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  Hot coronal secret and ion clocksJul 12, 2013 12:32 AM PDT | url
 
Added 2 new A* pages:It was another day where I came across a couple interesting BBC articles:
 
- Speedy tsunami seen on Sun's surface: (Say that five times fast :p) The part of this article that interested me was actually the note that readings by the Japanese satellite Hinode of the energy of magnetic waves coming up through the Sun's "polar coronal hole" show that they carry enough energy to account for the high temperature of the Sun's corona, explaining how the Sun's surface can remain a relatively cool 6,000 degrees C while the corona above it, where the magnetic field lines converge, is in excess of a million degrees C (the core itself is thought to be some 15 million degrees C).
 
- Optical lattice atomic clock could 'redefine the second': We've been using "atomic clocks" counting the oscillations of microwaved caesium atoms to achieve very accurate measurements of time--these "caesium fountain"-based atomic clocks are accurate to one second over 100 million years--but a new type of atomic clock using lasers to excite strontium atoms promises to be three times as accurate, thanks to the higher frequency of lasers versus microwaves. Even more interestingly, a final note mentions an experimental clock called an "ion clock," accurate to one second "every few billion years," but still too unstable for use as it relies on measurements of a single ion.
 
 
 
 
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