Earth as a Planet


1. What is the solar system?

The sun together with all the planets, asteroids, comets, and other bodies that revolves around it.

2. What is meant by a star?

A star is a very large ball of bright glowing hot matter in space.

The Sun (a star) is the nearest to Earth.

Trillions of stars compose the universe, only a few percentages are visible to the naked eye.  


3. Name the 8 planets of our solar system.

Planets are in order to distance from the sun.
1. Mercury
2. Venus
3. Earth
4. Mars
5. Jupiter
6. Saturn
7. Uranus
8. Neptune
Planets are in Order of Size
1. Jupiter
2. Saturn
3. Uranus
4. Neptune
5. Earth
6. Venus
7. Mars
8. Mercury

4. What is meant by planets?

The word “planet” comes from the Greek word “planets,” which means “wanderer,”. Planets are the bodies that revolve their own axis around the sun in the solar system.


5. What is meant by Satellite?

A satellite is a moon, planet, or machine that orbits a planet or star. For example, Earth is a satellite because it orbits the sun. Likewise, the moon is a satellite because it orbits Earth. Usually, the word “satellite” refers to a machine that is launched into space and moves around Earth or another body in space.

Earth and the moon are examples of natural satellites. Thousands of artificial, or man-made, satellites orbit Earth.


6. What is meant by geoid?

The actual shape of the earth is ‘Oblate Spheroid’ and is better described as ‘Geoid. The geoid is defined as the oceanic surface which approximates the mean sea level. It is perpendicular to the direction of the force of gravity.

Since the mass of the Earth is not uniform at all points, the magnitude of gravity varies, and the shape of the geoid is irregular.


7. Why is the earth called a blue planet?

The planet looks blue from outer space since two-thirds of the surface is covered with water, when looked at from space due to those water bodies, it appears blue. so, it is called a blue planet.


8. Earths Profile

Earth is the only planet that consists of life.

Location – Earth is the third planet on the basis of its distance from the sun, after mercury and Venus.

Distance from the Sun – 150 million km away    

       


Shape – The shape of the earth is like an oblate spheroid. The North and south poles are somewhat flattened and the equatorial region bulges out a little.


Mass of the earth – 5.972 x 1024 kg

Area (2D) – 510,072,000 square km.                    

Surface Area (3D) – 510,067,420 Square KM


Diameter – Equatorial Diameter (12757 km)   Polar Diameter (12714 km)


Concept of Shape of Earth Flat earth: Flat earth concept is an archaic belief that the earth’s shape is a plane or disc. This concept was held by many ancient cultures even in Greece until the Classical Period. Ancient Chinese people believed that China was the only landmass that represented the earth and it was surrounded by oceans filled with dragons and giant fishes.  

Spherical earth: The concept of spherical earth appeared in Greek philosophy with Pythagoras (6th century B.C.).
Aristotle accepted the spherical shape of the Earth on empirical grounds around 330 B.C.
Indian astronomer, Aryabhatta (476-550 A.D.) stated that the earth is spherical with a circumference of 39,968 km (Approx 40,000 km).
ProofsSighting of boat: At sea is possible to see the mast of a boat before the hull appears. Position of the Sun: The sun is seen lower in the sky as one moves away from the tropics. Length of Day and Night: The length of daylight varies more between summer and winter the farther you are away from the equator.
Lunar Eclipse: The earth throws its circular shadow on the moon during a lunar eclipse.
Circumnavigation: It is possible to circumnavigate the earth.
Gain or Los of a day: Travelers who circumnavigate the earth observe the gain or loss of a day.
Satellites: An artificial satellite can circle the earth continuously.
Aerial photograph: The aerial photograph taken from the space shows the disc shape of the earth.
Bedford level experiment: The experiment carried out by Dr. Wallace along the Bedford Canal of Britain also proves the curvature of the earth. He fixed three poles of equal length at regular intervals along the canal and found that the central pole was seen slightly above the poles at both ends.
The horizon of the earth: As one goes up sees the horizon spherical as well as wider.

Multiple Choice Questions (MCQ) (Answers Given Below)

1. The ‘Blue Planet’ is another name for-

A. Earth

B. Saturn

C. Venus             

D. Mars

2. The planet nearest to the earth is-

A. Mercury

B. Venus

C. Mars

D. Jupiter

3. The earth’s equatorial diameter is-

A. 12,712 Km     

B. 12,745 Km

C. 12,757 Km

D. 12,500 Km

4. The earth’s polar diameter is-

A. 12,400 Km     

B. 12,714 Km

C. 12,700 Km     

D. 12,720 Km

5. “The earth revolves around the sun.”— This was first stated by-

A. Galileo            

B. Copernicus

C. Aryabhatta

D. Varahamihir

6. The planet closest to the sun is-

A. Mercury         

B. Venus

C. Pluto

D. Neptune

7. “The earth revolves around the sun and on its own axis.” The first person to say this was-

A. Copernicus    

B. Aryabhatta

C. Galileo            

D. Newton

8. The average distance of the earth from the sun is-

A. 140 Million Km           

B. 150 Million Km

C. 160 Million Km            

D. 120 Million Km

9. The highest point on the surface of the earth is-

A. Mount Everest            

B. Pamir Plateau

C. Tibetan Plateau

D. North Pole Region

10. The deepest known point on the earth is

A. Mariana Trench

B. Sunda Trench

C. St. Louis Trench

D. South Pole Region

11. The difference between the earth’s polar diameter and the equatorial diameter is

A. 40 Km

B. 42 Km

C. 43 Km

D. 45 Km

12. An example of a dwarf planet is-

A. Pluto

B. Mercury

C. Mars

D. Neptune

13. The Bedford Canal Experiment was carried out by-

A. Wallace          

B. Torricelli

C. Foucault

D. Galileo

14. The average radius of the earth is-

A. 6,300 Km       

B. 6,371 Km

C. 6,500 Km

D. 6,600 Km

15. In 1797, scientist Henry Cavendish determined the earths-

A. Density           

B. Weight

C. Circumference

D. Diameter

16. In terms of distance from the sun, the earth is—

A. Second

B. Third

C. Fourth

D. Fifth

17. The average circumference of the earth is –

A. 40,400 Km

B. 40,075 Km

C. 40,500 Km

D. 40,200 Km

18. The sun is a

A. Planet

B. Satellite

C. Star

D. Galaxy

19. The sun is heavier than the earth by

A. 0.35 Million Times

B. 033 Million Times

C. 0.325 Million Times

D. 0.32 Million Times

20. The number of Jovian planets in the solar system is

A. 7

B. 8

C. 9

D. 6

21. The planet which has rings around it is—

A. Saturn

B.Earth

C. Mercury

D. Venus

22. The name of one satellite of Saturn is

A. Moon

B. Titan

C. Phobos

D. Haumea

23. The total number of components in a GPS is –

A. 3

B. 4

C. 6

D. 5

24. In ancient times, man believed that earth was

A. Sphere

B. Oblate Spheroid

C. Plane

D. Square

25. The ancient Mesopotamians believed that the earth was

A. Floating In Space

B. Floating On An Ocean

C. A Single Entity Standing On Its Own

D. Is Not Floating Anywhere

26. “The earth is round.” This statement was first made by—

A. Plato

B. Pythagoras

C. Aristotle

D. Strabo

27. Pythagoras was a—

A. Greek Philosopher

B. Roman Philosopher

C. British Philosopher

D. Portuguese Philosopher

28. The first empirical proof that the earth round was given by —

A. Pythagoras

B. Magellan

C. Columbus

D. Aristotle

29 A proof that the earth is round

A. The View From The Mast Of A Ship

B. Travelling Around The World In A Ship

C. Photographs Taken From Space

D. The View From The Top Of Mt. Everest

30. The person to calculate the earth’s circumference on the basis of the difference in the angle of incidence of sun rays was

A. Strabo

B. Aristotle

C. Eratosthenes

D. Plato

31. The Old Bedford River is in

A. England

B. France

C. Germany

D. Italy

32. The earth can be called an oblate spheroid because

A. the earth’s surface is elevated by 15 m at the North Pole

B. there is more water in the equatorial region

C. the highest point on earth is Mt. Everest

D. the poles are flattened and the equatorial region is bulging out

33. The earth’s gravitational force is the greatest

A. At The Equatorial Region

B. In The Ocean Beds

C. On Mountain Peaks Go

D. At The Poles

34. The pendulum clock experiment was conducted by

A. Pythagoras

B. Eratosthenes

C. Jean Richer

D. Galileo

35. The word ‘geoid’ means

A. Oblate Spheroid

B. Perfect Sphere

C. Flattened

D. Like The Earth

36. The shape of Mercury and Venus is

A. Oblate Spheroid

B. Perfect Sphere

C. Geoid

D. Flattened

37. To complete one revolution around the sun, Venus takes

A. 365 Days

B. 24 Days

C. 243 Days

D. 27 Days

38. One of the believers in the earth-centric model of the universe was

A. Copernicus

B. Aristotle

C. Bruno

D Brahe

39. The telescope was invented by

A. Kepler

B. Galileo Galilei

C. Newton

D. Edmond Halley

40. If we move 111.3 kilometres from the equator towards the poles, the angle of incidence of sun’s rays will increase by

A. 1  30’

B.  30’

C. 1  

D. 1  02’

41. To complete one revolution around the earth, the moon takes

A. 36 Days

B. 20 Days

C. 27 Days

D. 27 1/3 Days

42. The latitudinal coordinate of Paris is

A. 26  32′ N

B. 47° N

C. 49° N

D. 75° 03′ N

43. The Cayenne Islands are in 

A. North America

B. South America

C. Asia

D. Austria

44. The length of the earth’s orbit is

A. 9.6 Million Km

B. 11 Million Km

C. 14.70 Million Km

D. 15.20 Million Km

45. The deepest point in the Mariana Trench has a depth of

A. 10,053 M

B. 11,035 M

C. 11,350 M

D. 10,994 M

46. The earth’s centrifugal force is greatest at

A. Equatorial Region

B. Tropics

C. Polar Regions

D. Frigid Zone

47. The largest planet in the solar system is

A. Mercury

B. Venus

C. Jupiter

D. Mars

48. During a lunar eclipse, the shadow of the earth on the moon looks

A. Straight

B. Curved

C. Circular

D. Rectangular

49. As we go higher up from the surface of the earth, the line of horizon appears

A. Shorter

B. Longer

C. Stays the Same

D. None of The Above


Answers

1.    A2.     B3.    C4.     B5.     C6.    A7.    A8.    B9.    A10.  A
11.  C12.  A13.  A14.  B15.  B16.  B17.  B18.  C19.  B20.  B
21.  A22.  B23.  A24.  C25.  B26.  B27.  A28.  B29.  C30.  C
31.  A32.  D33.  D34.  C35.  D36.  B37.  C38.  B39.  B40.  C
41.  D42.  C43.  B44.  A45.  B46.  B47.  C48.  C49.  B 
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