Nicknamed the 'Molten Ring,' this deep-space phenomenon is 9.4 billion light-years away
TORONTO -- In 2020, the Hubble Space Telescope captured a rare and spectacular image of light from a far-away galaxy curving in a glowing arc around a cluster of dense gravity -- and now, new analysis has revealed that this light travelled 9.4 billion light-years to reach us.
The deep-space phenomenon is called an “Einstein ring,” and the image captured by Hubble last winter is one of the largest and most complete such rings ever seen, nicknamed the “Molten Ring.”
Jesse Rogerson, assistant professor of astronomy at York University, told CTV News Channel on Sunday that these light shows are more than just a sight to behold as they allow us to peer farther through space and time.
“A consequence of general relativity, Einstein’s theory of general relativity, is that mass, gravity, can bend light,” he explained. “If everything gets lined up properly, something that’s really, really far away, if it’s behind a massive object, light can get bent around that massive object towards us so that we can see it.
“And even more importantly, it gets magnified. It gets brightened. Which means we can see things way across the universe that we normally wouldn’t ever be able to see.”
The effect that produces the curved shape of these rings is called gravitational lensing. If you peer closely enough at the Hubble image, you can see that the galaxy’s light has been distorted in a way that produces duplicated images of the galaxy along the golden arc.
After the image of the Molten Ring’s original publication, scientists dug back through the data to understand just what they were looking at, with the results described in a paper published last week in the Astrophysical Journal.
They found the galaxy that was having its light bent into this curve was 9.4 billion light-years away from Earth, which means that we are seeing it at a younger age than the galaxies closer to us.
“The cool consequence about light travelling through the universe is that the further away we look, the further back in time we’re looking,” Rogerson explained.
“Which means when you see a galaxy really, really far away, you’re seeing a galaxy that existed at an earlier point in the universe’s timeline.”
The image captured of this galaxy shows it as it appeared when the universe was less than half the age it is now, according to a Hubble news release. At that time, it was going through an explosive period of star formation.
“They found that the star formation rate was about a thousand times higher in that galaxy […] than our galaxy today,” Rogerson said.
To come to these conclusions, researchers looked not only at the Hubble image, but also archival data relating to this specific galaxy -- collected by the European Southern Observatory’s Very Large Telescope -- in order to determine the redshift value of the galaxy. The redshift value refers to looking at specific wavelengths of light to determine whether an object in space is moving towards or away from us.
“The detection of molecular gas, of which new stars are born, allowed us to calculate the precise redshift and thus gives us confidence that we are truly looking at a very distant galaxy," Nikolaus Sulzenauer, PhD student at the Max Plank Institute for Radio Astronomy in Germany and member of the investigation team, said in a press release from the European Space Agency (ESA).
The unique thing about Einstein’s rings is that the magnification can allow researchers to see galaxies in higher detail than they would’ve been able to otherwise.
NASA and ESA explained in a release that the galaxy’s light had been magnified by a factor of 20. Essentially, the Einstein’s ring boosted Hubble’s viewing capability to that of a 48-metre-aperture telescope. According to the ESA -- which collaborates with NASA on the Hubble project -- “this is larger than the currently planned extremely large telescopes.”
“The universe, nature, is magnifying a really distant galaxy for us, which is incredible to see,” Rogerson said.
The foreground object that is distorting the light from the distant galaxy is believed to be an enormous cluster of galaxies.
Rogerson said one of the questions astronomers and scientists have when they look at galaxies closer to us is how those galaxies grew to their size.
“How do you get the Andromeda galaxy, how do you get M-87, how do you get these big huge galaxies?” he said.
Because of the magnifying effect of Einstein rings, researchers can see what galaxies looked like in their infancy.
“I love Einstein rings, it’s one of my favourite things in astronomy because it’s an example of nature really working for us,” Rogerson said. "Because nature doesn’t always make it so easy to learn things, but this is an example where nature does a lot of the heavy lifting.”