June 27, is the birthday of a song that is the biggest hit of all time — it is sung somewhere on Earth every day and was the first song to be performed in outer space. What else, but “Happy Birthday to You”? The melody dates back to this date in 1859, when it was composed by school teacher Mildred Hill of Louisville, Kentucky. The original lyrics were “Good Morning Dear Teacher, Good Morning to You.” With its more familiar lyrics, it was published in 1935 and immediately became an enduring hit. This year, some 4 million babies will hear it for the first time, sung by their off-key relatives around a cake with one candle. Girls born this year can expect to hear the familiar song 81 times and boys 75 times.