Multiple Choice
The Ring Nebula (image below) is a planetary nebula that currently has a radius of 0.4 pc and an expansion velocity of 250 km/s.Approximately how long ago did its parent star die and eject its outer layers? 
A) 1,600 years ago
B) 3,200 years ago
C) 5,400 years ago
D) 28,000 years ago
Correct Answer:
Verified
Correct Answer:
Verified
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