Inside a rotating or charged black holes there are bound periodic planetary orbits, which not coming out nor terminated at the central singularity. The stable periodic orbits inside black holes exist even for photons. We call these bound orbits by the orbits of the third kind, following to Chandrasekhar classification for particle orbits in the black hole gravitational field. It is shown that an existence domain for the third kind orbits is a rather spacious, and so there is a place for life inside the supermassive black holes in the galactic nuclei. The advanced civilizations may inhabit the interiors of supermassive black holes, being invisible from the outside and basking in the light of the central singularity and orbital photons.
MIT Technology Review has coverage
Vyacheslav Dokuchaev at the Institute for Nuclear Research of the Russian Academy of Sciences in Moscow points out that certain black holes can have a complex internal structure. And that this structure ought to allow photons, particles and perhaps even planets to orbit the central singularity without ever getting sucked all the way in.
Cosmologists have known for some time that there are regions inside charged, rotating black holes where objects such as photons can survive in stable periodic orbits.
Dokuchaev's contribution is to study these orbits in detail and to explore their dynamics. One of the problems that would at first seem to scupper any chance of planetary orbits inside a black hole is the way that the dimensions of space and time behave.
It's well known that a traveller passing through a black hole's event horizon arrives in a region in which the radial dimension becomes time-like, rather than space-like. Conventional orbits are clearly impossible here.
But travel further in and there is another horizon where the dimensions switch back again (at least, inside charged and rotating black holes). This is the inner Cauchy horizon and it's beyond here that Dokuchaev says the interesting orbits for massive planets exist.
He calculates that the stable orbits are nonequatorial and have a rich structure (see picture above). They would also be brightly illuminated by the central singularity and by photons trapped in the same orbit.
That raises an interesting question: whether a planet in such an orbit could support a complex chemistry that is rich enough to allow life to evolve.
Dokuchaev clearly thinks so. "Advanced civilizations may live safely inside the supermassive BHs in the galactic nuclei without being visible from the outside," he says, somewhat speculatively.
Of course, such a civilisation would have to cope with extraordinary conditions such as huge tidal forces and the huge energy density that builds up in these stable orbits as photons become trapped. There's also the small problem of causality violations, which some cosmologists predict would plague this kind of tortured space-time.
10 page pdf
A voyage inside the Black Hole (BH) event horizon may finished after a finite proper time of the traveler not in the central singularity, but again outside the event horizon. However, it would not be a returning to the native universe, but emerging in the other universe due to the complicated internal BH geometry. Is it possible live too long inside the BH by avoiding both the downfall to the central singularity and escaping to the other universe? The answer is positive, if a target BH is rotating, charged and massive enough for weakening to the acceptable level of tidal forces and radiation of gravitational waves. After traversing the BH event horizon at radius r = r+, a traveler will appear in the T-region, where his radial coordinate r is becoming the temporal one and inevitably diminishing toward the central singularity. The irresistible infall in the T-region will finish soon after traversing the inner Cauchy horizon at r = r− less than r+, which is nonzero for the rotating or charged BH. The internal space-time domain 0 less than r less than r− between the central singularity and the inner BH horizon is the R-region, where the stationary observers may exist, just as anywhere at the planet Earth. This internal BH domain, hidden by two horizons from the whole external universe, is indeed a suitable place for safe inhabitation. The only is needed, is to put your vehicle or your planet to a stable periodic orbit inside BH. Below we discuss some specific properties of stable periodic orbits of planets and photons inside the rotating charged BH, described by the Kerr-Newman metric.
Inside the inner Cauchy horizon of rotating charged BH there are the stable periodic orbits of particles (planets) and photons. In the case of nonrotating charged BH the stable periodic orbits exist only for particles with a large enough charge. All stable periodic planet and Inside the inner Cauchy horizon of rotating charged BH there are the stable periodic orbits of particles (planets) and photons. In the case of nonrotating charged BH the stable periodic orbits exist only for particles with a large enough charge. All stable periodic planet and photon orbits inside the rotating and noncharged BH are nonequatorial. The advanced civilizations may live safely inside the supermassive BHs in the galactic nuclei without being visible from outside. The naked central singularity illuminates the orbiting planets and provide the energy supply needed for living. An additional highlighting at night come from the eternally circulating photons. It worth to mention also some troubles (or advantages?) for living inside BH: the possible causality violation and the growing energy density in the very vicinity of Cauchy horizon.
Science Fiction covered this with Poul Anderson and the Heechee
If you liked this article, please give it a quick review on ycombinator or StumbleUpon. Thanks