• Question: is gravity weakening?

    Asked by Mr.MagicMonkeyMan to Chris, Joanne, Kathryn, Kieran, Sarah on 10 Nov 2017.
    • Photo: Kathryn Schoenrock

      Kathryn Schoenrock answered on 10 Nov 2017:


      gravity weakens as you move to the equator, and as you move away from the center of the earth… like on a mountain. Over time- I actually don’t know.

    • Photo: Chris Werner

      Chris Werner answered on 11 Nov 2017:


      Kind of…yes. First off gravity is really really weak as a force, much weaker than the strong and weak nuclear forces and electromagnetism. I’ll explain an example. You’ve got a small iron bar on a desk say it weighs 100g, which the Earth is pulling down with its gravitational pull, then you pull out a magnet and bring it close to the iron bar and then the bar defies gravity and gets attracted to the magnet. So you have the gravity of the entire planet (very very heavy) being beaten by the magnetism of a common school magnet weighing less than 1kg. So gravity is really weak.

      In a much broader term now that I’ve explained how weak gravity is, we know that the universe is expanding and a gravitational field has a certain density per unit volume (black holes high gravity – massive density small volume, Saturn, low gravity – lower density than water, big volume). So if the universe is expanding, then its density must be decreasing, then so will gravity. But would we notice it…no, we won’t see flying elephants anytime soon!

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