We Could Search for Aliens Harvesting Energy from their Pet Black Hole

Artist's illustration of a Dyson swarm. Archibald Tuttle - Own work

Of all the unanswered questions in modern science, perhaps the most talked about is whether we are alone in the Universe. A new paper looks at another way we might be able to detect advanced civilisations and at its centre is the need for energy! The more advanced a civilisation becomes, the greater their need for energy and one of the most efficient ways, according to current theories, is to harness the energy from an actively feeding black hole. The paper suggests a civilisation feeding matter into a black hole could harvest energy from it, more excitingly perhaps, the process could be detectable within 17,000 light years!

The search for intelligent life beyond Earth has been of fascination to scientists, philosophers and even inspired artists over the centuries. With hundreds of millions of stars in our Galaxy and billions of other galaxies across the cosmos, it seems the odds are in our favour of finding some other civilisations out there.

Planets everywhere. So where are all the aliens? Credit: ESO/M. Kornmesser

The discovery of thousands of exoplanets in recent decades adds to the excitement so, researchers have directed radio telescopes and space probes on the search for aliens. Projects like SETI, the Search for Extraterrestrial Intelligence has been scanning the sky looking for unusual patterns or messages that could reveal an advanced civilisation but despite the effort, there is a distinct lack of success, yet.

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A different approach is to search for advanced civilisations based upon their energy signatures. It’s an innovative idea that seeks to identify civilisations based upon artificial patterns in the electromagnetic spectrum. We have certainly seen how human energy demand has increased as we have become more advanced and so theoretically any more advanced civilisations would need to harness energy on a scale far in excess of what we currently use. It may be that civilisations use giant megastructures like Dyson spheres to harness energy from stars and it’s the output from these or their impact on the light from a star that may be detectable.

Artist’s impression of a Dyson Sphere, an proposed alien megastructure that is the target of SETI surveys. Finding one of these qualifies in a “first contact” scenario. Credit: Breakthrough Listen / Danielle Futselaar

In a paper authored by Shant Baghram and published in the Astrophysical Journal, the team begin by categorising civilisations on the Kardashev Scale. It categorises advanced civilisations by measuring their technological advancement based upon the amount of energy they are capable of harnessing and using. They also propose an alternate scale based upon the Kardashev scale and the distance a civilisation is able to explore space, suggesting more advanced can explore further from host planet.

The Atacama Large Millimeter/submillimeter Array (ALMA). Credit: C. Padilla, NRAO/AUI/NSF

As a paper based purely on a theoretical model, they take the advanced civilisation’s category and explore the idea that they may use Dyson sphere’s around primordial black holes as an energy source. The team also propose observational techniques that may be employed to detect such structures using infrared and sub-millimetre signatures. They do assert however that telescopes like ALMA (the Atacama Large Millimetre/Sub-millimetre Array) is well placed to make observations and even to detect signatures and maybe even megastructures at distances of approximately 5.4 kiloparsecs (178 light years.)

Source : In Search of Extraterrestrial Artificial Intelligence Through Dyson Sphere–like Structures around Primordial Black Holes

Mark Thompson

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PolishBear says:

January 8, 2025 at 8:38 AM

As I look at what we are doing to our own planet, how we are fouling our own nest, and I wonder if this is a fate shared by all advanced civilizations. It's fun to speculate about Dyson Spheres and galactic empires, but perhaps the reason we don't see other spacefaring races is because they doom themselves through their own narcissism and greed BEFORE they can progress beyond Type 0 on the Kardashev Scale.