Enroll Physics XI Sindh Board Course
The universe is made up of billions of galaxies, which are groups of many billions of stars, gas and dust. These can be spiral, elliptical and irregular in shape.
Galaxies often group together gravitationally, forming superclusters of galaxies. These are the largest structures in the universe, and they can stretch for hundreds of millions of light years.
The Great Wall of Hercules
The Hercules-Corona Borealis Great Wall, also known as the CfA2 Great Wall or Coma Wall, is an immense galaxy filament discovered in November 2013, when astronomers were mapping gamma ray bursts. Its redshift is in the range of 1.6 to 2.1, 10 billion light-years distant, and it is 7.2 billion light-years wide and almost 1 billion light-years thick.
Scientists say it is a very strong indicator of a large galaxy cluster. These are groups of galaxies that are tightly bound together by gravity.
It’s also one of the biggest structures to have been discovered so far, displacing the Sloan Great Wall as the largest in the universe. It defies a fundamental principle of modern cosmology: that matter should appear to be spread uniformly over a large enough scale.
The Hercules-Corona Great Wall is so humungous that it exceeds the structural size allowed by the inflation model of the universe. This means that it was in existence only four billion years after the Big Bang!
The BOSS Great Wall
As humans, we know the universe is full of incredible wonders. Whether we’re looking at the Milky Way or a galaxy-wide supercluster system, it’s always fascinating to explore what lies beyond our world.
One such structure is called the BOSS Great Wall, a network of superclusters found by astronomers in 2016. It contains 830 galaxies and its diameter is roughly one billion light years.
According to a study published in Astronomy & Astrophysics, this huge superstructure has a total mass that is 10,000 times greater than the Milky Way.
Scientists at the Canary Islands Institute of Astrophysics in Spain found evidence for this massive structure in early 2016, when they spotted it as part of the Baryon Oscillation Spectroscopic Survey (BOSS), an international effort to map galaxies and quasars. This new discovery should help astronomers to explore the overall structure of our universe, which has long been a mystery.
The Bootes Void
The Bootes Void is a massive, spherical zone of empty space that stretches for 700 million light years from Earth. It’s a mind-numbing distance that represents 0.27% of the entire observable universe, making it one of the largest known voids in the Universe.
The vast empty space is a stark contrast to the nearby galaxies of our own Milky Way galaxy, which are packed together in clusters of billions of galaxies. This is due to gravity, and is a natural process that occurs over time in the Universe.
In the early days of the universe, all the matter in the universe was tightly packed, but it soon experienced random quantum fluctuations that caused small differences in the distribution of particles. This caused some of the voids that exist in our universe to form.
The Milky Way
The Milky Way is an enormous galaxy consisting of several hundred billion stars. It has four spiral arms extending from its center like the arms of a Catherine wheel.
The central region of the Milky Way isn’t visible to the naked eye for much of the year, but it can be seen through telescopes. This is because the core of the Milky Way is too far from Earth for our eyes to see it.
One of the most remarkable features of the Milky Way is its collection of cloudlike gaseous objects called nebulae. The most conspicuous of these are emission nebulae, which contain hydrogen gas that’s been ionized by ultraviolet radiation from hot stars.
These bright nebulae are located within the plane of the Milky Way Galaxy, and many exist at intermediate distances from the Galaxy’s centre. They are also the most common regions of star formation in the Galaxy. They contain gas that has a total mass ranging from one or two solar masses up to several thousand.