Einstein Was Right – Euclid Just Captured Space-Time Warping in a Perfect Cosmic Ring – SciTechDaily
Source: SciTechDaily
Euclid, a space telescope on a mission to uncover the secrets of dark matter and dark energy, has already made a stunning discovery: a perfectly formed Einstein ring hidden in a well-known galaxy.
This rare phenomenon, predicted by Einstein’s theory of relativity, reveals the power of gravitational lensing, allowing scientists to glimpse far-off galaxies otherwise invisible. The find is a testament to Euclid’s groundbreaking capabilities, suggesting a future filled with even more cosmic surprises.
Euclid launched on July 1, 2023, beginning its six-year mission to explore the dark universe. Before the spacecraft could start its full survey, scientists and engineers on Earth needed to ensure all systems were functioning properly. As part of this early testing phase, Euclid sent back its first images in September 2023. These initial images were intentionally blurred for calibration purposes, but one caught the attention of Euclid Archive Scientist Bruno Altieri. Within the fuzzy data, he noticed something unusual — possibly a rare cosmic phenomenon — and decided to investigate further.
“I look at the data from Euclid as it comes in,” Altieri explains. “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.”
This Einstein ring, a rare and striking example of gravitational lensing, had been hiding in plain sight in a nearby galaxy. Known as NGC 6505, the galaxy sits about 590 million light-years from Earth — relatively close in cosmic terms. Thanks to Euclid’s advanced high-resolution instruments, this is the first time the luminous ring around its center has been detected.
The Einstein Ring, an extremely rare phenomenon, turned out to be hiding in plain sight in a galaxy not far away. The galaxy, called NGC 6505, is around 590 million light-years from Earth, a stone’s throw away in cosmic terms. But this is the first time that the ring of light surrounding its center is detected, thanks to Euclid’s high-resolution instruments.
The ring around the foreground galaxy is made up of light from a farther-out bright galaxy. This background galaxy is 4.42 billion light-years away, and its light has been distorted by gravity on its way to us. The far-away galaxy hasn’t been observed before and doesn’t yet have a name.
“An Einstein ring is an example of strong gravitational lensing,” explains Conor O’Riordan, of the Max Planck Institute for Astrophysics, Germany, and lead author of the first scientific paper analyzing the ring. “All strong lenses are special, because they’re so rare, and they’re incredibly useful scientifically. This one is particularly special, because it’s so close to Earth and the alignment makes it very beautiful.”
Albert Einstein’s general theory of relativity predicts that light will bend around objects in space, so that they focus the light like a giant lens. This gravitational lensing effect is bigger for more massive objects – galaxies and clusters of galaxies. It means we can sometimes see the light from distant galaxies that would otherwise be hidden.
If the alignment is just right, the light from the distant source galaxy bends to form a spectacular ring around the foreground object. These Einstein rings are a rich laboratory for scientists. Studying their gravitational effects can help us learn about the expansion of the Universe, detect the effects of invisible dark matter and dark energy, and investigate the background source whose light is bent by dark matter in between us and the source.
“I find it very intriguing that this ring was observed within a well-known galaxy, which was first discovered in 1884,” says Valeria Pettorino, ESA Euclid Project Scientist. “The galaxy has been known to astronomers for a very long time. 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. This discovery is very encouraging for the future of the Euclid mission and demonstrates its fantastic capabilities.
By exploring how the Universe has expanded and formed over its cosmic history, Euclid will reveal more about the role of gravity and the nature of dark energy and dark matter. The space telescope will map more than a third of the sky, observing billions of galaxies out to 10 billion light-years. It is expected to find around 100,000 strong lenses, but to find one that’s so spectacular – and so close to home – is astonishing. Until now, less than 1000 strong lenses were known, and even fewer were imaged at high resolution.
“Euclid is going to revolutionize the field, with all this data we’ve never had before,” adds Conor.
Although this Einstein ring is stunning, Euclid’s main job is searching for the more subtle effects of weak gravitational lensing, where background galaxies appear only mildly stretched or displaced. To detect this effect, scientists wi
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