The Earth in the Solar System

Q1. Fill in the blanks.

                       i.        The North Star indicates the north direction.

                      ii.        The sun is in the centre of the solar system.

                     iii.        We can see the full moon only once in about a month’s time.

                     iv.        Full moon night is also known as Poornima.

                      v.        Ursa Major or Big Bear is a constellation.

                     vi.        Aryabhatta was a famous astronomer of ancient India.

Q2. True/False

                       i.        All the planets move around the sun in an elongated path. True

                      ii.        It is huge and made up of extremely hot liquids. False

                     iii.        The word ‘planet’ comes from the Greek word “Planetai” which means ‘wanderers’. True

                     iv.        The moon is in the centre of the solar system. False

                       v.        Till recently (August 2006), Pluto was also considered a planet. True

                     vi.        Word geography is made of two Greek words, ‘ge’ meaning’ ‘earth’ and ‘graphia’ meaning ‘writing’. True

Q3. How long does it take to go from a new moon to a full moon?

Ans. A fortnight

Q4. Name few dwarf planets.

Ans. Pluto, Ceres, 2003 and UB313

Q5. Which is the third nearest planet to the sun?

Ans. Earth is the third nearest planet to the sun.

Q6. Which is the closest celestial body to our earth?

Ans. The moon is the closest celestial body to our earth.

Q7. Name the natural satellite of the earth?

Ans. Moon is the natural satellite of the earth.

Q8. Where are the most asteroids found?

Ans. They are found between the orbits of Mars and Jupiter.

Q9. How many times can we see full moon in a month time?

Ans. We can see the full moon only once in about a month’s time.

Q10. How long does it take for the moon to complete one revolution?

Ans. The moon moves around the earth in about 27 days.

Q11. What is a geoid?

Ans. A sphere with its ends flattened at poles (just like earth) is called geoid.

Q12. Why do the stars look so small in the sky?

Ans. The stars look so small in the sky because they are very far from us.

Q13. From where does Earth receive heat and light?

Ans. Earth gets all its heat and light from the sun, which is its nearest star.

Q14. What is the speed of light?

Ans. Light travels at the speed of about 300,000 km per second.

Q15. How much time light takes to reach the earth?

Ans. The light of the sun takes about eight minutes to reach the earth.

Q16. Who are called astronomers?

Ans. Those who study the celestial bodies and their movements are called astronomers.

Q17. What cast shadow on the moon?

Ans. It has mountains, plains and depressions on its surface. These cast shadows on the moon’s surface.

Q18. What is a Pole Star?

Ans. The North Star indicates the north direction. It is also called the Pole Star.

Q19. What is a galaxy?

Ans. A galaxy is a huge system of billions of stars, and clouds of dust and gases.

Q20. How can we locate the position of the pole star?

Ans. We can locate the position of the Pole Star with the help of the Saptarishi.