Einstein Ring: Galaxy SDP.81 is located about 12 billion light-years from Earth. It is known as a “starburst” galaxy, due to the extremely high rates of star births that have been observed. Starbursts create a lot of light, making it very easy to see the galaxies that are being formed.
Galactic explosions can occur in any galaxy, but those observed in SDP.81 are special. From Earth, we can see SDP.81 as a complete ring in the depths of space with the Atacama Large Millimeter/submillimeter Array (ALMA) telescope in the highest resolution galaxy image ever. The ALMA telescope consists of 66 radio telescopes located in the Atacama Desert of Chile.
The ring effect occurs because the distance between SDP.81 and Earth, about four billion light-years, is large enough to bend incoming light so precisely that SDP.81 appears almost like a perfect circle. It is a rare case of gravitational lensing, a phenomenon that Einstein had mentioned when he announced General Relativity.
The distorted image of SDP.81 is caused by the gravity of another galaxy or some other massive object that essentially distorts space with its gravity, causing light rays to follow a curved path. The phenomenon is known as an Einstein ring.
The light we see from the galaxy dates back almost to the beginning of the universe, which is estimated to be about 13,820,000,000 years ago.
"Gravitational focusing is used in astronomy to study very distant objects, the early Universe, because it gives even better results in our telescopes," said the Greek deputy director of the ALMA program, Katerina Vlahakis or Catherine Vlahakis, according to CNN.
"With the amazing level of detail in these new ALMA images, astronomers will now be able to reassemble the information contained in the distorted image we see as a ring and produce a reconstruction of the true image of the distant galaxy."
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