Number 11 on our countdown is SPICA, the brightest star in the constellation Virgo, the virgin. How can you find Spica? There is a popular phrase associated with the Big Dipper: “Follow the arc to Arcturus and speed on to Spica.” That is, find the Big Dipper’s handle, which is shaped like an arc. Follow the curve of the handle. The first bright star it points to is Arcturus (we will meet Arcturus later in the countdown). Continuing past Arcturus, the curve of the Big Dipper’s handle points to Spica.
You may have noticed that four of the first six stars on our countdown are found in constellations associated with the traditional Zodiac. The constellations of the Zodiac have a specific significance in astronomy because they are the constellations through which the paths of the planets, the moon, and the sun appear to travel.
Spica, in the constellation Virgo, is a great example of this right now because the planet Mars is currently passing through it. Look to the southeast an hour or so after sunset, and you will see the red planet just above and to the right of a bright star. That bright star is Spica. Mars and Spica will be in fine view all spring. Over the weeks and months, notice how Mars moves closer and farther away from Spica. The puzzle of Mars’s motion in the sky eventually led to the discovery that planets travel in ellipses around the sun.
Next: Bull’s Eye