Archive For September 26, 2018

Western Ghats

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The Western Ghats or SahyÄdri runs north to south along the western edge of the Deccan Plateau, and separates the plateau from a narrow coastal plain along the Arabian Sea. The range starts near the border of Gujarat and Maharashtra, south of the Tapti River, and runs approximately 1600 km through the states of Maharashtra,…

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Coal Resources in India

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Most of the coal mined in India comes from the rock formations of two geological ages viz. Lower Gondwana and Tertiary. About 80 per cent of the coal deposits in India is of bituminous type and is of non-coking grade. This is one of the reasons that India has to rely upon imports of coking…

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Black Holes : Key Facts and Types of Black Holes

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Each object has its own gravity which depends on its size and mass. The objects which have highest mass in smallest size would exert most gravity. The ultimate combination of large mass and small size is called a black hole. A black hole exerts such massive gravitational force that its escape velocity is equal or…

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Hubble Constant, Doppler Effect, Blue and Red Shift in Galaxies

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The expansion rate of the universe is called the Hubble Constant in honor of Edwin Hubble (1889–1953). Currently the best measured value of the Hubble Constant is about 73 kilometers per second per megaparsec. This implies that if a location in space is one million parsecs from another location, then in the absence of any…

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Galaxies: Types, Distribution, Clusters and Super Clusters

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A galaxy is a vast collection of stars, gas, dust, and dark matter that forms a cohesive gravitational unit in the universe. In a way, galaxies are to the universe what cells are to the human body: each galaxy has its own identity, and it ages and evolves on its own, but it also interacts…

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Interesting Facts and Notes on Venus Planet

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Venus is similar to Earth in many ways and is closer in distance to Earth than any other planet, and it has a similar size and composition. Key facts about Venus are as follows: A Venus year is equal to 225 days while a Venus day is equal to 243 days. Thus, a day on…

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Key Facts About Mars and Its Moons

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Mars is known as the red planet because it looks red from Earth. The reddish color comes from the high concentration of iron oxide compounds—that is, rust—in the rocks of the Martian surface. Some key facts about Mars are as follows: Martian year is of 687 days and Martian day is 24h 37m. Martian atmosphere…

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Demographic Dividend, Longevity Dividend and Zero Population Growth

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India is a nation of young people – out of a population of above 1.1 billion, 672 million people are in the age-group 15 to 59 years, – which is usually treated as the “working age populationâ€. A few years back, it was proposed that India in near future (30 years) will see a sharp…

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Nebula: Definition and Types of Nebulae

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A nebula is a cloud or collection of interstellar medium in one location in space. Nebulae are produced in different ways. For instance, they can be gathered together by gravity, dispersed by stars, or lit up by a powerful radiation source nearby. Most of these beautiful nebulae contain only a few thousand atoms or molecules…

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Dark Matter and Dark Energy

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In 1930s, astronomers noticed that in some galaxy clusters, some of the galaxies were moving extra fast than possible with available matter (and its gravitational force). The question was – Is there any matter which is not visible to us but exerts its gravitation responsible for keeping the galaxies put together? Again in 1970s researchers…

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Interesting Facts About Mercury Planet

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At 58 million kilometers distance, Mercury is closest planet to Sun.  Due this much proximity, mercury’s orbit is very much stretched into a long elliptical shape. Other important facts about mercury are as follows: Mercury takes 88 Earth days to complete one revolution around sun, however, it takes 59 Earth days to complete one rotation….

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Facts about Uranus

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Uranus is the seventh major planet in our solar system, and the third of four gas giant planets. It is 51,200 kilometers in diameter, just under four times the diameter of Earth. Like the other gas giant planets, Uranus consists mostly of gas. Its pale blue-green, cloudy atmosphere is made of 83 percent hydrogen, 15…

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Demographic Transition Theory

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The demographic transition theory studies the relationship between economic development and population growth. It discusses about changes in birth rate and death rate and consequently growth rate of population in assonance with the process of growth and development. It is also used to describe and predict the future population of any area. The theory tells…

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Facts About Saturn, Ring System and Moons

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Saturn is similar to Jupiter, although about one-third the mass. A day on Saturn is only 10 hours and 39 minutes long; it spins so fast that its diameter at the equator is 10 percent larger than its diameter from pole to pole. However, its day is longer than that of Jupiter. Saturn has a…

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Key Facts about Universe

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The universe is all of space, time, matter, and energy that exist. Universe is not just space, but space is just the framework or the scaffolding in which the universe exists. As Space and time are intimately connected in a four-dimensional fabric called space-time. Contents Age of Universe Size of Universe Cosmic Horizon Structure of…

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Stellar Evolution: All about Birth and Death of Stars

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Stellar evolution is a complicated process. All stars go through the continuous change and their life cycle is made of immature stage, mature stage and final changes towards end of their lives. Stars pass through a definite evolutionary sequence, which can be broadly divided into three parts viz. Pre-main sequence, Main sequence and Post-main sequence…

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Planets and Planetary Rings

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A planet is an object which is not a star {i.e. no nuclear fusion takes place in it} and that orbits around a star and is mostly round because its own gravitational pull has shaped it into more or less a sphere. As per current scientific classification, the planets must satisfy three basic criteria as…

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Population Pyramids : Meaning and Types

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The age-sex structure of a population refers to the number of females and males in different age groups. An age sex pyramid or population pyramid is used to show the age-sex structure of the population. The shape of the population pyramid reflects the characteristics of the population and also indicates whether the population is experiencing…

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Interesting Facts About Jupiter and Its Moons

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Jupiter is the largest planet in solar system, twice as massive as all the other planets, moons and asteroids in solar system put together. More than 90 percent of Jupiter’s mass consists of swirling gases, mostly hydrogen and helium; in this incredibly thick, dense atmosphere, storms of incredible magnitude rage and swirl. The largest of…

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Interesting Facts About Stars

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A star is a mass of incandescent gas that produces energy at its core by nuclear fusion. Most of the visible light in the universe is produced by stars. The Sun is also a star. Stars shine because nuclear fusion occurs in their core. Nuclear fusion changes lighter elements into heavier ones and can release…

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Key Facts and Comparison of Milky Way and Andromeda Galaxies

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The Milky Way is the galaxy we live in. It contains the Sun and 100 to 500 billion other stars. It is a barred spiral galaxy as grouped in the Hubble tuning fork diagram. It is located at the  outskirts of the Virgo supercluster. The centre of the Virgo cluster is about 50 million light-years…

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