“A window on the cosmic dawn.” Discovering the most distant galaxy in the universe

The James Webb Telescope discovered the most distant galaxy in the universe, called JADES-GS-z14-0. Its radiation took about 13.5 billion years to reach us, as light began its journey only 300 million years after the Big Bang.

The newly discovered galaxy is 1,600 light-years across, which means it takes 1,600 years for light to travel from one end of it to the other.

NASA's James Webb Telescope also discovered the second most distant galaxy in the universe, called JADES-GS-z14-1.

Brant Robertson, an astronomer at the University of California, Santa Cruz, and co-author of the study, described the discovery as "completely unexpected."

"It will likely be viewed as the James Webb Space Telescope's most important extragalactic discovery to date. JADES-GS-z14-0 points to more hidden treasures in the early universe," he said.

The James Webb Telescope is often described as being able to “see back in time,” and although this sounds fanciful, it is really true. Given the expansion of the universe, it can take billions of years for light from one galaxy to reach another galaxy.

When light reaches us from a distant galaxy, the light reveals a "snapshot" of the galaxy as it appeared when it began its journey billions of years ago.

In this case, the light from JADES-GS-z14-0 began its journey 13.5 billion years ago, according to co-author Francesco DiEugenio, an astrophysicist at the University of Cambridge.

Light is expanding by the time it reaches Earth from the farthest galaxies, due to the expansion of the universe and moving into the infrared region of the light spectrum, which Webb is equipped to detect with unprecedented clarity.

The team says that the large size of JADES-GS-z14-0 indicates that the light is produced by young stars that were very close to the other, less distant galaxy (JADES-GS-z14-1), as they appeared to be part of one larger object.

For the past two years, scientists have used GEMS Webb to explore the "cosmic dawn," the period after the Big Bang where the first galaxies were born.

These galaxies provide vital insight into the ways gases, stars and black holes changed when the universe was very young.