In Star Trek, an astral eddy is a subspace disruption anomaly.  In the Star Trek: Voyager episode "Real Life", a Vostigye science station was torn apart by an astral eddy, also trapping a probe and the shuttlecraft Cochrane piloted by Tom Paris while it was gathering plasma particles with bussard collectors from the wake of an eddy. The shuttle vanished and was sent to an 'interfold layer between space and subspace.' The Voyager crew are later able to conceive and execute a plan in which the shuttle rides the eddy back into normal space, where Paris can be rescued.


There is no such phenomena termed as astral eddies in real astrophysics. However, the images used to illustrate astral eddies in Star Trek very clearly indicate a phenomena similar to a black hole. Contemporary models proposed to describe the flow into a black hole from the turbulent flow of matter in initially circular orbits about the black hole do illustrate the possibility of eddy formations. The shear between fluid elements at slightly different orbital radii causes turbulent eddies to be formed. In this model, the turbulent eddy rotation period is presumed to be determined by the gradient in the gravity acceleration, leading to an eddy period proportional to the orbital period. If the flow speeds are supersonic but not relativistic, then the turbulent eddy size is set by the product of the eddy rotation period and the speed of sound. At a certain smaller radius, the orbital speeds and hence the dissipation rate are so great that the speeds become relativistic and the molecular speed tends toward its limit. Then the effective eddy size is controlled by the product of the eddy rotation period and the speed of light.  (see http://adsabs.harvard.edu/abs/1996IJMPA..11..161T )

 

IIllustration of  eddies from the accretion disk of a Black Hole pulling matter from a companion star