Recent research shows those waves leave behind “memories” –a permanent displacement of spacetime that comes from strong-field, general relativistic effects–that could help detect them even after they’ve passed, creating the potential to tell us about everything from the time following the Big Bang and the creation of cosmic strings–to more recent events in galaxy centers.
I can't read the article about gravitational waves as the link on the word "continue" is missing.
Daniel: Thank you! Fixed...