Hubble detects ‘Earendel,’ most distant star ever seen

A long time ago in a galaxy far, far away, there was a large and magnificently brilliant star that shined across the young, expanding universe. The starlight skewed blue. It was the cosmic morning, when everything in the universe was still new, raw, the galaxies still forming not long after the first stars had ignited and lit up the heavens.

The light from that blue star traveled through space for billions of years, and then one day a few thin beams crashed into a polished mirror – the light bucket of the Hubble Space Telescope.

In a report published Wednesday (3/30/22) in the journal Nature, a team of astronomers asserts that this is the most distant individual star ever seen. They describe it as 50 to 100 times more massive than our sun, and roughly 1 million times brighter, with its starlight having traveled 12.9 billion years to reach the telescope.

The lead author on the report, Brian Welch, a 27-year-old doctoral candidate at Johns Hopkins University, had the honor of giving the star a name: Earendel. It’s an Old English word, meaning “morning star,” he said. Earendel was found in a young galaxy known as the Sunrise Arc, and “morning star” seemed appropriate, Welch said.

“And it sounds cool,” he added. Moreover, “Earendil” is the name of a character in J.R.R. Tolkien’s “The Silmarillion,” which also inspired the name, Welch said.

“This is one of the major discoveries of the Hubble Space Telescope in its 32 years of observation,” said Rogier Windhorst, an Arizona State University astronomer and a co-author of the report.

Found in the constellation Cetus near the star Mira, Earendel’s light was emitted about 900 million years after the universe began its expansion – the big bang. If that estimated distance holds up to further scrutiny, the starlight would have been emitted nearly 4 billion years farther back in the universe’s history than that of the most distant individual star previously seen.

As with any stunning claim, this carries caveats and uncertainties, starting with the possibility that it is not a singular star at all. It is possible Earendel is a pair of stars, or even a trio or more, a common stellar phenomenon in which one bright member of the group does most of the illumination. (Alpha Centauri, the closest sun-like star, is part of a triplet).

Another possibility is that Earendel is, at its core, a black hole – the remnant of a massive individual star that has collapsed. Black holes are invisible, of course, but their gravity can lure rapidly moving and visible material, known as an accretion disk.

“The object is real. It’s not a smudge. There is something there,” Windhorst said. “The question is, whatever object is there, what is it really?”