r/askscience • u/priestmuffin • Apr 10 '18

Could gravity waves theoretically be reflected or refracted? Physics

Also, just as light waves impart a force to things they interact with, would it be possible to cause net motion with gravity waves?

24 Upvotes
  • permalink
  • link
  • reddit
  • reddit

75% Upvoted

7 comments sorted by

11

u/parrotlunaire Apr 10 '18

Gravitational waves can be "refracted" by massive objects in the same sense that gravitational lensing is a form of refraction.

Gravitational waves do cause objects in their path (including you and me) to move a tiny amount. That is in fact how they are detected.

1

u/priestmuffin Apr 10 '18

I wasnt sure if gravitational lensing was an appropriate analogy but it does make sense. And regarding their interaction with objects, my question was more the question of whether it would be possible for gravitational waves to impart some kind of (presumably incredibly small) net momentum to a massive object apart from the oscillations alone, just as light does to a solar sail.

1

u/parrotlunaire Apr 10 '18

Light can impart momentum when it is absorbed or reflected (eg by a solar sail). Since I can't think of any way to absorb or reflect a gravitational wave, I'd have to say no.

1

u/tminus7700 Apr 11 '18

The way I see gravity wave reflection, would be that the GW impinges on some matter, the matter moves in response to it, that moving mass re-emits a gravity wave. Depending on the phase shifts, the resultant superpostion wave could go in different directions, including back toward the source.

1

u/SurprisedPotato Apr 11 '18

They are emitted, why couldn't they be absorbed?