At NASA, scientists were looking at the sky on Independence Day for other reasons than fireworks. On the 4th of July, their Juno spacecraft finally entered Jupiter’s orbit, after having traveled for more than 5 years. But before being brought into orbit, Juno’s JunoCam ha captured a unique time-lapse movie of the Galilean “satellites” (moons) in motion about Jupiter.
Recordings for the movie begin on June 12th, with Juno being 10 million miles away from Jupiter, and ends on June 29th, at a distance of 3 million miles. The result is the same sight that made Galileo Galilei realize that the Earth was not the center of the Universe.
The innermost moon is volcanic and bares the name “Io.” Next in line is the ice-crusted ocean world Europa, followed by massive Ganymede, and finally, heavily cratered Callisto. Like Galileo observed, we see the moons change position with respect to Jupiter over the course of a few nights. This early 17th century observation forever changed humanity’s understanding of our place in the cosmos.
NASA calls its time-lapse “the motion of nature’s harmony.” For the first time in history, we can all “share in Galileo’s revelation.”