It turns out you can teach old space telescopes new tricks: NASA’s Hubble, which launched into low Earth orbit in 1990, recently discovered a record-breaking star so distant it required a combination of the telescope’s sophisticated instruments and gravitational lensing to spot.
Nicknamed Earendel by astronomers, the star emitted its light within the universe’s first billion years, according to NASA, making it the farthest individual star we’ve ever seen. This marks a “significant leap” beyond Hubble’s previous distance record, the agency said, citing 2018’s detection of a star some 4 billion years after the Big Bang.
To find Earendel (meaning “morning star” in Old English), Hubble took advantage of nature’s magnifying glass—an effect known as gravitational lensing; the telescope looked through space warped by the mass of the huge galaxy cluster WHL0137-08, which magnified the star’s light enough to be perceived.
The newly-detected star—an estimated 50 times the mass of our Sun and millions of times as bright—is so far away that its light took 12.9 billion years to reach Earth, appearing to us now as it did when the universe was only 7% of its current age. Previously, the smallest objects seen at such a distance were clusters of indistinguishable stars.
“We almost didn’t believe it at first, it was so much farther than the previous most-distant highest redshift star,” astronomer Brian Welch of Johns Hopkins University said in a statement. The discovery, published in the journal Nature, was made based on data collected during Hubble’s RELICS (Reionization Lensing Cluster Survey) program.
“Normally at these distances, entire galaxies look like small smudges, with the light from millions of stars blending together,” Welch said. “The galaxy hosting this star has been magnified and distorted by gravitational lensing into a long crescent that we named the Sunrise Arc.”
NASA’s new James Webb Telescope, which boasts a high sensitivity to infrared light, will follow up on the finding and hopefully learn more about Earendel’s brightness, temperature, and composition. It’s unlikely the celestial body is one of our universe’s first-generation stars, but astronomers are eager to gain insight into the environment of the early cosmos.
“With Webb, we may see stars even farther than Earendel, which would be incredibly exciting,” said Welch, “It’s like we’ve been reading a really interesting book, but we started with the second chapter, and now we will have a chance to see how it all got started.”
