Jupiter Today | 13 August 2015 | Callisto Transits, etc.

Hello!  Has anyone who reads this blog ever thought about how incredibly bizarre the situation we find ourselves in?  In so many ways, it's the most confounding set of circumstances I can possibly imagine.  This perspective feeds my unrelenting curiosity and motivates me to continue trying to make sense of what I'm experiencing.  On top of that, I'm not a casual observer of these phenomena.  Rather, I'm a participant and (ultimately) the creator of these phenomena.  Looking at it one way, we're all standing on this ball of matter flying through space at tens of thousands miles per hour (relative to certain things).  Can you feel the wind in your hair?  As I point out here every day with the numbers, we are currently decelerating towards Jupiter as we approach 'Superior Conjunction'.  And more than that, our deceleration is INCREASING every day.  According to the famous equation F=ma, a mass will feel a force if it's accelerated.  Ok -- so we are decelerating (negative acceleration) towards Jupiter.  What force does that impart?  Am I feeling this force and not being aware of it?  Plus, this is not a gravitational force (the force described by general relativity)!  This is force caused by an acceleration relative to the two bodies under consideration (in this case, Jupiter and Earth).  I don't think I can feel it and therefore I can't describe it or even know how to measure it.  It is, after all, just the relative motion between Jupiter and Earth and they orbit the Sun.  But just as we "feel" an acceleration towards the Sun, we'll also feel an acceleration towards all other bodies.  Does this connect us in a tangible way to everything in the universe?  Perhaps so.

JUPITER TODAY is a daily blog about the dynamic Jupiter system for the purpose of monitoring activity.

We start with the overall view of activity with the Jupiter system, showing the orbits of the four Galilean moons:

This is a view of the Jupiter system looking down on it.  Following the blue line to the left is the line of sight to Earth, while following the gray line to the left is the line of sight to the Sun.  The orbits of the four Galilean moons are shown.  The large dots indicate the position of each moon at 0h, 6h, 12h, 18h, and 24h (0h the next day) UTC for this date.  From this point of view, the moons revolve around Jupiter in a counter-clockwise motion.  For more information about this graphic, see the post from 30 July 2015.

At 0h UTC, Io begins the day in quad 4 moving east soon to pass behind Jupiter.  Europa is behind Io and also in quad 4 starting to move behind Jupiter.  Ganymede is in quad 1 moving east very near eastern elongation and will be moving into quad 2.  Callisto is finally moving out of quad 2 and into quad 3 heading west and transiting Jupiter.

By 6h UTC, Io and Europa have successfully moved behind Jupiter and are now in quad 1 moving east.  Ganymede will be in quad 2 moving west the rest of the day.

At 12h UTC, Io is near eastern elongation and moving into quad 2 heading west.  Europa is now firmly in quad 1 moving east.

At 18h UTC, Io is now firmly in quad 2 heading west.

By 0h UTC, Io is transiting Jupiter and moving into quad 3.  Europa is at eastern elongation and moving into quad 2 heading west.  Ganymede and Callisto continue in quads 2 and 3, respectively.

At 02:53 UTC, Io goes through a perijove at a distance of 420,040.1 km.  At 02:57 UTC, Europa goes through its apojove this orbit at a distance of 677,652.8 km.  At 23:54 UTC, Io goes through its apojove at a distance of 423,495.3 km.

At 0h UTC, Jupiter's RA is 10h 10m 02.8s and DEC is +12d 14m 13.9s.  The phase angle is 1.949 degrees, which is 0.137 degrees less than yesterday.  The angular distance between Jupiter and the Sun is 10.411 degrees, which is 0.742 degrees less than yesterday.  The distance between Jupiter and the Sun is 805,541,145 km, which is 37,192 km further apart than yesterday.  This gives a relative velocity of 1,549.667 km/h, which is 3.5 km/h slower than yesterday.  Wobble, Wobble, Wobble.  The distance between Jupiter and Earth is 954,168,373 km, which is 447,939 km further apart than yesterday.  This gives a relative velocity of 18,664.125 km/h, which is 1,272.166 km/h slower than yesterday.  Bump, Bump, Bump.

From 01:11 to 05:48 UTC, Callisto transits Jupiter.  At 01:18 UTC, Europa moves behind Jupiter.  At 01:39 UTC, Io moves behind Jupiter.  From 03:25 to 07:48 UTC, Callisto's shadow transits Jupiter.  At 04:09, Io reappears from Jupiter's shadow (it has passed Europa behind Jupiter!).  At 04:41 UTC, Europa appears from behind Jupiter.  From 22:53 to 01:12 UTC tomorrow, Io transits Jupiter.  From 23:06 to 01:25 UTC tomorrow, Io's shadow transits Jupiter.

No satellite mutual events today.  Too hard to see anyhow.

The Glorious Orbital Ribbons for today:

Jupiter is so near Superior Conjunction (taking place at 22:00 UTC on 26 August 2015) that photography and other data collection isn't practical.  We'll have to wait about a months after SC to start viewing the Jupiter system again.

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Please send me your feedback, comments, and questions to jupitertoday AT gmail DOT com or the comments section of this blog.

With my gratitude, the data used to create the orbit plots and ribbons was supplied by the JPL Horizons website.  The graphics showing the location of the four moons as seen from Earth are via 'Jupiter Viewer 2.8'.  Jupiter-Satellite and Satellite mutual events data is supplied from IMCEE.

Until tomorrow, I bid you Peace.