This past February, a hidden intermediate mass black hole–a one-way door out of our universe– 30,000 times mass of the Sun, was detected packed in a region much smaller than our Solar System only 20 light-years from the supermassive black hole at the Galactic center. The stealth object was detected from its effects on an interstellar gas cloud. This intermediate mass black hole is one of over 100 million quiet black holes hidden in the Milky Way.
It is conceivable that a civilization advanced enough to see itself in a cosmological context would think of a way to make itself known to the universe. In “The Messenger: A Galactic Center Gravitational-Wave Beacon” pre-print on Arxix, an international team of researchers have proposed a hypothetical alien craft, a beacon at the Milky Way’s Galactic Center, “The Messenger”, that emits gravitational waves that are “unambiguously artificial”.
“This discovery dramatically changes our view on the origin of fast-moving stars,” said Monica Valluri, an astronomer at the University of Michigan. “The fact that the trajectory of this massive fast-moving star originates in the disk rather that at the Galactic center indicates that the very extreme environments needed to eject fast-moving stars can arise in places other than around supermassive black holes.”