These types of galaxies are nothing like our Milky Way.
Nearly 110 million light-years away, a rare galaxy was discovered hiding within the well-known Pisces constellation, also known as The Fish.
The new galaxy has been named UCG 477, and it is a low surface brightness (LSB) galaxy. LSB galaxies were first proposed to exist in 1976 by astrophysicist Mike Disney, however they were not confirmed until 1986 with the discovery of Malin 1 — one of the largest spiral galaxies in the known universe, as well as a low surface brightness galaxy located 1.19 billion light years away in the constellation Coma Berenices, near the North Galactic Pole.
However, LSB galaxies are quite puzzling. They are more thinly spread than galaxies such as Andromeda or our own Milky Way, which are high surface brightness (HSB) galaxies, and most of the visible matter that makes up LSB galaxies is in the form of neutral hydrogen gas, rather than stars. In fact, their surface brightness is up to 250 times fainter than the night sky, meaning these galaxies are extremely tough to detect.
Unlike normal spiral galaxies, the centers of LSB galaxies do not contain a large number of stars. Astronomers suspect that, because LSB galaxies are mainly found in regions lacking other galaxies, they have experienced fewer galactic interactions and mergers which are responsible for high rates of star formation.
Rather, LSB galaxies like UGC 477 appear to be dominated by dark matter — the elusive and invisible substance that makes up 27 percent of all matter in the universe — so they are fantastic objects to study. However, their importance in dark matter has has only been realized recently because they had been underrepresented in previous galactic surveys.
LSBs — which tend to lie at all cosmic distances — are best to spot with wide-field telescopes, however astronomers have struggled to confirm their existence due to their characteristic low brightness. According to James Schombert, an astronomer at the University of Oregon, future LSB detection will require deep, dark sky surveys, he told Forbes.
So far, LSBs do not appear to contain the heavy elements that make it possible to form earth-like planets, making the discovery of complex life in LSBs unlikely. However, they do have longevity on their side.
“Many have neutral hydrogen reservoirs comparable to, or greater in mass, than their stars,” said Stacy McGaugh, an astronomer at Case Western Reserve University to Forbes. “So, many of these LSBs will be slowly forming stars still long after the Milky Way runs through its gas and sputters out.”
At least we can be sure that these objects will be around long enough for astronomers to study, they just have to find them first.
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