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                      | Light 
                        clock promises finer time |  
                     
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                                  | Today's 
                                    atomic clocks are so accurate that they would 
                                    lose a second only after 30 million years. 
                                    As impressive as this sounds, improving time-based 
                                    technologies like global positioning systems 
                                    requires more accurate clocks. Atomic clocks 
                                    that use lightwaves instead of microwaves 
                                    could be a thousand times more precise. A 
                                    prototype based on a single strontium ion 
                                    is a step toward redefining the second. Full 
                                    story
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