The oldest known black hole formed more than 13.3 billion years ago

The oldest confirmed black hole formed when the universe was a mere infant, within 500 million years of the Big Bang, researchers report.

The James Webb Space Telescope, or JWST, saw the enormous celestial body as it shaped its host galaxy more than 13 billion years ago. The findings, published in the Aug. 10 Astrophysical Journal Letters, could help astronomers better understand the early universe, particularly the curious coloration of objects called little red dots.  

Shortly after JWST began collecting data in mid-2022, it started imaging mysterious compact red points in the distant universe. These dots are often thought to be either black holes at the centers of galaxies or clusters of stars. “We started seeing these objects everywhere,” says astronomer Anthony Taylor of the University of Texas at Austin.

Taylor and his colleagues homed in on a little red dot called CAPERS-LRD-z9, suspected to be the oldest one found so far. In April, the team had JWST observe a wide range of infrared wavelengths emitted by the object. That’s a good way to view certain faraway bodies, whose light waves have stretched to become redder en route to Earth due to the universe’s constant expansion.

JWST detected elongated light waves from hydrogen atoms, which helped the team estimate that CAPERS-LRD-z9’s light traveled roughly 13.3 billion years to reach the telescope. The hydrogen also hinted at gas swirling at thousands of kilometers per second, a hallmark of matter rotating around and feeding a black hole that’s shaping its galaxy, Taylor says. That’s “one of the best pieces of smoking-gun evidence for finding an active black hole.”

The researchers estimate that the celestial body contains the mass of 38 million suns. Moreover, a dip in the light at a certain wavelength suggests that dense neutral gas might blanket the black hole. Such gaseous shells are a newly proposed component of early active galaxies, Taylor says, and a handful show signs of them. Computer simulations confirmed that a gas cloud could explain the patterns of light produced by CAPERS-LRD-z9.

That thick gas can block bluer wavelengths of light, Taylor notes. This phenomenon, combined with dust, may have skewed toward red the light from the disk feeding the black hole, contributing to the dot’s brilliant ruby color.