In your article, you state: "Civil twilight starts at sunset and ends roughly 45 minutes later, when the sun’s center has plunged six degrees below the horizon." However, the earth turns one degree every four minutes. Therefore, the earth will turn six degrees (or the end of civil twilight) in 24 minutes, not approximately 45 minutes as the article states.
In your article, you state: "Civil twilight starts at sunset and ends roughly 45 minutes later, when the sun’s center has plunged six degrees below the horizon." However, the earth turns one degree every four minutes. Therefore, the earth will turn six degrees (or the end of civil twilight) in 24 minutes, not approximately 45 minutes as the article states.