Galaxy cluster 'El Gordo' packs mass of 2 quadrillion suns   
       
   The biggest of the big, monster may one day reveal secrets about invisible   
   dark matter   
       
   A composite image shows El Gordo in X-ray light from NASA's Chandra X-ray   
   Observatory in blue, along with optical data from the European Southern   
   Observatory's Very Large Telescope (VLT) in red, green and blue, and infrared   
   emission from the NASA's Spitzer Space Telescope in red and orange.   
       
   [...]   
   Image released Jan. 10.   
   By Charles Q. Choi   
       
   AUSTIN, Texas - The largest cluster of galaxies seen yet in the early   
   universe, a giant that astronomers have dubbed "El Gordo," could one day   
   reveal secrets about the invisible dark matter that fills the universe,   
   researchers said.   
       
   El Gordo - which means "the fat one" in Spanish - is officially known as   
   ACT-CL J0102-4915 and "is located more than 7 billion light-years from Earth,   
   at a time when the universe was half its current age," study co-author John   
   Patrick Hughes at Rutgers University told Space.com. The universe is about   
   13.7 billion years old.   
       
   The monster galaxy cluster has mass about 2 quadrillion (that's 2 followed by   
   15 zeroes) times that of the sun, making it "the most massive known cluster in   
   the distant universe."   
       
   A galaxy cluster behemoth   
       
   Galaxy clusters form through mergers of smaller groups of galaxies. These   
   events depend on the amount of dark matter and dark energy in the universe,   
   and thus could shed light on these enigmas.   
       
   Dark energy seems to make up 73 percent of all the mass and energy in the   
   universe, and is driving the accelerating expansion of the universe. Unseen   
   and as-yet-unidentified dark matter makes up about 23 percent of all the   
   matter and energy in the universe - scientists know it exists because of the   
   gravitational effects it has on galaxies. The regular matter that makes up   
   humans, planets and stars constitutes only 4 percent of the universe.   
       
   El Gordo was discovered using NASA's Chandra X-ray Observatory in space and   
   the Atacama Cosmology Telescope in Chile. Its Spanish nickname is a nod to the   
   Chilean connection.   
       
   The scientists detailed their findings Tuesday at the annual meeting of the   
   American Astronomical Society here during a presentation that included a   
   separate announcement of the discovery of the most distant galaxy cluster ever   
   seen in the early universe.   
       
       
   Regards,   
       
   Roger   
      
   --- D'Bridge 3.72   
    * Origin: NCS BBS (1:3828/7)