Today, 23 February 2015, three of the four Galilean moons go through their perijoves. The perijove is the closest radial distance the moon will be from Jupiter in it's current orbit. This is the first triple perijove I've noticed since I started reporting apojoves and perijoves on 'Jupiter Today'.
The thing that I noticed pretty much right away is that the apojove of Io is pretty close to being on exactly the opposite side of Jupiter than the perijove of Europa. Same for the perijove and apojove and Io and Europa, respectively. They aren't exactly opposite, however, and I want to look a little more closely at what those positions are at those particular times and locations in their orbits around Jupiter.
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| Figure 1: The positions of the four Galilean moons on 2/23/2015 |
In Figure 1, you see the orbits of the four Galilean moons over the next 24 hours. The dots on each line represent six hour time intervals. As you can see, the perijoves of Io and Europa (the two colored squares) are on opposite sides of Jupiter.
It's very likely that within the next week or two that I'll be making some Orbital Crystals (or Orbital Ribbons) showing the locations of the perijoves over a period of time. Probably several years' worth of orbits so I can include Callisto with enough orbital information. I'm very curious to see what the patterns of the apojoves and perijoves will look like.
