CHINTAMANI HELEKAR

-- CHINTAMANI HELEKAR

The Big Bang theory developed from observations of the structure of the Universe and from theoretical considerations. In 1912 Vesto Slipher measured the first Doppler shift of a "spiral nebula" (spiral nebula is the obsolete term for spiral galaxies), and soon discovered that almost all such nebulae were receding from Earth. He did not grasp the cosmological implications of this fact, and indeed at the time it was highly controversial whether or not these nebulae were "island universes" outside our Milky Way.[14] [15] Ten years later, Alexander Friedmann , a Russian cosmologist and mathematician, derived the Friedmann equations from Albert Einstein's equations of general relativity, showing that the Universe might be expanding in contrast to the static Universe model advocated by Einstein at that time.[16] In 1924, Edwin Hubble's measurement of the great distance to the nearest spiral nebulae showed that these systems were indeed other galaxies. Independentl...

A plantation is a large artificially established forest, farm or estate, where crops are grown for sale, often in distant markets rather than for local on- site consumption. The term plantation is informal and not precisely defined. Crops grown on plantations include fast-growing trees (often conifers), cotton, coffee, tobacco, sugar cane, sisal, some oil seeds (notably oil palms) and rubber trees. Farms that produce alfalfa, Lespedeza, clover, and other forage crops are usually not called plantations. The term "plantation" has usually not included large orchards (except for banana plantations ), but does include the planting of trees for lumber. A plantation is always a monoculture over a large area and does not include extensive naturally occurring stands of plants that have economic value. Because of its large size, a plantation takes advantage of economies of scale . Protectionist policies and natural comparative ...

Industrialization spurred demand for affordable materials; aside from rags, ferrous scrap metals were coveted as they were cheaper to acquire than was virgin ore. Railroads both purchased and sold scrap metal in the 19th century, and the growing steel and automobile industries purchased scrap in the early 20th century. Many secondary goods were collected, processed, and sold by peddlers who combed dumps, city streets, and went door to door looking for discarded machinery, pots, pans, and other sources of metal. By World War I, thousands of such peddlers roamed the streets of American cities, taking advantage of market forces to recycle post- consumer materials back into industrial production.[5] Wartime Resource shortages caused by the world wars, and other such world-changing occurrences greatly encouraged recycling.[6] Massive government promotion campaigns were carried out in World War II in every country involved in the...

Wind power is the conversion of wind energy into a useful form of energy, such as using wind turbines to make electricity, wind mills for mechanical power, wind pumps for pumping water or drainage, or sails to propel ships. At the end of 2009, worldwide nameplate capacity of wind-powered generators was 159.2 gigawatts (GW).[1] (By June 2010 the capacity had risen to 175 GW. [2]) Energy production was 340 TWh, which is about 2% of worldwide electricity usage; [1][3] and has doubled in the past three years. Several countries have achieved relatively high levels of wind power penetration, such as 20% of stationary electricity production in Denmark, 14% in Ireland[4] and Portugal, 11% in Spain, and 8% in Germany in 2009. [5] As of May 2009, 80 countries around the world are using wind power on a commercial basis. [3] Large-scale wind farms are connected to the electric power transmission network; smaller facilities are used to p...

Deforestation is the removal of a forest or stand of trees where the land is thereafter converted to a nonforest use.[1] Examples of deforestation include conversion of forestland to agriculture or urban use. The term deforestation is often misused to describe any activity where all trees in an area are removed. However in temperate mesic climates, the removal of all trees in an area — in conformance with sustainable forestry practices — is correctly described as regeneration harvest.[2] In temperate mesic climates, natural regeneration of forest stands often will not occur in the absence of disturbance, whether natural or anthropogenic.[3] Furthermore, biodiversity after regeneration harvest often mimics that found after natural disturbance, including biodiversity loss after naturally occurring rainforest destruction.[4][5] Deforestation occurs for many reasons: trees or derived charcoal are used as, or sold, for fuel or as l...

The REVAi/G-Wiz i electric car charging from an on-street station in London. An electric car is a plug-in battery powered automobile which is propelled by electric motor(s). Electric cars have the potential of significantly reducing city pollution by having zero tail pipe emissions .[1][2][3] Vehicle greenhouse gas savings depend on how the electricity is generated. With the current U.S. energy mix, using an electric car would result in a 30% reduction in carbon dioxide emissions. Given the current energy mixes in other countries, it has been predicted that such emissions would decrease by 40% in the UK,[8] 19% in China,[9] and as little as 1% in Germany.[10][11] Electric cars are expected to have a major impact in the auto industry [12][13] given advantages in city pollution, less dependence on oil, and expected rise in gasoline prices. [14][15][16] World governments are pledging billions to fund development of electric vehicles and their components. The ...

This article is about all uses of solar energy. For generation of electricity using solar energy, see Solar power. Nellis Solar Power Plant in the United States, the largest photovoltaic power plant in North America. radiant light and heat from the sun, has been harnessed by humans since ancient times using a range of ever-evolving technologies. Solar radiation, along with secondary solar-powered resources such as wind and wave power, hydroelectricity and biomass, account for most of the available renewable energy on earth. Only a minuscule fraction of the available solar energy is used. Solar powered electrical generation relies on heat engines and photovoltaics. Solar energy's uses are limited only by human ingenuity. A partial list of solar applications includes space heating and cooling through solar architecture, potable water via distillation and disinfection, daylighting, solar hot water, solar cooking, and high temperature pr...

This article is about all uses of solar energy. For generation of electricity using solar energy, see Solar power. Nellis Solar Power Plant in the United States, the largest photovoltaic power plant in North America. radiant light and heat from the sun, has been harnessed by humans since ancient times using a range of ever-evolving technologies. Solar radiation, along with secondary solar-powered resources such as wind and wave power, hydroelectricity and biomass, account for most of the available renewable energy on earth. Only a minuscule fraction of the available solar energy is used. Solar powered electrical generation relies on heat engines and photovoltaics. Solar energy's uses are limited only by human ingenuity. A partial list of solar applications includes space heating and cooling through solar architecture, potable water via distillation and disinfection, daylighting, solar hot water, solar cooking, and high tem...

A greenhouse gas (sometimes abbreviated GHG) is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range. This process is the fundamental cause of the greenhouse effect.[1] The primary greenhouse gases in the Earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone. In the Solar System, the atmospheres of Venus, Mars, and Titan also contain gases that cause greenhouse effects. Greenhouse gases greatly affect the temperature of the Earth; without them, Earth's surface would be on average about 33 °C (59 °F)[note 1] colder than at present.[2][3][4] Since the beginning of the Industrial revolution , the burning of fossil fuels has increased the levels of carbon dioxide in the atmosphere from 280ppm to 390ppm.[5][6] Unlike other pollutants, carbon dioxide emissions do not result from inefficient combustion: CO2 is a product of ideal, stoichiometric combustion of carbon. [7] The emissions of carbon are directly proportion...

A hydrogen vehicle is an alternative fuel vehicle that uses hydrogen as its onboard fuel for motive power. The term may refer to a personal transportation vehicle, such as an automobile, or any other vehicle that uses hydrogen in a similar fashion, such as an aircraft. The power plants of such vehicles convert the chemical energy of hydrogen to mechanical energy either by burning hydrogen in an internal combustion engine , or by reacting hydrogen with oxygen in a fuel cell to run electric motors. Widespread use of hydrogen for fueling transportation is a key element of a proposed hydrogen economy . Hydrogen fuel does not occur naturally on Earth and thus is not an energy source, but is an energy carrier. Currently it is most frequently made from methane or other fossil fuels. However, it can be produced from a wide range of sources (such as wind, solar, or nuclear) that are intermittent, too diffuse or too cumbersome to direc...

- The Green house gases are the main culprits of the global warming. The green house gases like carbon dioxide, methane, and nitrous oxide are playing hazards in the present times. Green House Gasses are the ingredients of the atmosphere that add to the greenhouse effect. Al Gore Global Warming Initiative - Gore has written a book that archives his advice that Earth is dashing toward an immensely warmer future. The average facade temperature of the globe has augmented more than 1 degree Fahrenheit since 1900 and the speed of warming has been almost three folds the century long average since 1970. This increase in earth’s average temperature is called Global warming. More or less all specialists studying the climate record of the earth have the same opinion now that human actions, mainly the discharge of green house gases from smokestacks, vehicles, and burning forests, are perhaps the leading power driving the fashion. The ...