Bizarre Worlds in Proximity of Black Holes Might Not Be Science Fiction, Czech Physicists Say
Supermassive black hole rising in the sky of an exoplanet.
Planets similar to the Earth, inhabited by life forms similar to ours, could be orbiting a supermassive black hole. The possibility of the existence of bizarre worlds, like those presented in the science fiction film Interstellar, has been confirmed by computations made by physicists from the Faculty of Science at Palacký University Olomouc and from the Faculty of Philosophy and Science at Silesian University in Opava. Their surprising findings did not escape the attention of the international popular science magazine New Scientist.
Quantum optics scientist Tomáš Opatrný and relativist Lukáš Richterek, together with an astrophysicist from Opava, Pavel Bakala, calculated the conditions for existence of life on exoplanets (planets orbiting other stars than the Sun) in the proximity of supermassive black holes in the cores of galaxies, as well as black holes of medium size in globular star clusters. Their assumption was that life on the Earth is possible due to its hot Sun and cold sky. Thanks to this contrast, the Earth is provided with a great deal of negative entropy. The three physicists played with the idea of a world upside down: with hot skies and a cold sun, that is, a supermassive black hole.
The key trick is that the cold cosmic microwave background radiation, a remnant of the Big Bang which filled our whole universe with matter, is significantly warmed in the skies of exoplanets orbiting a black hole due to the extreme gravitation field. And the black hole would appear as a monstrous dark shadow on the sky. “Our calculations show that it depends on whether the black hole is rotating or not. Exoplanets orbiting non-rotating black holes at the present temperature of the cosmic microwave background, which is around 2.73 degrees Kelvin, do not have bright prospects. Such planets would have very little power to ensure the existence of a civilisation or life of a terrestrial type,” said Opatrný. On the other hand, exoplanets similar to the Earth and orbiting in close proximity of fast-rotating and supermassive Kerr black holes would. “In such a case, the extreme gravitational field would change the temperature map of the sky to allow for harvesting much more power,“ added the astrophysicist Bakala.
Czech researchers admit that they were inspired by exoplanets shown in the movie Interstellar. According to their calculations, the film water world with gigantic waves would in reality be an ocean of molten lead instead. However, if there were a planet with an orbit only a little farther away from the black hole, the conditions for life would be quite similar to those on Earth.
Czech scientists have developed their scenario even for a case when there are no planets orbiting a supermassive black hole, and a hypothetical civilisation could still want to use the black hole as a source of energy. “It could be possible in the early stages of the universe – if they built a black-hole version of the Dyson sphere around such a black hole. Dyson spheres are hypothetical megaconstructions that would surround a star, capturing all of its power and emitting the waste thermal energy into the universe,” explains Bakala. “The black-hole version of a Dyson sphere would work the other way round. It would absorb the energy from the microwave background radiation, sending the waste thermal energy into the black hole,” Opatrný specified. The Olomouc-Opava team has computed that if such a megaconstruction were built near a supermassive black hole with apparent radius equal to the radius of the Sun (696,000 kilometres), then due to the room-temperature microwave background radiation, it would receive power which is three orders of magnitude above the present solar energy reaching the Earth.
A preprint of the article written by the team of physicists, almost immediately after its location on arXiv.org, the international freely available online science archive run by Cornell University, met with significant acclaim in the scientific community. The research findings are noted both on the website and in the print version of the journal New Scientist, where they are commented on by prominent U.S. theoretical physicist (and a visitor for the last two years to Academia Film Olomouc) Lawrence M. Krauss.
