APOD: Moons Across Jupiter (2023 Jun 13)

[APOD Robot]

Moons Across Jupiter

Explanation: Jupiter's moons circle Jupiter. The featured video depicts Europa and Io, two of Jupiter's largest moons, crossing in front of the grand planet's Great Red Spot, the largest known storm system in our Solar System. The video was composed from images taken by the robotic Cassini spacecraft as it passed Jupiter in 2000, on its way to Saturn. The two moons visible are volcanic Io, in the distance, and icy Europa. In the time-lapse video, Europa appears to overtake Io, which is odd because Io is closer to Jupiter and moves faster. The explanation is that the motion of the fast Cassini spacecraft changes the camera location significantly during imaging. Jupiter is currently being visited by NASA's robotic Juno spacecraft, while ESA's Jupiter Icy Moons Explorer (JUICE), launched in April, is enroute.

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[javachip3]

This appears to be a "simulated" time-lapse video, with artist's interpretation. Jupiter's clouds do not move at all during the video. Neither do Io's or Europa's terminators, while Jupiter's terminator approaches at the right.

[RDaneelOlivaw]

I'm wondering what kind of gravitational interplay there is between Europa and Io when they pass as close to each other as they appear to in this video? -- Ron

[alex555]

This appears to be a "simulated" time-lapse video, with artist's interpretation. Jupiter's clouds do not move at all during the video. Neither do Io's or Europa's terminators, while Jupiter's terminator approaches at the right.

No. The clouds of the Great Red Spot are clearly seen rotating clockwise, as well as the parallel movements of the white clouds further below

Alex

[Chris Peterson]

I'm wondering what kind of gravitational interplay there is between Europa and Io when they pass as close to each other as they appear to in this video? -- Ron

Ganymede, Europa, and Io are in a 4:2:1 orbital resonance... created and maintained by their mutual gravitational influence.

[johnnydeep]

This appears to be a "simulated" time-lapse video, with artist's interpretation. Jupiter's clouds do not move at all during the video. Neither do Io's or Europa's terminators, while Jupiter's terminator approaches at the right.

No. The clouds of the Great Red Spot are clearly seen rotating clockwise, as well as the parallel movements of the white clouds further below

Alex

Correction: the Red Spot clouds are rotating counter clockwise.

[orin stepanek]

Nice set of moons!

[pclark@bigpond.net.au]

This appears to be a "simulated" time-lapse video, with artist's interpretation. Jupiter's clouds do not move at all during the video. Neither do Io's or Europa's terminators, while Jupiter's terminator approaches at the right.

No. The clouds of the Great Red Spot are clearly seen rotating clockwise, as well as the parallel movements of the white clouds further below

Alex

Erm, no, the Red Spot clouds don't clearly rotate at all. The caption uses the term "depicts" for good reason, Cover the moons with your hand and watch the background image very closely, marking point features. If you see movement you may need to see your optometrist.

[Chris Peterson]

This appears to be a "simulated" time-lapse video, with artist's interpretation. Jupiter's clouds do not move at all during the video. Neither do Io's or Europa's terminators, while Jupiter's terminator approaches at the right.

No. The clouds of the Great Red Spot are clearly seen rotating clockwise, as well as the parallel movements of the white clouds further below

Alex

Erm, no, the Red Spot clouds don't clearly rotate at all. The caption uses the term "depicts" for good reason, Cover the moons with your hand and watch the background image very closely, marking point features. If you see movement you may need to see your optometrist. ;) ;) ;)

How much cloud movement would you expect to see? It takes more than four days for the red spot to complete one rotation, and this sequence was maybe on the order of an hour.

[johnnydeep]

No. The clouds of the Great Red Spot are clearly seen rotating clockwise, as well as the parallel movements of the white clouds further below

Alex

Erm, no, the Red Spot clouds don't clearly rotate at all. The caption uses the term "depicts" for good reason, Cover the moons with your hand and watch the background image very closely, marking point features. If you see movement you may need to see your optometrist.

How much cloud movement would you expect to see? It takes more than four days for the red spot to complete one rotation, and this sequence was maybe on the order of an hour.

So what's happening between an early frame from the video and a later frame shown in this side-by-side:

The inner dark patch certainly seems to be rotating counter clockwise a little!

[Chris Peterson]

Erm, no, the Red Spot clouds don't clearly rotate at all. The caption uses the term "depicts" for good reason, Cover the moons with your hand and watch the background image very closely, marking point features. If you see movement you may need to see your optometrist. ;) ;) ;)

How much cloud movement would you expect to see? It takes more than four days for the red spot to complete one rotation, and this sequence was maybe on the order of an hour.

So what's happening between an early frame from the video and a later frame shown in this side-by-side:


red spot inner rotation cropped.jpg


The inner dark patch certainly seems to be rotating counter clockwise a little!

No idea, but I don't think this sequence is long enough for there to be more than a few pixels of movement in any of the Jupiter cloud systems. Maybe something related to the tweening or whatever process was used to create a smooth video out of a limited number of frames?

[javachip3]

This appears to be a "simulated" time-lapse video, with artist's interpretation. Jupiter's clouds do not move at all during the video. Neither do Io's or Europa's terminators, while Jupiter's terminator approaches at the right.

No. The clouds of the Great Red Spot are clearly seen rotating clockwise, as well as the parallel movements of the white clouds further below

Alex

Thanks! I agree, on closer inspection, the GRS rotates slightly counter-clockwise, and the white clouds at the bottom of the frame move leftward slightly faster than other features such as the white oval. As Chris suggests, it would be helpful to know the elapsed time from start to finish, and how many actual frames were recorded to produce this clip.