A rare black hole a billion times the mass of the sun could upend our understanding of how galaxies form
A rare supermassive black hole found lurking at the dawn of the universe could indicate there were thousands more ravenous monsters stalking the early cosmos than scientists thought – and astronomers aren’t sure why.
The primordial black hole is about 1 billion times the mass of our sun and was found at the center of the galaxy COS-87259. The ancient galaxy formed just 750 million years after the Big Bang and was spotted by the Large Atacama Millimeter Array (ALMA), a radio observatory in Chile, in a tiny patch of sky less than 10 times the size of the full moon.
Obscured under a cloak of turbulent stardust, the fast-growing black hole was seen consuming part of its accretion disk of orbiting matter while spitting out the remnants in a jet traveling at near speeds of the speed of light. The monster black hole appears to be in a rare intermediate stage of growth, somewhere between a dusty star-forming galaxy and a huge, bright black hole called a quasar.
And the cosmic monster could be just one of thousands of inexplicably large black holes lurking beneath the cloud cover of the early universe, the researchers suggest. They published their finding on February 24 in the journal Royal Astronomical Society Monthly Notices (opens in a new tab).
Related: ‘Leaky’ black hole the size of 20 million suns discovered speeding through space with a trail of newborn stars behind it (opens in a new tab)
“Frankly, explaining the existence of about 15 very old luminous quasars [from the same time period as COS-87259] was a great challenge for extragalactic astronomy given the short time there is to develop such a massive black hole since the big Bang“, lead author of the study Ryan Endley (opens in a new tab), an astronomer from the University of Texas, Austin, told Live Science. “If the first billion-solar-mass black holes are thousands of times more frequent than we originally thought (as our discovery implies, unless you assume we’ve been incredibly lucky) , it only exacerbates the problem further.”
A supermassive mystery
Black holes are born from the collapse of giants stars and grow by constantly gorging themselves with gas, dust, stars and other black holes in the stellar galaxies that contain them. If they grow large enough, the friction heats up the material that propagates through the mouths of black holes, and they turn into quasars – shedding their gaseous cocoons with bursts of light up to a trillion times brighter than the brightest stars.
Because light travels at a fixed speed in the vacuum of space, the deeper scientists look into the universe, the farther light they intercept and the more further back in time (opens in a new tab) they see. Past simulations of the “cosmic dawn” – the epoch encompassing the universe’s first billion years – have suggested that puffy clouds of cold gas could have merged into giant stars (opens in a new tab) which were destined to collapse rapidly, creating black holes. As the universe grew, these early black holes may have rapidly merged with others to seed even larger supermassive black holes throughout the cosmos.
But how these chaotic conditions led to the creation of so many supermassive black holes is a mystery; one that is deepened by the possibility that beasts may have numbered in the thousands when the universe had only reached 5% of its current age. A revision paper (opens in a new tab) suggested that large, bright quasars are the easiest black holes to spot, so they’re probably just the “tip of the iceberg” of monsters lurking in the young cosmos.
The answer to this riddle could point to a hole in our understanding of galaxy formation in the early universe. On February 22, another group of astronomers analyzing data from The James Webb Space Telescope discovered a group of six gargantuan galaxies – aged 500 to 700 million years after the Big Bang – that were so massive they were in tension with 99% of cosmological models (opens in a new tab).
One possible explanation may lie in the amount and frenetic activity of dense “starburst” clouds where the first black holes appeared. For example, in April 2022, the discovery of another fast growing black hole in transition (opens in a new tab) called GNz7q in a starburst galaxy of the same age as COS-87259 showed that the galaxy served up freshly baked stars 1,600 times faster than the Milky Way done today. COS-87259 bakes at a slightly slower rate of 1,000 times the current Milky Way, but its black hole is 20 times more massive and brighter than GNz7q.
“The discovery of both COS-87259 and GNz7q over the past year has been super surprising and really makes us wonder how we can make sense of this from the perspective of understanding the growth very early supermassive black holes,” Endsley said.
Originally published on Live Science (opens in a new tab).
