The goal line is marked inbounds, but extends beyond the in bounds line. The pylon is the point at which the goal line is out of bounds. It is used by the sideline officials (usually deep wings: FG & SG) to determine when a touchdown is scored or not on plays that are at made at one of the four corners of the endzone.
In the NFL, the ball has to be inside the pylon when running into the endzone to be considered a touchdown.
In the NCAA starting this year (2012), and part of the player can touch the pylon and as long as the ball is inside the goal line extended (extending into the out of bounds area), to be considered a touchdown.
In high school, the ball has to cross the goal line extended to be considered a touchdown.
According to referee Ed Hochuli who is quoted in the article that you can read at the 'Touchdown or No Touchdown' link below, a player who crosses out of bounds is awarded a touchdown if a part of his body touches in the end zone, or the pylon, after the ball crosses the 'imaginary' goal line outside the pylons. I interpret the question to ask if a player lands completely out of bounds but the ball crosses the 'imaginary' goal line outside the pylon, is it a touchdown? The way I understand what I read, the answer is no since no part of the player touched inbounds. Click on the 'Touchdown or No Touchdown' link to read the article and weigh in with your opinions. If I'm understanding your question right, you're asking about the hypothetical goal line that "travels around the world" indefinitely out of bounds. The NFL just changed this rule for the 2008 season, so that the extended goal line no longer exists. The player must now break the plane of the goal line within the field of play, or press the ball against the corner pylon, for the touchdown to count.
The NFL set precedence on December 14, 2008 on what a touchdown reception is. Typically, it is when any part of the ball, legally in possession of a player inbounds, breaks the plane of the opponent's goal line, provided it is not a touchback or when the ball is touched on the pylon before a player goes out of bounds. Apparently, now, it is when the players feet are both in the end zone and the ball is in their possession, but does not break the plane of the opponent's goal line. According to a Google search, the rule regarding pylon touchdown dives was revisited and clarified. Previously, a player just had to have some portion of his body over the goal line or pylon to count a touchdown, but the rule was revised for 2007 to make it necessary to have the ball touch the pylon or break the plane above the pylon to count as a touchdown.
No, the ball does not have to cross the goal line in the FOP to score a touchdown. The GL extends outside of the pylons and in theory, go around the world. If the ball breaks the plane of the GL extended, it is necessary in the NFL to have any part of the ball carrier's body cross over the pylon or inside the pylon, even though the ball crosses outside of the pylon.
The NFL moved the goal posts from the goal line to the end line for the 1974 season.
You cannot catch a punt while out of bounds in the NFL.
It is not known how far exactly NFL kickers stand from the line of scrimmage when attempting a field goal. Most NFL kickers average a field goal range of 35 yards.