View Full Version : Spirals, Tides, and M51

2009-Dec-11, 07:40 PM
Spiral galaxies are undoubtedly one of the most beautiful structures in the universe. Yet, their simple elegance belies a complex nature. How do such structures not "wind up" and what causes them in the first place? The answers to these questions is a long standing challenge. Under one model, spiral structure is created by spiral [...]

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