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"Everything should be as simple as it is, but not simpler", Albert Einstein
Browsing All Posts published on »October 25th, 2011«
Agreement to tie kilogram and friends to fundamentals
After decades of worry, toil and argument, metrologists have officially begun the process of tying the definitions of four basic units to nature’s fundamental constants. The General Conference on Weights and Measures (CGPM) in Paris, France, has unanimously agreed on a proposal that would lead to reform of the mole, kilogram, kelvin and ampere, according to the international system […]
Yesterday’s geomagnetic storm caused some great auroras
October 25, 2011
A CME hit Earth’s magnetic field on Oct. 24 at 1800 UT, sparking a strong (Kp=7) geomagnetic storm. Auroras were sighted in the United States as far south as Arkansas and California Video 1: The SOlar Heliospheric Observatory (SOHO) captured this “coronograph” – so-called because the images block the sun, and only show the sun’s […]
The Early Universe and Planck’s Radiation Law
October 25, 2011
Rainer Collier The classical Friedmann-Lemaitre equations are solved using a corrected version of Planck’s radiation law. The function curves of the scale parameter a(t) and the variations with temperature a(T) and t(T) are given. It is shown that a reasonable cosmological evolution is only possible in case of flat spatial slices (k=0). The initial singularity […]
October 25, 2011
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