · Comets are made up of clumps of ice, froze gases such as water vapour, ammonia, methane, carbon dioxide
- · Comets have a bright head and tail which always points the Sun
- · Comets revolve around Sun in elongated orbits
- · Comets take hundreds or thousands of years to revolve around the Sun
- · Comets become visible, when they travel close to the sun. Ice is melted and gases are swept into its tail
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