Whether the earth is the only intelligent species in the universe has always been an unresolved question. After all, human search technology is limited to tens of thousands of stars.
But if an intelligent alien civilization has enough technology, maybe we have a chance to detect the faint gravitational waves produced by the alien civilization’s giant spacecraft.
The electromagnetic waves used by human beings to communicate will attenuate when they propagate, and it is almost impossible to filter out the noise mixed with weak electromagnetic waves hundreds of light years away.
Therefore, there are not only few ways to find extraterrestrial civilizations, but even the search distance is quite limited.
But gravitational wave signals are different, they are not attenuated like electromagnetic waves, and they can travel longer distances.
If an intelligent alien civilization is technologically powerful enough to generate gravitational waves, maybe we can detect them across the entire galaxy.
Although gravitational waves are mainly generated by large-scale events, such as the gravitational waves detected by the LIGO detector so far are all caused by the collision of massive compact celestial bodies, black holes and neutron stars, but in fact, any object with mass acceleration will produce gravitational waves.
How The Alien Ships will be detected?
UCLA physicist Luke Sellers’ team set out to calculate, if a high-tech alien craft (the team calls RAMACraft) existed, how large and how fast the LIGO probe should be able to track it.
Analysis shows that LIGO can detect RAMacraft, which is equivalent to the mass of Jupiter, and its warp drive can be accelerated to 10% of the speed of light.
If such a giant spacecraft passed within 326,000 light-years of Earth, LIGO would be able to detect the gravitational waves emitted by it.
The diameter of the Milky Way is about 260,000 light-years, which means that we have a chance to capture any advanced intelligent civilization in the Milky Way.
Future gravitational wave detectors such as DECi-hertz will be 100 times more sensitive than the LIGO observatory, and the search volume will be magnified by 10 6 times. Scientists look forward to any more interesting observations.
The new paper, which has not yet been peer-reviewed, will be published in Monthly Notices of the Royal Astronomical Society.