Coming off their home win over the Panthers, the Vikings flew to LP Field for a Week 4 interconference duel with the Tennessee Titans. In the first quarter, Minnesota trailed early as Titans kicker Rob Bironas got a 20-yard field goal, while RB Chris Johnson got a 1-yard TD run. In the second quarter, the Vikes responded with RB Adrian Peterson getting a 28-yard TD run. However, Tennessee responded with Bironas kicking a 32-yard field goal, along with RB LenDale White getting a 1-yard TD run. The Vikings closed out the half with kicker Ryan Longwell getting a 42-yard field goal. In the third quarter, the Titans increased their lead with Bironas nailing a 49-yard field goal. In the fourth quarter, Minnesota tried to rally as Peterson got a 3-yard TD run, but Tennessee pulled away with Johnson's 6-yard TD run.

Based on the above article, answer a question. How long was the shortest field goal?
20-yard