Galaxies spotted by the Webb Space Telescope rewrite their previous understanding of the universe

Observations from NASA’s James Webb Space Telescope are shaking up understanding of the early universe, indicating the presence of large and mature but remarkably compact galaxies teeming with stars much earlier than scientists had thought possible.

Astronomers said data obtained by the telescope reveals what appears to be six large galaxies as mature as our Milky Way existing around 540-770 million years after the explosive Big Bang that launched the universe 13 years ago. 8 billion years. The universe was about 3% of its present age at the time.

These galaxies, one of which appears to have a mass rivaling our Milky Way but 30 times denser, appear to differ fundamentally from those that populate the universe today.

“Oh, they’re radically different – really bizarre creatures,” said astrophysicist Ivo Labbe from Swinburne University of Technology in Australia, lead author of the study published in the journal Nature. “If the Milky Way were an average adult of normal height, say about 5 feet 9 inches (1.75 meters) and 160 pounds (70 kg), they would be one-year-old babies weighing about the same weight but standing just under 3. inches (7 cm) tall. The early universe is a spectacle of monsters.”

Webb launched in 2021 and began collecting data last year. The findings were based on the first set of data released by NASA last July from Webb, a telescope with infrared sensing instruments capable of detecting light from older stars and galaxies.

“This is a stunning and unexpected finding. We thought galaxies form over much longer periods of time,” said Penn State astrophysicist and study co-author Joel Leja. “No one expected to find them. These candidate galaxies are simply too evolved for our expectations. They seem to have evolved faster than our standard models allow.”

Leja called them candidate galaxies because more observations are needed to confirm that they are all galaxies rather than another source of light like a supermassive black hole.

“What’s exciting is that even if only some turn out to be massive galaxies, these things are so massive that they alone would upset our measurements of the total mass of stars right now. That would suggest 10 to 100 times more mass in stars existing at this time than expected and would imply that galaxies are forming much, much faster in the universe than previously thought.”

Galaxies seem to contain a mass equivalent to 10 billion to 100 billion times that of our sun. This last figure is similar to the mass of the Milky Way.

The journey to galaxy formation after the Big Bang apparently relied on a mysterious material called dark matter that is invisible to us but known to exist due to the gravitational influence it exerts on normal matter.

“The main theory is that an ocean of dark matter filled the early universe after the Big Bang,” Labbe said.

“This dark matter – we don’t know what it really is – started out very gently, with only the smallest of the ripples. These ripples grew over time due to gravity and eventually the dark matter started to build up into concentrated clumps, dragging the hydrogen along. It’s this hydrogen gas that will eventually grow into stars. Clumps of dark matter, gas and stars, that’s what we call a galaxy.” Labbe added.

Astronomers suspect that the first stars began to form 100 to 200 million years after the Big Bang, each perhaps 1,000 times more massive than our sun but with a much shorter lifespan.

“Their explosion set off the chain of events that formed subsequent generations of stars,” Labbe said.

“Webb continues to amaze and surprise us,” Labbe added. “So yes, the early universe was much richer and much more diverse – monsters and dragons. And the curtain is still being lifted.”

© Thomson Reuters 2023