Jupiter Today | 18 December 2015 | Velocity Audio

Let's start with the sound of the relative velocities:

Velocity Audio | 18 December 2015

Here are the positions of the four Galilean moons of Jupiter as they orbit the planet over the next 24 hours.  This view is looking down on the system, and the moons are moving counterclockwise.  The blue line pointing towards the left is the line of site to Earth.  The red line pointing left is the line of site to the sun.

Here are the relative velocities between the four moons (six combinations):

The y-axis shows the velocity in kilometers per minute.  Negative values represent moons moving towards one another, positive values represent moons moving away from one another.  So for example, the blue line representing the relative velocity between Ganymede and Callisto shows that they are moving toward one another at a pretty constant velocity of 300-ish km/min.  Looking at the orbit plot above, you can see that Ganymede is "catching up" to Callisto just as the velocity plot shows.

Line color code:

• Cyan - Io / Europa
• Pink - Io / Ganymede
• Yellow - Io / Callisto
• Green - Europa / Ganymede
• Red - Europa / Callisto
• Blue - Ganymede / Callisto

Jupiter Today | 17 December 2015 | Velocity Audio

Here are the positions of the four Galilean moons of Jupiter over the next 24 hours:

This is a plot showing the relative velocities between the four moons:

Notice that at about 21:00 UTC, all but Io's motion relative to Ganymede is very nearly the same -- in this case, moving toward one another at about 200 km/minute.

Line color code:

• Cyan - Io / Europa
• Pink - Io / Ganymede
• Yellow - Io / Callisto
• Green - Europa / Ganymede
• Red - Europa / Callisto
• Blue - Ganymede / Callisto

And for fun and because these are usually so pretty, the orbital ribbons for today:

And finally, the sound of those velocities:

Velocity Audio | Jupiter Today 17 December 2015

The Sound of Velocity | Jupiter Today 11 December 2015

So instead of listening to the distances between the four Galilean moons of Jupiter, today I'm listening to the changes in distance -- otherwise known as velocity.

This first plot shows the orbits of the four moons as seen from above.  Rotation around Jupiter (which would be in the center) is counter-clockwise:

The blue line going left points to Earth.  The red line going left points to the Sun.

This next plot shows the changes in distance (velocity).  The y-axis units are in km/minute and the x-axis is the UT during 11 December 2015:

Line color code:

• Cyan - Io / Europa
• Pink - Io / Ganymede
• Yellow - Io / Callisto
• Green - Europa / Ganymede
• Red - Europa / Callisto
• Blue - Ganymede / Callisto

So in the plot above, the pink line shows the velocity between Io and Ganymede.  At 0h UTC, these two moons are moving away from one another at a velocity of about 800 km/minute.  By about 13:30 UTC, the relative velocities between the two moons is zero km/minute.  By the end of the day, the two moons are moving away from another at a velocity of almost 800 km/minute.

Also note that at about 16:11 UTC that the pink line and the yellow line cross.  This shows that at that moment in time, Io and Ganymede are moving away from each other at exactly the same velocity as Io and Callisto are moving away from each other.  HOWEVER, Io is accelerating (positive slope of velocity) towards Ganymede and decelerating (negative slope) towards Callisto!

Very very very coo, and mind blowing and dizzying.

And finally, the mixed sound itself:

The Sound of Velocity

Jupiter Today 09 December 2015

A nice day at Jupiter today.

Notice that at about 05:08 UTC, the distances between Ganymede / Callisto, Europa / Ganymede, and Io / Callisto are all about the same.  Pretty nice!  Notice also that this three-distance convergence involves all four moons.

Here are the orbits:

and here are the distances:

Here is the sound of the distances:

Jupiter Today 09 December 2015

Jupiter Today 07 December 2015

Jupiter Today is resuming but it probably won't be every day.

Listen to the sound of the distances between the four Galilean moons change over the next 24 hours.  Best heard with headphones!!!!

The Sound of Jupiter Today 07 December 2015

This first plot shows the positions of the moons as they orbit Jupiter over the next 24 hours.  We're looking from the top of the system, so all of the motion is counter-clockwise.  The blue line is the line of site to Earth.  The red lines are the lines of site to the Sun, and 90 degrees to that to designate quadrants.

The 2nd plot shows the distances between each of the moons (the y-axis) as a function of time (x-axis, number of minutes since midnight).

Cyan - Io / Europa
Pink - Io / Ganymede
Yellow - Io / Callisto
Green - Europa / Ganymede
Red - Europa / Callisto
Blue - Ganymede / Callisto

Listening to Varying Brightness

I took this blurred image of M13:

and looked at the pixel values (representing brightness in the SDSS u band) along column 115, which cuts more-or-less down the brightest part of the image.

I then created three sound files.  The first (shown in red in the plot below) represents the brightness of the pixel.  The second (shown in green in the plot below) represents the change in the brightness (1st derivative).  The third (shown in blue in the plot below) represents changes in the changes in the brightness (2nd derivative).

I've scaled all of the data to fall within a frequency range of 100-200 Hz, which is the y-axis of the plot.  The x-axis is the row number.

Once all three sound files were made, I mixed them into a single track.  Wear earphones for the best effect:

M13 Brightness Changes

What do you hear?

Jupiter Today

Check out my daily posts about the Jupiter system over at my new blog Curious Participants.