Q&A: Cosmology

Q:
It is my understanding that Hubble Space Telescope measured the universe to be about 15 billion years old. In your opinion is this correct? This is difficult to comprehend since most globular clusters average about 18 billion years old.

A:
The question of the age of the universe has yet to be settled, in my opinion. We need to know more about whether the expansion is accelerating, among other things. For now, 15 billion is a good rough estimate, with values between 12 and 16 billion years still being plausible. The age of globular clusters is likewise uncertain; they could be anywhere from 12 to 18 billion years old. One thing for sure: if the age of the globular clusters turns out to be older than the universe, we know we have real problems with the theory.