Playing around with Google's Ngram viewer, where you can see how many times a word is used in books, I stumbled on this:
It shows how often universe and Universe have been used in books.
I think it's somewhat interesting that around 1630 the use of these terms took off, and at 1750 there was a switch.
Anyone hazard any guesses to what happened around those years that caused the trends?
EDIT: It looks like the 1750 capitalization issue is more about the search data because the same phenomenon occurs for lots of terms. So maybe just what inspired the use of the word to take off around 1630.