I saw your advert in the paper <a href=" http://www.oktandrammen.no/buy-womenra.pdf#console ">buy womenra online</a> Researchers built these atomic clocks by trapping thousands of ytterbium atoms at high density. Each ytterbium clock depends on about 10,000 rare-earth atoms cooled to 10 microkelvin, or 10 millionths of a degree above absolute zero. The atoms are trapped in in optical lattice made of laser light. Another laser that “ticks” at a the incredible rate of 518 trillion times per second instigates a transition between two energy levels in the atoms. The massive number of atoms is the key to the clocks stability, researchers explained.