• Question: What is a gravitational pull?

    Asked by Amyw15 to Daniel, Maggie, Ry, Scott on 15 Nov 2017.
    • Photo: Daniel Williams

      Daniel Williams answered on 15 Nov 2017:

      It’s the force which objects with mass exert on other objects with mass. It happens because mass causes spacetime – the thing that everything sits in – to bend. When you try and travel in a straight line on a bent surface you end up looking like you’re walking on a curve to someone far away, and to you it feels like you’re being pulled towards the centre of the bent space.

    • Photo: Ry Cutter

      Ry Cutter answered on 15 Nov 2017:

      It’s hard to add to Daniel’s answer, it’s so good!
      A good way to imagine it is if an ant walks on a rolled up piece of paper. The ant thinks it’s moving in a straight line, but to us we can see it’s moving on a curved path!
      Brilliant question,
      Ryan

    • Photo: Maggie Lieu

      Maggie Lieu answered on 15 Nov 2017:

      Gravitational pull is the force that a more massive object has on a less massive object. So the gravity of the Earth (which is much heavier than you or me) is pulling us towards its centre of mass.

    • Photo: Scott Melville

      Scott Melville answered on 16 Nov 2017:

      So Maggie’s covered what Newton thought, and Dan and Ryan did a job covering Einstein. Let me just add that there’s a third way that we sometimes think of gravity nowadays (like just in the last thirty years or so, so you’ll never hear about this in school!). If you zoom in really close, and ask what gravity ‘looks like’, you might expect that (just like everything else) it’s made up of some kind of ‘particle’. We call these particles ‘gravitons’ (little chunks of gravity). So when you feel a gravitational pull, really what’s going (if you had a powerful enough microscope) is that you’re being attacked by a swarm of gravitons 😛 Gravitons fly around (at roughly the speed of light), looking for masses to pull on. If you have more mass, you absorb more gravitons, so there’s a stronger gravitational pull 🙂
      (we’ve only evoer bserved gravitons in large numbers though – never just a single one on it’s own – they’re very small!)

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