# What is the interaction of gravitational waves?

Please excuse my lack of knowledge about the subject but, If gravitational waves travel thru the fabric of space time do they interact with each other? Meaning do they create interference patterns such as a typical wave? If not why not? And, the other part of my question is since strong sources of gravity curve space-time what effect does this have on a gravitational wave traveling thru the fabric of space time. Does this act as a damper and/or amplifier on the traveling wave or is it somehow isolated from the effect of the space time curvature.

• Gravitational waves are (almost) always treated perturbatively. This means you assume a fixed background $g^{0}$ and the gravitational wave is imposed onto that as a series expansion $g=g^{0}+\epsilon h+\epsilon^2 h^{(2)}+...$. Usually only the linear term $\epsilon h$ is kept. In this case, the waves do not interact (however note that interference is just linear superposition, it is usually not considered interaction). One can take interaction into account by considering higher order terms. As far as I can recall one can calculate interesting effects in this case, such as... – Bence Racskó Oct 18 '18 at 17:30
• ... two waves meeting and upon interaction they form a black hole. – Bence Racskó Oct 18 '18 at 17:30
• @Uldreth, isn't your 'comment' more of an answer than a comment? – Alfred Centauri Oct 18 '18 at 18:11
• "Does this act as a damper and/or amplifier" - Have you considered the curvature acting as a (gravitational) lens? – safesphere Oct 18 '18 at 23:07
• Light interference is linear, but what happens when two jects of water cross? – safesphere Oct 18 '18 at 23:22