A Planetary Nebula Has a Radius of 0

question 79

Multiple Choice

A planetary nebula has a radius of 0.5 pc and is expanding at 20 km/s. What is the approximate age of this planetary nebula? (1 pc is equal to 3*10¹³ km and 1 year is equal to 3.15*10⁷ seconds.)

• A) 240 years
• B) 790,000 years
• C) 96,000 years
• D) 960 years
• E) 24,000 years

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