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Susan Kassin, an astronomer at the Science Center’s Space Telescope, showed images from older observatories compared to JWST’s. It was as if the optician was turning the lens so that the last lines of the eye chart were visible. “Thank you, Webb – that’s a $10 billion difference,” he said. People laughed and nodded.

JWST is unique in its ability to observe new universes, far away from us in space and time. Its infrared sensors, its coldest space in the atmosphere, and its solar shield – which blocks the light of the sun, the moon and the Earth – are particularly suitable for solving early galaxies and their stars. These objects are too faint and at the wrong wavelengths to be seen by space probes, such as the Hubble Space Telescope.

For astronomers, the vibe is collaborative. Many presentations at the KITP meeting included requests for input from colleagues and partners.

“It was a crazy race when the first data came down. Now it’s about generating ideas,” said Caitlin Casey of the University of Texas, Austin. “There’s a firehose of data, and each and every one has enough.

Astronomer Rachel Somerville, who organized the conference, said the public is still struggling to accept JWST data and its implications. Observers see things that are not explained in the latest theories about the evolution of the new universe.

Fabio Pacucci of Harvard University said: “Many studies showed that there is a conflict between thinking and taking care of things.” To confirm the confusion that astronomers feel about this once-in-a-lifetime telescope that upends our knowledge of the new universe, he flashed a tongue-in-cheek slide: a funny picture of the dog sitting at the table drinking coffee at home. flames, written “This is good.”

The Biggest and the Brightest

Astronomers kept talking about one of the most prominent galaxies seen so far, an unexpected bright light called, dryly, JADES-GS-z14-0. Hainline, of the University of Arizona, is part of the team that discovered it with JWST and confirmed its distance in May 2024. It is the oldest known galaxy, breaking the record holder, who found by the same group in 2023.

At the time when the galaxy was shining, the sound waves from the massive explosion that started the universe were still ringing through the void. The first stars had been born during the baby boom, and some had already died. The dark hearts of black holes lurk, too – regions of space where the gravitational pull is so strong that no light can escape. And there was this galaxy, resolved as a vague scorpion shape in the JWST movies. Two instruments on JWST were able to determine the brightness of JADES-GS-z14-0 and its location from Earth. Due to the rapid expansion of the universe, the most distant objects have moved back very far in time. Astronomers can tell their age based on the stretching of their light into longer wavelengths, known as redshift. Based on the latest measurements, the galaxy was determined to lie at a redshift of 14.18, which means we are seeing it as it appeared 300 million years after the Big Bang – when the universe was they are about 2% of their current age.

In the beginning, the astronomers felt that things so big, so bright on the beach, did not agree with the way it was talked about on the beach. But people are humble about it. Our best model of the universe – the set of equations that describe the evolution of matter and radiation as well as dark energy and dark matter – is not dead.

Alice Shapley of the University of California, Los Angeles, said: “There was a great feeling” in the early days of JWST. “There is no need for that. The details are excellent; let us study the universe we have.”

Astronomers are converging around three star-based theories about how the galaxies became bright so quickly. One believes that the stars at the dawn of the universe were very different from the stars today. The stars in JADES-GS-z14-0, for example, may be very bright but not very massive. Although this seems reasonable, it is also tricky for theorists to deal with. The relationship between a star’s luminosity and its mass is an important value entered into computer simulations. If this value – known as the initial mass function, or IMF – was different in the early universe, then researchers would have to rewrite their simulations to accommodate the changing IMF over time. it goes.

But nature does not care about our computer content, and the changing IMF is, in fact, one of the most reasonable ways to understand what we see. “The IMF is really the house of cards that we’re building everything on. There’s a lot of reason to believe that it’s very different from ‘very high redshift,'” Casey said.

Another theory states that the first super-luminous galaxies underwent a massive starburst. Over 10 million or 100 million years, a star’s brightness can vary by a factor of 100 as the star’s shape rises and falls. That is like a candle that turns into light after a few seconds. On the other hand, during these busy periods, supernova explosions may make things appear brighter than they would otherwise appear.

A third theory suggests that the star system was more efficient then than it is now. In a typical galaxy today, a small fraction of the gas is made up of stars; The Milky Way builds between two and six sun-sized stars per year. But perhaps the smallness and compactness of the early universe made it the best star factory. Some calculations suggest an almost 100% gas-to-star transition rate, which means faster and faster star birth, said Pratika Dayal of the University of Groningen in the Netherlands.

All these changes to existing theory come with side effects, such as changes in how much dust should be and doubts about how the baby boomers settled. And those aren’t the only ideas out there. Andrea Ferrara, a cosmologist at the Scuola Normale Superiore in Pisa, Italy, showed his colleagues at Santa Barbara a new model that tries to explain the first bright galaxies by changing the dust in them. of them, which would block the light of the stars. His model assumes that most of the dust was blown by the interstellar wind. “Dust reduction is my favorite idea, although I’m open to two more,” he told attendees. But, he admitted, his numbers may not hold up to 14, which means they may not work for galaxies like JADES-GS-z14-0.

“So please don’t discover any other constellations,” he concluded with a laugh.

Super Black Holes

Astrological theories are not the only theories. Some astronomers point to supermassive black holes, which they say can heat up the surrounding gas and make the necks of stars like JADES-GS-z14-0 appear so bright.

In a series of papers published in May, the JADES team argues that the galaxy contains stars, and that its luminosity cannot be explained by black holes. But some constellations have such dark hearts. We know of supermassive black holes weighing hundreds of millions or billions of solar masses covering the centers of modern galaxies. And JWST is seeing light stripped from many ancient galaxies, indicating that their gas is also being captured by the supermassive black hole. So, how did supermassive black holes get there?

Since black holes were first proposed as a result of Albert Einstein’s theory of gravity, astronomers have speculated how they might have formed from gravitational collapse. the gravity of the dying stars. They now know that the universe is full of black holes made this way. But cosmologists have struggled to understand supermassive black holes. These black holes somehow grew big enough, and accelerated enough, to form galaxies around them. If they started as falling stars, they would have to grow at an amazing rate that is not well explained.