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(C) 4 minutes

The orbits of planets are elliptical or elongated in shape.

1. The universe itself started some 13.7 billion years ago with a Big Bang. 

2. From this Big Bang, several galaxies were formed.

3. Within these galaxies, stars were formed.

4. Planets were formed around stars and went around them.

However these astronomical changes take place over thousands and even millions of years.

• Human life on earth dates back to one lakh years, whereas formation of the earth was four and a half billion years ago. 
• Man has constantly trying to change our surrounding to make it a better place to live in. 
• He looked on earth as a storehouse of resources and making use of it, at will. 
• Thus his greed led to exploitation of the earth.

We human beings arrived on earth about one lakh years ago.

Initially, people thought that the Earth was firm and stationary and all others went around it.

(1) D 

(2) E 

(3) B 

(4) C 

(5) A

(1) B 

(2) E 

(3) D 

(4) A 

(5) C

Pangaea: The massive supercontinent that existed 220 million years ago and broke apart into several large sections – continents. (Or) America, Greenland, and all of Eurasia North of the Indian subcontinent. Pangaea is a hypothetical continent from which present continents originated by drift.

(B) A is true and B is also true.

(C) Eastern and Northern

ISRO is located in Sriharikota in the SPSR Nellore district.

The moon is tidally locked to the earth. The moon’s rotation on its axis is exactly the same as its orbital time around the earth. So we can see only one side of the moon ever facing the earth.

The moon is a natural satellite of the earth while INSAT is an artificial satellite.

Neil Armstrong, an American was the first man to step on the surface of the moon on 21st July 1969.

Rakesh Sharma was the first Indian Astronaut to travel into space. He was part of the Soviet Union’s Soyuz T-11 expedition, which was launched on April 2, 1984.

People in olden times determined directions with the help of stars.

1. The semicircles connecting pole to pole are called longitudes. 

2. They are 360 in number. 

3. Some important longitudes are : 

a) Prime Meridian – 0° longitude 

b) International Date Line – 180° longitude

A comet is a celestial object made up of a head and a tail. Halley’s comet is one of the most famous comets. It comes close to the Earth every 76 years. It appeared in 1986 and will appear again in 2061.

Satish Dhawan is a scientist and the Former Chairman of the ISRO.

SHAR: Sriharikota High Altitude Range.

The source of light and heat in the solar system is the Sun.

Moon is the companion of the Earth.

The sun, eight planets, satellites, and other celestial bodies like asteroids and meteoroids are together known as a solar system.

Yes, the earth’s creatures have evolved through a series of contingent and fortuitous events. 

1. Our earth is just the right distance from the sun to have a stable orbit. Our orbit keeps us from getting too hot or too cold to survive. Any closer we’d burn up, any farther away we’d freeze to death. 

2. Our earth is perfect in both size and mass. Mass is critically important to the formation of an atmosphere. If the earth’s mass were less dense, an atmosphere could not have formed and remained. If it were more dense, the atmosphere would have been uninhabitable. 

3. Our earth has just the right mix of the 27 elements needed for life, including carbon, oxygen, nitrogen, phosphorous, potassium, iron, sodium, and copper. 

4. Our earth has just right amount of water in the proper ratios of liquid, solid, and gas.

A little more and the continents would probably be totally overrun with water and literally, drown.

Any less and the temperature of the earth would probably be too hot making life unbearable here. 

Thus we can say that our being on this earth is the result of fortuitous accidents.

Standard time: A uniform time for places in approximately the same longitude.

Total number of longitudes 360

Grid: A pattern of squares on a map that is formed of a bi-section of two latitudes and longitudes.

Latitudes: The horizontal circles that go around the earth.

• The world is divided into 24 time zones. 
• The width of each time zone is 15° of longitude. 
• This means that the difference between one time zone and the next is one hour.
• Some countries would have more than one time zone with less than one hour division. 
• This is considered too complicated to be useful. 
• That is why some countries choose the time along one of the meridians that pass throught their territory and follow the time of that meridian for the whole country. 
• This time is called standard time.

Answer is (A) 1

The super continent is Panthalsa

(A) Prime Meridian

(D) Universe

(D) Ocean species

Crust is the top most layer of the earth.

Crust is the top most layer of the earth.

(C) Longitude

(D) 6000 kms

Answer is (B) Mantle

(A) Outer core

(C) Outer core

Top layer of the earth is called Crust.

(A) 28.7°N, 77.1°E

Answer is (A) Crust

• Air pollution is one among the environmental crises we face. 
• Government of Delhi decided to allow the odd number plate vehicles to ply on the Delhi roads the other day.
• This alternate day journey provision definitely reduces the traffic congestion. 
• It also promises in reduction of pollution. 
• Already petrol vehicles ply on Delhi roads was banned. 
• Compressed Natural Gas is the need of the hour. 
• However, care must be taken to disallow everyone to have a vehicle with odd number and another with even.

(C) Collision of asteroids

Earth formed around 4.54 billion years ago by accretion from the solar nebula. Nearly all branches of natural science have contributed to the understanding of the main events of the earth’s past. The age of the earth is approximately one-third of the age of the universe. Biological and geographical change has been constantly occurring on our planet since the time of its formation. The process of plate tectonics has played a major role in the shaping of earth’s oceans and continents as well as the life on it.

It took us years of scientific investigation and analysis of data to form an understanding of the interiors of the earth. The main reason for this is that even the deepest mines we have dug do not go beyond a few kilometers under the surface while the radius or the distance to the centre of the earth is over 6000 kilometers.

Thus it is very difficult to study the formation of the earth and its structure.

• The matter deep inside the mantle shoots up through volcanoes and fissures on ocean floors. 
• In many regions on the earth part of the earth’s crust enters into the mantle and once again becomes molten. 
• The crust is still being changed by earthquakes, volcanoes, subduction of land and rise of mountains due to the processes happening deep down the earth. 
• This constant process of formation and destruction of the earth’s crust explains the fact that the earth is still very active.

Asteroids are large rocky objects in space, in orbit around the Sun. Meteoroids are much smaller rocks or particles in orbit around the Sun. Sometimes these Meteoroids come near the Earth and tend to drop upon it.

The small pieces of rocks which move around the Sun are called meteoroids.