Indian and World Geography Topic-wise Strategy Contents

Indian and World Geography 1-276

Part A: World Geography 6. Years, Months and Calendars 14 7. The Moon, Blood Moon and 1. The Universe 1 Red Moon 15 7.1 Phases of Moon 16 1. Origin of the Universe 1 7.2 Types of Moon 16 2. Solar System 1 8. Eclipses 16 3. The Sun 2 8.1 Solar Eclipse 16 3.1 Mercury 3 8.2 Lunar Eclipse 17 3.2 Venus 3 Self–Evaluation Test 17 3.3 Earth and the Moon 3 3.4 3 3. Geomorphology 18 3.5 Asteroid Belt 4 1. Earth’s Geological Time Scale 18 3.6 Jupiter 4 2. Interior of the Earth 19 3.7 Saturn 4 3. Information Sources About 3.8 Uranus 5 Earth’s Interior 20 3.9 Neptune 5 3.1 Direct Sources 20 3.10 Glossary 5 3.2 Indirect Sources 21 Self–Evaluation Test 7 4. The Theory of Continental Drift 21 4.1 Evidences in Support of the 2. The Earth 8 Continental Drift 22 1. Theories on the Origin of the Earth 8 5. The Theory of Plate Tectonics 22 2. Place of the Earth in the Universe 8 5.1 Seafloor Spreading 22 3. Position, Shape and Size 9 5.2 Evidence for Seafloor Spreading 23 6. Volcanoes 25 3.1 Earth as an Oblate Spheroid 9 4. Motions of the Earth and their 6.1 Magma 25 Consequences 9 6.2 Types of Volcanoes 25 6.3 World Distribution of Volcanoes 26 4.1 Rotation 9 7. Earthquakes 27 4.2 Revolution 10 7.1 Distribution of Earthquakes 27 4.3 Apparent Migration of the Sun 11 7.2 Types of Earthquake Waves 28 5. The Earth’s Grid System 12 7.3 Risk Zone 28 5.1 Latitude 12 8. Rocks 28 5.2 Longitude 12 8.1 Classification of Rocks 28 5.3 Longitudes and Time Zones 13 8.2 Rock Cycle 31 9. Endogenic Forces of Landforms 32 7.2 Spring and Neap Tides 55 9.1 Nappes 33 7.3 Cycle of Declination 55 9.2 Crustal Fracture 33 8. Coral Reefs 55 9.3 Rift Valley 33 8.1 Types of Coral Reefs 55 10. Exogenic Forces of Landforms 34 9. Mineral Resources of Oceans 56 11. Weathering 34 10. Ocean Energy Resources 57 11.1 Types of Weathering 34 10.1 Ocean Thermal Energy 57 12. Major Landforms of the World 35 10.2 Ocean Mechanical Energy 57 12.1 Mountains 35 11. Oil Spill 57 12.2 Plateaus 36 11.1 Directly 57 12.3 Plains 37 11.2 Indirectly 57 13. Fluvial Landform 37 Self–Evaluation Test 58 14. Karst Landforms 39 15. Coastal Landforms 41 5. Hydrosphere 59 16. Aeolian Landforms 44 1. Hydrologic Cycle 59 Self–Evaluation Test 48 2. Ocean 60 4. Oceanography 49 3. Soil Water 60 4. Sources of Water 60 1. Oceans of the World 49 4.1 Ground Water 60 1.1 Continental Shelf 49 4.2 Springs and Seeps 61 1.2 Continental Slope 49 4.3 Geyser 61 1.3 Deep Sea Plains 50 4.4 Wells 62 1.4 Ocean Deep or Trenches 50 5. Rivers 63 1.5 Submarine Canyons 50 2. Reliefs of Ocean: Basins 51 4.1 Parts of a River 63 6. Lakes 63 2.1 Pacific Ocean 51 2.2 Atlantic Ocean 51 6.1 Characteristics of a Lake 63 2.3 Indian Ocean 51 6.2 Preconditions of a Lake 64 3. Temperature of Ocean Water 51 6.3 Classification of Lakes 64 Self–Evaluation Test 64 3.1 Factors Affecting the Temperature of Oceans 51 6. Atmosphere 65 3.2 Vertical Distribution of Temperature 51 4. Salinity of the Oceans 51 1. Atmosphere 65 4.1 Pacific Ocean 52 2. Composition of the Atmosphere 65 4.2 Atlantic Ocean 52 3. Structure of the Atmosphere 65 4.3 Indian Ocean 52 3.1 Troposphere 65 5. Oceanic Deposits 52 3.2 Stratosphere 66 6. Ocean Currents 52 3.3 Chemosphere 66 6.1 Atlantic Ocean 52 3.4 Mesosphere 66 6.2 Pacific Ocean 53 3.5 Thermosphere 66 6.3 Indian Ocean 53 3.6 Exosphere 66 7. Ocean Tides 54 3.7 Homosphere 66 7.1 Diurnal and Semi Diurnal Tides 54 3.8 Heterosphere 67 4. Insolation and Heat Budget 67 17. Distribution of Rainfall 80 4.1 Heat Budget or Heat Balance 67 18. Major Atmospheric Disturbances 80 5. Terrestrial Radiation 68 18.1 Fronts 80 5.1 Global Heat Balance 68 18.2 Cyclones 81 6. Distribution of Temperature 68 18.3 Typhoons 81 6.1 Horizontal Distribution 68 18.4 Thunderstorm 81 6.2 Vertical Distribution 69 18.5 Hurricanes 82 6.3 Temperature Zones 69 18.6 Tornadoes 82 7. Pressure and Winds 70 18.7 Water Sprout 82 7.1 Causes of Pressure Changes 18.8 Temperate Cyclone 82 and Differences 70 18.9 Anticyclone 82 7.2 Relation between Pressure and Wind 70 19. Weather and Climate 83 7.3 Seasonal Shifting of the Pressure Belts 71 20. Types of Climate 83 7.4 Major Pressure Belts 71 20.1 Equatorial Climate 83 8. Humidity and Evaporation 72 20.2 Tropical Climates 85 8.1 Latent Heat 72 20.3 Temperate Climates 87 8.2 Evaporation 72 20.4 Cool Temperate Zone 88 8.3 Absolute Humidity 72 20.5 Cold Zone 89 8.4 Specific Humidity 72 20.6 Mountain Climate 89 8.5 Relative Humidity 73 21. Global Climatic Change 90 9. Winds 73 Self–Evaluation Test 91 9.1 Factors Affecting Wind 74 9.2 Isobars 74 7. Population and Human Diversity 92 9.3 Primary Winds 74 1. Population 92 9.4 Secondary Winds 75 10. Cooling of Air and Adiabatic 2. Races of the World 92 Change 77 3. Population Distribution 93 11. Stability and Instability of the 3.1 Densely Populated 93 Atmosphere 77 3.2 Sparsely Populated 93 12. Forms of Condensation 78 4. Demographic Transition Model 93 12.1 Mist 78 4.1 There are Four Stages of Transition 93 12.2 Dew 78 5. Age Sex Pyramid 94 12.3 Fog 78 6. Factors Affecting Distribution of 12.4 Frost 78 Population 94 13. Clouds 78 7. Migration 95 13.1 Classification of Clouds 78 7.1 Streams of Migration 95 14. Precipitation 79 7.2 Causes of Migration 95 15. Rainfall 79 7.3 Consequences of Migration 95 15.1 Origin of Rainfall 79 Self–Evaluation Test 96 15.2 Pre-conditions of Condensation 79 16. Types of Rainfall 79 8. Continents 97 16.1 Convectional Rainfall 79 1. Introduction 97 16.2 Orographic Rainfall 79 2. South America 97 16.3 Cyclonic or Frontal Rainfall 80 2.1 South America and Mexico Resources 99 3. Africa 99 5. Natural Regions of the World 122 4. Europe 101 5.1 Equatorial Region 122 4.1 Europe and CIS Resources 102 5.2 Savanna Region 123 4.2 Industrial Regions 103 5.3 Hot Desert Region 123 5. Asia 104 5.4 Mediterranean Region 123 5.1 Asia Resources 105 5.5 Temperate Grassland 123 5.2 China 106 5.6 Coniferous Forests 124 5.3 Korea 106 5.7 Tundra Region 124 5.4 South East Asia 106 Self–Evaluation Test 125 5.5 West Asian and Other Asian Countries 106 6. North America 107 10. Agriculture 126 6.1 North America Resources 108 1. Agriculture Production Practices 126 6.2 Industrial Regions 109 1.1 Climate change 126 6.3 Canada 109 1.2 Deforestation 126 6.4 Industrial Regions 110 1.3 Irrigation 127 7. Australia 110 1.4 Pollutants 127 8. Antarctica 111 1.5 Soil Degradation 127 9. Road Transport 114 10. Rail Transport 114 1.6 Nutrient Management in Agriculture 127 11. Ocean Transport: Major 1.7 Indiscriminate Use of Fertilizers and Trade Routes 114 its Effects 128 Self–Evaluation Test 115 1.8 Pollution by Indiscriminate use of Urea 128 1.9 Pollution by Indiscriminate Use 9. Natural Resources 116 of Phosphorus 128 1. Classification of Natural Resources 116 1.10 Indiscriminate Use of Potassium 128 2. Soils 117 2. Vermicompost 128 2.1 Soil Pedogenesis 117 2.1 Benefits of Vermicompost for Soil 128 2.2 Physical and Chemical Properties of Soil 118 2.2 Environmental Benefits of 2.3 The modified marbut system divides Vermicompost 128 the soil into three broad groups or 2.3 Disadvantages / Issues of zonal orders 118 Vermicompost: 129 2.4 Soil Horizons 119 3. Biofertilizers 129 3. Principal Pedogenic Processes 3.1 Biopesticides 129 (Soil Forming Processes) 120 3.2 Bioherbicides 129 4. Flora and Fauna 120 3.3 Bioinsecticide 129 4.1 Biome 120 3.4 Examples of Biopesticides 129 4.2 Monsoon Deciduous Forests 120 4. Modern Agriculture 129 4.3 Savanna Biome 122 4.1 Plantation Agriculture 130 4.4 Mediterranean Biome 122 5. Fisheries 130 4.5 Temperate Grassland Biome 122 5.1 Types of Fishes 130 4.6 Boreal Forest Biome or Taiga Biome 122 5.2 Major Fishing Zones 130 4.7 Tundra Biome 122 Self–Evaluation Test 131 9. The River Regimes 157 Part B: Indian Geography 10. Lakes 157 1. Physiography of 132 11. Watershed Development 157 Self–Evaluation Test 160 1. General Data 132 1.1 Size and Location 132 3. Climate of India 161 1.2 Indian Ocean 132 1. Introduction 161 1.3 India and the World 133 2. Factors Affecting the Climate 1.4 Locational Advantage 134 of India 161 1.5 Political Divisions of India 134 3. Monsoon Winds and its 2. India’s Geological Eras 134 Various Aspects 162 3. Geological History of India 134 4. Seasons in India 164 3.1 The Peninsular Plateau 134 4.1 The Cold Weather Season 3.2 The Himalayas 136 (Northeast Monsoons) 164 3.3 Evolution of Surface Features 139 4.2 The Hot Weather Season 164 4. Major Divisions 139 4.3 The South-West Monsoon Season 164 4.1 The Northern Mountains 139 4.4 The Retreating South West 4.2 The Indus-Ganga Brahmaputra Plain 142 Monsoon Season 165 4.3 Peninsular Plateau 142 5. Modern Explanation of Monsoon 166 4.4 The Great Indian Desert 145 5.1 Winter 166 4.5 The Islands 145 5.2 Spring 166 Self–Evaluation Test 146 5.3 Summer 166 2. India’s Drainage System 148 5.4 Autumn 167 6. Distribution of Rainfall in India 167 1. India’s Water Resources 148 6.1 Variability of Rainfall 167 2. Sources of Water 148 6.2 Spatio Temporal Variation in 2.1 Precipitation 149 the Rainfall 167 2.2 Surface Water 149 7. Climatic Regions of India 168 2.3 Ground Water 149 7.1 Koppen’s Climatic Classification 168 3. Drainage Pattern 150 7.2 Moisture Index of Thornthwaite 169 4. India’s Drainage System 151 8. The El-nino and La-Nina Effect 169 5. The Himalayan Rivers 151 9. Indian Ocean Dipole 170 5.1 The Indus System 151 9.1 Negative IOD Phase 170 5.2 The Ganga System 152 9.2 Neutral IOD Phase 171 5.3 The Brahmaputra River System 153 9.3 Positive IOD Phase 171 6. The Peninsular Rivers 154 Self–Evaluation Test 172 7. Major Rivers of the Peninsular Plateau 154 4. Natural Vegetation 173 7.1 Classification of Peninsular Rivers 157 1. India’s Natural Vegetation 173 8. Drainage of the Thar Desert Region 157 2. Floristic Regions of India 173 3. India’s Forest Cover 174 2. Distribution of Mineral Resources 192 4. Mangrove Cover 177 2.1 Iron Ore 192 5. Afforestation and Re-afforestaion 177 2.2 Manganese 193 6. Social Forestry 177 2.3 Bauxite 193 7. CAMPA Bill 178 2.4 Lead 193 Self–Evaluation Test 178 2.5 Zinc 193 2.6 Copper Ore 193 5. Soils of India 179 2.7 Limestone 193 1. Classification of Soil 179 2.8 Dolomite 194 1.1 ICAR Classification 179 2.9 Magnesite 194 1.2 Alluvial Soil 179 2.10 Kyanite 194 1.3 Red and Yellow Soil 180 2.11 Sillimanite 194 1.4 Black or Regur Soils 180 2.12 Phosphate 194 1.5 Laterite Soil 180 2.13 Common Salt 194 1.6 Saline or Alkaline Soil 181 2.14 Sulphur 194 1.7 Mountain Soil 181 2.15 Gold 194 1.8 Desert Soil 181 2.16 Mica 194 1.9 Peaty and Marshy Soil 182 2.17 Atomic Minerals 194 2. Pattern of Soil Erosion 182 3. Shale Gas in India 194 3. Soil Conservation 182 4. Lignite and Coal 197 Self–Evaluation Test 185 4.1 Lignite 197 6. The People of India 186 4.2 Coal 197 4.3 Coal Classification Based on 1. Ethnic Diversities 186 Carbon Content 197 1.1 Racial Groups of India Given 4.4 Important Coalfields 197 by R.S. Guha 186 4.5 Peat 198 2. Tribal Population of India 186 5. Petroleum 198 3. Population of India 187 5.1 On-Shore Oil Production in India 198 3.1 Population Highlights 187 5.2 Off-Shore Production in India 198 3.2 Population (0–6 years) Highlights 188 6. Gas Grid 200 3.3 Sex Ratio (0–6 years) Highlights 189 7. Regasification Infrastructure 3.4 Literacy 189 in the Country 200 3.5 Density of Population 189 8. City Gas Distribution (CGD) 200 Self–Evaluation Test 190 9. Hydroelectric Power Plants 201 7. Mineral & Power 10. Thermal Power 201 Resources of India 191 11. Atomic Power Plants 202 12. Different Forms of Renewable 1. Mineral Resources 191 Energy 202 1.1 Mineral Belts in India 192 Self–Evaluation Test 205 8. Agriculture in India 206 8. Cold Wave and Fog 223 9. Landslides 224 1. Agricultural Seasons of India 208 10. Tsunami 224 2. Mixed Cropping Pattern 208 11. Industrial and Chemical Disasters 224 3. Major Food Crops 208 12. Stampede 225 4. Green Revolution in India 210 13. Road Accidents 225 4.1 Components of Green Revolution 210 14. Mine Disasters 225 4.2 Impact of Green Revolution 210 15. Forest Fire 225 5. Vegetables 211 16. Epidemics in India 225 6. Floriculture 211 17. Nuclear Emergencies 226 7. Medicinal and Aromatic Plants 212 18. Regulatory Measures 226 8. Varieties of Crops 212 18.1 Present Structure for Disaster 9. Livestock 212 Management in India 226 9.1 Cattle 212 18.2 Preparedness, Mitigation 9.2 Buffalo 213 and Prevention 226 9.3 Sheep 213 19. National Disaster Management 10. Environmental Impact of Agriculture 214 Act 2005 227 10.1 Climate Change 214 20. National Disaster Management 10.2 Deforestation 214 Authority 227 10.3 Irrigation 214 21. Prevention and Mitigation 228 10.4 Pollutants 214 22. National Disaster Mitigation Fund 229 10.5 Soil Degradation 214 22.1 Role of District Administration 229 11. Land Resources 215 22.2 National Disaster Response Force (NDRF) 230 Self–Evaluation Test 216 23. Role of Local Bodies 230 9. Natural Disaster and Self–Evaluation Test 230 its Management 217 10. Water Resources 231 1. Introduction 217 1. Distribution of Irrigated Areas 231 1.1 Indian Scenario 217 2. National Water Grid 232 1.2 List of Various Disasters 218 3. Sources of Irrigation 233 1.3 Vulnerability Profile of India 218 4. Multi-Purpose Projects 235 1.4 Hazard Profile of India 218 4.1 Some Major Irrigation/ 2. Drought 218 Multipurpose Projects 235 3. Floods 219 5. Rivers Interlinking Project 238 4. Tropical Cyclones 219 Self–Evaluation Test 239 5. Heat Wave 221 5.1 Health Impacts of Heat Waves 222 11. Industry 240 6. Earthquakes 222 1. Geographical Factors for the Location 7. Thunderstorm, Hailstorm and of Industries 240 Dust Storm 223 2. Industrial Regions of India 241 2.1 Mumbai-Pune Industrial Region 241 2. Bharatmala Pariyojana 250 2.2 Hugli Industrial Region 241 2.1 Highlights of Bharatmala Pariyojana 250 2.3 Bengaluru-Chennai Industrial Region 242 2.2 Bharatmala Project Category 250 3. Railways 250 2.4 Gujarat Industrial Region 242 3.1 Gauges of Indian Railways 251 2.5 Chotanagpur Region 242 4. Water Transport 251 2.6 Vishakhapatnam-Guntur Region 243 4.1 Shipping 251 2.7 Gurgaon-Delhi-Meerut Region 243 4.2 Development of Gateway Ports 252 Self–Evaluation Test 245 4.3 Sagarmala Project 252 12. Transportation in India 246 4.4 National Waterways 252 4.5 Inland Port 254 1. Road Transport 246 5. Air Transport 255 1.1 Golden Quadrilateral Super Highways 246 5.1 Problems of Air Transport In India 255 1.2 National Highways 246 5.2 Regional Connectivity Scheme “UDAN” 255 6. Pipelines 256 1.3 State Highways 246 6.1 Petroleum Product Pipelines 256 1.4 District Roads 246 Self–Evaluation Test 259 1.5 Other Roads 246 1.6 Border Roads 246 Practice Set-World Geography 260 1.7 Road Density 248 Practice Set-Indian Geography 268 Part (A) World Geography

Chapter 1 The Universe

The Universe is all of space and time and their contents, including planets, stars, galaxies, and all other forms of matter and energy. The study of the Universe and mainly that of the solar system is must to understand the formation and pattern of the Earth. Hence, this chapter discusses about the basic principles related to the Universe and salient features of our solar system. Through this chapter students will be able to understand: � About the Universe � Big Bang Theory � Solar System � Facts about different Planets � Terminology associated with Universe

1. Origin of the Universe What is a Singularity? The Universe is the sum total of all existence. It is the entirety of In scientific terms, a gravitational singularity (or space-time time, space, matter and energy, that began expanding some 13.8 singularity) is a location where the quantities, that are used to billion years ago and has continued to expand ever since. No one measure the gravitational field, become infinite in a way that is entirely certain how extensive the Universe truly is, and no one is does not depend on the coordinate system. In other words, it is entirely sure how it will all end. a point in which all physical laws are indistinguishable from one The Big Bang hypothesis states that all of the current and past another, where space and time are no longer interrelated realities, matter in the Universe came into existence at the same time, roughly but merge indistinguishably and cease to have any independent 13.8 billion years ago. At this time, all matter was compacted into meaning. a very small ball with infinite density and intense heat called a Singularity. Suddenly, the Singularity began expanding and the 2. Solar System universe, as we know it began. • The solar system is made up of the Sun and everything that This theory also accounts for the expansion of the Universe, the orbits around it, including Planets, Moons, Asteroids, Comets existence of the Cosmic Microwave Background, and a broad range and Meteoroids. of other phenomena. • Many scientists think that our Solar system was formed from a giant, rotating cloud of gas and dust, known as the Solar Nebula. As the nebula collapsed because of its gravity, it spun faster and flattened into a disk. Most of the material was pulled toward the center to form the Sun. Other particles within the disk collided and stuck together to form asteroid-sized objects named as planetesimals, some of which combined to become the asteroids, comets, moons and planets. • The solar wind from the Sun was so powerful that it swept away most of the lighter elements, such as hydrogen and helium, from the innermost planets, leaving behind mostly small, rocky worlds. The solar wind was much weaker in the outer regions, however, resulting in gas giants made up mostly of hydrogen and helium. 2 Indian and World Geography

to the fact that the Sun is not a solid body like the Earth. Important Facts The differential rotation extends considerably down into the • The star closest to the Earth: Proxima Centauri interior of the Sun but the core of the Sun rotates as a solid • The outermost layer of the Sun: Corona (visible only body. during an eclipse) • Planets rotate from east to west: Venus and Uranus Projects to study the Sun • Inner planets: Mercury, Venus, Earth and Mars A. Parker Solar Probe: Mission to Touch the Sun • Outer Planets: Jupiter, Saturn, Uranus and Neptune It is NASA’s first planned robotic to study outer corona • Smallest planet of the Solar System: Mercury of the Sun. It is named after solar astrophysicist Eugene Parker, • Brightest planet of the Solar System: Venus first spacecraft of NASA to be named after living person. • Evening or morning star or twin of the Earth: Venus Scientific Goals of PSP • Blue planet (due to presence of water): Earth • Determine structure and dynamics of magnetic fields at • Red or fiery planet: Mars sources of solar wind. • Dusty planet: Mars • Trace flow of energy that heats Corona and accelerates solar • Largest planet: Jupiter wind. • Fastest rotating planet: Jupiter • Determine what mechanisms accelerate and transport • Slowest rotating planet: Venus energetic particles. • The outermost planet visible to the naked eye: Saturn • Explore dusty plasma near the Sun and its influence on solar • Planet which is known as a lying one: Uranus wind and energetic particle formation. • Planets according to the distance from the Sun: Mercury, Its data will also be useful in improving forecasts of major Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune eruptions on the Sun and subsequent space weather events that • Planets in order to distance from the Earth: Venus, Mars, impact technology on Earth, as well as satellites and astronauts Mercury, Jupiter, Saturn, Uranus and Neptune in space. • Planets according to size (descending order): Jupiter, B. Aditya-L1 mission Saturn, Uranus, Neptune, Earth, Venus, Mars and Mercury Aditya-L1 is the India’s first dedicated scientific mission, • Some Dwarf planets ordered in their distance from Sun which aims to send a satellite to study the dynamics of Sun’s are: Ceres, Pluto, Haumea, Makemake, Eris. Chromosphere. The mission is a joint venture between ISRO and physicists from various institutes including Indian Institute of Planets and their Satellites Astrophysics, Bengaluru; Inter University Centre for Astronomy Planets Important Satellites and Astrophysics, Pune; and Tata Institute of Fundamental 1. Earth Moon (Asteroids 3753 Cruithne and 2002 Research, Mumbai. AA29 have complicated orbital relationship Objectives with the Earth) • The objective of the mission is to study the dynamic 2. Mars Phobos, Deimos nature of the Sun’s outer most layers, the Corona and the Chromosphere, and collect data about Coronal Mass 3. Jupiter Cailesto Himalaya, Elara, Europa, Ganymede, Ejections (CME). 4. Saturn Atlas, Titan, Tenthis, Phoebe, Ria, Helen • It will also study on the origin of solar storms and their path 5. Uranus Miranda, Titenia, Belinda, Arial through the interplanetary space from the Sun to the Earth. 6. Neptune Titan, Nerid • The studies will also focus on collection of information for space weather prediction. 3. The Sun Significance This mission will present clear picture of Sun’s Chromosphere, • The Sun is by far the largest object in our Solar System, which in turn will help us to understand the concept of Sun’s containing 99.8 percent of the solar system’s mass. Corona visible during solar eclipse. Furthermore, it will help • It sheds most of the heat and light that makes life possible on to study the discharging of charged particles into space which Earth and possibly elsewhere. affect the environment there, called solar wind. Solar winds • Planets orbit the Sun in an oval-shaped paths called ellipses, are responsible for damage to satellites and affect the upper with the Sun slightly off-center of each ellipse. atmosphere, but Van Allen belt protects Earth’s atmosphere from getting affected by solar winds. • The Sun is at present, about 70 per cent hydrogen and 28 per cent helium by mass everything else (“metals”) amounts to • The Sun’s power (about 386 billion billion mega Watts) is less than 2 per cent. This changes slowly over time as, the Sun produced by nuclear fusion reactions. converts hydrogen to helium in its core. • The surface of the Sun, called the Photosphere, is at a • The outer layers of the Sun exhibit differential rotation: at temperature of about 5800 K. the equator the surface rotates once every 25.4 days; near • Sunspots are “cool” regions, only 3800 K (they look dark only the poles it’s as much as 36 days. This odd behavior is due by comparison with the surrounding regions). Sunspots are The Universe 3

complicated and not very well understood interactions with • A day on Venus (sunrise to sunrise) lasts 117 Earth days. the Sun’s magnetic field. • Its gravity on the surface is 90 per cent that of Earth’s. • A small region known as the Chromosphere lies above • Venus atmosphere is comprised of carbon dioxide with thick the Photosphere. The highly rarefied region above the clouds of sulphur dioxide. This atmosphere has the strongest Chromosphere, called the Corona, extends millions of greenhouse effect known in the solar system which keeps the planet at a reasonably constant temperature of 460°C. This kilometers into space but is visible only during a total solar makes Venus the hottest planet in the Solar System, far hotter eclipse. Temperatures in the Corona are over 1,000,000 K. even then mercury which is twice as close to the Sun. • The Sun’s magnetic field is very strong (by terrestrial standards) • Venus has a very weak magnetic field. and very complicated. Its Magnetosphere (also known as the Heliosphere) extends well beyond Pluto. Mission to Venus • In addition to heat and light, the Sun also emits a low density • In the 90’s NASA’s Magellan Spacecraft orbited the planet stream of charged particles (mostly electrons and protons) from 1990 to 1994, before deliberately crashing into the known as the solar wind, which propagates throughout the planet. Solar System at about 450 km/sec. The solar wind and the • Venus was last studied by Europe’s Venus Express Spacecraft, much higher energy particles ejected by solar flares can have which orbited the planet from April 2006 until crashing into dramatic effects on the Earth, ranging from power line surges it sometime in January, 2015. to radio interference to the beautiful aurora borealis. • Venus is currently being studied by the Japanese spacecraft Akatsuki. A rocket motor failure prevented Akatsuki from 3.1 Mercury entering orbit in 2010 causing it to orbit the Sun for 5 years • Mercury is the closest planet to the Sun. before being inserted into orbit in December, 2015 using its • It takes about 88 Earth days to orbit the Sun but rotates on its thrusters. Since May 2016 it has been carrying out scientific axis once every 59 Earth days. studies of the Venusian atmosphere. • Because of the slow rotation, a single day on Mercury (mid day to mid day) takes 176 Earth days. Its axial tilt is remarkably 3.3 Earth and the Moon small at 3/100ths of a degree, much smaller than any other • The third closest planet to the Sun is Earth and is the largest planet. and densest of the inner planets. • Its gravity on the surface is 1/3rd of the Earth’s gravity. • Earth orbits in a reasonably circular at 150 million km and is • Mercury has almost no atmosphere and is blasted (eroded) the first of the planets to have a moon. by the Sun during the day and exposed to cold space during • Earth takes 365.25 Earth days to orbit the Sun and rotates the night. This means that it undergoes some of the widest once every 23 hours, 56 minutes and 4 seconds. Because it temperature variation compared to any other planet in the rotates around the Sun, the length of a day on Earth (sunrise Solar System with temperatures reaching +430°C and dipping to sunrise) takes 24 hours (approx). down to -180°C. • The Earth has an axial tilt of 23.4 degrees and a diameter of • It has a highly cratered rocky surface and is known to have an 12742 km. iron core. However its magnetic field is much weaker than the • The Earth is thought to be 4.54 billion years old and has been Earth’s (1 per cent as strong). accompanied by the Moon for most of that time. It is believed that the Moon was formed when a large Mars sized body Missions to Mercury impacted the Earth causing enough material to be ejected • Before 2011, it had only been visited by 1 spacecraft - the which eventually coalesced into the Moon. The Moon has had Mariner 10 spacecraft which performed 3 fly-pasts in the effect of stabilising Earth’s axial tilt and is the source of the 1974/75 mapping about 45 per cent of its surface. Earth’s ocean tides. • Mercury was recently being studied by the Messenger • The Moon is 3,474 km in diameter (27 per cent that of Earth) Spacecraft. Messenger entered Mercury’s Orbit on 18th and orbits at a distance of between about 362,000 to 405,000 March 2011, the first manmade object ever to do so. km. It has also been affected by the gravitational pull of the • The next mission to Mercury will be ESAs Bepicolumbo Earth, which has over time caused the Moon’s rotation to be mission to be launched in October, 2018 and to arrive slowed until it matches the time it takes to orbit the Earth. This Mercury in late 2025. is why the same side of the Moon always faces the Earth. • Earth is protected from solar radiation by a strong magnetic 3.2 Venus field generated by movement of its core, which is mainly • Venus is the second closest planet to the Sun and orbits in an comprised of molten iron. almost circular orbit at 108 million km. • Venus takes about 225 Earth days to orbit the Sun and rotates 3.4 Mars at the incredibly slow rate of once every 243 days - and in a • Mars is the fourth closest planet to the Sun and orbits in a clockwise direction (as seen from looking down on the Sun’s fairly eccentric orbit at around 230 (+/–20) million km. North pole). Uranus (which almost spins on its side) also has a • Mars takes about 686 Earth days to orbit the Sun. clockwise spin. • It has a tilt (25.1 degrees) and rotational period (24 hour 37 minutes), which are both similar to the Earth with a day 4 Indian and World Geography

(sunrise to sunrise) lasting 24 hours, 39 mins. Because of the 3.6 Jupiter tilt it also has seasons in the same way as the Earth does. • Jupiter is the fifth closest planet to the Sun and is the first of • Mars is about half the size of the Earth with a diameter of what are called the outer planets (being outside the asteroid 6,792 km. However its mass is only a tenth of Earth’s, with belt). gravity on the surface being around 37 per cent that of Earth’s. • It is by far the largest planet in the Solar System having two • Because Mars no longer has a magnetic field to protect it, and a half times as much mass as all the other planets put Mars has lost its original atmosphere due to the effects of the together and one thousandth the mass of the Sun. solar wind interacting with the atmosphere, causing atoms to • Jupiter orbits the Sun once every 12 years (at about 780 million be lost into space. km) and is comprised of gas (75 per cent hydrogen and 24 per • Moons: Phobos and Deimos cent helium) and is presumed to have a rocky core surrounded by a sea of liquid metallic hydrogen which forms a ball 110,000 km Mission to Mars in diameter. Jupiter’s total diameter is 142,984 km. • The Mars Exploration Rovers, Spirit and Opportunity landed • In the upper atmosphere is a cloud layer 50 km thick. The clouds in 2004 for their 90 day mission. They both exceeded their are comprised of ammonia crystals and other compounds mission objectives with Spirit eventually failing in March which are arranged into bands moving at different speeds at 2010 and Opportunity is still performing. different latitudes. The Great Red Spot is a large stable storm • Mars is currently host to seven functioning spacecraft: vortex laying between two layers. five in orbit – the Mars Odyssey, , Mars • Considering its size, Jupiter rotates very quickly having one Reconnaissance Orbiter, ExoMars , Mars rotation at just under once every 10 hours. This means that Orbiter Mission, and two on the surface – Mars Exploration at the equator there is quite a large centrifugal force, which Rover Opportunity and the means the planet has a pronounced bulge - its diameter Curiosity. InSight - A from NASA, on it’s way and due around the equator is 9000 km greater than the diameter to arrive end of 2018. measured at the poles. Near future missions include a whole host of spacecraft to • Moons : Io, Europa, Ganymede and Callisto arrive 2020 to 2021: • Ganymede is the largest satellite in the Solar System and is • NASA’s Mission - a lander, and surprisingly larger than the planet Mercury. It is also covered in ice but is (because the atmosphere is so thin) a solar powered drone less geologically active with its surface marked by craters and to help with navigation. ridges. • ExoMars 2020 - the second part of ESA’s ExoMars mission to search for life. It comprises a rover to land in 2021. Mission to Jupiter A public competition is open to name the rover. • Galileo became the first spacecraft to orbit Jupiter in 1995. • 2020 Chinese Mars Mission - An orbiter and lander to • The Cassini probe flew past in 2000 and imaged Jupiter’s arrive in 2021. atmosphere revealing many unknown features. • Hope Mars Mission or ‘Al-Amal’ - A United Arab Emirates • The New Horizons probe flew past in 2007 on its way to orbiter to arrive in 2021. Pluto and studied the Jovian moons, magnetic field and India’s 2 - from the Indian Space • ring system. Research Organisation. An orbiter and possible lander • NASA currently has a mission underway to study Jupiter (2021-2022). in detail from a polar orbit. Named Juno, the spacecraft 3.5 Asteroid Belt launched in August 2011, arrived in July 2016 and will orbit • Between Mars and Jupiter lies the Asteroid belt which is the planet until 2018 when it will be de-orbited into Jupiter. comprised of thousands of rocks left over from the formation It passes very close to Jupiter on each orbit and therefore of the Solar System. These rocks vary in size from microscopic has to survive Jupiter’s intense radiation belts. up to Ceres (950 km diameter) which is classified as a dwarf • The next planned mission to the Jovian system will be planet. Dwarf Planet is a celestial body orbiting a star that is the European Space Agency’s Jupiter Icy Moon Explorer massive enough to be rounded by its own growing but has (JUICE), due to launch in 2022. not cleared its neighbouring region of Planetesimals and is 3.7 Saturn not a satellite. It has to have sufficient mass to overcome its Saturn is the sixth closest planet to the Sun. It is the second compressive strength and achieve hydrostatic equilibrium. • It is thought that Jupiter’s strong gravitational influence may largest planet in the Solar System having a radius 9 times that have prevented the asteroids coalescing into larger objects of the Earth (57,000 km) and a mass 95 times that of Earth. such as a planet. • Saturn orbits the Sun once very 29 years (at about 1400 million • Outside of the asteroid belt itself there are also three clusters km) and is mainly comprised of gas (96 per cent hydrogen of asteroids which are very much in Jupiter’s influence. These and 3 per cent helium) and is presumed to have a rocky core are the Trojan asteroids, which orbit ahead and behind Jupiter surrounded by a sea of liquid metallic hydrogen, which forms and the Hilda Asteroids which orbit twice for every 3 Jupiter a ball some 56,000 km in diameter. orbits. These asteroids are in Jupiter’s Lagrange points - areas • The upper layers are thought to comprise of liquid water, of gravitational stability. ammonium hydrosulfide, hydrogen and helium. Saturn’s core The Universe 5

is quite hot (11,700 degrees C) and it generates more heat Mission to Uranus than it receives from the Sun. • The cloud layers of Saturn are similar to those of Jupiter except • To date Uranus has been visited only once - by NASA’s Voyager 2 spacecraft. The fly-by occurred in 1986 and that the banding is weaker and wider. resulted in the discovery of 10 new moons and 2 rings. It • Saturn rotates at around 10 hours 39 minutes. also measured the chemical composition of the atmosphere Saturn’s Rings: These were first seen by Galileo Galilei in • and photographed the planet and its moons. This data is 1610 who, quite understandably, was confused by them and still being studied and in 2016 researchers claimed to have thought Saturn was being accompanied by two other planets discovered evidence for two new moons which may be which sat either side of it. The rings extend from 7000 km to causing disturbances in its inner most rings. 120,000 km above the surface of Saturn. • A “Uranus Orbiter and Probe” mission is in the study • Saturn has 62 moons with only seven being large enough to stages. become spherical in shape. By far the largest of all of Saturn’s moons is Titan which is larger than the planet Mercury, 3.9 Neptune and the second largest moon in the Solar System (Jupiter’s • Neptune is the eighth closest planet to the Sun and is (since Ganymede being the largest). the relegation of Pluto) the last Planet in the Solar System. • It is similar in size and composition to Uranus with a diameter Mission to Saturn of 49,000 km and a mass of over 17 times that of Earth. In 2004 the Cassini spacecraft became the first probe to enter • Neptune orbits the Sun once every 165 years at about 4500 into orbit around Saturn releasing the Huygens probe which million km. This is 30 times the distance from the Sun to the entered Titans atmosphere early in January 2005. The Huygens Earth which means that the strength of sunlight at Neptune probe successfully landed on the surface of Titan sending back is 1 per cent of its strength at Earth. Neptune spins on an axis images and data during its descent and from the surface. Cassini with a tilt of 28 degrees, which is quite similar to that of the has made many fly-pasts of Saturn’s moons and ring systems Earth, every 16 hours. making many new discoveries including new rings and weather • Unlike Uranus’ almost completely bland cloud layer, Neptune’s systems. The Cassini spacecraft continues to study the Saturnian weather systems are more pronounced with great dark spot system until 2017 when it was deliberately crashed into Saturn. storm systems being seen in the southern and northern hemispheres and other visible banding. 3.8 Uranus • Neptune’s Rings: Neptune has a ring system comprised of • Uranus is the seventh closest planet to the Sun and the three main rings with radii between 63,000 km and 42,000 km third largest and fourth heaviest of the planets. It’s diameter which appear to have a clumpy structure, in which they form (50,000 km) is four times that of the Earth with a mass over 14 arcs rather than complete rings. It is believed that gravitational effects from Neptune’s moons may cause the clumping. times that of the Earth. • Neptune has 14 known moons of which Triton (2700 km • Uranus orbits the Sun once every 84 years (at about 2900 diameter) is the most significant. The next largest moon, million km) but is unusual with the fact that it spins on its side Proteus, is only 420 km in diameter. Triton is the only large (with an axial tilt of 97 degrees). This means that its moons and moon to orbit in retrograde (e.g. in the opposite direction also its faint ring system also orbit in plane perpendicular to to most orbits) and is thought to be a captured object rather the plane of the ecliptic. than created in orbit. • It is believed to be comprised of a small rocky core surrounded by a deep mantle of water, ammonia and methane. This is in Mission to Neptune turn surrounded by an atmosphere of hydrogen, helium and • To date Neptune (like Uranus) has been visited only methane with an upper cloud layer. Another oddity in Uranus once - again by NASA’s Voyager 2 spacecraft. The fly-by is the fact that it is very cold. All the other gas giant planets occurred in 1989 and resulted in many discoveries including emit more heat radiation than they receive due to very hot Neptune’s weather systems, rings and 6 more moons. It also cores, but Uranus does not. A temperature of -224°C has been provided an accurate measurement of Neptune’s mass measured in Uranus’ atmosphere - the coldest in the Solar which allowed discrepancies in the orbits of Uranus and System. Neptune to be solved. • Uranus’ Rings: Uranus has the second most extensive ring • There are currently no missions planned to visit Neptune, system of the solar system after Saturn. since the Neptune Orbiter and Probe mission was • Uranus has 27 known moons with sizes ranging from over dropped in favour of the Uranus Orbiter and Probe mission. 1500 km diameter down to under 20 km. The moons consist of ice, rock and other trace elements. Some of the inner moons 3.10 Glossary undergo gravitation interactions with each other which may • Black Body: An idealized object that absorbs all electromagnetic radiation which falls on it, without passing in many millions of years lead to instabilities and collisions. through and without reflection. The radiation emitted from a 6 Indian and World Geography

black body is mostly infrared light at room temperature, but as • Aurora Australis or Southern Lights are dynamic displays the temperature increases it starts to emit visible wavelengths, of light that appear in the Antarctic Skies in winter. They from red through to blue, and then ultraviolet light at very are nature’s light show. It is the name given to light emitted high temperatures. by atoms, molecules, and ions that have been excited by • Black Hole: The warped space-time remaining after energetic charged particles. Common colors are pale green the gravity of a massive body has caused it to shrink down and pink in spiral curtains, arcs and streamers. to a point. It is a region of empty space with a point- • Aurora Borealis also know as Northern Polar lights are like singularity at the center and an event horizon at the outer natural occurring light display in the heavens in the Northern edge. It is so dense that no normal matter or radiation can hemisphere. They are nature’s light show. It is the name given escape its gravitational field, so that nothing - not even light - to light emitted by atoms, molecules, and ions that have been can ever escape (hence its blackness). It is thought that excited by energetic charged particles. Common colors are most galaxies have a supermassive black hole at their heart. pale green and pink in spiral curtains, arcs and streamers. • Cosmic Microwave Background Radiation: Cosmic • Binary Star is a star system composed of two stars that orbit a Microwave Background Radiation (CMB) is the “afterglow” common center. The primary star is brightest; the secondary is of the Big Bang, a microwave radiation which still uniformly referred to as the companion star. permeates all of space at a temperature of around -270°C • Heliopause – The point at which the solar wind meets the (about 3° above absolute zero). It is considered to be the best interstellar medium or solar wind from other stars evidence for the standard Big Bang model of the Universe. • International Space Station – A global cooperative program • Cosmic Rays: High speed, energetic particles (about 90 per between the United States, Russia, Canada, Japan, and cent of which are protons) originating from space that impinges Europe, for the joint development, operation, and utilization on Earth’s atmosphere. Some cosmic rays are generated by of a permanently habitat in space close to low-Earth orbit. our own Sun, some by supernovas, some by as yet unknown • Kuiper Belt – a region in the outer Solar System beyond events in the farthest reaches of the visible universe. The term Neptune’s orbit that contains billions of small, icy bodies; “ray” is a misnomer, as cosmic particles arrive individually, not Pluto is the largest known Kuiper Belt Object. in the form of a ray or beam of particles. • Meteor – A flash of light that occurs when a meteoroid burns • Dark Matter: Matter that gives out no light and does not up in Earth’s atmosphere, also known as shooting star. interact with the electromagnetic force, but whose presence • Meteor Showers – Period of meteor activity that occurs when can be inferred from gravitational effects on visible matter. It Earth collides with many meteoroids; an individual shower is estimated that there may be between 6 and 7 times as much happens at the same time each year and has all its meteors dark matter as normal, bright matter in the Universe, although appearing to radiate from a common point. its exact nature remains a mystery. • Meteorite – Rock from space that survives as it passes through • Light Year: A convenient unit for measuring the large the Earth’s atmosphere and falls to the ground. distances in the Universe. It is the distance that light travels in • Meteoroid – Small rock that orbits the Sun. one year which, given that light travels at 300,000 kilometers • Nebula – a cloud of interstellar gas and dust; some nebulae per second, works out to about 9,460,000,000,000 kilometers represent stellar nurseries, others represent stellar graveyards. (9.46 trillion kilometers). • Red Dwarf – Smaller star with a low mass, cooler, and less • Neutron Star: A star that has shrunk under its luminous than the Sun. own gravity during a supernova event, so that most of • Red Giant – Cool star nearing the end of its cycle. These have its material has been compressed into neutrons only expanded up a hundred times the diameter of the Sun. (the protons and electrons have been crushed together until • Van Allen Belts – Dual belts of charged particles from a solar they merge, leaving only neutrons). Neutron stars are very wind trapped in earth’s magnetic field above the atmosphere. hot, quite small (typically 20 to 30 kilometers in diameter), Radiation zone of charged particles surrounding Earth. Shape extremely dense, have a very high surface gravity and rotate of Van Allen belts is determined by Earth’s magnetic field. very fast. A pulsar is a kind of highly-magnetized rapidly- • Redshift: A shift in the lines of an object’s spectrum toward rotating neutron star. the red end. Redshift indicates that an object is moving away • Supernova: A cataclysmic explosion caused by the collapse from the observer. The larger the redshift, the faster the object of an old massive star which has used up all its fuel. For a short is moving. time, such an explosion may outshine an entire galaxy of • Pulsar: Pulsars belong to a family of objects called neutron a hundred billion ordinary stars. It leaves behind a cloud of stars that form when a star more massive than the Sun runs brightly colored gas called a nebula, and sometimes a highly out of fuel in its core and collapses in on itself. This creates a compressed neutron star or even a black hole. massive explosion called as a supernova. The Universe 7

 Self–Evaluation Test 1. Which of the following will be studied by NASA’s Juno Which of the above statements is/are correct? mission launched in 2011? (a) 1 only (b) 2 only 1. Evolution of Jupiter along with a study of its core (c) Both 1 and 2 (d) Neither 1 nor 2 2. Presence of water in its atmosphere 4. Which of the following statements is/are true about 3. Formation of the Magnetosphere Solar flares? Which of the above statements is/are correct? 1. These cause auroras at the poles when it interacts with (a) 1 and 2 (b) 2 and 3 Earth’s atmosphere. (c) 1 and 3 (d) All of the above 2. Solar flares are able to disrupt communications satellites, GPS and power grids. 2. The phenomena of Red Shift is related to which of the 3. Large solar bursts have energies equivalent to one following? billion hydrogen bombs. (a) Expansion of Universe Select the correct answer using the codes given below: (b) Sea-floor spreading (a) 1 only (b) 1 and 3 only (c) Dispersion of light (c) 2 and 3 only (d) All of the above (d) Evolution of life 5. Which of the following statements is/are correct? 3. Consider the following statements with regard to 1. The atmosphere of Mars is about 100 times thinner than asteroids: Earth’s. 1. Asteroids are a swarm of small bodies in between Jupiter 2. The Martian atmosphere contains methane. and Mars that revolve around the Sun. Select the correct answer using the codes given below: 2. They are considered to be the pieces of a planet which (a) 1 only (b) 2 only probably exploded after its birth. (c) Both 1 and 2 (d) Neither 1 nor 2

ANSWERS 1. (d) 2. (a) 3. (c) 4. (d) 5. (c)