31 October 2013

Global lightning strikes. And lodestones.


An interesting distribution, with some curiously sharp demarcations.

And this interesting tidbit, from the source Wikipedia page:
The intense currents of a lightning discharge create a fleeting but very strong magnetic field. Where the lightning current path passes through rock, soil, or metal these materials can become permanently magnetized. This effect is known as lightning-induced remanent magnetism, or LIRM. These currents follow the least resistive path, often horizontally near the surface but sometimes vertically, where faults, ore bodies, or ground water offers a less resistive path. One theory suggests that lodestones, natural magnets encountered in ancient times, were created in this manner.

4 comments:

  1. Surprising about Australia. I'd always heard it was the most lightning-prone place on the planet.

    ReplyDelete
  2. "Remanent"? Do they mean remnant?

    ReplyDelete
    Replies
    1. Here, let me Wiki that for you...

      http://en.wikipedia.org/wiki/Remanent

      Delete

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