There are hundreds of millions of planets in the universe where life could exist.
But so far, scientists have not found evidence of extraterrestrial life.
In a recent article published on the Preprint website, physicists discuss the possibility of using the Laser Interferometer Gravitational-Wave Observatory (LIGO) to search for traces of large alien spacecraft.
Physicists believe that when aliens fly large spacecraft around the Milky Way, their wake streams could produce gravitational waves strong enough to reach Earth and be detected by LIGO.
When the alien spacecraft is the size of Jupiter, travels at no less than 1/10th the speed of light, and is less than 326,000 light years away from Earth
Gravitational waves generated can be detected by humans.
In addition, if the spacecraft uses a warp drive to fly by compressing the space-time ahead and expanding behind, the gravitational waves generated can also be detected by LIGO.