Add Yahoo as a preferred source to see more of our stories on Google. At Pennsylvania's Capitol building, clocks that are more than a century old still help lawmakers tell the time. There are 273 ...

The most precise clocks ever built are now testing Einstein, hunting dark matter, and reshaping how we define time itself. In ...

At Pennsylvania's Capitol building, clocks that are more than a century old still help lawmakers tell the time. There are 273 vintage clocks inside the Capitol, that are all working. They've become ...