Sunday, January 13, 2013

Largest structure in the universe ever found

Astronomers have discovered something that appears to be the largest structure ever encountered in the entire universe. It consists of a group of quasars, which are highly energetic regions present inside the center of galaxies. It is known that such entities tend to clump together, but the newly discovered group of quasars is so big its vastness is not only beyond what we can imagine, it is also bigger than what we thought to be possible according to the laws of physics.

As said, quasars are known to clump together, and such groups are dubbed Large Quasar Groups (LHQ). The largest LHQ has now been found, and it is so big that light needs almost 4 billion years to travel from one side to another. Another way to put it, is that the structure is 1200 megaparsecs in length. A parsec is a unit of measurement used to quantify lengths in space, and represents around 30.9 trillion kilometres. That means 1200 megaparsecs represents around 370. kilometres.

Obviously, the size of the newly found LHQ is too big to imagine, but there are some astronomical scales that we can put it on. For example, our own galaxy, which is composed of billions of stars of already unimaginable size, is 0.75 megaparsec away from Andromeda, our nearest neighbour in terms of galaxies. Our Milky Way in itself  is 'only' 0.03 megaparsecs across. That means an LHQ of 1200 megaparsecs is so vast it can span an enormous cluster of galaxies with space in between.

Finding LHQ
We are able to find quasars because they are highly energetic and  produce high levels of electromagnetic waves that we can detect. They are therefore very useful for finding objects far, far away and determining their distance from the earth. So far, clusters of quasars have been found with sizes around 200 megaparsecs, and it was originally thought that they could not exceed 370 megaparsecs across. That means finding an LHQ with 1200 megaparsecs across may yield us new theories about our universe.
An artist rendering of a highly energetic galactic core, known as a quasar.

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