A group of NASA physicists published an article in the arXiv preprint repository in which the authors proposed using LIGO gravitational wave detectors to search for giant spacecraft of hypothetical extraterrestrial civilizations.

According to the conclusions of scientists, one of the conditions for the detection of such waves is the gigantic size of the starships that generate them, which should be comparable to Jupiter. The authors called such ships Fast and/or massive accelerating spacecraft, or RAMAcraft (Rapid And/or Massive Accelerating spacecraft). They must also travel very fast, up to one-tenth the speed of light. Finally, the devices should be in relative proximity to the Earth, at a distance of 326 thousand light years.

The researchers also note that if aliens are using "warp drives" to warp the space-time continuum, astrophysicists should be able to detect them, as such a craft would also generate noticeable gravitational waves.

The advantage of LIGO over the traditional method of searching for extraterrestrial civilizations using radio telescopes is that gravitational wave detectors register signals simultaneously from all directions and sources, of which there are about a hundred billion, while radio detectors cover only a few tens of thousands of stars. In addition, in the future, gravitational wave instruments will become more sensitive, which will make it possible to register weaker signals.