Einstein’s Clocks and Poincare’s Maps, Author: Peter Gallison.
Einstein’s Relativity Coming to Power Grid Near You
GE – It was not until the arrival of telegraph and train time that clocks started beating in unison.
In Bern, Switzerland, the old train station was one of the first buildings in the city to have coordinated clocks. It stood across the street from the Bern patent office and the desk of Albert Einstein. Peter Gallison writes that Einstein was wrestling with two questions in Bern: What does it mean that two distant events are simultaneous? How do I compare the reading of my watch here to a train’s arrival at another station there at 7 o’clock? The answer led him to the theory of relativity.
Synchronization has since expanded from train schedules to many other industries. One of the latest is power distribution. “When it comes to the modern grid, timing is everything,” says Rich Hunt, senior product manager at GE Digital Energy. “Without it relays would trip and power lines could go out.”
In the past, companies used expensive and complex analog copper wire systems to deal with the problem. But GE engineers now found a clever way to turn the digital network that’s causing the delays into the solution. The system can do this because the devices on the network use clocks connected to the Global Positioning System (GPS) [2, 3, 4].
GPS satellites fly so high and fast that their clocks run slightly slower compared to ours and we must include relativity to make the system work.
Without correcting for it, GPS would give readings that are off the mark by as much as 7 miles a day. Many drivers, hikers and other users would get quickly lost. more> http://tinyurl.com/q59k3ul