Quasars, which have been known since the 1960's, are sources of tremendous energy found in the center of distant galaxies and thought to be powered by matter falling into massive gravitational sinks called black holes.

In principle, the spectral maps should define the structure of the whirlpool of gas and other stellar matter being drawn inexorably into a gravitational sink known as a black hole.

It is assumed that these enigmatic objects are dense collections of matter at the heart of galaxies, perhaps associated with gravitational sinks known as black holes.

Left in the enveloping twilight will be stillborn stars like brown dwarfs, stellar ghosts like white dwarfs and neutron stars and those powerful gravitational sinks known as black holes.

In the 1960's, huge dish antennas first detected radio waves emitted by gases being sucked into enormous gravitational sinks in space known as black holes.

Those tremendous cosmic gravitational sinks known as black holes used to come in two weight classes: small (the mass of a huge star) and super (the heft of billions of stars).

Quasars are extremely distant and bright objects believed to be powered by black holes, those gravitational sinks at the cores of many galaxies.

They are created in abundance by exploding stars, the annihilation of matter and antimatter and the turbulent regions around what are thought to be gravitational sinks known as black holes.

The hammock was the fabric of space-time, Hank decided, and he was a gravitational sink, warping the geodesics around his body.

Dense gravitational sinks known as black holes could also be hiding places of dark matter.