Written by: Alexandra Weitzie
When NASA built its newest and most advanced telescope, the James Webb Space Telescope, it wanted to peer through its lenses to the distant parts of the universe and extend the view to the dawn of time. And now she gets what she wants, and with great success. Since we received the first images and scientific data from the telescope, about a month ago, astronomers have come up with a series of preliminary discoveries, including those related to a number of galaxies that are candidates to be the most distant galaxies we have ever observed.
In the images of the “Webb” telescope, a crowd of galaxies that glow in the far reaches of the universe appear, so that we can see them in the form they were in when the Big Bang, which occurred 13.8 billion years ago, was only hundreds of millions of years ago. The telescope’s dazzlingly clear images shattered preconceived notions that astronomers had of the early universe. “We had an idea of what galaxies would look like when they were like this,” says Jehan Kartaltibi, an astronomer at Rochester Institute of Technology in New York. From a distance, as well as how many details we will be able to see, but the reality exceeded all imaginations.” Here are some of what astronomers knew from the first “Webb” telescope observations.
Countless galaxies
The James Webb Telescope can capture infrared radiation, which makes it able to observe galaxies that formed in the early universe; As the universe expands, the light rays expand to settle at redder wavelengths. In the telescope’s first observational program, which began last June, it discovered several galaxies far beyond the reach of other observatories, including the Hubble Space Telescope.
“This is an indication that there are galaxies farther than what we saw with the Hubble telescope, which supports the opinion that many of us have previously said,” says Richard Ellis, an astronomer at University College London. Universe”; That is, about 250 million years after the Big Bang, when the first stars were formed to split the darkness of the universe. Then, the following generations of stars gathered in galaxies, the faint red masses that the Webb telescope began to explore. We saw many of the telescope’s images, which were studded with galaxies from the ends of the universe, which had not been found by the human eye. “There is hardly a patch of sky devoid of something,” says Karaltepe. One study examined the data of many fields of distant galaxies that the “Webb” telescope had detected so far, to study the rate of star formation in the early stages of the universe, so it discovered 44 galaxies that did not It was previously known, dating back approximately 300 million years after the Big Bang. This discovery, along with 11 previously discovered galaxies, testifies to the existence of a large number of galaxies containing stars in the early universe1. In an initial draft of the study, the research team led by Clam Dunant, a researcher at the University of Edinburgh in the United Kingdom, said that these findings “reaffirm the enormous role that the wider Webb telescope’s observational programs can play in making a huge leap.” in our understanding of the universe in its youth.
The most distant of all: not a single galaxy.. but galaxies
Amid this frantic quest to publish research, research teams scramble to identify the most distant galaxy, among the galaxies that appeared in the telescope images. The researchers have found several candidates for the most distant of all, but they need more study to see how far away they are. What is certain is that all of these galaxies break the record for the most distant galaxy observed by the Hubble telescope, a galaxy that formed after the Big Bang about 400 million years 2.3.
One of those galaxies emerged in a survey of James Webb telescope data, called GLASS, and another, slightly closer, galaxy appeared in one image4. “It was a big surprise to find these two bright galaxies,” says Marco Castellano, an astronomer at the Italian National Institute of Astrophysics in Rome. the same two galaxies), “We can see disc-shaped galaxies much earlier than we previously thought.”
Astronomers calculate the distance that separates us from a galaxy based on a measurement called “redshift”, which is a measurement of the redshift of the wavelength of light coming from the galaxy, and the greater the shift, the greater the distance. The galaxy in Glass’s study has a displacement of about 13. But on the 25th and 26th of last July, days after scientists announced the aforementioned galaxy, the arXiv research draft website flooded with papers claiming to find galaxies with a larger displacement. “This is only the beginning,” says Rohan Naidoo, an astronomer at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, US.
Another galaxy, a candidate for the title of “farthest ever”, appeared with a redshift of 14, in a survey called “CEERS”, which is one of the most important projects of the first survey “Webb” telescope. The lead researcher in the aforementioned study, Stephen Finkelstein from the University of Texas at Austin, USA, named this galaxy “Maisie’s Galaxy” after his daughter’s name6. Another study focused on examining the first deep-field image taken by the telescope, which was published by US President Joe Biden on the eleventh of last July. The researchers behind the study found in that image two galaxies with a displacement of 16; This means that they formed only 250 million years after the Big Bang. And there are papers on the “Archiv” website that indicate other galaxies are candidates for the title, and it is likely that the displacement may reach 20 in some of them.
Some of the first galaxies were complex
The distal galaxies unveiled by the James Webb Telescope turned out to have a more regular structure than astronomers had previously thought. The researchers behind the study of the first deep-field image taken by the telescope were surprised. They found a large number of distant disk-shaped galaxies9. The astronomers, based on what was previously observed by the Hubble telescope, had concluded that distant galaxies are less regular than their nearby counterparts, which usually take regular shapes, such as the shape of a disk, for example, as is the case in our galaxy, the Milky Way. They concluded from this to the theory that the first galaxies are usually distorted by the mutual influences between them and the neighboring galaxies. But what was observed by the “Webb” telescope indicates that the number of distant galaxies that take the form of a disk may be ten times the number that scientists estimated in the past.
“Thanks to the high-resolution images of the James Webb Telescope, we can see disc-shaped galaxies much earlier than we previously thought,” says Alison Kirkpatrick, an astronomer at the University of Kansas in Lawrence. She sees this as a problem. Because it contradicts previous theories about the evolution of galaxies.
Another initial draft indicates that massive galaxies formed much earlier in the life of the universe than previously thought. A research team led by Ivo Laby, from Swinburne University of Technology in Melbourne, Australia, announced that it had found seven massive galaxies in the “Sears field”, with a displacement between 7 and 10 (see reference 1010). A very early stage in the life of the universe.
Studies of galactic chemistry from telescope data paint a rich, complex picture. In the first deep-field image taken by the telescope, an analytical study of the light coming from galaxies, with a displacement of 5 or more, detected an unexpected abundance of certain chemical elements, such as oxygen 11. (There is a correlation between the spectral lines that appear at different wavelengths and the chemical elements that make up the galaxy.) Astronomers used to think that chemical fertilization, the process in which stars fuse hydrogen and helium to form heavier elements, would take a long time. But their presence in early galaxies “would make us rethink how quickly stars form,” Kirkpatrick says.
The nearest galaxies are smaller than expected
The surprises of this telescope do not stop at the early stages of the evolution of the universe, but go beyond them to the subsequent stages. One of the studies focused on what the telescope observed from the “back of the universe,” the period that came three billion years after the Big Bang, when the activity of star formation in the universe reached its peak.
Ren Seuss, an astronomer at the University of California, Santa Cruz, compared Hubble Telescope images of galaxies at the “back of the universe” with those from the James Webb Telescope. It was found that most of the massive galaxies appeared much smaller in the infrared images taken by the “Webb” telescope than they did in the images of the “Hubble Telescope” 12. “This could change our view of how galaxies change in size over time,” she says. Studies conducted on the Hubble images indicated that galaxies start small and then get bigger, but what the Webb telescope has shown tells us that the Hubble telescope did not reveal the whole truth, and that the evolution of galaxies may be more complex than we thought.
Scientists realize that we are on the verge of many changes. The James Webb Telescope is still taking its first steps, in its work journey that is scheduled to last twenty years. “These days, I find myself in bed at three in the morning, my eyes dry, and a voice in my soul asks: Is everything I’ve done wrong?” Kirkpatrick says.