The Shell of a Planetary Nebula Is Measured by the Doppler

question 263

Multiple Choice

The shell of a planetary nebula is measured by the Doppler shift of emission lines to be expanding outward at a speed of 10⁴ m/s,while its radius is measured to be 1 ly,or about 10¹⁶ m.Roughly how long has the shell been expanding? (Hint: 1 year = 3.15 × 10⁷ sec.)

• A) 30 years
• B) 30,000 years
• C) 30 million years
• D) 10¹² years

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Definitions:

Female Defense Polygyny

A mating system where males guard multiple females to ensure exclusive mating access, often seen in animals with defendable, clustered females.

Resources

Natural or man-made assets that organisms utilize for survival, including food, water, territory, and mates.

Polygynandry/Promiscuity

A mating system in which both males and females have multiple mating partners over a breeding season, promoting genetic diversity.

Polyandry

A mating system in which a female has multiple male partners during a breeding season, often leading to increased genetic diversity among her offspring.