Question

question 7
1 pts
what is the difference between an sbb galaxy and an sb galaxy?
the sbb galaxy has more tightly wound spiral arms than the sb galaxy.
the sbb galaxy is more elliptical than the sb galaxy.
the sbb galaxy has less tightly wound sprial arms than the sb galaxy.
the sbb galaxy has a bar of material passing though the center and the sb galaxy does not.
the sbb galaxy is an irregular galaxy but the sb galaxy is not.

Explanation:

In the Hubble sequence, spiral galaxies are categorized as "S" (ordinary spirals) or "SB" (barred spirals). The lowercase letter (e.g., b) indicates the tightness of spiral arms (b = moderately wound for both). The key difference is the presence of a central bar: SBb galaxies have a bar through their center, while Sb galaxies do not.

Answer:

The SBb galaxy has a bar of material passing though the center and the Sb galaxy does not.