USA TODAY International Edition
‘ Impossibly massive galaxies’ create problems for science
New research from scientists using NASA’s James Webb Space Telescope is challenging what was previously understood about how galaxies formed at the start of the universe.
The international team of astronomers discovered six massive, mature “candidate galaxies” in the early universe, according to a study published in the peer- reviewed journal Nature on Wednesday.
The galaxies existed about 500 to 700 million years after the Big Bang.
“These objects are way more massive than anyone expected,” Joel Leja, study co- author and assistant professor at Penn State University, said in a Penn State news release. “We expected only to find tiny, young, baby galaxies at this point in time, but we’ve discovered galaxies as mature as our own in what was previously understood to be the dawn of the universe.”
Each of the six galaxies appears to weigh billions of times more than our sun.
For one of the objects, the total weight of all its stars may be as much as 100 billion times greater than our sun, the scientists said.
“We just discovered the impossible. Impossibly early, impossibly massive galaxies,” Ivo Labbé, the study’s lead author and associate professor at Australia’s Swinburne University of Technology, wrote in a column for The Conversation on Wednesday.
If the findings are verified with spectroscopy, “the stellar mass density in massive galaxies would be much higher than anticipated” from previous research, the study notes.
How did the astronomers find the galaxies?
The researchers spotted these galaxies using the James Webb Space Telescope, which has infrared- sensing instruments capable of detecting light from ancient galaxies and stars.
Astronomers estimate that the universe is about 13.8 billion years old. And the Webb Telescope allows scientists to see back about 13.5 billion years, Leja said.
After NASA released Webb’s first full- color images and spectroscopic data in July, the researchers dived in and “these massive things popped out really fast,” Leja said.
“We started doing the modeling and tried to figure out what they were, because they were so big and bright. My first thought was we had made a mistake. ... But we have yet to find that mistake, despite a lot of trying.”
Discovery challenges previous understandings of the early universe
Because of the galaxies’ age and massiveness, the team’s discovery conflicts with 99% of existing models for the origins of the universe.
The findings call on scientists to rethink fundamental understandings of early galaxy formation.
“We looked into the very early universe for the first time and had no idea what we were going to find,” Leja said. “It turns out we found something so unexpected it actually creates problems for science. It calls the whole picture of early galaxy formation into question.”
Need to confirm with spectrum image
One way to confirm the team’s findings would be to take a spectrum image of the galaxies, Leja explained in Penn State’s news release. This would help the researchers determine accurate distances of the galaxies, their true size and what they’re made of.
“A spectrum will immediately tell us whether or not these things are real. ... It will show us how big they are ( and) how far away they are,” Leja said.
Leja added that, while the data indicates the discovered objects are galaxies, there’s also a possibility of a few of them being obscured supermassive black holes.
Regardless of the outcomes, the amount of mass that the team found “means that the known mass in stars at this period of our universe is up to 100 times greater than we had previously thought,” Leja said. “Even if we cut the sample in half, this is still an astounding change.”