Paul M. Sutter – astrophysicist at Suny Stony Brook and the Flatiron Institute – published an article last Friday (6), in Space, in which he affirms the possibility of life on planets that orbit supermassive black holes in fast rotation. According to him, the forces around a black hole are capable of heating a planet, however, for life to exist, the celestial body must orbit at the speed of light.
Sutter’s study took as its starting point the life we know here on Earth, which needs liquid water and oxygen to survive. The researcher states that it is very difficult to find water in its liquid form, as well as a heat source that does not evaporate. However, despite these factors, balance is possible in the so-called ‘habitable zone of the stars’ and also under the icy crusts of some moons of planets outside our system.
The scientist said that although black holes might seem inhospitable to life at first, they are after all made of pure gravity and, therefore, pull anything close to their horizons, this force can provide a surprise. This is because the universe is permeated by something called Cosmic Microwave Background Radiation (CMB), which is the remaining radiation from the beginning of the universe.
CMB is by far the largest source of radiation in the cosmos and floods all stars and galaxies by many orders of magnitude. Sutter explains that CMB is cold, has an average temperature of 3 ° above absolute zero, and when its light falls into a black hole, it turns blue, being pumped to higher energies, changing to infrared and even ultraviolet proportions. Thus, in a black hole, the CMB goes from cold to very hot.
When the CMB falls into a rotating black hole, it can focus the light on a narrow beam, causing a single point to appear in the sky, similar to a sun.
Thus, if a planet is able to approach a black hole, it will become very hot, and its ice could be converted into liquid oceans (a potential home for life). Sutter ponders that “for life to thrive, it also needs a heat sink, which can be easily supplied by the black hole itself. Close to it, gravitational distortions increase the appearance of the event horizon, increasing much more than you naively imagine ”.
The scientist ended his article by stating that, however much life is possible on a planet orbiting a black hole, the scenario would not be pretty, because the celestial body would have to orbit at the speed of light for his life to continue to exist in these conditions. That means that, every second of it, many of our hours would pass. Sutter also said, ‘Still, the work shows that we need to keep our minds open when it comes to possible homes for all lives, including some of the most terrible environments in the universe.’