Category Archives: Navigation

Battleship Guns and Danger Space

Posted on 19-April-2013 by mathscinotes

I have been reading a couple of excellent books about battleships ("Naval Firepower" and "Guns at Sea"). During my reading, I have encountered the term "Danger Space" that appears with nearly every table describing the large naval guns. Of course, I had no idea what danger space was when I began investigating it. It turns out that danger space describes an important metric for battleship guns and it is worthwhile documenting what I have learned about it here. Continue reading →

Posted in History of Science and Technology, Military History, Naval History | 7 Comments

Questions That Don't Need to Be Asked

Posted on 17-April-2013 by mathscinotes

Some "interesting" questions come my way -- one just rolled in about my plans for dealing with an electromagnetic pulse attack (I don't have any plans for that situation). When I say interesting, I mean that this question really did not need to be asked. The best example of this type of question is one I heard when I was on a cruise ship. When I am on a cruise ship, I always ask if I can get a tour of the bridge -- they often do host a tour. During this tour, the ship’s navigator will sometimes offer to host a seminar on how the ship navigates. This actually happened and a number of passengers attended. During this seminar, the navigator mentioned that the ship normally navigated using GPS, but was equipped for celestial navigation if it was needed. The navigator then sheepishly added that his celestial navigation was very rusty because it had been so long since he had used it. A passenger than very seriously asked, “What if global thermonuclear war broke out and all the GPS satellites were destroyed – how would we find our way home?” The audience sat in stunned silence. I don't think that question needed to be asked. Continue reading →

Posted in Military History, Navigation | Comments Off on Questions That Don't Need to Be Asked

GPS and Relativity

Posted on 5-November-2010 by mathscinotes

A friend just sent me some viewgraphs from a presentation that he recently attended on the history of the Global Positioning System (GPS). The presentation was given by Hugo Fruehauf, one of the key GPS developers. In this presentation, he … Continue reading →

Posted in Astronomy, Navigation | Tagged , , | 1 Comment