NASA James Webb telescope solves ‘universe-breaking’ mystery of black holes
by Bethan Finighan · Manchester Evening NewsThe James Webb Space Telescope just solved a ‘universe-breaking problem’ it created for astronomers more than two years ago.
In December 2022, the NASA telescope revealed ‘impossible’ black holes that had never been seen before, which scientists called ‘little red dots’ (LRDs).
Astronomers found that a large fraction of the LRDs, most of which existed during the first 1.5 billion years after the big bang, showed signs of containing growing supermassive black holes.
The faint, ancient red dots baffled researchers as, in theory, it shouldn’t have been possible for these giant galaxies to form stars and solar systems given their relatively young age.
Effectively, the light put out by the LRD’s stars was brighter than astronomers had imagined. The dots also had massive black holes that shouldn’t have had time to grow.
This led some to suggest that cosmology was “broken,” NASA said. Existing theories could not explain how these galaxies had grown so big, so fast.
However, new insights from the James Webb telescope, which orbits 1 million miles away from Earth, suggests the light from the dots is actually generated by active black holes, also known as active galactic nuclei (AGN).
If the light is coming from black holes (and not stars, like previously suggested), this implies the presence of more lightweight galaxies that can be understood by existing theories.
“This is how you solve the universe-breaking problem,” said Anthony Taylor, a co-author of the study at the University of Texas at Austin.
“Contrary to headlines, cosmology isn’t broken,” wrote NASA.
(Image: NASA, ESA, CSA, STScI, Dale Kocevski (Colby College))
Upon Webb’s discovery in 2022, scientists were initially perplexed by the LRDs and wondered what triggered their bright colours and what this could tell us about the universe.
“We’re confounded by this new population of objects that Webb has found. We don’t see analogues of them at lower redshifts, which is why we haven’t seen them prior to Webb,” said Dale Kocevski of Colby College in Waterville, Maine, and lead author of the study.
“There's a substantial amount of work being done to try to determine the nature of these little red dots and whether their light is dominated by accreting black holes.”
The team used the Red Unknowns: Bright Infrared Extragalactic Survey (RUBIES) to get data on some of the LRDs in their sample. They found that about 70 percent of the targets showed evidence for gas rapidly orbiting 2 million miles per hour (1,000 kilometres per second).
This is a sign of an accretion disk around a supermassive black hole. This suggests that many LRDs are accreting black holes, or AGN
“The most exciting thing for me is the redshift distributions. These really red, high-redshift sources basically stop existing at a certain point after the big bang,” said Steven Finkelstein, a co-author of the study at the University of Texas at Austin.
“If they are growing black holes, and we think at least 70 percent of them are, this hints at an era of obscured black hole growth in the early universe.”
The James Webb telescope is a collaborative project between NASA, ESA (European Space Agency), and CSA (Canadian Space Agency). It was launched on 25 December, 2021 from the Guiana Space Centre in French Guiana.
The JWST was sent to its operational location at the second Lagrange point (L2), approximately 1 million miles from Earth, and became operational for scientific observations in July 2022.