by neufer » Thu Aug 13, 2009 9:40 pm
http://en.wikipedia.org/wiki/Irregular_galaxy wrote:
<<Some galaxies do not have a regular shape, like a spiral or an elliptical galaxy. Those galaxies are known as irregular galaxies. Their shape is uncommon. They do not fall into any of the regular classes of the Hubble sequence, and they are often chaotic in appearance, with neither a nuclear bulge nor any trace of spiral arm structure. Collectively they are thought to make up about a quarter of all galaxies. Most irregular galaxies were once spiral or elliptical galaxies but were deformed by gravitational action. Irregular galaxies also contain abundant amounts of gas and dust.
There are two major Hubble types of irregular galaxies:
* An Irr-I galaxy (Irr I) is an irregular galaxy that features some structure but not enough to place it cleanly into the Hubble sequence. de Vaucouleurs subtypes this into galaxies that have some spiral structure Sm, and those that do not Im.
* An Irr-II galaxy (Irr II) is an irregular galaxy that does not appear to feature any structure that can place it into the Hubble sequence.
A third classification of irregular galaxies are the dwarf irregulars, labelled as dI or dIrrs. This type of galaxy is now thought to be important to understand the overall evolution of galaxies, as they tend to have a low level of metallicity and relatively high levels of gas, and are thought to be similar to the earliest galaxies that populated the Universe. They may represent a local (and therefore more recent) version of the faint blue galaxies known to exist in deep field galaxy surveys.
Some of the irregular galaxies are small spiral galaxies that are being distorted by the gravity of a larger neighbor.
The Magellanic Cloud galaxies were once classified as irregular galaxies, but have since been found to contain barred spiral structures, and have been since re-classified as "
SBm", a fourth type of barred spiral galaxy,
the barred Magellanic spiral type.>>
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http://en.wikipedia.org/wiki/Baker_Street_Irregulars wrote:
<<The original Baker Street irregulars were a group of fictional characters featured in the Sherlock Holmes stories. They were a group of street urchins who helped Holmes out from time to time. The head of the group was called Wiggins. Holmes paid them a shilling a day (plus expenses), with a guinea prize (worth one pound and one shilling) for a vital clue. They first appeared in Conan Doyle's original Sherlock Holmes story, A Study In Scarlet (1886).
The modern organization
The Baker Street Irregulars is also the name of an organization of Sherlock Holmes enthusiasts founded in 1934 by Christopher Morley. Members have included John Stevens Berry, Rex Stout, Banesh Hoffmann, U.S. presidents Franklin Delano Roosevelt and Harry S Truman, actors Douglas Wilmer and Curtis Armstrong and the science fiction and fantasy writers Poul Anderson, Fletcher Pratt, Isaac Asimov and Neil Gaiman. They continue to convene every January in New York City for an annual dinner, which forms part of a weekend of celebration and study involving other Sherlockian groups and individuals as well.>>
[quote=" http://en.wikipedia.org/wiki/Irregular_galaxy"]
<<Some galaxies do not have a regular shape, like a spiral or an elliptical galaxy. Those galaxies are known as irregular galaxies. Their shape is uncommon. They do not fall into any of the regular classes of the Hubble sequence, and they are often chaotic in appearance, with neither a nuclear bulge nor any trace of spiral arm structure. Collectively they are thought to make up about a quarter of all galaxies. Most irregular galaxies were once spiral or elliptical galaxies but were deformed by gravitational action. Irregular galaxies also contain abundant amounts of gas and dust.
There are two major Hubble types of irregular galaxies:
* An Irr-I galaxy (Irr I) is an irregular galaxy that features some structure but not enough to place it cleanly into the Hubble sequence. de Vaucouleurs subtypes this into galaxies that have some spiral structure Sm, and those that do not Im.
* An Irr-II galaxy (Irr II) is an irregular galaxy that does not appear to feature any structure that can place it into the Hubble sequence.
A third classification of irregular galaxies are the dwarf irregulars, labelled as dI or dIrrs. This type of galaxy is now thought to be important to understand the overall evolution of galaxies, as they tend to have a low level of metallicity and relatively high levels of gas, and are thought to be similar to the earliest galaxies that populated the Universe. They may represent a local (and therefore more recent) version of the faint blue galaxies known to exist in deep field galaxy surveys.
Some of the irregular galaxies are small spiral galaxies that are being distorted by the gravity of a larger neighbor.
The Magellanic Cloud galaxies were once classified as irregular galaxies, but have since been found to contain barred spiral structures, and have been since re-classified as "[b]SBm[/b]", a fourth type of barred spiral galaxy, [b]the barred Magellanic spiral type[/b].>>[/quote]
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[quote=" http://en.wikipedia.org/wiki/Baker_Street_Irregulars"]
<<The original Baker Street irregulars were a group of fictional characters featured in the Sherlock Holmes stories. They were a group of street urchins who helped Holmes out from time to time. The head of the group was called Wiggins. Holmes paid them a shilling a day (plus expenses), with a guinea prize (worth one pound and one shilling) for a vital clue. They first appeared in Conan Doyle's original Sherlock Holmes story, A Study In Scarlet (1886).
The modern organization
The Baker Street Irregulars is also the name of an organization of Sherlock Holmes enthusiasts founded in 1934 by Christopher Morley. Members have included John Stevens Berry, Rex Stout, Banesh Hoffmann, U.S. presidents Franklin Delano Roosevelt and Harry S Truman, actors Douglas Wilmer and Curtis Armstrong and the science fiction and fantasy writers Poul Anderson, Fletcher Pratt, Isaac Asimov and Neil Gaiman. They continue to convene every January in New York City for an annual dinner, which forms part of a weekend of celebration and study involving other Sherlockian groups and individuals as well.>>[/quote]