Posted on 02/18/2011 10:01:33 AM PST by LibWhacker
ESA’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 their are billions and billions of galaxies in the observable universe (as well as some seven trillion dwarf galaxies) . Here's the breakout of the visible universe within 14 billion light years:
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 realized this past year that they may have underestimated the number of galaxies in some parts of the universe by as much as 90 percent, according to a study reported by 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 a child.
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 could add powerfully to knowledge about the timeline by which stars and then galaxies formed.
If you look closely enough you can see Helen Thomas.
It’s one of the red ones.
7 trillion Dwarf galaxies ping
7 trillion dwarfs? Poor Snow White!
While probably quite informative, this picture is no where near as lovely as the one the Hubble took.
Kudos for finding an article that uses the expression ‘30 billion trillion’ that isn’t about the national debt.
So this is where all the unseen 'missing matter' is.
wow - amazing
Psalm 104:1-4
Can anyone over the age of 40 read that sentence without thinking of a certain scientist?
They are sea shells, washed up on the shores of infinity. What civilizations are out there? What strange empires? Or is it just some little green man sitting in his back yard and asking “Is there anyone out there?”
3x10²² is extremely puny compared to the probabilities needed for life or the laws of nature to turn out just right by itself.
You mean the one who had the Universe for a co-star on PBS?
Rhight! Every gram of real matter found is one less gram of “dark matter” required!
It’s hard to wrap my brain around those numbers - reminds me of the fisherman’s prayer: “O, God Thy Sea Is So Great And My Boat Is So Small.”
You made me laugh.
Thanks for that, it was needed.
And thats just the ones we can't see..
Its possible there are others "we" don't even know about..
I do indeed refer to Carl Sagan. He thus had the largest co-star in the history of television. (Although that's only because Michael Moore always worked alone.)
I do indeed refer to Carl Sagan. He thus had the largest co-star in the history of television. (Although that's only because Michael Moore always worked alone.)
Please add me to that list, too, thanks.
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