Another reason
 

Well said. However, you will have about a day to learn
Celestial Navigation as these particle do not travel at
the speed of light.

Charlie Morgan wrote:
Another reason why sailors should not become overly reliant on any one
method of navigation...

http://www.newscientisttech.com/channel/tech/dn10189-solar-flares-will-disrupt-gps-in-2011.html