Explanation: What would it be like to fly over the largest moon in the Solar System? In June, the robotic Juno spacecraft flew past Jupiter's huge moon Ganymede and took images that have been digitally constructed into a detailed flyby. As the featured video begins, Juno swoops over the two-toned surface of the 2,000-km wide moon, revealing an icy alien landscape filled with grooves and craters. The grooves are likely caused by shifting surface plates, while the craters are caused by violent impacts. Continuing on in its orbit, Juno then performed its 34th close pass over Jupiter's clouds. The digitally-constructed video shows numerous swirling clouds in the north, colorful planet-circling zones and bands across the middle -- featuring several white-oval clouds from the String of Pearls, and finally more swirling clouds in the south. Next September, Juno is scheduled to make a close pass over another of Jupiter's large moons: Europa.
01:12 Wao, Jupiter fits so nicely inside Orion constellation. May be too nicely ? Are the stars in the background a digital map or Juno's real acquired image ?
krajesh304 wrote: ↑Mon Oct 11, 2021 4:28 am
Isn't Ganymede more than 5000 km wide ? I suppose 'wide' would refer to the diameter of the object rather than its radius.
You are correct! Ganymede is actually larger than Mercury!
I have no idea where they got 2,000 km…
Wow! Stop the video at 2:14 and look straight ahead. The clouds form a long-haired woman riding a horse, horse running to the left. Amazing. It's Rhiannon maybe.
krajesh304 wrote: ↑Mon Oct 11, 2021 4:28 am
Isn't Ganymede more than 5000 km wide ? I suppose 'wide' would refer to the diameter of the object rather than its radius.
You are correct! I have no idea where they got 2,000 km…
Careful scientific measurement & analysis by these folk.
Alex_515 wrote: ↑Mon Oct 11, 2021 8:44 am
01:12 Wao, Jupiter fits so nicely inside Orion constellation. May be too nicely ? Are the stars in the background a digital map or Juno's real acquired image ?
The images from the Juno camera don't capture stars, or at best only a few of the brightest. This is a synthesized flyby video where the surfaces of the bodies are painted with actual imagery. The star fields are likely synthesized, although hopefully they are accurately located with respect to the camera path chosen.
Chris
*****************************************
Chris L Peterson
Cloudbait Observatory https://www.cloudbait.com
Anyone know what the bright flashes scattered throughout the video are? Lightning or small meteor strikes? I’d guess lightning, but some appear to leave small black spots…
Locutus76 wrote: ↑Mon Oct 11, 2021 3:29 pm
Anyone know what the bright flashes scattered throughout the video are? Lightning or small meteor strikes? I’d guess lightning, but some appear to leave small black spots…
Lightning. Also synthesized, I think.
Chris
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Chris L Peterson
Cloudbait Observatory https://www.cloudbait.com
Guest wrote: ↑Mon Oct 11, 2021 3:50 pm
Lightning? I was wondering the same thing. But synthesized? WTF! APOD should have required non-synthesized video. If they synthesize one thing, where does it end?
APOD should do no such thing. It is made clear that this is a digitally synthesized video made from actual imagery. It is an accurate representation of what such a flyby would look like, which is the entire point. This flyby did not occur at all, but it is fantastic that we have the capability to accurately represent how it would appear.
Chris
*****************************************
Chris L Peterson
Cloudbait Observatory https://www.cloudbait.com
Alex_515 wrote: ↑Mon Oct 11, 2021 8:44 am
01:12 Wao, Jupiter fits so nicely inside Orion constellation. May be too nicely ? Are the stars in the background a digital map or Juno's real acquired image ?
The images from the Juno camera don't capture stars, or at best only a few of the brightest. This is a synthesized flyby video where the surfaces of the bodies are painted with actual imagery. The star fields are likely synthesized, although hopefully they are accurately located with respect to the camera path chosen.
This image of the dark side of the Jovian moon Ganymede was obtained by the Stellar Reference Unit star camera aboard NASA's Juno spacecraft during its June 7, 2021, flyby of the icy moon.
Usually used to keep the spacecraft on course, the navigation camera was able to obtain an image of the moon's dark side (the side opposite the Sun) because it was bathed in the dim light scattered off Jupiter; the camera operates exceptionally well in low-light conditions.
Alex_515 wrote: ↑Mon Oct 11, 2021 8:44 am
01:12 Wao, Jupiter fits so nicely inside Orion constellation. May be too nicely ? Are the stars in the background a digital map or Juno's real acquired image ?
The images from the Juno camera don't capture stars, or at best only a few of the brightest. This is a synthesized flyby video where the surfaces of the bodies are painted with actual imagery. The star fields are likely synthesized, although hopefully they are accurately located with respect to the camera path chosen.
:arrow: This image of the dark side of the Jovian moon Ganymede was obtained by the Stellar Reference Unit star camera aboard NASA's Juno spacecraft during its June 7, 2021, flyby of the icy moon.
Usually used to keep the spacecraft on course, the navigation camera was able to obtain an image of the moon's dark side (the side opposite the Sun) because it was bathed in the dim light scattered off Jupiter; the camera operates exceptionally well in low-light conditions.
Of course, even if it weren't stated explicitly, the fact that the imagery is in color tells us that we're seeing JunoCam images, not images from the star guider. But it's cool that they can use the star guider for images, too.
Chris
*****************************************
Chris L Peterson
Cloudbait Observatory https://www.cloudbait.com
This image of the dark side of the Jovian moon Ganymede was obtained by the Stellar Reference Unit star camera aboard NASA's Juno spacecraft during its June 7, 2021, flyby of the icy moon.
Usually used to keep the spacecraft on course, the navigation camera was able to obtain an image of the moon's dark side (the side opposite the Sun) because it was bathed in the dim light scattered off Jupiter; the camera operates exceptionally well in low-light conditions.
Of course, even if it weren't stated explicitly, the fact that the imagery is in color tells us that we're seeing JunoCam images, not images from the star guider. But it's cool that they can use the star guider for images, too.
By my calculation a full Jupiter at Ganymede (magnitude: −16.65)
is about 400 times dimmer than the Sun at Jupiter (magnitude: -23.15).
This image of the dark side of the Jovian moon Ganymede was obtained by the Stellar Reference Unit star camera aboard NASA's Juno spacecraft during its June 7, 2021, flyby of the icy moon.
Usually used to keep the spacecraft on course, the navigation camera was able to obtain an image of the moon's dark side (the side opposite the Sun) because it was bathed in the dim light scattered off Jupiter; the camera operates exceptionally well in low-light conditions.
Of course, even if it weren't stated explicitly, the fact that the imagery is in color tells us that we're seeing JunoCam images, not images from the star guider. But it's cool that they can use the star guider for images, too.
By my calculation a full Jupiter at Ganymede (magnitude: −16.65)
is about 400 times dimmer than the Sun at Jupiter (magnitude: -23.15).
Good estimate Art
From Ganymede, JPL HORIZONS lists the full Jupiter occurred very early on June 5 at mag = -16.60 and the Sun at mag = -23.23 → 450x dimmer than the Sun. Off hand, I don't know HORIZONS uncertainty here, but only 11% difference seems pretty good.
(A side note: Juno's close approach to Ganymede was ~1000km)
A pessimist is nothing more than an experienced optimist
Guest wrote: ↑Mon Oct 11, 2021 3:50 pm
Lightning? I was wondering the same thing. But synthesized? WTF! APOD should have required non-synthesized video. If they synthesize one thing, where does it end?
APOD should do no such thing. It is made clear that this is a digitally synthesized video made from actual imagery. It is an accurate representation of what such a flyby would look like, which is the entire point. This flyby did not occur at all, but it is fantastic that we have the capability to accurately represent how it would appear.
I agree with Guest and disagree with Chris. Adding lightning flashes where they weren't observed crosses the line into artistic interpretation and should be disclosed as such. The explanation of the video states that the Juno spacecraft "took images that have been digitally constructed into a detailed flyby." This simply suggests that Juno took a series of still photos that were rendered into a time-lapse video. Artwork should not be superimposed on scientific images without clear disclosure as such. Visualization of real-time lightning flashes on Jupiter is a milestone that has not yet been reached. Of course, I would love to be wrong and find out that these flashes are indeed real.
Guest wrote: ↑Mon Oct 11, 2021 3:50 pm
Lightning? I was wondering the same thing. But synthesized? WTF! APOD should have required non-synthesized video. If they synthesize one thing, where does it end?
APOD should do no such thing. It is made clear that this is a digitally synthesized video made from actual imagery. It is an accurate representation of what such a flyby would look like, which is the entire point. This flyby did not occur at all, but it is fantastic that we have the capability to accurately represent how it would appear.
I agree with Guest and disagree with Chris. Adding lightning flashes where they weren't observed crosses the line into artistic interpretation and should be disclosed as such. The explanation of the video states that the Juno spacecraft "took images that have been digitally constructed into a detailed flyby." This simply suggests that Juno took a series of still photos that were rendered into a time-lapse video. Artwork should not be superimposed on scientific images without clear disclosure as such. Visualization of real-time lightning flashes on Jupiter is a milestone that has not yet been reached. Of course, I would love to be wrong and find out that these flashes are indeed real.
APOD should do no such thing. It is made clear that this is a digitally synthesized video made from actual imagery. It is an accurate representation of what such a flyby would look like, which is the entire point. This flyby did not occur at all, but it is fantastic that we have the capability to accurately represent how it would appear.
I agree with Guest and disagree with Chris. Adding lightning flashes where they weren't observed crosses the line into artistic interpretation and should be disclosed as such. The explanation of the video states that the Juno spacecraft "took images that have been digitally constructed into a detailed flyby." This simply suggests that Juno took a series of still photos that were rendered into a time-lapse video. Artwork should not be superimposed on scientific images without clear disclosure as such. Visualization of real-time lightning flashes on Jupiter is a milestone that has not yet been reached. Of course, I would love to be wrong and find out that these flashes are indeed real.
Exactly. We know what they look like, and where the occur. The animation is MORE accurate by including them, since we would see them in a flyby like this one.
Chris
*****************************************
Chris L Peterson
Cloudbait Observatory https://www.cloudbait.com
javachip3 wrote: ↑Fri Oct 15, 2021 5:37 am
Adding lightning flashes where they weren't observed crosses the line into artistic interpretation and should be disclosed as such.
Well, they have been seen in "real time" as brief flashes, just not as nicely portrayed as in this APOD.
Exactly. We know what they look like, and where the occur.
The animation is MORE accurate by including them, since we would see them in a flyby like this one.
The artist's interpretation of Jovian lightning is inaccurate in many ways: the flashes are depicted as frequent (same region of Jupiter a few seconds apart), large (many pixels in size), very bright, and having light curves with fairly slow attack and decay characteristics. All of these details conflict with what is known about Jovian lightning.
javachip3 wrote: ↑Mon Oct 18, 2021 11:37 pm
The artist's interpretation of Jovian lightning is inaccurate in many ways: the flashes are depicted as frequent (same region of Jupiter a few seconds apart), large (many pixels in size), very bright, and having light curves with fairly slow attack and decay characteristics. All of these details conflict with what is known about Jovian lightning.
https://en.wikipedia.org/wiki/JunoCam wrote:
<<JunoCam is not one of the probe's core scientific instruments; it was put on board primarily for public science and outreach, to increase public engagement, and to make all images available on NASA's website. It is capable of being used for science, and does have some coordinated activities in regards to this, as well as to engage amateur and as well as professional infrared astronomers.>>
The Juno spacecraft also carries three Lego minifigures representing Galileo Galilei, the Roman god Jupiter, and his sister and wife, the goddess Juno. In Roman mythology, Jupiter drew a veil of clouds around himself to hide his mischief. Juno was able to peer through the clouds and reveal Jupiter's true nature. The Juno minifigure holds a magnifying glass as a sign of searching for the truth, and Jupiter holds a lightning bolt. The third Lego crew member, Galileo Galilei, has his telescope with him on the journey. The figurines were produced in partnership between NASA and Lego as part of an outreach program to inspire children's interest in science, technology, engineering, and mathematics (STEM). Although most Lego toys are made of plastic, Lego specially made these minifigures of aluminum to endure the extreme conditions of space flight.>>
Careful scientific measurement & analysis by these folk.
