The Memory Effect of Gravitational Waves

The memory effect of gravitational waves is a consequence of general relativity. It's one we've seen in the math, but we've never actually seen it out there in the universe. We don't think that our current experiments like LIGO are going to be capable of seeing this very easily. But you're right, it's also much, much smaller than gravitational waves. And predicted to be like 20 to 50 times smaller than current gravitational waves effects we have measured.