The phrase, another trip around the sun, refers to the time period of one year—the length of time it takes for the Earth to travel around our sun. The word trip means journey, which creates the idea that each of us makes a journey around the sun, each year. Therefore, the phrase is often used on a person’s birthday when a person has made “one more” or “another” trip around the sun:
Let us raise a toast to another trip around the sun!
The phrase was recently made popular as the title of a Jimmy Buffet song (2004) about his birthday, although it is unlikely he was the first person to use it this way. The phrase might also be used on anniversaries, New Year’s Eve, or other occasions celebrating “one more year” of life on planet Earth.