• Question: The magnetic poles are supposed to swap on average every 1000 to 10,000 years, and haven't in 780,000 years- what would it mean for humans if they swapped again?

    Asked by bridget to Amy, Drew, Julia, Kimberley, Sara on 21 Jun 2011.
    • Photo: Sara Imari Walker

      Sara Imari Walker answered on 20 Jun 2011:

      Hi bridget! Interesting question. Although the Earth has undergone many pole reversals in its history, there is not direct evidence that such events have disrupted the Earth’s biosphere (i.e. we don’t observe mass-extinctions correlating with any pole reversals). Even humans have survived a few reversals in our history (including the last one around 780,000 years ago!). The one major threat I can think of is radiation exposure. The Earth’s magnetic field protects us from vast amounts of cosmic radiation. It is possible that during a pole reversal, the magnetic field could weaken, limiting our protection from such radiation. This radiation could cause mutations, including cancer. But the most detrimental effects (seeing as humans have clearly survived past events) would be to our technological devices – all of them are susceptible to sun storms! Imagine no protection – all our electronics might fail! That probably would be the worst case scenario of a pole reversal and is something ancient man would not have had to worry about!

    • Photo: Drew Rae

      Drew Rae answered on 20 Jun 2011:

      Hi Bridget,
      Sara is right that we don’t know for sure what would happen, but that technology might be more vulnerable than living things. Be very careful with averages though. We don’t actually know what caused historical pole reversals, and the fact that the current interval is longer than “average” isn’t necessarily meaningful.

      When you were a baby, your nappy was changed every couple of hours. It’s been years since that happened – OMG a drastic nappy change is way overdue!

    • Photo: Julia Griffen

      Julia Griffen answered on 20 Jun 2011:

      I so never knew this!

    • Photo: Amy MacQueen

      Amy MacQueen answered on 21 Jun 2011:

      Hey Bridget thanks for the question – thanks for the answer guys…I had wondered this as well! 🙂