When Does "Star Wars: Episode IV - A New Hope" (1977) Take Place?
"Star Wars" (retroactively released as "Star Wars: Episode IV - A New Hope") is a science fiction film written by George Lucas and released May 25th, 1977.
It takes place on the fictional Star Wars timeline in the year:
We know this because ALL the Star Wars franchise stories are simply set “A long time ago in a galaxy far, far away…”. As stated on Wikipedia, the final scenes depict a space dogfight and "This battle has become known as the Battle of Yavin, and its date is used as a place-marker for events in the expanded Star Wars universe. Events before the Battle of Yavin are marked by BBY ("Before the Battle of Yavin"), and events that occur after are marked by ABY ("After the Battle of Yavin")."
There are also two more fictional calendars created for the Star Wars universe in the 2010s. By the CRC or Coruscant reckoning calendar, year 0 is 7977. It's explained on Wookieepedia. By the Lothal Calendar, year 0 is 3277 LY (for Lothal year). It's explained on Wookieepedia.
It takes place on the fictional Star Wars timeline in the year:
0 BBY/0 ABY or simply 0
We know this because ALL the Star Wars franchise stories are simply set “A long time ago in a galaxy far, far away…”. As stated on Wikipedia, the final scenes depict a space dogfight and "This battle has become known as the Battle of Yavin, and its date is used as a place-marker for events in the expanded Star Wars universe. Events before the Battle of Yavin are marked by BBY ("Before the Battle of Yavin"), and events that occur after are marked by ABY ("After the Battle of Yavin")."
This is the system most fans use as it was introduced first. It originates in a 1996 role-playing game. Wookieepedia includes an explanation entry.
There are also two more fictional calendars created for the Star Wars universe in the 2010s. By the CRC or Coruscant reckoning calendar, year 0 is 7977. It's explained on Wookieepedia. By the Lothal Calendar, year 0 is 3277 LY (for Lothal year). It's explained on Wookieepedia.
If you want to read a scientific attempt at making sense of an actual year on the Gregorian calendar when the Star Wars franchise takes place, there's an excellent article at Wired. Taking the "long time ago" part as gospel but recognizing the time it takes for any "galaxy far, far away" to form with stars and solar systems and planets with intelligent lifeforms. The author, Patrick Johnson, can only place it somewhere between 4.7 billion years ago to the more recent past something like 1,000 years ago.