Wednesday, October 31, 2012

Answer to Question 114

A114: Our Milky Way galaxy is a 'Barred Spiral', type SBc. 

Edwin Hubble classified these types of spiral galaxies as "SB" ("Spiral", "Barred") in his Hubble sequence, and arranged them into three sub-categories based on how open the arms of the spiral are. 

SBa types feature tightly bound arms. 
SBc types are at the other extreme and have loosely bound arms. 
SBb type galaxies lie in between. 
SBm, was subsequently created to describe somewhat irregular barred spirals, such as the Magellanic Cloud galaxies, which were once classified as irregular galaxies, but have since been found to contain barred spiral structures.

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