Did humans, at some point, believe that the universe is 18 billion years old, prior to the 13.8 billion estimate?
When I was a kid (or perhaps a teenager), I distinctly remember at one point believing the universe was around 18 billion years old, but I can’t remember where my memory would’ve gotten that estimate prior to more modern estimates.
Before 1999, astronomers had estimated that the age of the universe was between 7 and 20 billion years. But with advances in technology and the development of new techniques we now know the age of the universe is 13.7 billion years, with an uncertainty of only 200 million years. How did this come to be?