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The Sun is the source of energy for most of life on Earth. As a star, the Sun is heated to high temperatures by the conversion of nuclear binding energy due to the fusion of hydrogen in its core. This energy is ultimately transferred (released) into space mainly in the form of radiant (light) energy.

In physics, energy is the quantitative property that must be transferred to an object in order to perform work on, or to heat, the object. Energy is a conserved quantity; the law of conservation of energy states that energy can be converted in form, but not created or destroyed. The SI unit of energy is the joule, which is the energy transferred to an object by the work of moving it a distance of 1 metre against a force of 1 newton.

Common forms of energy include the kinetic energy of a moving object, the potential energy stored by an object's position in a force field (gravitational, electric or magnetic), the elastic energy stored by stretching solid objects, the chemical energy released when a fuel burns, the radiant energy carried by light, and the thermal energy due to an object's temperature.

Mass and energy are closely related. Due to mass–energy equivalence, any object that has mass when stationary (called rest mass) also has an equivalent amount of energy whose form is called rest energy, and any additional energy (of any form) acquired by the object above that rest energy will increase the object's total mass just as it increases its total energy. For example, after heating an object, its increase in energy could be measured as a small increase in mass, with a sensitive enough scale.

Living organisms require energy to stay alive, such as the energy humans get from food. Human civilization requires energy to function, which it gets from energy resources such as fossil fuels, nuclear fuel, or renewable energy. The processes of Earth's climate and ecosystem are driven by the radiant energy Earth receives from the sun and the geothermal energy contained within the earth.

Selected article

Escape E85 Flex Fuel Hybrid WAS 2010 8941.JPG
A flexible-fuel vehicle (FFV) (or flex-fuel vehicle) is an alternative fuel vehicle with an internal combustion engine designed to run on more than one fuel, usually gasoline blended with either ethanol or methanol fuel, and both fuels are stored in the same common tank. The most common commercially available FFV in the world market is the ethanol flexible-fuel vehicle, with around 21 million automobiles, motorcycles and light duty trucks sold worldwide by mid 2010, and concentrated in four markets, Brazil (10.6 million), the United States (9.3 million), Canada (more than 600,000), and Europe, led by Sweden (199,000). Also a total of 183,375 flexible-fuel motorcycles were sold in Brazil in 2009. In addition to flex-fuel vehicles running with ethanol, in Europe and the US, mainly in California, there have been successful test programs with methanol flex-fuel vehicles, known as M85 flex-fuel vehicles.

Though technology exists to allow ethanol FFVs to run on any mixture of gasoline and ethanol, from pure gasoline up to 100% ethanol (E100), North American and European flex-fuel vehicles are optimized to run on a maximum blend of 15% gasoline with 85% anhydrous ethanol (called E85 fuel). This limit in the ethanol content is set to reduce ethanol emissions at low temperatures and to avoid cold starting problems during cold weather, at temperatures lower than 11 °C (52 °F). The alcohol content is reduced during the winter in regions where temperatures fall below 0 °C (32 °F) to a winter blend of E70 in the U.S. or to E75 in Sweden from November until March. Brazilian flex fuel vehicles are optimized to run on any mix of E20-E25 gasoline and up to 100% hydrous ethanol fuel (E100). Read more...

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Wind Turbines and Power Lines, East Sussex, England - April 2009.jpg

Photo credit: Diliff
An electrical grid is an interconnected network for delivering electricity from generation facilities such as wind farms to consumers.

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Selected biography

John Davison Rockefeller, Sr. (July 8, 1839 – May 23, 1937) was a controversial American industrialist who revolutionized the oil industry and defined the structure of modern philanthropy. He is often regarded as the richest person in history.

Rockefeller founded the Standard Oil Company in 1870 and ran it until he retired in the late 1890s. He continued to retain his stock and his title as president until 1911, when the company was broken up for carrying out illegal monopoly practices. The new companies formed included the predecessors of Conoco, Amoco, Chevron, Esso, Mobil and Sohio. Rockefeller, who had rarely sold shares, owned stock in all of them. As gasoline had grown in importance his wealth had soared and he became the world's richest man and the first billionaire.

Rockefeller's fortune was used to create the modern systematic approach of targeted philanthropy with foundations that had a major impact on medicine, education, and scientific research. His foundations pioneered the development of medical research, and was instrumental in the eradication of hookworm and yellow fever. At his death, at the age of 98, Rockefeller's remaining fortune was estimated at $1.4 billion. As a percentage of the United States economy, no other American fortune has ever come close. Read more...


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