Our first instance of determining when or where the Star Wars universe is was during the opening shot of Episode IV. We’re told that this takes place in “A long time ago, in a galaxy far, far away…” Since the Big Bang started approximately 13.7 billion years ago, that’s a wide timeframe to figure out when exactly a “long time ago” is. A physicist is trying to figure that out.
Dr. Patrick Johnson wrote The Physics of Star Wars, and he tries to use science to explain the things that happen in the Star Wars universe.
In terms of the timeframe, it’s assumed that the Star Wars universe is in the same universe. Dr. Johnson uses clues such as full planets and intelligent life in order to narrow down the timeframe.
Without getting into the total nuances of science, which you can see in the excerpt, that the timeframe is that the movies took place less than 4.7 billion years ago. So while it’s still a wide timeframe, at least Dr. Johnson was able to cut about nine billion years off of that.
The location of the Star Wars universe is even more difficult and complicated to figure out but the entire excerpt and the book seems fascinating. While it can never be really proven and this isn’t a part of Star Wars canon, it’s interesting to look at possibly when this all occurred.