Pulsar Signals Could Provide Galactic GPS 146
KentuckyFC writes "We're all familiar with GPS. It consists of a network of satellites that each broadcast a time signal. A receiver on Earth can then work out its position in three-dimensional space by comparing the arrival times of the signals from at least three satellites. That's handy, but it only works on Earth. Now astronomers say that the millisecond signals from a network of pulsars could allow GPS-style navigation on a galactic scale. They propose using four pulsars that form a rough tetrahedron with the Solar System at its center, and a co-ordinate system with its origin at 00:00 on 1 January 2001 at the focal point of the Interplanetary Scintillation Array, the radio telescope near Cambridge in the UK that first observed pulsars. The additional complexity of working with signals over these distances is that relativity has to be taken into account (which is why the origin is defined as a point in space-time rather than just space). The pulsar GPS system should allow users to determine their position in space-time anywhere in the galaxy to within a few nanoseconds, which corresponds to an accuracy of about a meter." Pulsars slow down over time, and the arXiv paper doesn't seem to mention this. The paper is mainly about establishing a coordinate system and a reference selection of pulsars. Any proposed Galactic Positioning System would have to take the slowing into account, and since it is poorly understood and not completely predictable, this would limit accuracy.
I would be pedantic, but... (Score:5, Funny)
At this point, I'd normally be ranting about how the G in GPS stands for "Global", and that the summary is making an awful analogy, but then I realized that "Galactic" also begins with a G.
And then I realized that that still doesn't make "Galactic Global Positioning System" any better.
Europe is planning a competing system... (Score:1, Funny)
...that uses metric pulsars.
Old Hat: The Pilgrims knew it before (Score:4, Funny)
Not interested (Score:2, Funny)
Re:I would be pedantic, but... (Score:3, Funny)
Emperor of Mankind (Score:1, Funny)
The only galactic GPS system I use is the beacon sent by the Emperor of Mankind. Granted the cost of a thousand psychers a day is high, but it's worth it.