There
is no such thing as a stationary blackhole. Every blackhole in the
Universe is
gravitationally paired with every other object in the
Universe. Consequently, every blackhole is constantly converging
on or diverging from
everything else in the Universe. The distances
involved are usually so great that individual mutual
gravitypulls are too weak to be seriously effective but en
masse all gravitypulls are
significant. What this means is that the stability condition of every
blackhole is constantly changing as the
mechanism described here
retunes it to cope with the myriad of gravitypulls it is simultaneously
experiencing.
The
mechanism isn't exclusive to
blackholes, of course. It is constantly at work in everything in
the Universe that is made of gravitons, often as part of a
multiprocess.
It contributes to the unique behaviour of
photons and it is a major
factor in maintaining the stability of
electrons and
nucleons in a
wide range of conditions. In more complex objects like planets,
stars, and galaxies, the mechanism is obscured from easy view but
it is still there and still
important.