Galaxy Collision Produces Massive ‘Eye’

Galaxies are made of billions of stars - and to have two of them collide is a violent event that has recently been observed by astronomers with the help of the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile.

Galactic collisions are not uncommon, but this particular one, which took place around 114 million light-years from Earth, is something worth noting, as the two interacting galaxies came together to produce a dazzling formation that resembled a pair of eyelids, as reported by the International Business Times.

The structure was said to have formed when a "tsunami" of stars and gas crashed through a spiral galaxy known as IC 2163, when it grazed another spiral galaxy called NGC 2207. The authors of the study that was published in Astrophysical Journal noted that detailed the observation said that only a handful of galaxies with the said structures are known to exist. They noted that such eyelids only last a few tens of millions of years, which in galactic terms, is very brief. Lead author Michele Kaufman said in a statement, "Finding one in such a newly formed state gives us an exceptional opportunity to study what happens when one galaxy grazes another."

Phys.org  also reported that the data revealed that the gas in the outer portion of IC 2163 had been racing inward at speeds of over 100 kilometers per second, while the gas decelerated and became more chaotic in motion. Eventually, the galaxies changed trajectory and alighed itself with the rotation of the galaxy, and didn't continue its rush to the center.

As predicted by computer models, such eyelid-like features could only evolve if galaxies interacted in a very specific manner. While astronomers believe that these collisions were common in the early universe when the galaxies were closer together, galactic disks are usually clumpy and irregular, so it is likely that other processes overwhelmed the formation of these said eyelid features.