Life on a Planet Orbiting a Black Hole May Not be Impossible After All

For all we know, life in the universe could exist in the most remote places imaginable to us. One such remote and unlikely place may be a planet orbiting a supermassive black hole.

In a new study, a NASA astrophysicist has taken a look at the problems that could get in the way of life existing on a planet that is orbiting a black hole somewhere int he distant universe.

Jeremy Schnittman has recently published an article titled “Life on Miller’s Planet: The Habitable Zone Around Supermassive Black Holes” on the arXiv preprint server, that details his thoughts on the idea.

Scientists are skeptical about the idea that life could exist on a planet that orbits a black hole, mainly due to the probability that there is no star around to provide light and energy.

For Hollywood of course, this isn’t a biggie; the movie Interstellar showed astronauts (after traveling through a wormhole) observing a dozen planets near a black hole as possible future homes for humans.

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After watching the movie, Schnittman decided to reflect on the idea of habitable planets near black holes.

“In this paper, we discuss a number of additional astrophysical effects that may be important in determining the (un)inhabitable environment of a planet orbiting close to a giant, accreting black hole. Foremost among these effects is the blueshift and beaming of incident radiation on the planet, due to the time dilation of an observer orbiting very close to the black hole. This results in high-energy flux incoming from surrounding stars and background radiation, with significant implications for habitability,” the researcher points out in the recently published study.

Schnittman points out that although there may not be a sun around that provides light and energy for life on such a planet, that may not be a sufficient reason to discard life existing on such a planet.

When you think about it, it turns out that there are plenty of other energy sources for a planet orbiting a supermassive black hole. The most apparent is that supermassive black holes aren’t black at all.

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“Most of what we know about black holes comes from observing the electromagnetic radiation coming from gas as it accretes onto the black hole,” says Schnittman. “One could naturally imagine that replacing the sun with an accreting black hole might not be the end of life on Earth after all.”

The scientist points out in his paper that black holes generally have accretion discs consisting of hot gas and other matter. Such a disk could provide a planet with sufficient light and energy for life to persist.

However, Schnittman points out that light would be affected by the change in time (as shown with a dramatic effect on the film): the black hole would displace the light that reaches the planets near higher energies, which could be catastrophic for life.

Such a change would amplify all the light that reaches the planet, including harmful UV rays.

Schnittman points out that it is still unclear whether planets could exist near a black hole, much less those that could host life. But he also points out that mental experiments that focus on such things are good for science because they help scientists think about how the universe works.

Therefore, even if the idea of sending astronauts to a planet near a black hole seems far-fetched, think about why it might prove enlightening.

Despite the fact that we can’t possibly know with our given technology if there are life-bearing planets orbiting a black hole, the idea set forth by Schnittman is certainly an interesting one worth keeping in mind in the future.