Posted on 01/08/2007 5:03:49 PM PST by KevinDavis
SEATTLE - The discovery of several large, metal-poor stars located far from the center of the Andromeda galaxy suggests our nearest galactic neighbor might be up to five times larger than previously thought.
The newfound stars are massive, bloated stars known as red giants. Although found far beyond the most visible portion of Andromeda—its swirling disk—the stars are still gravitationally bound to the galaxy and make up part of its extended "halo."
"We're typically used to thinking of Andromeda as this tiny speck of light, but the actual size of the halo…extends to a very large radius and it actually fills a substantial portion of the night sky," said study team member Jason Kalirai of the University of California, Santa Cruz.
(Excerpt) Read more at space.com ...
bump
The view of the stars tonight from Commece, GA was fantastic.
Is this just another attempt to make Earth, the Milky Way, and humanity's placement in the universe not special (and yes, you could state that the same argument could be made by geocentrists)? Considering they have difficulty sizing up the Milky Way, they shouldn't be so quick to unilaterally state that Andromeda is the largest galaxy in the Local Group.
Well I have a feeling we are not alone....
The Great Debate Over the Size of the Universe
http://www.aip.org/history/cosmology/ideas/great-debate.htm
The so-called "Great Debate" before the National Academy of Sciences on 26 April 1920 is one of the more dramatic episodes in the history of astronomy... The debate has often been characterized as centering upon whether spiral nebulae were island universes. However, Harlow Shapley, from the Mount Wilson Observatory in Southern California, preferred to discuss his new and vastly larger estimate of the size of our galaxy. Shapley wrote to a colleague that he was coming to Washington to discuss the scale of the universe and that he did not intend to say much about spiral nebulae because he did not have a strong argument. In the debate, Shapley argued that "Recent studies of clusters and related subjects seem to me to leave no alternative to the belief that the galactic system is at least ten times greater in diameter - at least a thousand times greater in volume - than recently supposed."
The 'Great Debate': What Really Happened
by Michael A. Hoskin, Editor, Journal for the History of Astronomy
http://antwrp.gsfc.nasa.gov/diamond_jubilee/1920/cs_real.html
From evidence to be referred to more fully later, Dr. Shapley has derived very great distances for the globular star clusters, 220,000 light-years for the most remote. The apparent distribution of these globular clusters shows incontrovertibly that they are an integral feature of our galactic system. This evidence has formed the main reason for Dr. Shapley's adoption of a diameter of 300,000 light-years for our galactic system, fully ten times greater than that accepted hitherto.
Our Solar System's Location in the Milky Way Galaxy
http://www.enchantedlearning.com/subjects/astronomy/solarsystem/where.shtml
The sun is about 26,000 light-years from the center of the Milky Way Galaxy, which is about 80,000 to 120,000 light-years across (and less than 7,000 light-years thick).
Nice graphic! ;')
It strikes me as another nail in the coffin of supposed cosmological constant studies. We don't know what is out there, so we should 't be playing number games to try to make it fit into our models of the universe. Our time is much better spent trying to see what is than trying to figure out what isn't.
I think you misunderstood the article, which is not referring to the visible portion of M31.
"Using the Mayall Telescope at Kitt Peak and the DEIMOS spectrograph on the the Keck II Telescope in Hawaii, the researchers found previously unseen red giant stars out to a distance of at least 500,000 light years from Andromeda's center.
The researchers picked out Andromeda's faint halo stars using a technique developed by Karoline Gilbert, a UCSC graduate student, which distinguishes the halo stars from the more numerous foreground stars in our Milky Way."
Then I don't get the implication you see for the cosmological constant.
It's an attempt to see what is.
I find this wasteful. Instead of guessing at why the numbers don't work, I think we should be using our resources to find out why the numbers don't work. How much mass is missing? (I used to know.) How can we be missing (failing to observe) it? How can we discover it? Or is there a problem with the theory and we haven't yet realized it?
When we go back to forcing our data to fit our model with cosmic constants and such, the data are speaking and we're not listening. Or, as a famous smartass once wrote, "When the facts do not fit the theory, they must be disposed of."
Great, another thousand light years of "Are we there yet?"
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