In the Star Trek: Voyager episode "Real Life", an interfold layer was a region in space that is the spawning ground of astral eddies and found to contain thousands of these small eddies.  While Tom Paris was gathering plasma particles, with the bussard collectors of the class 2 shuttle Cochrane, from the wake of an astral eddy, the shuttle was also pulled into the interfold layer by a collapsing eddy.

Images used to illustrate astral eddies in Star Trek very clearly indicate a phenomena similar to Black Holes, so an interfold layer could be thought to be a spawning ground where Black Holes can be formed. In actual astrophysics, it was once thought that the complex gravitational interactions in globular clusters would eject newly-formed black holes. The Hubble Space Telescope has produced observations indicating that globular clusters named M15 and G1 may contain intermediate-mass black holes, based on the sizes and periods of the orbits of the stars in the globular clusters.

It is also thought that a number of black holes also orbit the supermassive black hole that is found in the Sagittarius A* region in the Milky Way's Galactic Centre. These are possibly the remnant of a massive star cluster that has been stripped down by the Galactic Centre and supports the idea that supermassive black holes grow by absorbing nearby smaller black holes and stars.


A shuttle is trapped in an interfold layer in Star Trek: Voyager.

An artist’s concept of a black hole at the heart of a globular star cluster.