Why Is It Surprising That Spiral Arms Are Stable Structures

question 6

Multiple Choice

Why is it surprising that spiral arms are stable structures, lasting billions of years?

• A) Differential rotation should tear the arms apart.
• B) Gas and dust clouds should run out of material to make young stars.
• C) Supernova explosions should disrupt the arms.
• D) Globular clusters are continuously passing through the arms.
• E) Gravity should pull the arms down into the center of the galaxy.

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Definitions:

Compass Sense

An ability observed in some animals, allowing them to navigate using Earth's magnetic field.

Map Sense

An inherent ability to understand and navigate the spatial environment, often used in reference to animals or humans who can orient themselves without explicit landmarks.

Polygyny

A mating system in which one male mates with multiple females, often found in animal societies.

Intersexual Selection

A form of natural selection in which individuals of one sex (usually females) choose mates from the opposite sex based on certain desirable traits, affecting the fitness of individuals.