By Donna Lu
The first black hole we have ever directly imaged now has a nickname – but astronomy’s governing body says it will take a while to make it official.
Pictures of the supermassive black hole were unveiled on Wednesday by the Event Horizon Telescope (EHT), a global network of eight telescopes that turned Earth into one giant radio telescope.
The black hole, 55 million light years away at the centre of the galaxy M87, has been dubbed “Pōwehi” by Hawaiian language professor Larry Kimura, in collaboration with Hawaii-based astronomers involved in EHT.
Fittingly, “Pōwehi” means “embellished dark source of unending creation”. The name originates from the Kumulipo, an 18th-century Hawaiian chant that describes a creation story.
Conventionally, the official naming of objects in the universe is managed by the International Astronomical Union, which has done so since 1919.
“Objects are split into different categories such as surface features of objects in the solar system, or stars,” says the IAU’s Lars Christensen.
Naming celestial objects is occasionally a source of controversy. For example, the dwarf planet Haumea was disputed for years before a name was finally chosen, because two teams claimed to have discovered it.
“Typically discoverers of objects propose a name to a working group, who then vets the name and checks for various issues like duplication or political meaning,” says Christensen.
The names of these objects differ from “designations”, which are similar to a catalogue of numbers. For example, the interstellar object known as ‘Oumuamua has a designation 1I/2017 U1.
Black holes don’t have consistent naming conventions, but are often given the designation of their host galaxy.
“For the case of M87*, which is the designation of this black hole, a (very nice) name has been proposed, but it has not received an official IAU approval,” says Christensen.
“There is so far no working group who has been delegated with [the] naming of such objects, as this is the first in its class,” he says. “Typically these things take quite a while.”