I've been studying a bit of human history recently and as many of you have probably heard, the worldwide population count increased sharply in the last century or so. link
the world's population was between 250 million and 500 million throughout the entire medieval age (500 AD to 1500 AD), so i assumed 330 million people on average (which it was around 1000 AD). 330 million people for a thousand years makes 330 billion human-years.
In the time period since 1970, approximately 6 billion people lived on earth on average, so that makes 55 * 6 billion = 330 billion human-years.
so, roughly speaking, as many human-years happened since 1970 than in the entire medieval history.
that might do a part in explaining why technological and societal progress has been so fast in the last couple of decades.
i have that a lot. i guess it's because of un-conventional sentence structure, i.e. if you consider a field of interest for the first time, there's a lot of new vocabulary and typical-word-groups to consider, and your brain pauses for a moment to absorb that new kind of thinking. that's why we take a pause for a second. i have the same phenomenon when i read research articles about new topics i've never really read before.