Dyson Spheres

Technologically-savvy aliens could be powering their society using a hypothetical megastructure called a Dyson sphere to harvest energy from a black hole. And the sphere might radiate in peculiar ways, allowing telescopes on Earth to discover the existence of intelligent beings elsewhere in the universe, a new study suggests.

A Dyson sphere is a speculative structure that would encircle a star with a tight formation of orbiting platforms in order to capture starlight and produce power, according to Live Science's sister site Space.com. First proposed by theoretical physicist Freeman Dyson in 1960, the idea might be realized by a spacefaring extraterrestrial species who had spread out across their star system and therefore required ever-increasing amounts of energy.

During a coffee break, astronomer Tiger Yu-Yang Hsiao of National Tsing Hua University in Taiwan and his colleagues read a paper about Dyson spheres and began wondering if it were possible to build one around a black hole instead of a star.

"Black holes are one of the brightest objects in the sky," Hsiao told Live Science.

While we normally think of them as being dark and all-consuming, black holes can radiate incredible amounts of energy, he added. Material often forms a disk as it falls into a black hole's maw, much like water circling a drain.

As the gas and dust in this disk spin and bump against each other, they heat up through friction, sometimes to millions of degrees, producing light in the X-ray portion of the electromagnetic spectrum, Hsiao said. Colossal beams of energy can also shoot from a black hole's poles.  READ MORE