Astronomers discover biggest ever seen black hole jets, which blast hot plasma well beyond their own host galaxy

Astronomers have spotted the biggest pair of black hole jets ever seen, spanning 23 million light-years in total length. That's equivalent to lining up 140 Milky Way galaxies back to back.

"This pair is not just the size of a solar system, or a Milky Way; we are talking about 140 Milky Way diameters in total," says Martijn Oei, a Caltech postdoctoral scholar and lead author of a Nature paper reporting the findings. "The Milky Way would be a little dot in these two giant eruptions."

The jet megastructure, nicknamed Porphyrion after a giant in Greek mythology, dates to a time when our universe was 6.3 billion years old, or less than half its present age of 13.8 billion years. These fierce outflows—with a total power output equivalent to trillions of suns—shoot out from above and below a supermassive black hole at the heart of a remote galaxy.