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REPUBLIKA.CO.ID, JAKARTA — Using the James Webb Space Telescope (JWST), scientists have discovered that the early galaxies in the universe must have grown much faster than expected. Plus, the same team also discovered that 10 billion years ago, the cosmos was not as messy and chaotic as previously thought.
An international team led by researchers from Durham University, United Kingdom (UK) reached this conclusion by finding evidence of structures called “star bars” forming in galaxy which existed only a few billion years after the Big Bang.
Star bars are elongated regions of increased star density found at the heart of spiral galaxies such as the Milky Way and other disk galaxies. When formed star bars pushing gas towards the heart of their respective galaxies, thereby regulating the birth of stars. The presence of these central bars structures indicates that a galaxy has entered a calmer and more mature phase.
Zoe Le Conte, team leader and researcher at Durham University, in a statement, revealed that galaxies in the early universe evolved much faster than we thought.
“This is a real surprise because you might expect the universe at this stage to be very turbulent, with lots of collisions between galaxies and lots of gas that hasn’t yet turned into stars,” said Conte, reported by Space, Friday (26/4/2024).
“But thanks to JWST, we see many of these bars much earlier in the life of the universe, meaning that galaxies are at a more stable stage in their evolution than previously thought. This means we have to adjust our view of early galactic evolution.”
Visit the bar for JWST
This isn’t the first time scientists have visited the bar in the early 13.8 billion year history of the universe. The Hubble Space Telescope also witnessed these features, but the orbiting eye of the universe could only have moved so far eight billion to nine billion years ago.
However, increased sensitivity and wavelength range JWST have extended these observations to at least 1 billion years into the future. This revealed the formation of bars in the galaxy that were visible between eight billion and 11.5 billion years ago.
Of the 368 disk galaxies….
In fact, of the 368 disk galaxies the team considered for this research, 20 percent already had bars. This number is twice the number observed by Hubble
“We found that there were more bars in the early universe than previously discovered in Hubble studies, which implies that bar-driven galaxy evolution has been going on for much longer than previously thought,” said team member and Durham University scientist Dimitri Gadotti.
The further back in time the team looked at JWST, the fewer bar structures they observed in the galaxy. They believe this may have happened because galaxies in the early stages of the universe had not yet formed properly.
The alternative is that shorter bars are more common in earlier galaxies. Even JWST’s impressive observational power wasn’t enough to spot these short bars in early galaxies.
With these results, the team now wants to use JWST to peer even further into cosmic time, looking back as far as 12.2 billion years. This could reveal whether bar growth was a common occurrence just 1.6 billion years after the Big Bang.
“The simulations of the universe now need to be looked at to see if we get results similar to the observations we made with JWST,” Gadotti concluded. “We have to think beyond what we think we know.”
