page_title: Hercules–Corona Borealis Great Wall
hierarchical_section_title: Hercules–Corona Borealis Great Wall
caption_attribution_description: English: This enormous image shows Hubble’s view of massive galaxy cluster MACS J0717.5+3745. The large field of view is a combination of 18 separate Hubble images. Studying the distorting effects of gravity on light from background galaxies, a team of astronomers has uncovered the presence of a filament of dark matter extending from the core of the cluster. The location of the dark matter is revealed in a map of the mass in the cluster and surrounding region, shown here in blue. The filament visibly extends out and to the left of the cluster core. Using additional observations from ground-based telescopes, the team was able to map the filament’s structure in three dimensions, the first time this has ever been done. The filament was discovered to extend back from the cluster core, meaning we are looking along it.
context_page_description: The Hercules–Corona Borealis Great Wall is the largest known super-structure in the universe.
  It is a huge group of galaxies forming a giant sheet-like pattern. It is about 10 billion light-years long, 7.2 billion light-years wide, and almost 1 billion light-years thick. It is about 10 billion light-years away in the constellations of Hercules and Corona Borealis, hence its name.
  It was discovered in November 2013 by mapping gamma-ray bursts. They are very luminous explosions of distant, massive stars, the most powerful explosions in the universe. A typical burst releases more energy in less than a tenth of a second than the Sun will in its whole life of 10 billion years.
  Gamma-ray bursts are very rare: only one happens in a typical galaxy every few million years. The stars which cause these explosions are very massive, so the material required for them to be formed must be in great amounts. So, these explosions can be used to track down if there is a galaxy in that direction, or there is a large group of matter in there.
context_section_description: The Hercules–Corona Borealis Great Wall is  the largest known super-structure in the universe.
  It is a huge group of galaxies forming a giant sheet-like pattern. It is about 10 billion light-years long, 7.2 billion light-years wide, and almost 1 billion light-years thick. It is about 10 billion light-years away in the constellations of Hercules and Corona Borealis, hence its name.
  It was discovered in November 2013 by mapping gamma-ray bursts. They are very luminous explosions of distant, massive stars, the most powerful explosions in the universe. A typical burst releases more energy in less than a tenth of a second than the Sun will in its whole life of 10 billion years. 
  Gamma-ray bursts are very rare: only one happens in a typical galaxy every few million years. The stars which cause these explosions are very massive, so the material required for them to be formed must be in great amounts. So, these explosions can be used to track down if there is a galaxy in that direction, or there is a large group of matter in there.
  Between the years of 1997 to 2012, astronomers mapped these bursts in the sky, with the help of the robotic satellites Swift and Fermi which looks for gamma-ray bursts and measures their redshifts. In the map they produced, they noticed something interesting; 14 gamma-ray bursts have very similar redshifts and are very close to each other. This means that there is a very large group of galaxies and matter in the region. They say, from measuring these bursts, comes up with a very large structure measuring 10 billion light-years in diameter.
  For comparison, the Milky Way, the galaxy we live in, measures only 100,000 light-years, and the distance from the Milky Way to the Andromeda Galaxy measures only 2.5 million light-years. The Huge-LQG (the Huge Large Quasar Group), the previous largest structure in the universe, is 4 billion light-years long.
  The discovery of the Hercules–Corona Borealis Great Wall contradicts a theory proposed by Albert Einstein known as the cosmological principle. The cosmological principle says that the entire universe is approximately equal; any two regions in the universe will look very similar, even if those two regions are very far apart, assuming those regions have sizes larger than 250 to 300 million light-years. Maximum sizes of structures must be around 1.2 billion light-years based on the meaning above, and no structure must be larger than that, assuming that matter is spreaded equally from the Big Bang. However, the structure, is eight times larger than the limit, contradicting the cosmological principle.
  The structure also contradicts theories about the evolution of the universe. The structure is 10 billion light-years away, which means that we see the structure 10 billion years ago, when the universe is only 13.8 billion years old, and its light was just approaching us. The 13.8 billion year span of time is too short for a giant structure 10 billion light-years long to form. Even Istvan Horvath, the discoverer of the structure, says he has no idea how the structure has formed in that amount of time. For now, the existence of the structure is still a mystery for cosmologists.
caption: A massive galaxy cluster named MACS J0717.5+3745, which may be similar to the Hercules–Corona Borealis Great Wall.
exif: {"Image ImageDescription": "This enormous image shows Hubble\u2019s view of massive galaxy cluster MACS J0717.5+3745. The large field of view is a combination of 18 separate Hubble images. Studying the distorting effects of gravity on light from background galaxies, a team of astronomers has uncovered the presence of a filament of dark matter extending from the core of the cluster.\u00a0 The location of the dark matter is revealed in a map of the mass in the cluster and surrounding region, shown here in blue. The filament visibly extends out and to the left of the cluster core. Using additional observations from ground-based telescopes, the team was able to map the filament\u2019s structure in three dimensions, the first time this has ever been done. The filament was discovered to extend back from the cluster core, meaning we are looking along it.", "Image Artist": "", "Image Copyright": ""}