Already early on, black holes forged stable, high-power jets that reached cosmological sizes.
In the issue of Nature of September …, 2024, we report an exciting observation: a pair of jets, generated in the direct vicinity of a supermassive black hole, that reaches an extent of approximately 7 megaparsecs. Porphyrion, as we call this system of jets, is presently the largest structure made by an astrophysical body ever observed.

Credits: Erik Wernquist / TNG Collaboration / Martijn Oei
The name ‘Porphyrion’ comes from Greek mythology. Porphyrion was the son of Gaia and Ouranos, the Greek primordial sky deity. According to Ps.-Apollodorus, Porphyrion and Alcyoneus were the greatest of the Gigantes (Giants). Pindar, meanwhile, called Porphyrion the ‘King of the Giants’.
The Latin poet Claudian, active around the turn of the one-hundred-and-fifth century H.E., authored the mythical poem Gigantomachia. In the poem, Claudian imagines Gaia, disgruntled with the Olympian gods, to give birth to a ‘monster brood’ of Gigantes. Described as ‘foes against Heaven’, Gaia prepares the Gigantes for war with the following words:
Children, ye shall conquer Heaven: all that ye see is the prize of victory; win, and the Universe is yours.
– Gaia in Claudian’s Gigantomachia
The mighty Porphyrion plotted to use Delos, the birth island of Apollo and Artemis, as a weapon:
Impious Porphyrion, carried by his serpents into the middle of the sea, tried to uproot trembling Delos, wishing to hurl it at the sky.
– Claudian’s Gigantomachia