What integer range did Edwin Hubble initially use to classify elliptical shapes?
Answer
E0 to E7
Edwin Hubble developed an initial morphological classification system that categorized elliptical galaxies based purely on their apparent shape, specifically using an integer designation ranging from E0 to E7. The designation E0 signifies a galaxy that appears nearly perfectly spherical, while E7 denotes a galaxy that is the most elongated or oval in appearance. This classification was determined by measuring the ratio between the major and minor axes of the galaxy's visible profile. However, subsequent analysis revealed complications, as apparent elongation is dependent on the viewing angle, and some highly elongated forms might actually be lenticular galaxies viewed edge-on.
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