2
$\begingroup$

To visualize the space curvature related to gravity, there is a model or analogy using an elastic sheet and a weight. A rubber sheet is spanned like a very soft trampoline, and a heavy ball on it creates curvature in the sheet.

In this model, ist there a way to represent gravitational waves?

Dropping a ball on a rubber sheet creates a change in the shape of the sheet. This change does not affect the whole sheet instantly, it propagates from the impact away. Does the propagation have the form of a surface wave? Is that wave somehow analogous to a gravitational wave?

$\endgroup$
3
$\begingroup$

The problem with the rubber sheet is that it's a Riemannian manifold while spacetime is a Lorentzian manifold, and also that it has a preferred coordinate system. Both of these limit its usefulness for anything other than popular science applications. In addition to this a gravitational wave is a tensor wave while a wave in a rubber sheet is not.

As a very basic guide to the general public elastic waves in a rubber sheet could be used to describe the general idea of a gravitational wave, but historically the rubber sheet model has caused much misunderstanding and I'm not sure I would encourage its use.

$\endgroup$
1
  • $\begingroup$ One more problem is that in a gravitational wave, time variable is also distorted, while with the rubber sheet analogy we can only model distortion of space (unless we take one of directions on the sheet as time, which is even worse for general public). $\endgroup$ – Ruslan Jul 23 '19 at 8:09
2
$\begingroup$

In this model, ist there a way to represent gravitational waves?

Yes! See https://youtu.be/dw7U3BYMs4U

As John Rennie already commented, I myself am unsure if the rubber sheet analogy contributes more to my understanding or confusion of the topic. However, in my opinion the video shows quite nicely how the acceleration and not linear motion of bodies is relevant for the creation of gravitational waves.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.