Scientists believe that it may be possible to detected advanced alien civilizations that use spaceships powered by miniaturized black holes using gamma-ray telescopes.
Using a Black Hole as an Engine
The idea of using a black hole to power a starship might seem wild, but it has some basis in science. Black holes emit radiation when they consume matter, known as Hawking radiation, and this could serve as fuel for future space ships, according to some.
Building off this idea, a new paper published [PDF] on the preprint server Arxiv suggests that scientists could use existing telescopes to detect the gamma ray output of these starships and thereby detect alien civilizations, according to a report in Universe Today.
Dr. Louis Crane, a mathematician at Kansas State University, authored the paper as well as an earlier paper [PDF] exploring the possibility of black hole-based propulsion.
She told Universe Today in an email that, “An advanced civilization would want to harness a microscopic black hole because it could throw in matter and get out energy. It would be the ultimate energy source. In particular, it could propel a starship large enough to be shielded to relativistic velocities. None of the starship concepts NASA studied turned out to be viable… It might be the only possibility.”
Advanced Civilizations Only
Such a system of propulsion would be orders of magnitude more complicated than anything humanity is currently capable of, at least a Type II civilization on the Kardashev Scale.
Still, it isn’t outside the realm of possibility, and SETI researchers believe that this is exactly the kind of technology we should be looking for in order to detect alien life in the galaxy, known as “technosignatures”.
Such technologies as a black-hole-drive would create what Prof. Philip Lubin described as “spillover” in a 2016 study. By looking for signs of directed energy, we might be able to find signs of advanced civilizations.
“If some advanced civilization already had such starships, current VHE gamma ray telescopes could detect it out to 100 to 1000 light years if we were in its beam” Dr. Crane said.
“They could be distinguished from natural sources by their steadily changing redshift over a period of years to decades. To investigate this, astronomers would need to keep time series of frequency curves of the point-like gamma ray sources. This does not seem to be something they currently do.”