If every part of the universe has aged differently owing to time running differently for each part, why do we say the universe is 13.8 billion years old?

Question

For some parts relative to us, only a billion years would have passed, for others maybe 20?

In: Physics

Answer 1

Yes very true. We just say that because on average, it is that old but truly, different sections would be different years old. Section 7A56IP- in the universe would be way younger than our section.