Part-3: GEOGRAPHY - World Geography
1. The Universe
Constellations:
Recognizable patterns formed by groups of stars (more accurately called Asterisms). Astronomers use 'constellation' to refer to a specific area of the sky.
Orion: Known as 'The Hunter' or 'Mriga'. Visible in the evening, located on the celestial equator. Brightest winter constellation. Contains bright stars like Betelgeuse and Rigel. Helps locate Sirius.
Ursa Major: Known as 'Great Bear'. Northern sky constellation, visible year-round in N. Hemisphere. Contains the 'Saptarishi' asterism (seven stars). Visible early summer nights.
Ursa Minor: Another northern constellation.
Cassiopeia: Northern constellation.
IAU Recognition: The International Astronomical Union (IAU) recognizes 88 official constellations covering the entire sky.
Size: Largest constellation: Hydra. Smallest constellation: Crux.
Naming: The IAU (HQ: Paris, founded 1919) is responsible for naming constellations and celestial bodies.
Stars:
Massive, luminous spheres of plasma held together by gravity.
Composition: Primarily Hydrogen (~70%) and Helium (~28%), with trace other elements.
Energy Source: Nuclear fusion (Hydrogen fuses into Helium).
Sirius (Dog Star / Alpha Canis Majoris): Brightest star in Earth's night sky. Visible in Northern Hemisphere winter. It's a binary star system. NOT a constellation.
Galaxies:
Huge systems containing billions of stars, dust, and gas. Millions of galaxies make up the universe.
Milky Way: Our home galaxy. It's a medium-sized barred spiral galaxy, about 13.6 billion years old, containing ~100 billion stars. Our solar system is in an outer spiral arm. Galileo first resolved its stars (1610).
Andromeda Galaxy: The nearest spiral galaxy to the Milky Way. Visible to the naked eye.
Types:
Spiral: Flattened disc shape with spiral arms (e.g., Milky Way, Andromeda).
Elliptical: Symmetrical, elliptical shape; contain older red stars; little new star formation.
Irregular: No defined shape or axis of rotation.
The Universe:
Age: Approximately 13.8 billion years old.
Composition: Made up of 'matter' (living and non-living). Most abundant element: Hydrogen (H). Second most abundant: Helium (He).
Study: Cosmology is the branch of astronomy studying the origin and evolution of the universe.
Big Bang Theory: Proposed by Georges Lemaître (1927). States the universe began from an infinitely hot, dense point and has been expanding ever since.
Hubble's Law: Galaxies are receding from Earth; recession velocity is proportional to distance. Supports universe expansion.
Other Objects/Concepts:
Nebulae: Interstellar clouds of dust, hydrogen, helium, and ionized gases (e.g., Helix Nebula).
Exoplanets: Planets outside our solar system. Kepler-452b is called "Earth's Cousin" or "Earth 2.0".
Celestial Body: Any natural object outside Earth's atmosphere (e.g., stars, planets, moons). Oceans are NOT celestial bodies.
2. The Solar System
Definition: The gravitationally bound system comprising the Sun and the objects that orbit it (planets, dwarf planets, moons, asteroids, meteoroids, comets).
Formation Age: Approximately 4.6 billion years old.
Heliocentric Model: Proposed first by Nicolaus Copernicus. Model where Earth and planets revolve around the Sun.
Planetary Motion: Planets revolve around the Sun in fixed elliptical paths called orbits (Kepler's Laws). Most planets rotate anti-clockwise (W to E); Venus and Uranus rotate clockwise (E to W).
Planet Classification:
Inner/Terrestrial Planets: Mercury, Venus, Earth, Mars.
Outer/Jovian Planets: Jupiter, Saturn, Uranus, Neptune.
Planet Order (from Sun): Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.
(i) The Sun:
Center of the solar system; source of energy (nuclear fusion: H -> He).
Composition: Primarily Hydrogen (~70%), Helium (~28%).
Layers (Outer to Inner): Corona (outermost, ~1M °C, visible during eclipse), Transition Region, Chromosphere, Photosphere (visible surface, ~6000°C), Convection Zone, Radiation Zone, Core (~1.5x10^7 °C).
Sunlight Travel Time to Earth: ~8 minutes 20 seconds (500 seconds).
Distance to Earth: ~149.6 million km (1 AU).
Sunspots: Cooler, darker areas on the photosphere.
Solar Flares: Short bursts of energy from the photosphere.
Solar Eclipse: Occurs when the New Moon passes between the Sun and Earth.
Lunar Eclipse: Occurs when Earth passes between the Sun and Full Moon.
Angle with Earth's surface: ~32 minutes.
(ii) Mercury:
Closest planet to the Sun. Smallest planet.
No natural satellites (moons). Rocky with a large iron core. Fastest orbital period (88 Earth days).
(iii) Venus:
Second planet from the Sun. Hottest planet.
Thick atmosphere (mostly CO2) with clouds of Sulphuric Acid.
No natural satellites (moons). Rotates clockwise (East to West).
Similar in size and mass to Earth ("Earth's Twin", "Sister Planet").
Known as the "Morning Star" and "Evening Star" due to brightness. Brightest planet. Named after Roman goddess of love/beauty.
(iv) The Earth:
Third planet from the Sun. Fifth largest planet.
Shape: Geoid / Oblate Spheroid (slightly flattened at poles).
Axial Tilt: 23.5° relative to orbital perpendicular (or 66.5° relative to orbital plane). Causes seasons.
Rotation: ~24 hours. Revolution: ~365.25 days. Orbital speed: ~67,000 mph.
Atmosphere: ~78% Nitrogen, ~21% Oxygen, ~0.93% Argon, ~0.04% Carbon Dioxide.
Hydrosphere: ~71% of surface covered by water ("Blue Planet").
Satellite: One natural satellite (The Moon).
Mass: ~5.97 x 10^24 kg. Ultimate energy source: The Sun.
Study: Geology (study of Earth structure/history), Geomorphology (study of landforms).
(v) Mars:
Fourth planet from the Sun. Known as the "Red Planet" (due to iron oxide).
Orbit/Rotation: ~687 Earth day orbit; rotation period similar to Earth's.
Satellites: Two small moons: Phobos and Deimos. Deimos is the smallest moon in the solar system.
Features: Olympus Mons (largest volcano/mountain in solar system).
(vi) Jupiter:
Fifth planet from the Sun. Largest planet by mass and volume.
Primarily composed of Hydrogen and Helium (gas giant).
Features: Great Red Spot (persistent anticyclonic storm). Orange colour with white stripes/bands.
Satellites: Has many moons. Four largest (Galilean Moons, discovered by Galileo 1610): Io, Europa, Ganymede, Callisto. Ganymede is the largest moon in the solar system. (Note: Saturn currently holds the record for most known moons).
(vii) Uranus/Neptune/Pluto:
Uranus: Seventh planet. Discovered by William Herschel (1781). Rotates clockwise (E to W). First planet discovered using a telescope.
Neptune: Eighth planet. Also appears blue.
Pluto: Discovered 1930 (Clyde Tombaugh). Classified as a dwarf planet since 2006 (IAU). Located in the Kuiper Belt. Largest known dwarf planet by volume. Has 5 moons (Charon is the largest).
(viii) The Moon:
Earth's only natural satellite. Fifth largest moon in the solar system.
Orbit/Rotation: Orbits Earth in ~27.3 days. Rotation period is also ~27.3 days (synchronous rotation), so the same face always points towards Earth.
Phases: Cycle repeats approx. every 29.5 days (Synodic month). Phases include New Moon (invisible), Crescent, First Quarter (Half Moon), Gibbous, Full Moon, Third Quarter (Half Moon), Crescent. Half Moon occurs twice a month.
Appearance: Brightest object in the night sky. Shines by reflecting sunlight.
Blue Moon: The second full moon occurring within a single calendar month.
(ix) Asteroids:
Rocky objects orbiting the Sun, smaller than planets.
Asteroid Belt: Most are found between Mars and Jupiter.
Ceres: Largest object in the asteroid belt; classified as a dwarf planet. First asteroid discovered (Giuseppe Piazzi, 1801).
(x) Comets, Meteors, and Meteorites:
Comet: Body of ice, rock, and dust orbiting the Sun. Develops a tail of gas and dust that points away from the Sun when close to it. Halley's Comet appears every ~76 years (next visible ~2061).
Meteoroid: Small piece of rock or debris orbiting the Sun.
Meteor: A meteoroid that enters Earth's atmosphere and burns up, creating a streak of light ("shooting star").
Meteorite: A meteoroid that survives its passage through the atmosphere and lands on Earth's surface.
3. The Earth
* **(i) Internal Structure:**
* **Crust:** Outermost thin shell (<1% of Earth's volume). Part of the lithosphere. Oceanic crust (~5-10 km thick), Continental crust (~30-50 km thick). Most abundant metal: Aluminium (Al). Most abundant element: Oxygen (O). Second most abundant element: Silicon (Si). Mica forms ~4% of the crust.
* **Mantle:** Layer beneath the crust. Thickest layer. Source of magma.
* **Lithosphere:** Rigid outer part, includes crust and upper mantle.
* **Asthenosphere:** Part of the upper mantle below the lithosphere. Highly viscous, mechanically weak, ductile region. Allows tectonic plates to move. Location of convection currents.
* **Core:** Innermost layer. Outer core (liquid), Inner core (solid). Primarily Iron and Nickel.
* **Magma:** Molten/semi-molten rock beneath Earth's surface (in mantle). **Lava** is magma that reaches the surface.
* **Densest Substance:** Osmium (Os) is the densest naturally occurring element on Earth.
* **(ii) Latitudes:**
* Imaginary lines running parallel to the Equator, measuring distance North or South of the Equator (0° to 90° N/S).
* **Equator (0°):** Longest line of latitude. Divides Earth into Northern and Southern Hemispheres. Cities on Equator: Pontianak (Indonesia).
* **Tropic of Cancer (23.5° N):** Sun is directly overhead on Summer Solstice (~June 21). Passes through 8 Indian states (Gujarat, Rajasthan, MP, Chhattisgarh, Jharkhand, W. Bengal, Mizoram, Tripura). Does NOT pass through Assam.
* **Tropic of Capricorn (23.5° S):** Sun is directly overhead on Winter Solstice (~Dec 22).
* **Arctic Circle (66.5° N)**
* **Antarctic Circle (66.5° S)**
* **Equinox:** Occurs when Sun is directly overhead at the Equator (~March 21 - Vernal, ~Sept 23 - Autumnal). Day and night are of equal length everywhere. Occurs twice a year. Neither pole is tilted towards the Sun.
* **Solstice:** Occurs when Sun reaches its highest/lowest point relative to the celestial equator. Summer Solstice (~June 21): Longest day in N. Hemisphere. Winter Solstice (~Dec 22): Shortest day in N. Hemisphere (longest day in S. Hemisphere). India experiences shortest day on Dec 22.
* **Doldrums:** Area of low pressure and calm winds around the Equator (related to ITCZ).
* **(iii) Longitude:**
* Imaginary lines (meridians) running from North Pole to South Pole, measuring distance East or West of the Prime Meridian (0° to 180° E/W).
* Lines converge at the poles (unlike parallel latitudes).
* **Prime Meridian (0°):** Passes through Greenwich, London. Basis for time zones.
* **International Date Line (IDL):** Roughly follows 180° longitude. Separates consecutive calendar days. Not perfectly straight. Passes through Pacific Ocean.
* **Indian Standard Time (IST):** Based on 82.5° E longitude meridian, passing near Prayagraj (Allahabad/Naini). IST = GMT + 5:30 hours. Passes through 5 states (UP, MP, Chhattisgarh, Odisha, Andhra Pradesh). Does NOT pass through Bihar.
* **Time Zones:** Regions observing uniform standard time. France (incl. territories) has the most (12). Russia has 11. USA has 6 (by law). India has one standard time zone.
* **Time Lag:** Due to Earth's rotation, there's approx. 4 minutes difference per degree of longitude. Time lag between Gujarat and Arunachal Pradesh is approx. 2 hours.
4. Rock
Definition: Naturally occurring solid aggregate of one or more minerals.
Types:
Igneous Rocks: Formed from the cooling and solidification of magma or lava. Often hard, granular, lack fossils. Examples: Granite, Basalt, Gabbro, Diorite, Pegmatite. Granite is light-colored, forms below surface (slow cooling). Basalt forms from lava (fast cooling).
Sedimentary Rocks: Formed from the accumulation and cementation (lithification) of sediments (fragments of rocks, minerals, organic matter). Often layered, may contain fossils. Examples: Sandstone, Limestone, Shale, Conglomerate.
Metamorphic Rocks: Formed when existing rocks (igneous, sedimentary, or other metamorphic) are changed by heat, pressure, or chemical reactions. Examples: Marble (from Limestone), Slate (from Shale), Quartzite (from Sandstone), Schist, Gneiss. Quartzite is typically white/brown.
Rock Cycle: Continuous process where rocks are created, changed, and destroyed.
Asphalt: Black/brown petroleum-like material, NOT technically a rock in the geological sense used here.
Petrology: Branch of geology studying the origin, composition, structure, and classification of rocks.
Lithification: Process converting unconsolidated sediments into solid rock.
Bauxite: Ore deposit formed from decomposition of aluminium-silicate rich rocks; primary source of Aluminium.
Folds: Bends in rock layers due to compression. Anticline (upward fold), Syncline (downward fold).
5. Earthquake
Definition: Sudden shaking of the Earth's surface caused by the release of energy in the Earth's lithosphere (often due to movement along faults).
Causes: Tectonic plate movement (most common), volcanic eruptions, underground explosions, landslides.
Focus (Hypocenter): Point within the Earth where an earthquake originates.
Epicenter: Point on the Earth's surface directly above the focus.
Seismic Waves: Energy released travels as waves.
Body Waves: Travel through Earth's interior.
P-Waves (Primary): Fastest, arrive first. Compressional (longitudinal). Can travel through solids, liquids, gases.
S-Waves (Secondary): Slower than P-waves. Shear/Transverse waves (particles move perpendicular to wave direction). Can only travel through solids. Involve transverse displacement.
Surface Waves: Travel along Earth's surface. Cause most damage. Slower than body waves. (Rayleigh and Love waves).
Measurement:
Magnitude: Measure of energy released. Richter Scale (logarithmic, based on wave amplitude).
Intensity: Measure of shaking/damage at a specific location. Mercalli Scale (based on observations).
Study: Seismology.
Tsunami (Seismic Sea Wave): Large ocean wave(s) caused by sudden displacement of water, often by underwater earthquakes, volcanic eruptions, or landslides. Warning sign: Water rapidly receding from the beach. Soil erosion is NOT a cause. Also known as 'Harbour Wave' (Japanese). Usually requires magnitude > 7.5 earthquake.
Seismic Zones (India): Grouped into Zone II, III, IV, V (V being most active, II least). Raipur is in the lowest zone among options. Andaman & Nicobar Islands fall under Zone V.
Tides: Rise and fall of sea levels caused by gravitational pull of Moon and Sun.
Spring Tides: Highest high tides and lowest low tides. Occur during New Moon and Full Moon when Sun, Earth, Moon align.
Neap Tides: Moderate tides. Occur during First and Third Quarter Moon when Sun and Moon are at right angles relative to Earth.
6. Volcano
Definition: Opening (vent) in Earth's crust through which magma, ash, and gases erupt. The landform created is also called a volcano.
Volcanic Mountains: Formed by eruptions building up layers of lava and ash (e.g., Mt. Fuji, Mt. Kilimanjaro, Mt. Fujiyama).
Active Volcano: Currently erupting or has erupted recently and expected to erupt again (e.g., Mt. Etna, Stromboli, Barren Island).
Dormant Volcano: Not currently erupting but has erupted in recorded history and may erupt again (e.g., Mt. Kilimanjaro, Mt. Fuji, Mauna Kea).
Extinct Volcano: Not expected to erupt again.
Locations:
Mount Fuji: Japan (Volcanic peak, highest in Japan).
Kilimanjaro: Tanzania, Africa (Highest mountain in Africa, dormant volcano).
Mount Etna: Sicily, Italy (Active volcano).
Vesuvius: Italy (Active/Dormant).
Cotopaxi: Ecuador (Active volcano).
Stromboli: Italy (Active, known as 'Lighthouse of the Mediterranean').
Barren Island: Andaman Sea, India (Only confirmed active volcano in South Asia).
Mount St. Helens: USA (Active volcano).
Mauna Kea: Hawaii, USA (Dormant volcano).
Tamu Massif: Pacific Ocean (Largest shield volcano on Earth).
Ojos del Salado: Andes (Argentina/Chile border, highest active volcano).
Ninety East Ridge: Indian Ocean (Submarine volcano ridge).
Mt. Vinson: Antarctica (Highest peak in Antarctica, NOT volcanic).
Mont Blanc: Alps (France/Italy, Highest peak in Alps, NOT volcanic).
Pacific Ring of Fire: Zone around the Pacific Ocean with high volcanic and seismic activity (~75% of Earth's volcanoes). Length approx. 40,000 km. Includes western coasts of Americas, eastern coasts of Asia/Oceania.
7. Humidity and Rainfall
Humidity: Amount of water vapor present in the air. Measured by Hygrometer / Psychrometer (dry/wet bulb).
Evaporation: Process of water turning into vapor. Driven by Sun's energy.
Condensation: Process of water vapor turning into liquid water, forming clouds.
Precipitation: Any form of water (liquid or solid) falling from clouds to Earth (rain, snow, sleet, hail). Occurs when cloud particles become too heavy.
Clouds: Mass of water droplets or ice crystals suspended in the atmosphere. Classified by altitude (Cirrus - high, Cumulus - middle/vertical, Stratus - low, Nimbus - rain-bearing).
Dew: Formed by condensation of water vapor onto a cold surface, especially overnight.
Water Cycle (Hydrological Cycle): Continuous movement of water on, above, and below Earth's surface. Driven by the Sun. Includes evaporation, condensation, precipitation, runoff, infiltration.
Monsoon: Seasonal reversal of winds, often accompanied by changes in precipitation. Derived from Arabic 'mausim' (season).
Western Disturbances: Weather systems originating in the Mediterranean, causing winter rainfall in Northwest India.
El Niño: Climatic pattern involving unusual warming of surface waters in the eastern tropical Pacific Ocean. Affects global weather, often reducing monsoon rainfall in India. Derived from Spanish ('The Little Boy').
La Niña: Opposite of El Niño; unusual cooling of surface waters in the eastern tropical Pacific.
8. Cyclone, Atmosphere
Atmosphere: Layer of gases surrounding Earth, held by gravity.
Layers (Bottom to Top):
Troposphere: Lowest layer (0-~10/18 km). Contains most weather, clouds, water vapor. Temperature decreases with altitude (normal lapse rate). Thickest at the Equator. Separated from Stratosphere by Tropopause.
Stratosphere: (~10/18 - 50 km). Contains the Ozone Layer. Temperature increases with altitude. Separated from Mesosphere by Stratopause.
Mesosphere: (~50 - 80 km). Temperature decreases with altitude. Separated from Thermosphere by Mesopause.
Thermosphere: (~80 - 400+ km). Temperature increases significantly with altitude. Contains the Ionosphere. Separated from Exosphere by Thermopause.
Exosphere: Outermost layer, merges with space. Lowest density.
Composition: Nitrogen (~78%), Oxygen (~21%), Argon (~0.93%), Carbon Dioxide (~0.04%), trace gases. Argon is the most abundant rare gas. Oxygen is used in combustion, respiration, nitrogen oxide formation. Nitrogen can be 'fixed' by lightning.
Ozone Layer: Concentrated in the Stratosphere (~15-30 km). Absorbs most harmful UV radiation from the Sun. Depletion (thinning) leads to increased UV exposure (risk of skin cancer, immune issues). Ozone hole observed over Antarctica.
Ionosphere: Region within Thermosphere/Exosphere containing ionized particles. Reflects radio waves, enabling long-distance communication.
Air Pressure (Atmospheric Pressure): Force exerted by the weight of air above. Measured by Barometer. Decreases with altitude. Sudden drop indicates storm; slow drop indicates rain; slow rise indicates clear weather.
Winds: Movement of air from high pressure to low pressure areas.
Planetary Winds: Global scale winds (Trade Winds, Westerlies, Polar Easterlies).
Katabatic Winds: Downslope flow of dense, cold air.
Anabatic Winds: Upslope flow of air warmed by heating.
Chinook Winds: Warm, dry winds descending eastern slopes of Rockies (N. America). Called 'snow eaters'.
Coriolis Effect: Apparent deflection of moving objects (like wind) due to Earth's rotation. Deflects to the right in N. Hemisphere, left in S. Hemisphere. Maximum at poles, zero at equator. Arises from rotation, NOT pressure difference.
Cyclones: Large rotating storm systems with low pressure centers.
Tropical Cyclone: Forms over warm tropical waters. Brings strong winds, heavy rain, storm surge. (e.g., 'Fani'). Rotate counter-clockwise in N. Hemisphere, clockwise in S. Hemisphere.
Mesocyclone: Rotating updraft within a thunderstorm.
Air Masses: Large bodies of air with uniform temperature and humidity. Classified by source region (e.g., cT - Continental Tropical: hot, dry, from deserts; cP - Continental Polar: cold, dry; mP - Maritime Polar: cool, moist; mT - Maritime Tropical: warm, moist; cA - Continental Arctic: very cold, dry). Continental Tropical (cT) is warm.
Inter Tropical Convergence Zone (ITCZ): Belt of low pressure near the equator where trade winds converge. Associated with cloudiness and rain. Position shifts seasonally, following the sun (north in N. Hemisphere summer, south in N. Hemisphere winter). Also related to the 'doldrums'.
Aurora (Borealis - North, Australis - South): Natural light display caused by charged particles from the sun interacting with atoms in the upper atmosphere.
9. Continent/Island
Continents: Earth's large continuous landmasses. (Asia, Africa, North America, South America, Antarctica, Europe, Australia).
Pangaea: Ancient supercontinent that included almost all landmasses. Proposed by Alfred Wegener (father of Plate Tectonics / Continental Drift).
Gondwanaland: Southern supercontinent formed after Pangaea split. Included S. America, Africa, India, Australia, Antarctica. France was NOT part of it.
Laurasia: Northern supercontinent formed after Pangaea split.
Largest Continent: Asia (by area and population).
Smallest Continent: Australia.
Most Populated Countries: Top 6 are located in Asia.
Island: Landmass smaller than a continent, completely surrounded by water.
Archipelago: A group or chain of islands (e.g., Indonesia, Seychelles, Philippines, Japan).
Largest Island: Greenland (politically part of Denmark).
Largest Island Country: Indonesia (by area and number of islands).
Specific Islands/Locations:
Sicily: Largest island in the Mediterranean Sea (Italy).
Australia: Smallest continent; also an island country.
Seychelles: Archipelago nation in the Indian Ocean.
Maldives: Archipelago nation in the Indian Ocean. Capital: Male.
Filitheyo: Island in the Maldives.
Hawaiian Islands: Island state of the USA in the Pacific Ocean. Capital: Honolulu.
Manitoulin Island: Canada (Largest lake island in the world).
Tierra del Fuego: Archipelago at the southern tip of South America (split between Chile and Argentina).
Borneo, Java, Sumatra: Islands belonging to Indonesia's archipelago.
Landlocked Country: Country entirely enclosed by land, with no direct access to the sea (e.g., Nepal, Kazakhstan, Bolivia, Paraguay, Mongolia). Kazakhstan is the largest. No landlocked countries in N. America or Australia.
Transcontinental Country: Country located on more than one continent (e.g., Russia, Turkey, Egypt, Kazakhstan, Georgia, Indonesia).
10. Hydrosphere
* **(i) Relief of the Ocean Floor:** Includes continental shelf, slope, rise, abyssal plain, trenches, ridges.
* **Ocean Trenches:** Deepest parts of the ocean.
* **Mariana Trench:** Deepest point on Earth, located in the Pacific Ocean. Contains the Challenger Deep.
* **Java Trench (Sunda Deep):** Deepest point in the Indian Ocean.
* **Tonga Trench:** Second deepest trench, SW Pacific.
* **Puerto Rico Trench:** Deepest point in Atlantic Ocean.
* **(ii) Ocean/Sea:**
* Oceans cover ~71% of Earth's surface. Average surface water temperature ~17°C.
* **Largest Aquatic Body / Salt Lake:** Caspian Sea (bordered by Russia, Kazakhstan, Turkmenistan, Iran, Azerbaijan).
* **Saltiest Sea:** Dead Sea has highest salinity among major bodies, but Lake Van (Turkey) is saltier. Red Sea is saltier than Black Sea or Baltic Sea.
* **Mediterranean Sea:** Large sea connected to Atlantic. Largest island: Sicily. Connected to Red Sea via Suez Canal, Atlantic via Strait of Gibraltar, Black Sea via Bosphorus Strait.
* **Arabian Sea:** Part of Indian Ocean, West of India.
* **Tasman Sea:** Separates Australia and New Zealand.
* **Bermuda Triangle:** Region in the western North Atlantic Ocean.
* **(iii) Oceanic Currents:** Continuous movement of seawater.
* **Warm Currents:** Flow from low latitudes (tropics) towards high latitudes (poles). Examples: Gulf Stream (Atlantic), Kuroshio Current (Pacific, also 'Black Current'/Japan Current), Alaskan Current (Pacific), Brazil Current (Atlantic).
* **Cold Currents:** Flow from high latitudes towards low latitudes. Examples: Labrador Current (Atlantic), Oyashio Current (Pacific), Humboldt Current (Pacific, also Peru Current), Benguela Current (Atlantic).
* **El Niño:** A warm ocean current pattern along the Peruvian coast (Pacific Ocean).
* **Kuroshio Current:** Flows in the Pacific Ocean.
* **Gulf Stream:** Originates in Gulf of Mexico, flows NE in Atlantic. Warm current. Confluence with cold Labrador Current near Newfoundland creates rich fishing grounds (Grand Banks).
* **Humboldt Current (Peru Current):** Cold current along the west coast of South America (Pacific).
* **(iv) Channel/Strait:** Narrow waterway connecting two larger bodies of water.
* **Strait:** Naturally formed. Often lies between two landmasses.
* **Channel:** Can be natural or man-made. Often wider than a strait.
* **Palk Strait:** Between Tamil Nadu (India) and Jaffna (Sri Lanka). Connects Bay of Bengal and Palk Bay. Separates India and Sri Lanka.
* **Strait of Magellan:** Connects Atlantic and Pacific Oceans at southern tip of South America.
* **Bering Strait:** Between Alaska (USA) and Russia. Connects Arctic Ocean and Pacific Ocean (Bering Sea).
* **Strait of Gibraltar:** Connects Atlantic Ocean and Mediterranean Sea. Separates Spain (Europe) and Morocco (Africa).
* **Dover Strait:** Connects English Channel and North Sea. Separates England and France.
* **Sunda Strait:** Between Java and Sumatra (Indonesia). Connects Java Sea and Indian Ocean.
* **Cook Strait:** Between North and South Islands of New Zealand.
* **Strait of Hormuz:** Between Persian Gulf and Gulf of Oman/Arabian Sea.
* **10 Degree Channel:** Separates Andaman Islands and Nicobar Islands (India) in Bay of Bengal.
* **8 Degree Channel:** Separates Minicoy (India) and Maldives.
* **9 Degree Channel:** Separates Minicoy from main Lakshadweep archipelago (India).
11. Major Lake and Waterfall of the World
Lakes:
Largest Freshwater Lake (by volume): Lake Baikal (Siberia, Russia). Also the world's deepest lake. UNESCO site.
Largest Freshwater Lake (by surface area): Lake Superior (North America - USA/Canada border). Largest of the Great Lakes.
Largest Lake (overall, saline): Caspian Sea.
Largest Salt Lake: Caspian Sea. Salar de Uyuni (Bolivia) is the world's largest salt flat.
Highest Navigable Lake: Lake Titicaca (Andes - Peru/Bolivia border). Largest lake in South America by volume.
Dead Sea: Highly saline lake bordering Jordan and Israel/Palestine. Very high salinity.
Lake Pangong Tso: Endorheic lake shared by India (Ladakh) and China (Tibet).
Great Lakes (N. America): Superior, Michigan, Huron, Erie, Ontario. Niagara Falls is between Erie and Ontario.
Waterfalls:
Highest Waterfall: Angel Falls (Venezuela). On Rio Churun. Height ~979m.
Niagara Falls: Collective name for three falls on Niagara River, border of USA (New York) and Canada (Ontario). Between Lake Erie and Lake Ontario.
Victoria Falls: On Zambezi River, border of Zambia and Zimbabwe (Africa). Local name 'Mosi-oa-Tunya' (Smoke that Thunders).
Iguazu Falls: Border of Argentina and Brazil.
12. Topography
Geomorphology: Study of landforms, their origin, evolution, and processes shaping them.
River Features:
Meanders: Sinuous bends or curves in a river channel, especially in plains/deltas.
Floodplains: Flat area alongside a river, subject to flooding.
Oxbow Lake: U-shaped lake formed when a meander is cut off from the main river.
Delta: Landform created by deposition of sediment where a river flows into an ocean, sea, lake, etc. Ganges-Brahmaputra delta is the world's largest.
Desert Features:
Barchans: Crescent-shaped sand dunes. Common in Thar desert.
Glacial Features:
Moraine: Accumulation of rock debris (till) carried or deposited by a glacier.
Crevasse: Deep crack or fracture found in a glacier.
Glacier Formation: Accumulation and compaction of snow over many years, recrystallizing into ice.
13. Major Canals of the World
Suez Canal: Artificial sea-level waterway in Egypt. Connects Mediterranean Sea and Red Sea. Opened 1869. Shortest sea route Europe-Asia. Separates Africa and Asia.
Panama Canal: Waterway in Panama connecting Atlantic Ocean and Pacific Ocean across Isthmus of Panama. Opened 1914. Uses lock system.
Beijing-Hangzhou Grand Canal: China. Longest canal in the world. Links Yellow River and Yangtze River.
Kiel Canal: Germany. Connects North Sea and Baltic Sea.
Corinth Canal: Greece. Connects Gulf of Corinth and Saronic Gulf (Aegean Sea).
14. Major Rivers of the World
Longest River: Nile (Africa, ~6650 km). Flows North through NE Africa, drains into Mediterranean. Runs through Egypt, Sudan, etc.
Largest River (by discharge volume): Amazon (South America, ~6400-7000 km). Flows West to East across N. South America (Peru, Brazil, etc.), drains into Atlantic. Largest drainage basin. Does not flow into Africa.
Third Longest River: Yangtze (Asia, China, ~6300 km). Longest river in Asia.
Yellow River (Huang Ho): Second longest in China (~5400 km). Called 'Yellow' due to silt. Also called 'Sorrow of China' due to devastating floods.
Indus River: Flows through China (Tibet), India, Pakistan. Drains into Arabian Sea. Known as 'Darya-e-Sindh' in Urdu (Pakistan). Does not flow through Afghanistan.
Ganges & Brahmaputra: Form the world's largest delta (India/Bangladesh).
Volga River: Longest river in Europe (~3690 km). Flows through Russia, drains into Caspian Sea.
Danube River: Second longest in Europe (~2850 km). Passes through most countries (10). Germany to Black Sea.
Thames River: Flows through London, England.
Hudson River: Flows through New York state, USA, including New York City.
Zambezi River: Southern Africa. Victoria Falls located on it.
Congo River: Central Africa. Second largest by discharge. Inga Dams located on it.
Niger River: West Africa.
Orange River: Southern Africa.
Magdalena River: Main river of Colombia (South America).
Tarn River: France. Millau Viaduct (tallest bridge) crosses it.
Hamza River: Proposed subterranean 'river' beneath the Amazon River basin.
Kelani River: Sri Lanka (NOT in India).
15. Major Countries of the World
Largest Country (Area): Russia.
Second Largest Country (Area): Canada.
Sixth Largest Country (Area): Australia.
Largest Land Area: Russia (Canada is 2nd, China 3rd/4th, USA 3rd/4th).
Smallest Country: Vatican City.
Landlocked Countries: Surrounded by land (e.g., Nepal, Mongolia, Kazakhstan, Bolivia, Paraguay). Kazakhstan largest. Mongolia is between Russia/China.
Boundaries:
49th Parallel: USA / Canada.
38th Parallel: North Korea / South Korea.
Durand Line: Pakistan / Afghanistan.
McMahon Line: India / China.
Radcliffe Line: India / Pakistan.
Maginot Line: France / Germany (historical fortification).
Hindenburg Line: Germany / Poland (WWI).
Oder-Neisse Line: Germany / Poland (post-WWII).
Former Names: Abyssinia (Ethiopia), Persia (Iran), Ceylon (Sri Lanka), Gold Coast (Ghana), Temasek (Singapore).
'Hermit Kingdom': Term often applied to North Korea.
Country Information:
Sri Lanka: Island nation SE of India. Separated by Palk Strait/Gulf of Mannar. Former capital Anuradhapura. Sinhala is major language. Hambantota port leased to China.
Mongolia: Landlocked, East Asia. Known as 'Land of the blue sky'. Capital Ulaanbaatar.
Ethiopia: Horn of Africa. Capital Addis Ababa.
Finland: Northern Europe. Known as 'Land of Thousand Lakes'. Currency: Euro. Capital: Helsinki.
Malaysia: SE Asia. Capital Kuala Lumpur. Currency Ringgit. Flag has 14 red/white stripes.
Singapore: City-state in SE Asia. Former name Temasek.
Brazil: Largest country in South America. Largest city Sao Paulo (coffee hub). Official language Portuguese. Capital Brasilia. Amazon river flows through it.
Canada: Second largest country. Manitoulin Island located here. Shares 49th parallel border and Niagara Falls with USA.
Australia: Smallest continent. 6th largest country. Most densely populated city Sydney. Capital Canberra.
Chile: Long, narrow country in South America. Contains part of Andes.
Iran: Chabahar port located here. Former name Persia.
Egypt: Location of Suez Canal. Nile river flows through it. Capital Cairo.
Japan: Island nation, East Asia. Mt. Fuji is highest peak. Currency Yen. CHASHMA-III nuclear plant NOT in Japan (it's in Pakistan).
Indonesia: Largest island country. Archipelago. Contains Borneo, Java, Sumatra. Capital Jakarta.
Italy: Currency Euro. Contains Mt. Etna, Vesuvius, Stromboli volcanoes.
UK: Currency Pound Sterling.
Denmark: Capital Copenhagen. Currency Krone.
Cyprus: Island nation, Mediterranean. Capital Nicosia.
Uganda: East Africa. Capital Kampala.
Syria: Middle East. Capital Damascus. Currency Pound.
Pakistan: Indus river flows through it. Capital Islamabad. Borders Afghanistan (Durand Line). CHASHMA-III nuclear plant located here. Bolan Pass located here.
Afghanistan: Landlocked. Borders Pakistan (Durand Line, Khyber Pass). Helmand province famous for opium. TAPI pipeline passes through. Dari language official.
Nepal: Landlocked. Borders India. Madhesi community in southern plains (Terai). Topographic regions: Himalayas, Hills, Terai. Capital Kathmandu. Currency Rupee.
Bhutan: Eastern Himalayas. Landlocked. Capital Thimphu. Official language Dzongkha. Currency Ngultrum.
Myanmar: SE Asia. Rohingya ethnic community from here. Currency Kyat. Capital Naypyidaw.
China: Largest population. 3rd/4th largest area. Yellow River, Yangtze River. Gobi desert shared with Mongolia. Capital Beijing.
USA: 3rd/4th largest area. Capital Washington D.C. Alaska was purchased from Russia. Mount St. Helens volcano. Niagara Falls shared with Canada.
Russia: Largest country by area. Capital Moscow. Shares border with China, Mongolia, Kazakhstan etc. Ural mountains separate Europe/Asia. Volga river flows through it.
Kazakhstan: Largest landlocked country. Shares border with Russia, China. Part of Caspian Sea border. Capital Nur-Sultan.
Uzbekistan: Central Asia. Capital Tashkent.
Azerbaijan: Caucasus region. Capital Baku. Borders Caspian Sea, Iran. Currency Manat.
Armenia: Caucasus region. Currency Dram.
Albania: SE Europe. Capital Tirana. Currency Lek.
Croatia: SE Europe. Currency Kuna.
France: Western Europe. Capital Paris. Most time zones (incl. territories). Currency Euro.
Ireland: Island west of Great Britain. Capital Dublin. Currency Euro.
Sweden: Northern Europe. Borders Gulf of Bothnia. Currency Krona.
Thailand: SE Asia. Currency Baht. Capital Bangkok.
Vietnam: SE Asia. Capital Hanoi.
North Korea: East Asia. Capital Pyongyang. Founded under Kim Il-Sung.
South Korea: East Asia. Capital Seoul.
16. Capital and Currency of the Countries of the World
Refer to the specific country details in Section 15 above for capital/currency pairs mentioned.
Examples: Uzbekistan (Tashkent), UAE (Abu Dhabi), Iraq (Baghdad), Turkey (Ankara), Kazakhstan (Nur-Sultan), Kyrgyzstan (Bishkek), Libya (Tripoli), Bahamas (Nassau), Belgium (Brussels), Malaysia (Kuala Lumpur / Ringgit), Italy (Rome / Euro), Japan (Tokyo / Yen), Denmark (Copenhagen / Krone), Cyprus (Nicosia / Euro), Uganda (Kampala / Shilling), Maldives (Male / Rufiyaa), Pakistan (Islamabad / Rupee), Nepal (Kathmandu / Rupee), Sri Lanka (Colombo - commercial, Sri Jayawardenepura Kotte - administrative / Rupee), Myanmar (Naypyidaw / Kyat), Brazil (Brasilia / Real), Cuba (Havana / Peso), China (Beijing / Yuan), Thailand (Bangkok / Baht), Syria (Damascus / Pound), Finland (Helsinki / Euro), Ireland (Dublin / Euro), France (Paris / Euro), Jordan (Amman / Dinar), Croatia (Zagreb / Kuna), Albania (Tirana / Lek), Azerbaijan (Baku / Manat), Armenia (Yerevan / Dram), North Korea (Pyongyang / Won), South Korea (Seoul / Won), Vietnam (Hanoi / Dong), Cambodia (Phnom Penh / Riel).
17. Major Cities of the World
Most Densely Populated (Australia): Sydney.
Largest City (Brazil): Sao Paulo.
Location on Rivers: Alexandria (Nile), Budapest (Danube), Baghdad (Tigris), London (Thames), Paris (Seine), New York City (Hudson).
'Pines City': Baguio (Philippines).
'Forbidden City': Located in Beijing, China.
Holy City 'Mecca': Located in Saudi Arabia.
Cape Canaveral: Space launch site on coast of Florida, USA.
18. Major Languages of the World
Official Language (Bhutan): Dzongkha.
Official Language (Brazil): Portuguese.
Castellano: Another name for the Spanish language. Widely spoken, official UN language.
Dari: Form of Persian; official language of Afghanistan.
Sinhala: Major language of Sri Lanka. Indo-Aryan language.
Most Spoken (Native Speakers): 1st Mandarin Chinese, 2nd Spanish. (Note: English is most spoken including non-native speakers).
19. Major Tribes of the World
Maasai: Natives of East Africa (Kenya, Tanzania). Pastoral nomads.
Zulu: Tribe belonging to South Africa.
Kurdish: Ethnic group in the Middle East (Iraq, Turkey, Syria, Iran, Armenia).
Rohingya: Ethnic community from Myanmar (mostly Muslim).
Madhesi: Community residing in the southern plains (Terai) of Nepal.
Tipi: Conical tent traditionally made from animal skins on wooden poles (Native American plains tribes).
Igloo: Snow shelter (Inuit).
Other African Tribes: Himba (Namibia), San/Bushmen/Khoisan (Southern Africa), Ndebele (South Africa), Samburu (Kenya).
Pashtuns, Sindhis: Tribes in Pakistan.
Gonds, Bhils, Munda: Tribes in India.
Manchu, Hui: Groups in China.
20. Agriculture and Animal Husbandry
Largest Coffee Producer: Brazil. Coffee plantations called 'Fazendas'.
Largest Milk Producer: India.
Largest Wheat Producer: China.
Largest Cocoa Producer: Ivory Coast (Côte d'Ivoire).
Opium Cultivation: Helmand province, Afghanistan is a major region.
Clove Cultivation: Pemba island (Tanzania) is famous for it.
Silk Origin: China.
Farming Systems/Techniques:
Crop Rotation: Growing different crops sequentially to restore soil fertility.
Taungya System: Growing agricultural crops between rows of planted trees (agroforestry). Common in Myanmar.
Wetland Farming: Rainfed farming in areas with sufficient rainfall for water-intensive crops (e.g., rice, jute).
Truck Farming: Specializing in vegetable cultivation for distant markets.
Viticulture: Science and practice of grape cultivation. Mediterranean region is a specialty area.
Soil Fertility:
Nitrogen Fixation: Process converting atmospheric nitrogen into usable compounds. Legume crops (beans, peas) enhance soil fertility this way via root nodules.
Fallow Land: Land left uncultivated for a period (≤ 1 year = current fallow; > 1 to 5 years = other fallow) to restore fertility.
Net Sown Area: Physical area where crops are sown and harvested.
Culturable Waste Land: Land uncultivated for > 5 years.
Barren Land: Land unsuitable for cultivation (desert, mountains).
Water Requirements: Rice requires waterlogged conditions.
Siberian Ibex: A species of large, heavy wild goat.
Geographical Indication (GI): Sign used on products with a specific geographic origin and qualities/reputation due to that origin.
21. Minerals/Industrial Centres
Fossil Fuels (Coal, Petroleum, Natural Gas): Exhaustible, non-renewable resources formed from ancient organic matter. Cause pollution and global warming. Are limited resources.
'Black Gold': Term for Petroleum (crude oil).
Largest Natural Gas Reserves: Russia.
Industrial Regions:
Ural Industrial Region: Russia (rich in various ores and minerals).
Pittsburgh Industrial Area: USA (Pennsylvania) - Famous for iron and steel.
Ruhr Region: Germany - Major coal, steel, and heavy industry area (~80% of Germany's steel).
Nuclear Power: CHASHMA-III plant is in Pakistan. Japan does NOT possess nuclear weapons (among options). Countries with nuclear weapons include Russia, USA, China, France, UK, Pakistan, India, North Korea, Israel (undeclared).
22. Transport
Ports:
Santos Port: Brazil ('Coffee Port').
Hambantota Port: Sri Lanka.
Chabahar Port: Iran (joint project with India). Only Iranian port with direct Indian Ocean access.
Busiest Seaport (Europe): Rotterdam (Netherlands). 11th busiest globally.
Other Major European Ports: Le Havre (France), Antwerp (Belgium), Southampton (England).
Major Asian Ports: Osaka (Japan), Singapore, Shanghai (China).
Sea Routes:
Busiest Sea Route: North Atlantic Sea Route (connects Europe and North America).
Pipelines:
TAPI Pipeline: Trans-national gas pipeline (Turkmenistan-Afghanistan-Pakistan-India). Iran is NOT part of it.
Big Inch Pipeline: USA (historically transported petroleum from Gulf Coast to Northeast).
Railways:
Longest Railway Line: Trans-Siberian Railway (Russia, ~9,289 km).
Longest Railway Network: USA has the largest network length.
23. Cartography
Cartography: Study and practice of map making.
Geography: Study of Earth's lands, features, inhabitants, phenomena.
Geology: Study of Earth's structure, substances, history, processes.
Calligraphy: Art of decorative handwriting.
Contour Line: Line on a map connecting points of equal elevation (height) above a datum.
Isobath: Line on a map connecting points of equal depth below a water surface.
Isobar: Line connecting points of equal atmospheric pressure.
Isohaline: Line connecting points of equal salinity.
Isogloss: Line on a map marking the boundary between linguistic features.
24. Miscellaneous
Amazon Rainforest: Located mainly in South America (Brazil). Known as 'lungs of the Earth' due to vast oxygen production and CO2 absorption. Tropical rainforest biome.
Tundra Ecosystem: Treeless biome found in high latitudes (Arctic) or high altitudes.
Biomes Sequence (Arctic Circle to Equator): Tundra -> Taiga (Boreal Forest) -> Temperate Forest -> Tropical Rain Forest.
Natural Region: Geographical area with similar climate and natural vegetation.
Global Commons: Resources/areas outside national jurisdiction (High Seas, Atmosphere, Antarctica, Outer Space, Deep Seabed). Antarctica is considered one.
Geographical Isolation: Separation of populations preventing interbreeding; can lead to divergence (e.g., caste origin difference example).
Passes:
Bolan Pass: Pakistan (Balochistan).
Khyber Pass: Connects Afghanistan and Pakistan (Hindu Kush range).
Glaciers:
Largest Glacier: Lambert-Fisher Glacier (Antarctica).
Siachen Glacier: Karakoram Range (Kashmir region). Second largest non-polar glacier.
Land Use: How humans utilize land. Determined by physical factors (topography, climate, soil) and human factors (population, technology).
Conservation: Avoiding overuse of non-renewable resources (coal, petroleum) and systems that consume them (excessive air conditioning/heating).
Institutes:
International Rice Research Institute (IRRI): Headquarters in Los Banos, Philippines.
Zodiac Signs (Astronomy): 12 divisions of the ecliptic path (Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn, Aquarius, Pisces). Ophiuchus is a constellation near the ecliptic but not traditionally one of the 12 zodiac signs.
Bay vs Gulf: Bay is usually smaller and less enclosed than a Gulf. Bay mouth is typically wider.
Estuary: Transition zone where a river meets the sea; mix of freshwater and saltwater.
Creek: Small stream or inlet.
Geography (Term Origin): Coined by Eratosthenes (considered 'Father of Methodical Geography'). Hecataeus often called 'Father of Geography'.
Inga Dams: On Congo River (DRC). Potential for massive hydropower generation.
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