What is the biggest single object in the observable universe?

The biggest single object in the observable universe is the Hercules-Corona Borealis Great Wall, a colossal galactic supercluster complex. This structure was discovered in 2013 through the analysis of gamma-ray bursts, which are the brightest electromagnetic events known to occur in the universe. The Hercules-Corona Borealis Great Wall stretches across approximately 10 billion light-years, making it the largest known structure in the observable universe. Its vast size challenges some cosmological theories, particularly those related to the homogeneity and isotropy of the universe on large scales, which suggest that the universe should be relatively uniform. 

 This massive structure is so enormous that it defies the general understanding of cosmic structures' formation. Typically, galaxy clusters form into superclusters, which are bound together by gravity. However, the sheer size of the Hercules-Corona Borealis Great Wall is puzzling because it suggests that the universe's matter distribution is not as uniform as previously thought. This structure's discovery has led to further investigations into the large-scale structure of the universe and the processes that could lead to such vast formations. The Hercules-Corona Borealis Great Wall is not just significant due to its size but also because of what it represents in terms of the cosmic web—a vast network of interconnected filaments of galaxies and dark matter. This cosmic web is the large-scale structure of the universe, with voids, filaments, and walls where galaxies and clusters of galaxies are located. The Great Wall is one of the densest regions in this web, containing a significant number of galaxies and clusters that are gravitationally bound together. Despite its vast size, the Hercules-Corona Borealis Great Wall is not a uniform structure; it has varying densities and regions of different galaxy populations. This variation adds another layer of complexity to understanding how such a massive object formed. Its discovery has prompted astronomers to question whether current models of the universe's evolution fully account for such large-scale structures, pushing the boundaries of current cosmological theories. In conclusion, the Hercules-Corona Borealis Great Wall is the largest known object in the observable universe, spanning 10 billion light-years. Its discovery has raised important questions about the universe's large-scale structure and the processes that govern its formation. This colossal structure is a key piece in the puzzle of understanding the universe, challenging existing theories and inspiring further research into the nature of cosmic formations and the true scale of the universe.