Astronomy Picture of the Day

A Force from Empty Space: The Casimir Effect


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zorg.ch
#112150 by @ 04.01.2010 00:00 - nach oben -
A Force from Empty Space: The Casimir Effect

Explanation: This tiny ball provides evidence that the universe will expand forever. Measuring slightly over one tenth of a millimeter, the ball moves toward a smooth plate in response to energy fluctuations in the vacuum of empty space. The attraction is known as the Casimir Effect, named for its discoverer, who, 50 years ago, was trying to understand why fluids like mayonnaise move so slowly. Today, evidence is accumulating that most of the energy density in the universe is in an unknown form dubbed dark energy. The form and genesis of dark energy is almost completely unknown, but postulated as related to vacuum fluctuations similar to the Casimir Effect but generated somehow by space itself. This vast and mysterious dark energy appears to gravitationally repel all matter and hence will likely cause the universe to expand forever. Understanding vacuum fluctuations is on the forefront of research not only to better understand our universe but also for stopping micro-mechanical machine parts from sticking together. Note: An APOD editor will review astronomy images of 2009, hosted by the Amateur Astronomers Association of New York on Friday, January 8 at the American Museum of Natural History, NYC. digg_url = 'http://apod.nasa.gov/apod/ap100103.html'; digg_skin = 'compact';

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zorg.ch
#112166 by @ 10.01.2010 11:40 - nach oben -
Also das mit de dark energy wo macht das s'universe sich expandiert findi jetzt scho chli wiit hergholt. isch das nöd de glich effekt wie wennt es gas in rum uselohsch, das sich jetzt halt eifach dur d'entropie usdehnt?
zorg.ch
#112168 by @ 10.01.2010 12:22 - nach oben -
wenn du materie in en ruum lohsch, gohsch jo devo us, dassd scho en ruum hesch, wo sich die materie drin cha usdehne.

dunkli materie macht halt, dass de ruum selber sich usdehnt. fürs system als ganzes chasch jo nöd die gliche gsetz bruche wie im system drin.