• Question: when a comet comes does it go the way the gravitational wave is going?

    Asked by Abu.D15 to Ryan, Maggie, Hannah, Daniel on 14 Nov 2017.
    • Photo: Maggie Lieu

      Maggie Lieu answered on 14 Nov 2017:


      Gravitational waves are made by mergers of really massive things like black holes so comets don’t emit gravitational waves. Comets are orbiting our sun, so they travel in all directions

    • Photo: Ryan Cutter

      Ryan Cutter answered on 14 Nov 2017:


      Not quite. They follow the curvature of space time! This is like rolling a ball on a hill, the parts where the hill is steeper will move the ball more in that direction. The comet is like the ball and space time is like the hill. We then measure gravity by how steep these hills are in space time!
      Gravitational waves act at right angles to the direction of motion. So if a comet could make a gravitational wave, it would travel away from the comet.
      Fantastic question! 🙂
      Ryan

    • Photo: Daniel Williams

      Daniel Williams answered on 15 Nov 2017:


      As a comet orbits a star (like the sun) it will emit gravitational waves. Those waves will be very tiny however, and none of the detectors which we have at the moment would be able to see them.

      As an object travels through space the gravitational waves it produces expand away from it in quite a complicated way; spacetime doesn’t ripple in quite the same way as the surface of a pond does when you throw a stone in, but it instead stretches and contracts: here’s a good video on youtube which shows you what happens to the Earth when a gravitational wave passes through it, but it’s really exaggerated: the effect in real life is absolutely tiny.

    • Photo: Hannah Middleton

      Hannah Middleton answered on 15 Nov 2017:


      Gravitational waves are everywhere! Any accelerating mass makes gravitational waves, or ripples in space time. So even if you move your arms around in circles, you are making gravitational waves!

      But they are mostly too small to detect. So the gravitational wave we have found

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