1. The Hubble classification has some important limitations. Summarize
the limitations caused by each of the following:
(a) orientation as seen from Earth for an elliptical
(b) orientation as seen from Earth for a spiral
(c) application to distant galaxies
(d) the visual, rather than quantitative (i.e., based
on measurement), nature of the system.
2. The most common galaxies in the Universe are thought to be dwarf galaxies. Yet these do not appear in the Hubble classification. Explain.
3. The notation Eq is given to an elliptical galaxy whose minor axis b and major axis a satisfy the equation: q = 10(1-b/a). What is the ratio b/a for the most flattened elliptical galaxy, an E7?
Last updated January 8, 2008