Scientists using the James Webb Space Telescope (JWST) have discovered the oldest known black hole in the universe.
Nestled within a glowing red galaxy, it dates back 13 billion years and provides a rare glimpse into the universe’s earliest moments.
The black hole and the galaxy it belongs to are called CAPERS-LRD-z9. It is part of a series of galaxies known as the Little Red Dots. Compared to other galaxies, they are tiny, and they emit red light.
Since 2022, scientists have been puzzled by the red spots. Observed in the distant realms of our universe, astronomers thought they were either a cluster of faraway stars or black holes at the center of different galaxies. The fact that they emit so much light suggested that they might be clusters of stars. However, they formed at such an early time that so many stars together was improbable.
A new class of galaxy
“We started seeing these objects everywhere,” Anthony Taylor, co-author of the new study, told Science News. It is now generally accepted that the Little Red Dots are a new class of galaxy that formed in the early stages of the universe.
The team decided to focus the JWST on one in particular, which seemed to be the oldest. This was CAPERS-LRD-z9. It emitted a huge range of infrared wavelengths. Using spectroscopy to split the light, the team studied the wavelength characteristics, looking for the fingerprint of a black hole.
As fast-moving gas is sucked into black holes, it circles and creates a certain pattern of wavelengths of light. The gases moving toward us stretch into red wavelengths, while those moving away compress into blue wavelengths.
“There aren’t many other things that create this signature. And this galaxy has it!” exclaimed Taylor in a statement.
A blink of time
A few even more distant spots could potentially be older black holes, but researchers have yet to see the same spectroscopic signature from them. This means that, at the moment, this is the oldest black hole ever discovered. At 13.3 billion years old, it formed just 500 million years after the Big Bang — a blink of time in the scale of the universe.
“When looking for black holes, this is about as far back as you can practically go,” said Taylor. “We’re really pushing the boundaries of what current technology can detect.”
Though the galaxies are quite small, the black hole at the center of CAPERS-LRD-z9 is not. It is about 300 million times the mass of our Sun, and roughly 10 times more massive than Sagittarius A*, the black hole at the center of the Milky Way. Even more intriguingly, its mass might represent around half of its galaxy’s total stellar mass, a proportion far greater than in younger galaxies.
Studying CAPERS-LRD-z9 doesn’t just confirm the existence of a black hole. It gives astronomers a crucial testing ground to refine theories of early galaxy and black hole evolution.
“We only ever survey very tiny areas of the sky with the James Webb Space Telescope,” said co-author Steven Finkelstein, “So, if we find one thing, there’s got to be a lot more out there.”