Astronomers recently discovered the largest pair of black hole jets ever observed, and they’ve named the system Porphyryon. Imagine something that big lining up 140 Milky Way galaxies in a row. Then multiply that thought by two. It’s almost too much for our minds to handle, but that’s exactly what they found.

Meet the Porphyryon black hole jet system

Martijn Oey is a postdoctoral researcher at the California Institute of Technology with the ability to unravel the mysteries of the universe. His latest work is published in a new paper NatureI got everyone talking.

Oey and his team discovered this pair of massive black hole jets, called Porphyrion. Derived from Greek mythology, Porphyrion is a fitting nickname for such a massive structure. Not only does the jet megastructure span 23 million light-years in total, it also dates back to when our universe was only 6.3 billion years old.

That’s less than half its current age of 13.8 billion years. To put it in perspective, the universe still seems like it’s in its teens. These violent jets of energy, with a combined power equivalent to trillions of suns, are emanating from a supermassive black hole at the center of a distant galaxy.

Before Porphyrion, the record holder for the largest jet system was another giant, Alcyoneus, named after a character in Greek mythology. Discovered by the same team in 2022, Alcyoneus is equivalent in size to 100 Milky Ways. In comparison, the jets of Centaurus A, the closest major jet system to Earth, extend only 10 Milky Ways across.

What makes Porphyrion’s discovery even more groundbreaking is its implications for our understanding of galaxy formation, said co-author George Giorgowski, a professor of astronomy and data science at Caltech.

“Astronomers believe that galaxies and the black holes at their centres have co-evolved, and one of the key aspects of this is that jets can release enormous amounts of energy that affect the growth of their host galaxies and other nearby galaxies,” he says. “This discovery suggests that their effects may go much further than we thought.”

But Porphyrion’s scale suggests that the impact of these jets could go far beyond our previous understanding.

Scanning space and jet black holes

The discovery of Porphyrion is part of a larger survey of the sky that has revealed a staggering number of structures of this type, more than 10,000. This huge population of giant jets was discovered by the European radio telescope LOFAR (Low Frequency Array).

“Giant jets were known about before we started the campaign, but we had no idea there would be so many of them,” says Martin Hardcastle, the study’s second author and a professor of astrophysics at the University of Hertfordshire in England.

“Usually when we get a new observation opportunity, such as the combination of LOFAR’s wide field of view and very high sensitivity to extended structures, we find something new, but it was still very exciting to see so many of these objects pop up.”

Porphyrion’s landing took the team across continents and observatories. They used additional data from the Giant Metrowave Radio Telescope (GMRT) in India and the Dark Energy Spectroscopic Instrument (DESI) at Kitt Peak National Observatory in Arizona.

The observations pointed the group to a massive galaxy about 10 times larger than the Milky Way as Porphyrion’s birthplace.

Jet system of a Porphyry-sized black hole

Porphyrion is 7.5 billion light-years from Earth. Its remote location and emergence from a radiation black hole suggest it may not be a lone titan, but a harbinger of countless giant jets yet to be discovered.

Oei suggests the same, saying: “We may be looking at the tip of the iceberg.”

There are still many unanswered questions about these giant black hole jet systems: How do they extend so far and grow so large without becoming destabilized?

“Martin’s work showed us that there’s nothing special about these giant sources that would cause them to grow to such large sizes,” says Hardcastle, an expert in the physics of black hole jets.

“My interpretation is that we need extremely long-term and stable accretion around the central supermassive black hole to keep it active for so long (about a billion years) and to keep the jets pointing in the same direction for all that time. What we’ve learned from so many giants is that this should be a relatively common event,” Hardcastle concluded.

Environmental influence and magnetism

How do they affect the environment? And perhaps most interestingly, do these giant jets radiate magnetism into space?

“We know that magnetism permeates the cosmic web, then makes its way to galaxies, stars and eventually planets, but the question is: Where does it begin?” He is right.

This research is the exciting beginning of a new chapter in our understanding of the universe. With the discovery of Porphyrion, we are reminded that we still have much to discover about the mysteries of the universe. Even the starry sky is just the beginning. The study was published in the journal Nature.