"90% of Distant Galaxies in Universe Undetected" --(2012 Most Popular)
The European Space Agency’s Herschel space telescope has discovered that previously unseen distant galaxies are responsible for a cosmic fog of infrared radiation. The galaxies are some of the faintest and furthest objects seen by Herschel, and open a new window on the birth of stars in the early Universe. Astronomers estimate that there are billions and billions of galaxies in the observable universe (as well as some seven trillion dwarf galaxies). ESA astronomers say that for every ten far galaxies observed, a hundred go undetected.
Superclusters in the visible universe = 10 million
Galaxy groups in the visible universe = 25 billion
Large galaxies in the visible universe = 350 billion
Dwarf galaxies in the visible universe = 7 trillion
Stars in the visible universe = 30 billion trillion (3x10²²)
Astronomers realize that they may have underestimated the number of galaxies in some parts of the universe by as much as 90 percent, according to Matthew Hayes of the University of Geneva's Observatory, who led the investigation using the world's most advanced optical instrument -- Europe's Very Large Telescope (VLT) in Chile, which has four 8.2-meter (26.65-feet) behemoths. They turned two of the giants towards a well-studied area of deep space called the GOODS-South field.
In the case of very distant, old galaxies, the telltale light may not reach Earth as it is blocked by interstellar clouds of dust and gas -- and, as a result, these galaxies are missed by the map-makers.
"Astronomers always knew they were missing some fraction of the galaxies... but for the first time we now have a measurement. The number of missed galaxies is substantial," said Matthew Hayes of the University of Geneva's observatory, who led the investigation.
The team carried out two sets of observations in the same region, hunting for light emitted by galaxies born 10 billion years ago.The first looked for so-called Lyman-alpha light, the classic telltale used to compile cosmic maps, named after its U.S. discoverer, Theodore Lyman. Lyman-alpha is energy released by excited hydrogen atoms. The second observation used a special camera called HAWK-1 to look for a signature emitted at a different wavelength, also by glowing hydrogen, which is known as the hydrogen-alpha (or H-alpha) line.
The second sweep yielded a whole bagful of light sources that had not been spotted using the Lyman-alpha technique. They include some of the faintest galaxies ever found, forged at a time when the universe was just an infant.
The astronomers conclude that Lyman-alpha surveys may only spot just a tiny number of the total light emitted from far galaxies. Astonishingly, as many as 90 percent of such distant galaxies may go unseen in these exercises.
"If there are 10 galaxies seen, there could be a hundred there," said Hayes. The discovery adds powerfully to knowledge about the timeline by which stars and then galaxies formed.
The image at the top of the page shows the discovery of a previously unresolved population of galaxies in the GOODS fields and the first measurements of properties of galaxies in the almost unexplored far-infrared domain are among the first exciting scientific results achieved by Herschel's PACS and SPIRE instruments. These findings confirm the extraordinary capabilities of ESA's new infrared space observatory to investigate the formation and evolution of galaxies.
The Daily Galaxy via ESA
Image credit: GOODS-South field, ESA/PACS Consortium/PEP Key Programme Consortium
Comments
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So what does this do to the whole closed / open Universe thingy!
Posted by: Allan W Janssen | December 31, 2012 at 11:44 AM
Is this not exactly what Dr. Mamet of Canada discovered?
That molecular hydrogen cloaks galaxies? He predicted the discovery when advanced telescopes progressed enough to see the cool hydrogen.
Posted by: katesisco | January 01, 2013 at 06:07 AM
Quote: "The second sweep yielded a whole bagful of light sources that had not been spotted using the Lyman-alpha technique. They include some of the faintest galaxies ever found, forged at a time when the universe was just an infant".
- Which of course means that even older galaxies can and will be found as the telescope powers increases, constantly pushing the supposed age of the Universe further and further away from the Big Bang hypothesis, ending up in a hypothesis of an eternal motion of formation in the Universe.
Posted by: Ivar Nielsen | January 01, 2013 at 06:48 AM
"Infinite" is not a word well understood. It means, to go on forever.
Posted by: Kent B Douglas | January 01, 2013 at 09:29 AM
And when you do hit a barrier or some kind of change then . . it keeps going on for ever.
Posted by: Kent B Douglas | January 01, 2013 at 09:30 AM
So does this mean that the previously accepted 100 billion galaxies in the visible universe was off by a factor of 10 meaning 1 trillion galaxies? Each possibly holding up to a anywhere from 100 billion to 1 trillion stars? The possibilities for life are endless.
Posted by: Matthew | January 03, 2013 at 02:21 AM