According to the main sequence turn-off points of the oldest globular clusters, they areabout:
A)4.5 billion years old.
B)6.8 billion years old.
C)10 billion years old.
D)12 billion years old.
E)16 billion years old.

Question

Quizplus · Accepted Answer

The main sequence turn-off point of the oldest globular clusters indicates an age of around 12 billion years. This method of dating is based on the time it takes for stars to evolve and leave the main sequence on the Hertzsprung-Russell diagram. Therefore, choice D, 12 billion years old, is the best answer. The main sequence turn-off point of the oldest globular clusters corresponds to the end of the hydrogen-burning phase in the stars that are just completing it. Measurements of the main sequence turn-off points suggest that the oldest globular clusters have ages of around 12 billion years.

According to the Main Sequence Turn-Off Points of the Oldest