A team of European Space Agency (ESA) scientists detected an Einstein Ring, in which light from one galaxy is sucked into the gravity of another, then encircles it. The team reported the finding in the journal Astronomy & Astrophysics.
The phenomenon is named after Albert Einstein, because his general theory of relativity predicts that light will bend around objects in space, focusing the light like a massive lens. The larger the object, the bigger the gravitational lensing effect appears. If the two galaxies are aligned just right, the light from the farther galaxy forms a ring around the nearer one.
Accidental Discovery
The finding was even more unusual because it was essentially accidental. After Euclid blasted off in 2023, the Earthbound team monitored data from the space telescope and conducted routine instrument testing.
The initial images in September 2023 were out of focus, because the space telescope had not yet been calibrated. But one fuzzy picture caught Bruno Altieri’s eye.
“I look at the data from Euclid as it comes in,” the ESA scientist said in a press release. “Even from that first observation, I could see it, but after Euclid made more observations of the area, we could see a perfect Einstein ring. For me, with a lifelong interest in gravitational lensing, that was amazing.”
Read More: From Billions to Trillions Light Years Away, These are the Furthest Stars and Exoplanets From Earth
Einstein Ring Close to Home
The siting was also unusual because in space distance, it is relatively close to Earth. The galaxy it encircles (NGC 6505) is around 590 million light-years from Earth.
The background galaxy from which the light emanates, at 4.42 billion light years, is much farther away. That galaxy, unlike the much-observed NGC 6505 has never been investigated and was unnamed at the time of its discovery. Astronomers first detected NGC 6505 in 1884. The fact that Euclid saw the ring around a heavily studied galaxy, but emanating from a much farther unknown one makes the finding that much more special. It also validates the power of Euclid’s instruments.
“The galaxy has been known to astronomers for a very long time,” Valeria Pettorino, ESA Euclid Project Scientist, said in a press release. “And yet this ring was never observed before. This demonstrates how powerful Euclid is, finding new things even in places we thought we knew well.”
Euclid’s mission is to explore the effects of gravity throughout the Universe. It is tasked with observing billions of galaxies out to 10 billion light-years. Astronomers expect to observe many more examples of gravitational lensing during Euclid’s mission. Finding such a spectacular one early in the space telescope’s journey is an encouraging sign that Euclid will find many more fantastic phenomena.
Read More: Dark Energy Debunked By "Lumpy" Universe Expansion
Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
Astronomy & Astrophysics. Euclid: A complete Einstein ring in NGC 6505
The European Space Agency. Euclid
Before joining Discover Magazine, Paul Smaglik spent over 20 years as a science journalist, specializing in U.S. life science policy and global scientific career issues. He began his career in newspapers, but switched to scientific magazines. His work has appeared in publications including Science News, Science, Nature, and Scientific American.
