sábado, 28 de enero de 2012

Astronomy - Galaxy Clusters & Great Walls (The Largest Structures in the Universe)


A stunningly beautiful galaxy cluster 840 million light years from Earth with a few hundred galaxies gets its name from the strong radio source, Hydra A, above, that originates in a galaxy near the center of the cluster. 

Chandra Space Observatory X-ray observations reveal a large cloud of hot gas that extends throughout the cluster.The gas cloud is several million light years across and has a temperature of about 40 million degrees in the outer parts decreasing to about 35 million degrees in the inner region.  Also a bright white wedge of hot multimillion degree Celsius gas is seen pushing into the heart of the cluster. 
As the largest gravitationally bound objects in the universe, galaxy clusters provide crucial clues for understanding the origin and fate of the universe.
The Milky Way, for example, is a member of a group of about 40 galaxies we call the Local Group. Observations have shown that galaxies and galaxy clusters appear to be loosely structured in giant chains ans sheets, forming giant structures called superclusters. Between the vast structures of galaxies lie huge cold voids containing few, in many cases, no galaxies.
The vastest structure ever is a collection of superclusters a billion light years away extending for 5% the length of the entire observable universe. If it took a God one week to make the Earth, going by mass it would take him two quintillion years to build this thing - far longer than science says the universe has existed for, and it's kind of fun to have those two the other way round for a change.  


The great wall is a massive array of astronomical objects named after the observations which revealed them, the Sloan Digital Sky Survey.  An eight year project scanned over a quarter of the sky to generate full 3-D maps of almost a million galaxies.  Analysis of these images revealed a huge panel of galaxies 1.37 billion light years long, and even the pedantic-sounding .07 there is six hundred and sixty billion trillion kilometers.  This is science precisely measuring made-up sounding numbers.
This isn't the only wall out there - others exist, all with far greater lengths than width or depth, actual sheets of galaxies forming some of the most impressive anythings there are.  And these walls are only a special class of galactic filaments, long strings of matter stretched between mind-breaking expanses of emptiness.
The immensity of existence truly defies human understanding - which makes it very humanly awesome of us to try anyway.  If people could understand for a single second the true scale of everything out there, all our idiotic problems would evaporate instantly.  


Source: The Daily Galaxy via Chandra X-ray Observatory

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