An Epic Approach to Jupiter, as seen by Juno
When the Juno mission arrived at Jupiter on July 4th, 2016 and executed a tricky orbital insertion maneuver around the giant planet, it was as epic an achievement as any legendary god or hero or heroine of ancient times could hope for. The science team celebrated with a short video that showed a time-lapse of Jupiter’s moons in orbit around the planet as the spacecraft approached. It’s a three-minute-long timelapse covering a 17-hour period a few days before arrival at Jupiter. As I watched, it really felt like I was on the bridge of a spacecraft approaching the planet. But, listening to the video was a much more visceral experience because of the music and the history it evokes.
Jupiter Orbital Insertion: Historical Roots
The music bed on this video is by Vangelis, created for the movie Alexander. The piece is called “Titans”, named for the divine beings who eventually gave birth to the gods Zeus, Hades, Poseidon, Hera, Hestia, and Demeter. In the Greek tradition, Zeus was the mightiest of the gods, and as the great leader Alexander the Great knitted together his 4th century (BCE) empire, Zeus went along for the ride to confer kingship and greatness. In later traditions, the Romans (who were once part of Alexander’s vast empire), renamed Zeus as “Jupiter” and eventually that name was assigned to the mightiest planet in the solar system.
Alexander the Great spread Hellenistic art and culture across much of the known world in his day as he conquered country after country — from India through the Middle East to Africa and parts of Western Europe. Due to his rule, the influences of the Greeks, along with other cultures he eventually assimilated into his empire, are still seen today in the names we use for the stars and planets. Good examples are Betelgeuse (from the Arabic) for the bright star in Orion’s shoulder and, of course, Jupiter (the romanized Zeus) for the planet.
As I listened to the music in the video and watched the approach to Jupiter as captured by the JunoCam, it simply felt right to combine the two. Exploration was at the core of Alexander’s “mission” all those centuries ago, and now the exploration of a world named in the tradition of a great deity inspired by Greek mythology carries on that tradition of seeing “what’s out there.”
Give the video a watch a few times — with and without the music. It begins with the view that Alexander, Galileo, you and I can see of Jupiter in the night sky. And then… it changes to something only a spacefaring civilization would recognize: the view you would see if you were about to achieve standard orbit around a distant world.
Juno’s journey is, as I said above, as epic as anything the heroes and heroines of old achieved in antiquity. And, as you watch the Jovian moons orbit — from innermost volcanic Io and ice-crusted ocean world Europa to massive Ganymede heavily cratered Callisto — think about this: those motions are what Galileo first glimpsed from his hillside in Padua, Italy in 1610. He watched as they changed position around Jupiter in just a few nights, and that opened his eyes to something no one had quite realized before: that the universe is in motion. It’s not moving around Earth — instead, it moves in a self-consistent way that puts planets around stars, stars circling in galaxies, and galaxies orbiting in fantastic dances within their clusters. His was a small observation, but it forever changed our understanding of our place in the cosmos. Earth was not the center of the universe.
Juno Changes our View Again
Juno shows us what Galileo saw, if imperfectly at first. As scientist Scott Bolton pointed out to us right after Juno achieved its orbital insertion, watching these worlds orbit Jupiter illustrates the motion of nature’s harmony. Appreciating that harmony is a huge part of “doing” science, and if it stirs up some feelings of awe and wonder along with some inspiring music — well, it’s all part of the deal we make when we study the cosmos.