Juno is bringing Jupiter’s moon Io into sharper focus
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I am always in awe at the resilience and versatility of our scientific exploration craft. From the Voyagers to the myriad Mars rovers to Juno, they deliver(ed) on their primary missions in spades and then continue to give us years of rich “bonus material“ the original planners might never have even envisioned.
Keep up the stellar work, intrepid explorers!
Keep up the stellar work, intrepid explorers!
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the craziest bit for me is finding out Io's solid rocky surface bulges 5 times more than our oceans do during high and low tide. no wonder it's got constant volcanic activity!
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That's somewhat funny (*), seeing as Juno was often the last one to glom on to and focus on what Jupiter was up to! But when she did, sparks would fly (actually: people would die).
(*) for Graeco-Roman mythology nerds, please don't hurt me
(*) for Graeco-Roman mythology nerds, please don't hurt me
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Fun fact : Since Io is tidally-locked to Jupiter, the crust-busting tides are caused by the other moons (mostly Ganymede) and the orbital excentricity.
If Jupiter had an ocean as a surface, the tides there would be quite interesting...
If Jupiter had an ocean as a surface, the tides there would be quite interesting...
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I still wish they put a better optical camera on Juno. It's less than 2 MP. I understand the science missions needed to come first, but seriously, NASA's DSN could have handled higher resolution. Right?
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This is fantastic - the ability to see change over time on the surface of other bodies in the solar system has completely changed our understanding of planetary processes and what is possible. What a gift this is.
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I love every shot of Io - they remind me of the excitement of receiving the Jan 1980 issue of National Geographic with this gloriously alien cover:
So low-res compared to even Juno's Walmart camera, but so rich with the excitement of discovery of new worlds. Most of all I'm happy to find that four decades later I'm still giddy with the excitement that these probes bring.
So low-res compared to even Juno's Walmart camera, but so rich with the excitement of discovery of new worlds. Most of all I'm happy to find that four decades later I'm still giddy with the excitement that these probes bring.
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Naïve question: could this be the precursor behaviour before it gets torn apart forming a ring?
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JunoCam is pretty much an afterthought. From Wikipedia: "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, with all images available on NASA's website." But it's a very cool afterthought.
https://en.wikipedia.org/wiki/JunoCam
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Pssst, "tides."
All the photography we get from these outer planets reminds me of how precious those few images from Pioneer and Voyager were, blown up as large as possible and put into pop science books for literal decades because that's all we had that didn't come from telescopes on Earth.
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fellow human
Ars Praefectus
There's something mind-expanding about looking at images of distant planets. Thrilling.
More images link minus the twitter wrapper:
https://www.missionjuno.swri.edu/junocam/processing?source=public&p=1
More images link minus the twitter wrapper:
https://www.missionjuno.swri.edu/junocam/processing?source=public&p=1
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Not exactly. It's the other moons which cause the eccentricity. But since all three are in resonant orbits, I'm not sure how you could say it's mostly Ganymede. But given that forced eccentricity, Io isn't exactly tidally locked. There is a lot of libration, and the sub-Jupiter point wobbles around. That lets Jupiter's gravity produce those tides and tidal heating.
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Not really, no. The tidal stresses on Io would have to become significantly greater to tear it apart.
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Somebody better at sigfigs than me, tell us: shouldn't that be 300 feet, not 330, since there's apparently only 1 sigfig in the "100 meters" tidal shaping figure?
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It's a unit conversion of an approximation, so it has zero significant figures. If you are doing anything requiring decimal places of precision on the basis of that data, you need better data.
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If they had tried that, Juno might not have had a camera at all. Because it was just an education and outreach add-on, it was exempt from a lot of the requirements other instruments had to deal with. Such as being radiation hardened to last 33 orbits. That made it much smaller and cheaper.
As far as the DSN is concerned, no. They are badly oversubscribed. In fact, we're getting back far more images from Juno than planned. The images are compressed, and it's hard to know how well a lossless routine will compress an image. So they take a lot more images than they could realistically send down, prioritize them, and send down as many as they can until the data volume allocation is expended. So far, that's been a lot more than the original goal of a few per orbit.
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No. That only happens if a satellite is below synchronous orbit. Above that (and Io is well above synchronous orbit) tidal forces make it move outward. And that makes the tidal forces weaker.
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It's actually not that bad. The average geothermal heat flux is on par with the island of Hawai'i or the Yellowstone caldera. Which, for an entire world, is a lot. And you certainly wouldn't want to spend time near a very active region like Loki. But overall, it's no worse than Hilo, which has been inhabited for a thousand years and been a sizable city for over a century. Except that once or twice a decade a suburban development gets destroyed by a lava flow...
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Thanks. I didn't realize the camera got so many exemptions and I guess if the DSN is that congested then 2 MP is plenty of data for the bitrates out that far.
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Great article but the embedded tweet is pretty gross.
(What's up with that being visible anyway, didn't Elon promise I wouldn't have to see any more tweets if I didn't log in?)
(What's up with that being visible anyway, didn't Elon promise I wouldn't have to see any more tweets if I didn't log in?)
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It's more the change in the downlink rates. The primary science instruments on Juno are all fairly low rate. Radio science is basically free, microwave radiometry doesn't need much (hundreds of bits per second during periapsis), magnetometry can't actually use more than 1 kbps even if they tried. The particle and field instruments can dial their data rates up and down by a huge amount, but the core science doesn't require much. So the project wasn't going to ask the DSN for a massive increase in their planned allocations for an add-on, public outreach camera.
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On Mars, volcanism is suspected to have kept the early atmosphere present for longer than it might have existed otherwise. As far as I'm aware, Io only has an exosphere. Do interactions with Jupiter destroy any chance Io would otherwise have to create an envelope of.... something around itself?
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As a joke, since that's what it was, I'll note a letter to the editor the Washington Post published at the time. Around then, that newspaper had a habit of running headlines which where really bad puns. So someone wrote that he was disappointed that Voyager hadn't discovered that one of Jupiter's moons wasn't found to be made of a precious metal. If it had, the Post could have used the horrible puns, "Io Silver" as a headline.I love every shot of Io - they remind me of the excitement of receiving the Jan 1980 issue of National Geographic with this gloriously alien cover:
So low-res compared to even Juno's Walmart camera, but so rich with the excitement of discovery of new worlds. Most of all I'm happy to find that four decades later I'm still giddy with the excitement that these probes bring.
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"One of its top science results was finding evidence for a large, potentially dissolved core inside Jupiter, upending a hypothesis that Jupiter had a smaller, solid core at its center."
Don't we know what Jupiter's core is already... It;s a giant diamond isn't it?? Or am I thinking of Ganymede??
(Bonus points for getting this reference....)
Don't we know what Jupiter's core is already... It;s a giant diamond isn't it?? Or am I thinking of Ganymede??
(Bonus points for getting this reference....)
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That's a matter of debate among scientists who study Io. The bottom of an exosphere is where the mean free path between molecules is equal to the scale height of the atmosphere. In the case of Io, that's near the surface, or at the surface in some places. Depending on who you talk to.
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Yes. JunoCam takes a lot of images. It sends as many as it can, depending on data volume allocations and compression ratios. But there are plenty of low priority images which are never sent down. I don't know what the current statistics are, but it's a lot better to send down the top 100 images and junk the other 300 than one which use a scheme which assures ten images, no more and no less.
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Surfs up, dude?
I'm so glad the camera made it onboard. It might be little scientific value but pictures like this make my heart miss a beat.
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Juno's a gift that keeps on giving.
I'm also curious what the Europa Clipper will send us should it be succesful.
Personally I'm of the opinion that Ganymede has better odds of harbouring life than Europa as it's farther/safer from Jupiter ánd has both a magnetic field and atmosphere IIRC.
But I don't need to be right and will be happy with any result be it positive or not. Maybe we'll hit the jackpot on Europa, Callisto ánd Ganymede!
I'm also curious what the Europa Clipper will send us should it be succesful.
Personally I'm of the opinion that Ganymede has better odds of harbouring life than Europa as it's farther/safer from Jupiter ánd has both a magnetic field and atmosphere IIRC.
But I don't need to be right and will be happy with any result be it positive or not. Maybe we'll hit the jackpot on Europa, Callisto ánd Ganymede!
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Was involved in a few space projects... It is not like you can "zip tie" a commercial camera on Juno and be done with it. I.e. radiation hardened circuits are needed, which changes the design completely. These things are also not mass produced, so reusing an older design is not that simple.
That said, the latest project we did was designed to go in all satellites as a general purpose component for motor control.
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Thanks for the lesson! What defines 100 m as an approximation here, as opposed to a single significant figure? Perhaps that, given the context, this is likely a power-of-10 estimate ("eh, it's surely more than 40m and less than 400m...")?
...or I may be missing the point. Maybe since the 330 ft figure is the article helping readers understand what 100m means, not the scientist doing a conversion, 330ft is appropriate.
Either way, it's always neat whenever I'm reminded that sig figs don't actually have a hard and fast rule, and it depends on the context how many to use.
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Having been sailing in the Bay of Fundy, I can attest that both tides and rides is appropriate...
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Fun fact about tides, earth's "land" has a tidal bulge too. I forget how big it is though, maybe half a meter?
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