天の川 literally means “river in heaven” or “heaven’s river” in Japanese, and refers to what we understand as the “Milky Way” in English.
Ancient Japanese people viewed the Milky Way as a river in heaven and thought that heaven was a whole empire of gods and goddesses, much like the Greeks did with their mythology. One well known myth related 天の川 is the story of Hikoboshi, a cow herder, and Orihime, the goddess of weaving, who fell instantly in love with each other and never wanted to be separated.
However, the more they fell in love, the worse life for humans became because the two began to neglect their duties. The emperor of gods became angry and separated them by a heavenly river, the 天の川. After seeing how sad the two were afterwards though, the emperor felt sorry for the couple and created a beautiful bridge across the Milky Way so they could meet once a year on July 7th. We call this day 七夕 (Evening of the Seventh) and have festivals to celebrate it each year! And in the night sky, Orihime is represented by the star Vega, and Hikoboshi is represented by the star Altair.
We also have another word for “galaxy”, 銀河, which translates to “silver river.” You may wonder why this word uses the 河 character instead of 川 to mean “river” - it’s because 河 usually refers to bigger and deeper rivers than the standard 川 kanji character.
Do you know the myth about the Milky Way?
Look! The Milky Way is so clear!