Teen Astronomer Accidentally Discovers Giant Black Hole ‘Echo’ – The Biggest Ever?

A high school student searching for signs of exploded stars ended up discovering what could be the largest black hole light echo ever recorded.

A Surprising Finding

Seventeen-year-old Julian Shapiro, a student at The Dalton School in New York City, made the accidental discovery while exploring data from the DECaPS2 survey. This project maps the southern galactic plane using the Dark Energy Camera at Chile’s Cerro Tololo Inter-American Observatory.

He was originally looking for supernova remnants and planetary nebulae, but one object stood out. It didn’t match the usual patterns seen in remnants of supernovae. The finding also lacked a supernova at its centre. “It was a real surprise to stumble upon this,” Shapiro told Live Science.

A Cosmic Ghost In The Sky

What Shapiro found appears to be a light echo; a glowing area of gas still lit up by radiation from a once-active black hole. These echoes are like a ghostly afterglow, left behind after the black hole becomes quiet.

“There are these outer regions of gas being ionised by a supermassive black hole, which results in this echo,” Shapiro explained during his talk on 20 March at the 2025 American Physical Society (APS) Global Physics Summit in Anaheim, California.

He studied the object further using data from the Southern African Large Telescope. He found high levels of oxygen and ionised sulphur in the region. These elements suggest that the gas had been shocked, which supports the theory of a past burst of black hole activity.

Possibly The Biggest Light Echo Ever Seen

Shapiro estimates that the light echo is between 150,000 and 250,000 light-years wide. That’s up to twice the size of the Milky Way. If confirmed, it could be the largest black hole light echo on record.

“This object covers a large area in the sky, which makes it a bit easier to get in-depth images of,” he said.

Astronomers Take Note Of Teen’s Discovery

Astrophysicist Sasha Plavin of Harvard University, who was not involved in the research, praised Shapiro’s work. “I really like how carefully [Shapiro] looked into these images,” he told Live Science. “These galactic events are always of interest, and I think these echoes are a great way of studying them.”

Plavin added that it would be useful to compare this new discovery with other known light echoes. “Putting this discovery in a wider context could be useful in the future,” he said.

Teen Scientist Eyes Deeper Exploration

Shapiro now hopes to study the object’s composition in greater detail. By analysing its different regions, he aims to uncover more about the black hole’s past activity. For now, he’s simply thrilled to contribute to this field of research — even if it happened by accident.

“My involvement in this area of research came as a bit of a surprise to me,” he said. “But I hope this object, in particular, helps expand the knowledge of galaxy activities that we don’t have too great of an understanding of.”