The James Webb Space Telescope has surpassed the Hubble Space Telescope in power and precision, and has allowed astronomers to finally gain some insight into where and how the first galaxies were created.
It was a common theory that galaxies had a relation between how many stars and heavy elements were formed; the more massive a galaxy, the more heavy elements it possessed. However, researchers are now finding that the relation may not hold for the earliest galaxies in the universe.
Galaxies, a large collection of stars and gas, can be found throughout the universe. Scientists are able to use the placement of galaxies and light phenomena to essentially create a visual representation of the evolution of the universe. This is done by determining the time it takes for light to reach the Earth. Previously, scientists were not able to look very far because the farther away light travels through space, the longer the wavelength it has. This means that one would have to look through infrared light in order to see this part of the universe. The James Webb Telescope is the first telescope big enough and sensitive enough to see so far due to its usage of Mid-Infrared Instrument (MIRI).
The James Webb Telescope has proven successful: it has been able to see into distant galaxies, giving scientists a foundation to form theories regarding heavy elements and stars and their relationship to the birth of galaxies that are different from what has been previously thought.
In a new study published in the journal Nature Astronomy, a team of astronomers from the Cosmic Dawn Center at the Niels Bohr Institute and DTU Space in Copenhagen, have discovered some of the very first galaxies that are still in the formation process.
“Until recently it has been near-impossible to study how the first galaxies are formed in the early universe, since we simply haven’t had the adequate instrumentation. This has now changed completely with the launch of James Webb,” said Kasper Elm Heintz, leader of the study and assistant professor at the Cosmic Dawn Center.
What does it mean that scientists can see galaxies forming? It means that they can see gravity gathering clumps of gas to form stars. If these “infant galaxies” are left undisturbed, the star can fuse helium to form heavier elements, such as carbon and oxygen, until iron and nickel are formed. In between its formation and the addition of heavy elements, there are large amounts of unpolluted gas that move faster than the stars themselves.
“When we analyzed the light from 16 of these first galaxies, we saw that they had significantly less heavy elements, compared to what you’d expect from their stellar masses and the amount of new stars they produced,” said Kasper Elm Heintz.
This observation is the first insight into the earliest stages of galaxy formation and the idea that unpolluted gas is highly connected to galaxies rather than heavy elements — more so than what scientists originally hypothesized.
“This is one of the first James Webb observations on this topic, so we’re still waiting to see what the larger, more comprehensive observations that are currently being carried out can tell us. There is no doubt that we will shortly have a much clearer understanding of how galaxies and the first structures began their formation during the first billion years after the Big Bang,” Heintz concludes.
The James Webb Space Telescope continues to be one of NASA’s greatest strengths with its ability to give astronomers a more complete picture of the universe. The latest example of its potential is from October 10, 2023, where it captured a new image of NGC 346, the brightest and largest star-forming region in the Small Magellanic Cloud, a dwarf galaxy near the Milky Way.
