What visual feature defines the descriptive power of 'globular' when viewing the cluster's light profile?

Answer

The concentration of light creating a visual gradient from a bright core to a diffuse edge.

The visual gradient, where the light is most concentrated and bright toward the center and gradually fades outward, is a defining feature that visually supports the globular description.

What visual feature defines the descriptive power of 'globular' when viewing the cluster's light profile?
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