Black Holes Caught in the Act of Cosmic Creation

Astronomers have glimpsed the telltale signs of newly formed stars inside the powerful winds of a supermassive black hole.

An artist’s impression of a stars forming in powerful outflows of material coming from a supermassive black hole inside a galaxy
An artist’s impression of a stars forming in powerful outflows of material coming from a supermassive black hole inside a galaxy (ESO / M. Kornmesser)

In the universe, the places with the most extreme, destructive conditions can sometimes spawn something new.

A group of European astronomers have spotted new stars flaring to life inside the cosmic wind blasts expelled by a supermassive black hole. The black hole sits at the center of two merging galaxies 600 million light-years away, according to a study published Monday in Nature. The astronomers say this is the first clear evidence of star formation inside this kind of environment, previously suspected to be good for breeding stars.

The findings come from the aptly named Very Large Telescope, a ground-based telescope located in northern Chile and run by the European Southern Observatory. Searching for young stars, the astronomers trained the telescope’s instruments on a collision between two distant galaxies, known together as IRAS F23128-5919. A supermassive black hole sits at the center of the pair’s southern galaxy, doing what black holes do best: Gobbling up matter, heating up surrounding areas, and spewing out gas in powerful, dense blasts. The Very Large Telescope’s sensitive instruments detected that nearby, cooler gas clouds were illuminated, a phenomenon that results from the radiation from hot, young stars. This suggested, the astronomers say, that the black hole’s outflows housed an infant stellar population.

The astronomers believe the stars are less than a few tens of millions of years old, which makes them babies compared to stars like our sun, which is about 4.5 billion years old. The baby stars appear hotter and brighter than those formed under calmer conditions, like in swirling clouds of interstellar gas and dust.

The outflows appear to be star-making machines. Astronomers believe stars about 15 times the mass of the sun are being created every year in the galaxies’ eastern outflow, and about 30 times the mass of the sun inside their western outflow. The outflows, they say, are creating more than a quarter of the total stars being made in the merging galaxy system.

And the stars are on the move. The detection of light inside the merging galaxies suggests their baby stars are speeding away from the galaxy center where they exploded into existence, trapped in a current of fast-moving material. Stars that form close to the center might slow down and even be sucked back in, while the ones that form further down in the outflow might fly out of the galaxy altogether. Many years from now, IRAS F23128-5919 will look entirely different.

The new research is a reminder of how much influence black holes can have on galaxies. In some galaxies, black holes consume enough dust to spit out streams of material hot enough to stop star formation, postponing the process until the area cools down again. The size of a black hole is correlated with the size of the galaxy, which suggests these matter-eating mouths may have something to do with galaxy formation, but astronomers haven’t yet figured out the specifics.

Black holes remain the most mysterious of cosmic objects, and perhaps that unknowableness has contributed to a bad reputation. Outside of scientific papers, they are usually described as “monsters,” and they’re usually always “lurking,” made to sound like the bogeyman of the cosmos. Sure, black holes can swallow anything that slips into their gravity’s grip. But they can also, as this new research shows, ignite stars into being. Doesn’t seem so bad, does it?