A lucky lineup may have revealed a star that started shining before the universe’s one billionth birthday. This star appears to be the most distant one ever seen. Its light began traveling some 12.9 billion years before it reached Earth. That’s about 4 billion years longer than the former record holder.
Researchers reported the news March 30 in Nature.
The universe includes all things that are found today in space and time. Studying this early starlight could help researchers learn more about what the universe was like when it was very young. It is now about 13.8 billion years old.
“These are the sorts of things that you only hope you could discover,” says astronomer Katherine Whitaker. She works at the University of Massachusetts Amherst. She did not take part in the new study.
The newfound object appears in images of a cluster of galaxies taken by the Hubble Space Telescope. The sun is one of hundreds of billions of stars in the Milky Way galaxy, so these images from Hubble show ginormous numbers of stars. That one cluster alone contains many galaxies. These galaxy clusters can bend and focus light that comes from things even farther away. Such a bending of light is known as gravitational lensing.
In images of one galaxy cluster, a group of astronomers from around the world noticed a long, thin red arc. That team includes Brian Welch from Johns Hopkins University in Baltimore, Md. The team realized that the arc was made of light from a galaxy located even farther away than the ones they were studying. The light from this background galaxy had been stretched and magnified.
Atop that red arc, the researchers found one bright spot they think is too small to be a small galaxy or a cluster of stars. “We stumbled into finding” this ancient star, Welch explains.
His team now estimates that the starlight they spotted was from only 900 million years after the Big Bang. The Big Bang happened at the birth of our universe, when a very dense and heavy collection of matter expanded incredibly fast.
Welch and his colleagues nicknamed the newfound object “Earendel.” It comes from an old English word meaning “morning star” or “rising light.” They think this star is at least 50 times as massive as the sun. But the researchers need to make more detailed measurements before they can say more — and can confirm that it’s a star.
The researchers plan to use the recently launched James Webb Space Telescope to examine Earendel more closely. That telescope, also known as JWST, will begin studying the distant universe this summer.
JWST can pick up light from more distant objects than can Hubble. That could help it uncover objects from even farther back in the history of our cosmos. Welch hopes that JWST will find many more such hidden, faraway stars. Indeed, he says, “I’m hoping that this record won’t last very long.”