The largest object in the universe
• It is not easy to accurately determine the largest body in the universe – there is no certainty that we have already explored everything that exists in it.
• However, in this article, I will build on existing data and tell you about the largest object in the universe known to modern science.
The largest superstructure in the universe
• This is the Great Wall of Hercules-Northern Crown (Hercules-Corona Borealis Great Wall) or simply the Great Wall. It is located about 10,5 billion light-years away and is a group of an uncounted number of galaxies bound together by the force of gravity.
• The length of this galactic filament is estimated at 10-15 billion light years. Astronomers learned this by mapping gamma-ray bursts from this cluster of galaxies.
• The width of the Great Wall is 7,2 billion light years. For comparison, the Milky Way galaxy is about 100 light-years wide.
• “Why does the author call a group of galaxies an object?” the reader may ask. But the planets are also considered separate objects, despite the fact that they contain countless different components. On Earth, the individual objects we use in everyday life are made up of countless atoms, yet we still view them as single objects.
• Simply put, we often ignore the individual components of an object and simply view the entire structure as a whole. The same is true for galaxy clusters, which, although they contain many galaxies, can be considered as single objects on an extremely huge scale.
How did scientists find the Great Wall?
• In 2013, a team of scientists studied an anomalously high volume of gamma-ray bursts that were concentrated about 10 billion light-years away, in the direction of the constellations Hercules and the Northern Corona.
- Gamma-ray bursts are the strongest and most powerful form of radiation in the electromagnetic spectrum. This type of radiation is quite rare, it is observed only in a few cases. One such event is a supernova explosion, which releases more energy than the Sun can produce in its entire lifetime.
- The purpose of studying these bursts is that they make it possible to detect huge structures in the Universe. Their study allows astronomers to learn a lot about the formation of stars.
- In addition, supernova explosions can lead to the formation of planetary systems such as our solar system.
• Based on data obtained from the SWIFT observatory, the researchers divided the sky into 9 sections. In each of the sites, 31 gamma-ray bursts were studied. In one of the areas, 14 bursts were concentrated in a region with an angular radius of 45° and a redshift from 1,5 to 2,0. This indicates that there are many (perhaps millions) of galaxies in this area. And so an object of incredible size was discovered – the Great Wall.
• At first, the researchers could hardly believe what they found. However, there was less than a 1% chance that this set of gamma rays would randomly appear at that location. Because of this, it is reasonable to believe that the Great Wall of Hercules-North Corona exists. For the same reason, the structure is often referred to as the Great Wall of GRBs.
How does the largest object in the universe defy the cosmological principle?
• According to the basic position of modern cosmology, the Universe is very homogeneous. For example, the residual heat from the Big Bang appears to be extremely uniform in all directions. Matter in the universe follows the same rule.
- Of course, there is some local inhomogeneity in the Universe. For example, there are clusters of stars, galaxies and other clusters of matter, localized in certain areas.
- But the basic cosmological principle remains – the matter in the Universe as a whole is distributed very evenly.
- Otherwise, clusters of matter would be attracted to each other. As a result, the universe would shrink due to its own gravity.
• But the cluster of galaxies in the Great Wall is not homogeneous.
• In addition, this giant structure is 10 billion light-years away, which means that scientists are observing the object as it was 10 billion years ago, or about 3,8 billion years after the Big Bang. And, according to modern models of the evolution of the Universe, such large and complex structures could not have arisen at this stage.
What other large objects are there in the Universe?
- Huge group of quasars – held the record for the largest object ever identified in the universe until it was broken in 2013. This is a cluster of 73 quasars (massive celestial objects that emit a huge amount of energy). This structure, located in the constellation Leo, is about 4 billion light-years across.
- There is also a giant ring of 9 gamma-ray burstsdiscovered in 2015. This structure is approximately 5,6 billion light years in diameter. It is believed that it has a spheroidal or annular shape. The distance from this ring to Earth is about 9,1 billion light years.
- In 2021, an object named "Maggie" was discovered in the Milky Way galaxy. – in honor of the Magdalena, the longest river in Colombia. This massive hydrogen filament is 39 light-years long and lies over 55 light-years from Earth. "Maggie" is five times larger than the largest known gas clouds that have been recorded in recent history.
- South Pole Wall is a colossus of a huge cluster of galaxies, stretching for a huge 1,37 billion light-years between the constellations of Cetus and Bird of Paradise. The South Pole Wall is special because it is very close to the Milky Way galaxy, only 500 million light-years away. And they discovered it relatively recently – in 2020.