JAKARTA – The universe is actually wider than humanity can imagine. If depicted, the Earth where humans live actually only resembles an almost invisible dot when compared to the billions of planets, stars and other celestial bodies.
In astronomy, experts call a ‘region’ in space a galaxy. Judging from the explanation, a galaxy is a part of the universe in which there are millions to billions of planets, stars, clouds, dust and gas.
Because of the billions of stars they contain, several galaxies also often form constellations that are visible from Earth. Meanwhile quoted from BBC Science, scientists believe that currently there are more than 2 trillion galaxies scattered in the universe. One of them is the place where the Earth and the solar system are located, namely the Milky Way galaxy.
So what are the rows of galaxies in the universe that are interesting to know? Here are some of them:
Ursa Major Galaxy
Among scientists, this galaxy which is located ‘neighboring’ the Milky Way has many nicknames. But the two most famous are M101 and the large bear/polar bear galaxy (polar bear).
The nickname big bear galaxy is obtained because the Ursa Major galaxy has seven main stars whose points form a constellation pattern (rasi) shaped like a polar bear. On Earth, the direction of the constellation Ursa Major is believed to be the benchmark for the north when sailing for early fishermen before there was a compass.
The size of the Ursa Major galaxy is also quite large, namely twice the size of the Milky Way with a distance between the two reaching around 10 million light years. However, if you want to know a more specific distance, the distance from Earth to the Ursa Major galaxy is estimated at 23 million light years.
Andromeda Galaxy
A type of galaxy whose name is familiar and often heard among ordinary people, Andromeda is also said to be one of the closest galaxies to the Milky Way. Identified as Messier 31 by scientists, the Andromeda galaxy is one of the galaxies that can be seen with the naked eye from Earth after Ursa Major. However, in detail, this galaxy can be seen in certain locations from September to November.
It is said that Andromeda was first identified by a Persian expert named Abd Al-Rahman Al-Sufi, who explained the characteristics of this galaxy in a book entitled The Book of Fixed Stars, around 964 AD.
Closer than Ursa Major, this galaxy which is said to be twice the diameter of the Milky Way is ‘only’ about 2.5 million light years away.
The Magellanic Galaxy
Still introduced by previous astronomers, the Magellan galaxy was also first described by observations by Abd Al-Rahman Al-Sufi in the same book and year. Ursa Major and Andromeda may be categorized as large galaxies, but this is different with Magellan which scientists have identified as a ‘dwarf’ galaxy.
Al-Sufi in his book estimates that Magellan was originally formed from one of the largest stars in the universe which exploded in the 4th century. The star in question became known as SN 1987 A or Supernova which had a very bright light.
If Andromeda, Ursa Major, or the Milky Way have billions of stars, Magellan only consists of thousands of stars or celestial bodies in it. Because of its smaller shape, this galaxy is also more commonly referred to as the ‘Magellan Cloud’ instead of a galaxy.
2023-10-09 11:45:05
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