Medical research

Producing vaccines without the use of chemicals

Producing vaccines is a tricky task – especially in the case of inactivated vaccines, in which pathogens must be killed without altering their structure. Until now, this task has generally involved the use of toxic chemicals. ...

Psychology & Psychiatry

Energy drinks do not make youngsters smarter, study finds

Drinking one energy drink has no effect whatsoever on the cognitive performance of secondary school pupils. This is the conclusion reached by University of Twente psychologist Pascal Wilhelm (department of Instructional Technology) ...

Autism spectrum disorders

Study shows gene defect's role in autism-like behavior

Scientists affiliated with the UC Davis MIND Institute have discovered how a defective gene causes brain changes that lead to the atypical social behavior characteristic of autism. The research offers a potential target for ...

Oncology & Cancer

Aspirin's 'double hit' on bowel cancer

(Medical Xpress) -- Aspirin kills cancer cells by controlling two key processes that influence energy use in cells and could explain how aspirin can prevent bowel cancer. The research is published in this month’s Gastroenterology.

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World energy resources and consumption

In 2005, total worldwide energy consumption was 500 Exajoules (= 5 x 1020 J) with 80-90% derived from the combustion of fossil fuels. This is equivalent to an average energy consumption rate of 16 TW (= 1.585 x 1013 W). Not all of the world's economies track their energy consumption with the same rigor, and the exact energy content of a barrel of oil or a ton of coal will vary with quality.

Most of the world's energy resources are from the sun's rays hitting earth - some of that energy has been preserved as fossil energy, some is directly or indirectly usable e.g. via wind, hydro or wave power. The term solar constant is the amount of incoming solar electromagnetic radiation per unit area, measured on the outer surface of Earth's atmosphere, in a plane perpendicular to the rays. The solar constant includes all types of solar radiation, not just visible light. It is measured by satellite to be roughly 1366 watts per square meter, though it fluctuates by about 6.9% during a year - from 1412 W/m2 in early January to 1321 W/m2 in early July, due to the Earth's varying distance from the sun, and by a few parts per thousand from day to day. For the whole Earth, with a cross section of 127,400,000 km², the total energy rate is 1.740×1017 W, plus or minus 3.5%. This 174 PW is the total rate of solar energy received by the planet; about half, 89 PW, reaches the Earth's surface.

The estimates of remaining worldwide energy resources vary, with the remaining fossil fuels totaling an estimated 0.4 YJ (1 YJ = 1024J) and the available nuclear fuel such as uranium exceeding 2.5 YJ. Fossil fuels range from 0.6-3 YJ if estimates of reserves of methane clathrates are accurate and become technically extractable. Mostly thanks to the Sun, the world also has a renewable usable energy flux that exceeds 120 PW (8,000 times 2004 total usage), or 3.8 YJ/yr, dwarfing all non-renewable resources.

This text uses material from Wikipedia, licensed under CC BY-SA