• Question: How far is it to the centre of the Earth?

    Asked by anon-256881 on 12 Jun 2020.
    • Photo: Ricardo González-Gil

      Ricardo González-Gil answered on 12 Jun 2020:

      From Eart’s surface to the centre, it is approximately 6371 km

    • Photo: Liam Herringshaw

      Liam Herringshaw answered on 13 Jun 2020:

      The Earth isn’t a perfect sphere – it bulges more at the Equator than it does at the poles, so you’d have to drill through 6378 km of crust, mantle, and core at the Equator, but only 6357 km at the poles (at least, according to NASA: https://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html. I haven’t tried it myself).

    • Photo: Oli Wilson

      Oli Wilson answered on 19 Jun 2020:

      To put those distances into context, if you could drive 70mph along a motorway that went straight down from Earth’s surface to its centre it would take you 56.75 to 56.95 hours to make the journey. That’s two days, eight hours and 45-57 minutes of continuous driving! Interestingly, that bulge Liam mentioned would only add about 12 minutes of travel – for comparison, driving the height of Everest at 70mph would take you five minutes.
      You would, of course, have to build the through-Earth motorway first, and it turns out that that would be tricky for a whole host of reasons… https://what-if.xkcd.com/135/

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