Scientists’ systematic observations of the Pandora Cluster of galaxies, recorded by the James Webb Space Telescope, have confirmed the existence of the second and fourth most distant galaxies ever observed. The galaxies are described in a publication in the Astrophysical Journal Letters.

An international team led by Penn State researchers confirmed the distance of these ancient galaxies and inferred their properties using new spectroscopic data from the telescope.

Unlike other galaxies confirmed at this distance, the new galaxies are larger. One is elongated, almost like a peanut, and the other is like a fluffy ball. Although expected to have formed from similar materials, they show signs of being very different from each other.

The research team estimates that the light detected by the telescope was emitted by the two galaxies when the universe was about 330 million years old and traveled about 13.4 billion light-years to reach James Webb. But the galaxies are now 33 billion light-years away from Earth, due to the expansion of the universe during that time. Incredibly distant galaxies offer insights into how the first galaxies may have formed.

“The light from these galaxies is ancient, about three times as old as Earth,” says Joel Leia, assistant professor of astronomy and astrophysics at Pennsylvania State University.

“Prior to our analysis, we knew of only three galaxies that had been confirmed at around this extreme distance,” explains first author Bingzhi Wang, a postdoctoral researcher at Pennsylvania State University.

It is worth noting that the two galaxies are significantly larger than the three galaxies previously detected at these extreme distances. One is at least six times larger with a diameter of about 2,000 light years. As the early universe is thought to have been very compressed, it is surprising, according to Wang, that the galaxy is so large.

The two galaxies were among 60,000 light sources in the Pandora Cluster detected in one of the James Webb Space Telescope’s first deep-field images during 2022, its first year of scientific operation.

Within months the research team narrowed down the 60,000 bright sources to 700 candidates for further study, eight of which they thought could possibly be among the first galaxies. The telescope then turned again to the Pandora Cluster recording the spectra of the candidate light sources.