We all know that our solar system has eight planets. They revolve around the sun at different speeds in their respective orbits. The five planets closest to us are named in Chinese after the five elements, called Wu Xing (五行): Mercury is for Water, Venus is for Metal, Mars is for Fire, Jupiter is for Wood, and Saturn is for Earth. Some people might ask when these five planets will align within 30 degrees in the sky, which is equivalent to the angular width of one sign of the zodiac, known as a "planetary alignment." Ancient people considered a planetary alignment a very auspicious omen, and some dynasties experienced such alignments during their rise to power. If the moon and the sun were also within this 30-degree range at the same time, it was called "Sun-Moon in conjunction, seven luminaries in one sign."