In all likelihood, we humans are not alone in the universe. In the past 30 years, more than 5,000 planets have been discovered outside our solar system, known as exoplanets. Some of these have conditions favorable to more highly evolved life, such as water on the surface. So, the question is rather not whether there is extraterrestrial intelligence (ETI), but: How can we recognize it?
The more advanced living beings on other planets are, the more powerful their computer systems will be. On Earth, we currently see the transition from binary computing processes to quantum computing with many simultaneous operations. Since our solar system is relatively young, it is reasonable to assume that more highly evolved inhabitants of older star systems are already using sophisticated quantum technologies.
The role of quantum mechanics
The authors derive step by step why black holes are likely to be used for this purpose. “The laws of physics apply throughout the universe. Even if aliens are made of other matter particles and their chemistry is different from ours, we are connected by the laws of quantum physics and gravity”, explains Gia Dvali, who heads the Department of Cosmology and Particle Physics at the MPP. Quantum mechanical principles state that black holes are the most efficient stores of quantum information.
The black holes used for computing would likely be artificial and microscopic, unlike their large and naturally occurring siblings. Says Gia Dvali, “We have analyzed how fast information can be retrieved from black holes. To optimize information volume and processing time, it would be beneficial for ETI to produce many microscopic black holes instead of a few large ones.”
Search for extraterrestrial life
The particular make of black-hole-based quantum computers also holds the possibility of detecting extraterrestrial life. One feature of black holes is Hawking radiation, which is universal to all types of particles in existence. “Therefore, ETI quantum computers must also radiate neutrinos and photons”, says Gia Dvali. “We can detect these particles on Earth.” Neutrinos, in particular, are suitable messengers because they can fly through matter and therefore all protective devices for quantum computers.
The authors also assume that inhabitants of other stellar systems create their microscopic black holes with the help of particle collisions in high-energy accelerators. “This provides a characteristic fingerprint for ETI: a flux of very energetic neutrinos originating both from the Hawking radiation of information-storing black holes and from the collision 'factories'.”
In their paper, Gia Dvali and Zaza Osmanov show that the IceCube neutrino observatory at the South Pole, for example, would be able to observe such technosignatures. “For decades we have searched for extraterrestrial intelligence in the radio frequency spectrum - so far without results,” explains Gia Dvali. “Our research points in a very exciting new direction for finding life beyond Earth.”