Energy is a set of physics measures. Popularly the term is most often used in the context of energy as a technology: energy resources, their consumption, development, depletion, and conservation. Biologically, bodies rely on food for energy in the same sense as industry relies on fuels to continue functioning. Since economic activities such as manufacturing and transportation can be energy intensive, energy efficiency, energy dependence, energy security and price are key concerns. Increased awareness of the effects of global warming has led to global debate and action for the reduction of greenhouse gases emissions; like many previous energy use patterns, it is changing not due to depletion or supply constraints but due to problems with waste, extraction, or geopolitical scenarios.
In the context of natural science, energy can take several different forms: thermal, chemical, electrical, radiant, nuclear, etc. These are often grouped as being either kinetic energy or potential energy. Many of these forms can be readily transformed into another with the help of a device - from chemical energy to electrical energy using a battery, for example. Most energy available for human use ultimately comes from the sun, which generates it with nuclear fusion. The enormous potential for fusion and other basic nuclear reactions is expressed by the famous equation E = mc2.
The concepts of energy and its transformations are useful in explaining natural processes on larger scales: Meteorological phenomena like wind, rain, lightning and tornadoes all result from energy transformations brought about by solar energy on the planet. Life itself is critically dependent on biological energy transformations; organic chemical bonds are constantly broken and made to make the exchange and transformation of energy possible. Read more...
Ethanol fuel in Brazil provides a ~22% ethanol blend used nationwide, plus 100% hydrous ethanol for four million cars. The Brazilian ethanol program provided nearly 700,000 jobs in 2003, and cut 1975–2002 oil imports by a cumulative undiscounted total of US$50 billion. Brazil gets more than 30% of its automobile fuels from sugar cane-based ethanol.
The Brazilian government provided three important initial drivers for the ethanol industry: guaranteed purchases by the state-owned oil company Petrobras, low-interest loans for agro-industrial ethanol firms, and fixed gasoline and ethanol prices where hydrous ethanol sold for 59% of the government-set gasoline price at the pump. These pump-primers have made ethanol production competitive yet unsubsidized.
In recent years, the Brazilian untaxed retail price of hydrous ethanol has been lower than that of gasoline per gallon. Approximately US$50 million has recently been allocated for research and projects focused on advancing the obtention of ethanol from sugarcane in São Paulo. Read more...
Hansen is a vocal critic of the Bush Administration's ideology on climate change. In 2005 and 2006, he claimed that NASA administrators have tried to influence his public statements about the causes of climate change. He has also claimed that the White House edited climate-related press releases from federal agencies to make global warming seem less threatening, and that he is unable to speak 'freely', without the backlash of other government officials.
"For those who want some proof that physicists are human, the proof is in the idiocy of all the different units which they use for measuring energy." – Richard Feynman
"The energy produced by breaking down the atom is a very poor kind of thing. Anyone who expects a source of power from the transformations of these atoms is taking moonshine." – Ernest Rutherford
"If you take a bale of hay and tie it to the tail of a mule and then strike a match and set the bale of hay on fire, and if you then compare the energy expended shortly thereafter by the mule with the energy expended by yourself in the striking of the match, you will understand the concept of amplification." – William Shockley