James Webb Telescope Solves Mystery Of Pablo’s Galaxy’s Demise: Was It ‘Death By A Thousand Cuts’?

Last Updated:January 14, 2026, 23:31 IST

Officially known as GS-10578, Pablo’s Galaxy existed about three billion years after the Big Bang and lies roughly 11 billion light-years from Earth.

At the heart of Pablo’s Galaxy sits a supermassive black hole that repeatedly pushed gas outward at extreme speeds. (Representational)

Astronomers using the James Webb Space Telescope and the Atacama Large Millimeter Array uncovered what killed a massive, distant galaxy nicknamed Pablo’s Galaxy. Scientists said that the galaxy was slowly starved to death by its own central black hole in findings published in Nature Astronomy. The galaxy faded quietly rather than exploding spectacularly, they said, in a process described as a cosmic “death by a thousand cuts."

What Is Pablo’s Galaxy?

Officially known as GS-10578, Pablo’s Galaxy existed about three billion years after the Big Bang and lies roughly 11 billion light-years from Earth. At its peak, it was a star-forming giant with a mass equivalent to about 200 billion Suns. For its era, it should have been bustling with stellar activity. Instead, Webb’s observations show a galaxy that stopped forming stars around 400 million years ago.

What Did Webb And ALMA Discover?

ALMA detected virtually no carbon monoxide in the galaxy, a chemical marker used to trace cold gas needed to form new stars. The absence of this signal indicates that Pablo’s Galaxy has been almost completely stripped of its star-forming fuel.

“What surprised us was how much you can learn by not seeing something," said co-first author Dr Jan Scholtz of Cambridge University, adding, “There was essentially no cold gas left. It points to a slow starvation rather than a single dramatic death blow."

How Did The Black Hole Kill Pablo’s Galaxy?

At the heart of Pablo’s Galaxy sits a supermassive black hole that repeatedly pushed gas outward at extreme speeds- up to 2.2 million miles per hour. Each outflow removed a little more fuel, preventing fresh gas from cooling and collapsing into new stars. Over time, these repeated episodes drained the galaxy’s reserves. Researchers estimate the galaxy has been losing around 60 solar masses of gas every year, meaning it could have exhausted its supply in as little as 16 million years or at most a few hundred million.

Was There A Violent Collision?

Surprisingly, no. Despite its demise, Pablo’s Galaxy still looks calm and orderly- a rotating disk with no signs of a major merger or collision. That’s important, scientists said, because it rules out dramatic external events as the cause.

“The galaxy looks like a calm, rotating disk," said co-first author Dr Francesco D’Eugenio, explaining, “That tells us it didn’t suffer a major, disruptive merger. Instead, repeated black hole activity likely kept the fuel from ever coming back."

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