Black holes are pitch black celestial objects which suck in even light. Matter and light that are pulled in are unable to ever escape again. But is it possible to use observations to find these dark celestial objects known as black holes? The gas which is pulled in by the black hole forms a radiant disk right before it is consumed by the black hole. There are also cases where strong jets are ejected from the disk. By observing these jets and the light radiated by the disk, we can find black holes which should be invisible.

Mechanism behind a Black Hole’s Bright Light

The gas captured by the strong gravity of the black hole orbits around and around, gradually speeding up as it approaches the black hole. At high speeds, a revolving disk of gas forms. Internal friction heats this gas disk. The gas emits copious light when it reaches high temperatures, so that the gas disk shines with bright light. The energy conversion mechanism occurring within the gas disk has a much higher efficiency than the nuclear reactions occurring within stars; it is said to be the highest efficiency in the Universe. For this reason, black holes surrounded by gas disks are some of the brightest objects in the Universe.

Text by: Ken Osuga (NAOJ Division of Theoretical Astronomy/Center for Computational Astronomy)
Translation by: Ramsey Lundock (NAOJ)

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Related Link

• Division of Theoretical Astronomy
• Center for Computational Astronomy