Incredible Einstein ring images offer a glimpse of the early universe

8 Apr 2015

A composite image of the Einstein ring. Image via ALMA (NRAO/ESO/NAOJ); B. Saxton NRAO/AUI/NSF; NASA/ESA Hubble, T. Hunter (NRAO)

With the power of one of the most high-resolution cameras in existence, the Atacama Large Millimeter/submillimeter Array (ALMA) has snapped a distant galaxy that appears as a ring, known as an Einstein ring.

The menacing sight, which is eerily reminiscent of Sauron’s all-seeing eye in the Lord of the Rings films, is the result of a chance alignment of two galaxies that appears as a ring due to gravitational lensing, something Albert Einstein had calculated would happen in his life’s work.

According to ALMA, this gravitational lensing occurs when a massive galaxy or cluster of galaxies bends the light emitted from a more distant galaxy leading to the incredible, but distorted, effect we see in what is the highest resolution photo ever taken.

To put its power into perspective, ALMA achieved a resolution of 23 milliarcseconds, which is about the same as seeing the rim of a basketball hoop atop the Eiffel Tower from the observing deck of the Empire State Building.


The bright orange central region of the ring (ALMA’s highest resolution observation ever) reveals the glowing dust in this distant galaxy. Image via ALMA (NRAO/ESO/NAOJ); B. Saxton NRAO/AUI/NSF

‘A new frontier in astronomy’

At a distance of 12bn light years away, the galaxy designated SDP.81 is being lensed by the foreground galaxy that is a much closer 4bn light years away in what is one of the most perfectly lined-up formations ever captured, which also offers us a glimpse of a time when the universe was in its earliest stages.

“The exquisite amount of information contained in the ALMA images is incredibly important for our understanding of galaxies in the early Universe,” said astronomer Jacqueline Hodge of the National Radio Astronomy Observatory.

“This unravelling of the bending of light done by the gravitational lens will allow us to study the actual shape and internal motion of this distant galaxy much more clearly than has been possible until now.”

ALMA’s director Pierre Cox said: “These results open a new frontier in astronomy and prove that ALMA can indeed deliver on its promise of transformational science.”

A composite image of the Einstein ring. Image via ALMA (NRAO/ESO/NAOJ); B. Saxton NRAO/AUI/NSF; NASA/ESA Hubble, T. Hunter (NRAO)

Colm Gorey was a senior journalist with Silicon Republic