"This is a niche in the electromagnetic spectrum that hitherto has not been really sampled."-Ian Wong

Starts at 2:35. Spectroscopy is the basis of astronomy. Telescopes penultimate tequnique. This camera sees a bigger spectra than Hubble can. Spectroscopy sometimes follows probes. The probes tell the engineers what an instrument planetary science to look for. JWST is the machine previous probes demanded.

Overall this is mostly a teaser lecture. Promises of epiphanies JWST will produce. The slides are eye-candy, the lecture meanders. 

• Slide at 6:25 illustrates the topic. JWST is looking at spectra we haven't had a good telescope for.
• 15:40, JWST seeing DART hit the board.
• 21:50, Jupiter Aurora, IO flux tube, Ganymede magnetosphere, JWST is perfect for studying these things.
• 30:10. Titan stuff. Mostly teaser, that color structure exists at all is proof spectroscopy has a lot to work with.
• 33:20, Uranus. Seems like yesterday we were arguing over which would get a probe next. Now they seem so far away. JWST will have to do.
• 35:50 Neptune and Triton. JWST will pay off there too.

 "If you look at this sort of picture that I drew."-Nick Borsato

Skip ahead to 4:50.

I like this guy; he speaks to my level. Belt'n out facts that might be obvious if I could be bothered to infer things.

I have to admit I don't have near the same interest in exoplanets as in planetary science, but I would be interested in any planetary science of exoplanets. That's what this video delivers. It's quite a bit more satisfying than it looks.

• I feel like the slide at 8:50 should be a meme.
• At 10:58, he's really good at selling his samples.
• The theme of the remaining talk is to categorically list all the measurable information that can conclude something. So it's a good reference. 
• Summary at 43:25.

This talk seems to have ulterior motives, homeboy may be applying for a grant. Nobody ad-libs this much salesmanship; but they do talk extemporaneous this way. Best wishes if he is, good talk regardless. 

 "It's already making beeping sounds at me." -Oliver White

Skip ahead to 3:40. 

Dear god Oliver White is a caricature of Oxford. Aside that, just seeing this video pop up and my first thought was "Charon shine." The reflection off of Charon to illuminate the dark side of Pluto is Charon shine, and it was hoped it would be enough to illuminate the dark side to get some imagery. That was just post flyby, and I've not heard about it since.

As expected of a geological map proposal, this video is packed. It may be the best reference to anything Pluto related for a long while to come. There's at least 2 slides in here that are worthy of being wall-hangings. 

• At 9:45 The Haze-lit, space seems to be the only result of waiting for Charon-Shine images. They would have been dim anyway as one can imagine.  
• Slide at 12:00 has two good looking maps shown without the nitrogen glacier/heart, but it's the map at 10:40 that we've been waiting for.
• At 13:30, a graph showing the first-I've-ever-seen-it six geological periods of Pluto's history and their names. They are dated by crater supposition, so it's just a scale of 'Older or Younger' then a specific crater, not, by chunks of measured time. The heart-lobe crater named sputnik is the oldest and therefore the first divider of eras. 
• At 32:30. This RTS, a ring of rifting around Pluto longitudinally, and seemingly of the bedrock stuff of Pluto, the hard water ice. Similar to Tethes. These global features come up a lot but with variable circumstances. For example Charon has a canyon all the way around it's equator. Longitudinal is a new variation.   
• At 35:00, Sputnik mountains seem to be described as tumbling, brecciated, blocks. That's a new one.
• At 41:45, He presents his argument that the paleo-RTS is an equatorial feature from before Pluto got knocked over by the Sputnik impact.
• Thoughts at 49:45

"Actually wrote a paper explaining why we probably wouldn't find sand dunes on Titan, which was spectacularly wrong."-Ralph Lorenz 

 Skip ahead to 3:40. Introductions prior. 

Ralph Lorenz is a good and regular speaker. He has a book on Titan, which I recommend. This LPI is four years old which means he had a year to mull things over prior to this talk.

This LPI is well detailed with lots of good slides. Very self informative so I don't need to set it up much. If you like Titan, you should enjoy it.

• Slide at 7:16. If you are unaware of it, Titan has a more chemically complex atmosphere than Earth, and maybe Venus too. That's a big deal, because it means we can't stick our necks out and make too many hard statements about what the alien atmosphere can and can't do. There's certainly new weirdness to be explored.
• 16:15, He solicits the documentary Destination:Titan, A BBC documentary featuring his younger self. It's certainly worth the watch and covers the development of the Huygens probe.
• 22:54, Comparing Titans dunes to the Namib. A single very periodic river ends the dunes in the Namib. Keep in mind ending dunes only has to be something that operates at about the same speed as they travel. One storm a year can do it. Other things could too, albeit less likely things. But dead-end dunes can be evidence for weather on other worlds.
• 28:05, When Cassini flew around Saturn then came to Titan they would expect the North Pole to be in a predictable reliable place. It wasn't. They were tying to get better radar coverage and image spaces they haven't. They kept missing the target. That lead to an announcement that Titans crust was detached from Titans core, by a deep global interior ocean. 
• 44:55. The disappearing island, which I'll assume you've heard of, is best explained by a radar anomaly. Radar reflects dark and well off smooth surfaces, white and grainy off rough surfaces. The disappearing island is likely a stormy patch of sea.
• 52:15, Acrylonitrile. The potential life forming molecule that Titan has. Not long prior Lorenz was speaking of "salts" as the more volatile molecules evaporate. What do the "salts" and other compounds left behind do when concentrated? Something, otherwise they would talk about 'salty basins' in these lectures, which so far they don't. 
  

Titan is still quite mysterious. There are whole subtopics which are only beginning to be explored. The Dragonfly mission will be targeting the Selk Crater Basin in part because it's a place where heat was for a while, and also because it's a place where frozen chemical reactions may be entombed in ice. I suspect that will get weird and open even more mysteries rather than answer any current questions. 

"NASA said we need you to find a way to dispose of Cassini, that would protect these particular worlds."-Linda Spilker

This LPI is a classic. Linda Spilker (one of the rock-stars in planetary science) has her hands on just about every probe from Voyager on. This lecture comes shortly after the end of the Cassini mission, so it has a certain somber. Cassini's grand exit was a depressing time, since it was giving back weekly good stuff. She categorically goes over some time points of Cassini, which most of us are familiar with by now. At the time of this video it was all still quite new and exciting. 

• At 13:20, the octagon. What jet-streams want to do if unobstructed.
• A tour of the rings at 15:00.
• At 16:30, ring shadows and what they imply. Half a kilometer tall ripples. Peggy.
• At 22:05, Pan, Atlas, and Daphnis and their skirts. Daphnis surfing the rings.
• at 26:60, Titans Lakes, Dunes, and Mountains.
• Enceladus at 29:00.
• Slide at 33:35. That discovery of, among other things, the electric exchange between the D-ring and Saturn. I've often liked to compare IO to Enceladus, and missed that powerful IO flux-tube, hoping that Enceladus would one day show something similar. But the rings were likely once a tiny moon, (35:00) and it's possible that moon did have an IO like flux-tube.

Cassini was so successful, so unexpectedly successful, that it compares to the Apollo, Voyager, then all the Mars missions combined. It redefined what a flagship mission can max out as. A little known fact is that Cassini actually had a contingency plan to actually leave Saturn then travel to Uranus, if Saturn had proven too boring, or it's instruments couldn't pernitrate Titan's atmosphere. Ridiculous in hindsight. 

"Frank comes in everyday, he writes this equation on the board, we don't know what it means."-Seth Shostak

Skip ahead to 4:50. There's this thing they sometimes do where one person announces the person who will introduce the speaker. So the speaker is the third person you see. 

This is probably the closest thing to a Fermi-Paradox / Drake equation video LPI has produced. It features a speaker that LPI has used a number of times; I linked one recently. And it really does have everything you would want to know 

• At 7:25 the alien guy mentions the Crimean War. Coincidence? Very likely.
• Slide at 31:50 pretty much sums up the video.

To me the simplest/best explanation is one I'm quite satisfied with; we are the "old-ones". The concept is that stars need to saturate the universe through high powered super-novae. Things energetic life would need such as Phosphorus, maybe molybdenum, maybe sulfur. You get the idea. The star-cycles have got the stuff out there but not very much, and life will be more common when they do. My favorite part about this is that it puts the responsibility on us, and we have not been great with responsibility as a species.

When a telescope looks at a star it's seeing the past, and this works in reverse too. Any alien observer cannot see us until light has had time to move from us to them. So there are not very many opportunities for them to see us before we see them. We improve over time, and they need time to travel. FTL certainly takes a long while to develop. Hence, we are the old-ones, certainly within the area we've had the chance to look at, we are the more advanced society. One wonders if we can handle that.

"But then in the middle you have Tethys which has a density of less than one, [less dense than water.]"-Sierra Ferguson

Couple things. First, why do some people insist Mimas is the Death Star Moon when Tethys also has the mojo and might be hollowed, and second, why isn't Iapetus included in this video. I imagine the second question will get answered. 

This video is about a discrepancy. Saturn's mid-size moons don't line up in a nice clean manner. They are rambunctiously sorted not according to size or density, nor crater population. If one could figure out why, they would discover a tool to use in the modeling of the early solar system. Also it would be awesome by itself.

• 5:35, "The Pluto Charon system," is the correct way to refer to it in my opinion, and I'll fight over it. It ain't a planet, give it up. But it is a binary, and that's neat.
• At 18:20 the crater counting begins. Note that she is looking for patches of craters with about the same wear, not crater counting the whole world. 
• 25:05, "Rose" diagrams. They show directional data in a circle. Think like a pilot picking which way to point the nose of an aircraft in 3D. Needless to say these diagrams come up in planetary science but only for a few things like impactor vectors here, or stuff like shadows; maybe seismology.
• Conclusions at 50:00

Our speaker is young, nervous, and apparently had the hiccups or was pizza/beer lunch burpy. I've never seen her before, and hope to again, but she complicates her talk, torn between wanting to display the shiny new words she's been learning and talk like a paper, vs trying to get press through it smoothly. But she brought great slides so just pause it periodically, the points she's sloppy with are usually in the slides.

Her overall work is not done. This to her is updating her overseers that she is making progress and finding good science. She has some wonky crater stuff and is working it to constrain a relative dating range, but she hasn't got that far yet. Even the relative dating between Hershel and Odysseys and their backgrounds isn't in here. But that's because she's the one doing it, and it's underway right now. This LPI is only a few days old. 

"We are flying the entire payload. Nothing was terminated."-Curt Niebur

https://www.youtube.com/watch?v=YjG3TVxr3O4

When you dig through LPI's YouTube channel you find a lot of videos. Most aren't lectures per se, and the ones that are come with great variety. Small vids showing a gif of something are common, talks about how the scientific community can de-jargon, outreach to students, a group of students giggling at their own jokes while feigning to give a talk, all these things are common. So are videos that cover budgets and plans. 

This a sort of a staffing, planning, and budgetary video, also it's a list of active missions. Sounds a little more boring than it is, but the major upside is that it's providing overviews of everything JPL is overseeing from the time of this talk. Much of that is old, but now you have new context. It's easy to forget how many active and ongoing missions there are; I can't remember them all. These types of talks help remind, and give a clear behind the scenes look.

• OSIRIS-REx at 6:55, now old news, the practice maneuvers put the very recent DART impact into Dimorphos in perspective. On that note here's Dimorphos at the point of impact.  
• DART gets a slide at 8:10 
• LUCY at 8:25. Will be going to Jupiter's Trojans.
• Europa Clipper at 9:35
• SIMPLEx at 12:15 is a program involving five sub-programs, all involve low-budgets and some proof-of-concept.
• Mars Sample Return at 13:00.
• Artemis III (yup "3",) at 21:30.

I saw this when it was new, and later couldn't pick it out in my memory or in LPI. I was reminded because someone and I had a chat about Europa Clipper, and no one was sure what instruments were adjusted or cut, but we both were sure something was. From timestamp 24:45 you see why I went looking. Since this video is dated, I cannot swear by it, but I wanted to show everyone because I feel like these budget & management videos offer a lot of context.

Kevin D. McKeegan. William Bottke. Solomon/Nittler/Anderson/Byrne. M.E. Schmidt. E.B. Rampe. Carol Raymond. Fran Bagenal. Robert Pappalardo. Ralph Lorenz. Hunter Waite. Krista Soderlund. Dale Cruikshank.

https://www.youtube.com/watch?v=WQEEtyF3xBQ

This LPI lecture is more than three hours long, so take breaks between speakers. It's meant to be a treat

The opening bit is a talk by Kevin McKeegan titled From a Sun-Kissed Moon to the Solar Nebula. It's a talk about protoplanetary conditions with emphasis on Oxygen isotopes; those being a major method of finding out which asteroid came from what parent body. Have I mentioned yet that most speakers will have a specific probe they focus on in their talk? This one is the Genesis mission. Probably the coolest looking steampunk probe so far, though future Venus landers may compete one day. Summary at 16:20.

The next talk starts at 18:58 and is titled Highlights of Planet Migration and Bombardment, by William Bottke. It's about the mysterious first billion years of Sol, and the most certain events that took place then. This is a very exciting period and knowing it better would provide a great deal of aid to current questions, but just think about it; Thea, the Mercury chaos-impactor, the two Vestan impactors, The Mars north-pole impactor (if there ever was one). All these planetesimals; each could have been a world. They existed, and the solar system was quite different then. Questions and Conclusions at 30:26.

The next talk is titled First Rock from the Sun: 50 years of Mercury Exploration. Featuring Messenger, one of my favorite probes. At 39:42 an interesting detail comes up. You see, with Mercury its high density remains unsolved. Messenger created more questions than it answered. A giant impact is evident on the surface. One that seems to have shattered off the original crust and sent ripples through the planet. It would be nice if we could tie-in that event to help explain other things like a big core, but the high percent of surface volatiles doesn't fit, and the premise of a highly reducing formation could have slurped certain metals like Iron into the core, creating a whole new headache for chemists. Beppi Colombo has been called for since Messengers message was a shrug.

The Exploreation of Venus spoken by Paul Byrne comes next. Featuring a few missions such as Magellan and ESA's crowning jewel until JUICE, Venus Express. It has come to our attention that we know way less about Venus than we should. One should be able to blow-off or confirm something as shocking as phosphine. But we never even knew how Venus replaces it's H₂SO₄. The context of Venus has changed greatly over the years. Instead of certain probe doom the tech to land something a bit more durable has appeared, and balloon probes including seismometers are viable. Venus has a number of mysteries concerning it's super-cell and crustal properties. One hypothesis that's making rounds is the idea that a Venusian volcano sat stationary atop its hotspot and grew so large that it sank and pulled the whole crust in with it. It's also possible that there are patches of stuff buoyant enough to have survived. Queries at 1:01:00. 

The next talk is titled Igneous Mars: Crust and Mantle Evolution as seen by Rover Geochemistry, Martian Meteorites, and Remote Sensing. Presented by M.E. Schmidt. I find it interesting that she opens by calling out the-law-of-superposition then noting the altitude of the Noachian. At the same time she shows a slide depicting the Hellas impact at the division of the Prenoachian and Noachian, which she doesn't follow up on, and I've never seen before. At about 1:05:00 she shows a fantastic progression on an XY graph which is showing you how probes have been constraining the mineral distribution as it's been discovered by meteorites and the rovers. Whereas this talk is one of the better information-dumps regarding Mars with many excellent observations in sequence, there still aren't a lot of answers. Altogether she does indeed make a good case to show there is evidence that Mars' lithosphere is chemically changing as it cools, grows, and thickens. Summary at 1:16:35.

There is a second talk about Mars titled The Sedimentary History of Mars as Observed by Rovers, presented by E.B. Rampe. Slide at 1:22:12, a common slide I've seen many times but with a great twist. You see, the era's of Mars tell a story that sidesteps a lot of controversy. Originally scientists with 70's era probes and information divided two Era's, the Hesperian and Amazonian. Plains vs Volcano stuff, and the volcano stuff was lumped together as where they saw sulfates from fly-by's. Sulfates form when volcanic gasses interact with water in any form, so where there are sulfates, that proves volcanoes and ice or something, were at the same place and time. Later the large flow basins were forming a pattern, so the Noachian era (Named for Noah from The Bible) was separated from the Hesperian. Then the crater counts started coming in, and there was clearly a Pre-Noachian. That's how the four era's evolved. It's never been up for debate... the Noachian flows came before the Hesperian volcanoes. Where this slide has a marker, something changed. The clays that didn't have sulfates in them before, now did. These slides are observational and packed with information. Enough to load up several hypothesis, not enough to shoot too many down. 

Ceres and Vesta: Diverse, Enigmatic Small Planets from the Dawn of the Solar System is the title of the next talk presented by Carol Raymond. Timestamp 1:36:06 "Of the Howard at you cried diet tonight" (closed-captioning is fun.) Howardite, Eucrite, Diogenite, what almost all asteroids are made of, and what Vesta is made of. You see, the Asteroid-Belt is a myth. Vesta, Ceres, Pallas, and Hygiea make up half the Asteroid-Belt by weight. And most of the rest of it, used to be Vesta. It's very likely Jupiter tacked in, then out, and compressed the orbits of Mars and the Asteroid-Belt while doing so. Warming an ice-ball Mars and bunching up objects that were further apart prior. At 1:41:42 no Olivine is exposed in Vesta's interior. That means Vesta never, never ever, even when it was whole, had an Earth-like mantle. We know it was differentiated, because we just saw that in the previous slide, and that means it was liquefied three times to some depth. The core isn't exposed but it would be interesting to see whats it there because it may have differentiated three times. The heavy stuff that sank went to the core the first time for sure, but may have stopped short later. If the Rheasilvia impact melted more than Veneneia, then there would be only one melt-limit, but if they melted about the same there may be two off-center. Some seismometers would be a blast. 

Fran Bagenal speaks for Jupiter at 1:49:20. Exploration of Jupiter is the title. At 1:52:50, the IO Plasma Torus. Probably the second most awesome thing in the solar system nobody seems to know about, right after the IO Flux Tube. Jupiter and IO are connected by a rather large voltage that traces a regular aurora around Jupiter. That’s the Flux Tube. The Plasma Torus is a diffuse ring filling IO’s orbit, very similar to Enceladus and Saturn's E-ring. The difference between the E-ring and the Plasma Torus is they are made of different stuff, and the Plasma Torus also carries a large voltage. The Galileo mission expanded on Jupiter in a number of ways, but when talking about Jupiter, we really are talking about energy in so many ways. Gravity, Electromagnetism, and Radiation. The radiation of Jupiter is mostly not emitted from Jupiter, it’s solar radiation trapped in Jup̨iter’s magnetosphere. Galileo found that Ganymede also has a rare magnetosphere, and that radiation is less, not more, above the surface of Ganymede. Normally Jupiter deletes atmospheres from it’s moons. IO is trying as hard as it can to have an atmosphere, but Ganymede can fight back a little, and does have a very slight atmosphere of mostly elemental forms of oxygen. So you see Jupiter is intimately connected with IO and Ganymede. They are practically touching. Summary at 2:00:48.

Robert Pappalardo starts his talk at 2:03:00 titled From the Moon to the Icy Galilean Satellites. You have to let it sink in how odd and wonderful Ganymede and Callisto are. Because they are icy, that builds-in alien physics with sublimation being a thing. Chondritic caps can protect what they cover, and hoodoos can form directly under what they don't. Random bubbling under a clear pane of ice will form and spray out CO₂ when heated by any little thing. The surface might at places look like Bryce Canyon made of glass, and when The-Sun hits it, snowing up like you're in the tail of a comet. None of the cameras that have been there can resolve down close enough to say that's not there, so I'm free to guess the dull cratered worlds are perhaps labyrinths of shimmering clear crystal, glorious and intimidating if you were actually there. Europa, if you haven't had this epiphany yet, is very-probably habitable by some definitions. You could engineer animals that could live there later tonight. All that's left to do is to go there, which sadly is a process we are only getting started. Europa will be a big screaming deal from now until the distant-foreseeable future. It's inevitable. Check out that slide at 2:11:37, then make sure you understand what's being told. Allow it to blow your mind. 

The next speaker, Ralph Lorenz, has a talk titled Titan Since Apollo. Certainly Titan needs it's own lecture. From Voyager to Cassini was probably the largest knowledge burst in the history of space exploration. And Titan went from a shrouded mystery to a roughly North-Carolina-Avenue but certainly green on the Monopoly board tiles of real-estate. Titan has an obvious source of exploitable energy, Lunar gravity, hyperabundant water and over an atmospheric bar, so you certainly could put an outpost there, you would just need a lot of insulation and patience. Titan is quite far away, that distance gap puts this kind of speculative-fiction outside my, and probably everyone else's lifetime, but it can be done. You don't have to take my word for any of this. As proof, Dragonfly was green-lit the moment it hit the proposal table. That was a first, and I'm slightly exaggerating. Titan went from a near complete unknown to among the most interesting places in the solar system the moment it was kinda known. Even now there are few definite's to say. It's atmosphere is complex, it's dunes are complex, it's erosional history is alien and complex. It will be a core target for exploration for decades to come.  

The next talk is titled Enceladus: A Habitable Ocean World presented by Hunter Waite, and lets take a moment to dwell on a recent point. You may have noticed some of the most famous planetary scientists do not hesitate to beg-promote for probes. You would too given the audience and constraints. Dragonfly was going to be green-lit. An Enceladus mission is far less likely, but as likely as average for now. Enceladus may be, is the beauty queen of the solar system, but the Europa Clipper is already doing the trick that an Enceladus Clipper is trying to pull, and the Europa Clipper is a Special Flagship Mission, not a proposal. So it may be that a mission to Enceladus may be delayed till after we see how Europa Clipper preforms in order to build a better sniffer. It could also just be delayed to death. Venus, Europa, Titan, a Uranus or Neptune Flagship, which will put Triton on the table, did I mention Mars, they will never sit down and shut-up. Enceladus' appeal won't go away, but may have already lost it's edge. All that said, this speaker nervously dumps a ton of technical Enceladus info. Speaking for myself I have already recklessly leapt to the conclusion that Enceladus is a world that tried to rebuild from the moon or moons that were destroyed to make Saturn's rings, then rebuilt itself to a point of equilibrium where Saturn won't let it grow larger. I also believe the E-ring can compare to the Plasma Torus beyond what is currently measured, but all these speculations are nothing-but until a probe goes and gets the hard proof.  

Krista Soderlund presents her talk, Exploration of Uranus and Neptune: Looking Into the Past and Towards the Future of Ice Giant Planets. Note that both ice giants and their many moons are lumped into one talk. That's because other than Voyager and some space telescope spectrometry, they are completely unexplored. Of the moons of Uranus, Miranda is truly unique, and all the moons larger than Miranda have lower resolution images. But something's going on with the shape of Titania, and Titania and Oberon both look old. Callisto old, so the crater morphology on one or both could go a long way to narrowing the formation of the solar system mysteries. Then Neptune and Triton are obvious. There's a ton of virtually unexplored, yet certainly intriguing stuff out there, and one flagship mission cannot be enough. At 3:01:24 she gives a nice priority scale for each Ice-Giant. Conclusions at 3:02:00.

The final talk is spoken by Dale Cruikshank and titled Fifty Years of Exploring Pluto: From Telescopes to the New Horizons Mission. I'm going to pistol-whip the next person who tries to recite to me the histories of Percival Lowell or Clyde Tombaugh. A long time ago, when the New Horizons flyby was happening, there was a part of the mission where they tried to see the "dark side" of Pluto using "Charon-shine" for light. I'm getting impatient. It hasn't come. It's implicit that there's been a problem, but they haven't mentioned a problem either. There's just silence on the topic. Slide at 3:09:23 is worth watching this far. A bit of a geological map. Incomplete without the Charon-shine. The nitrogen glaciers and the "tectonics without tidal heating," are a huge deal. This truly makes large KBO's distinct from comets. KBO binaries (which will one day be the final nomenclature of the P-C system) exchange material and energy, and while the P-C System is moving away and into shadow for centuries, other KBO binaries will appear from the shadows. Looking so far away, the suns light plays angles. KBO's too distant to have come into the light will emerge as the P-C system fades. Most likely Haumea and it's cluster of KBO's have some intimate relationship. Eris and Dysnomia may have more of a classic moon relationship, whereas Charon tidally locks Pluto and the two have four satellites together that orbit them both proportionately. I think a theme of these KBO's is likely to emerge, and the P-C system is after-all the only proven binary in our solar system, making it extra special.   

 

"The boundary between the northern and southern hemispheres is quite sharp."-Jessica Sunshine.

One concept in planetary science I take particular umbrage with is the very idea of a habitable zone. I don't think they exist. Oh sure, if you force a particular atmospheric mix on the concept you can say it's from some distance to another where liquid water can do whatever, fine. But what if you instead define it by wherever you can engineer life to persist? Europa is arguably more habitable than Earth if you slant your definition that way. Why should an ice-shell not be just as good as an atmosphere? There's liquid water at some depth and that arbitrary distance. Even tying your definition to water seems to display a lack of imagination to me. Water seems to be applicable because it's polar. There are other combinations of polar and non-polar solvents and solids that might sort natural chemicals. 

If we stop presuming and ask a comet what it thinks, what will it reply? Comets say something changes at 2.5AU. Volatiles sublimate and form the comet plasma at that range, roughly the orbit of asteroid 25-Phocaea. And comets cross that line often, from any angle. But they also do similar comet stuff at 15AU. What are comets telling us about the path they travel and what it contains, either because the comet withdrew or deposited there at some point in time.

This lecture is about hyper-active comets. That's to say, comets that have a lot more chemistry going on than normal. Hyper-active comets are a lingering annoyance proving that we don't yet know how comets, the Kuiper Belt, or the Ort Cloud actually work.  

• At 16:30 get the ingredients for a blue comet. 
• At 21:00 comet 64P-Wirtanen is the first hyper-active comet described. 
• Summary at 45:40

There's no great need to call attention to too many slides because the talk is laid out almost in story form. The story being the discovery and study of hyperactive-comets. It ends in test proposals and implications. Is the polished surface of comets literally polished by tumbling particles? Seems plausible. I often wonder if the Solar wind hydrogen, the CO2 of Venus, the dust of Mars, the whatever ejected from IO & Enceladus, are all blown into the solar wind until heliopause where it tumbles along to find some point of aggregation? The odds seem low as things spread apart, yet also inevitable since they may be in something of a closed and irregularly shaped container. That's just speculation for now, but seems to be using similar physics as the mysteries of comet study seem to be leaning.  

"The inside probably tastes different"- Steve D. Vance

Take note of this young speaker. Steve Vance may become a household name by the time of and after the Europa Clipper. He's a very good speaker, and has been a regular background player in just about everything in the outer solar system. Regular PBS & BBC level documentaries often feature Carolyn Porco, Fran Bagenal, and Robert Pappalardo (who makes a brief appearance) and Vance has been working near them all along. He may one day become one of the great rock-stars in planetary science like they are.

• Check out this wonderful slide at 3:50. I wish more such slides came with pre-mission probe lectures. Connecting the instrument payload with the science they hope to glean.
• This speaker often uses a lot of busy X-Y slides, but like the one at 12:55, you can unpack them if you pause and read before listening. Note how it's implicit that he has five of these profiles for the five most studied ice-worlds. He only goes over this particular one for Europa though.
• Slide at 19:40. The word clathrate keeps coming up. A clathrate is a crystal that has some other compound imprisoned inside it, like a hydrogen in a buckyball or a fly trapped in ice. Clathrates are very relevant in ice-worlds because they will be around odd places. You can think of Ice-3 forming around benthic clays, or Ice-3 forming around a brine in the water-column then snowing-up. It depends on the temperature and pressure. On Callisto, the snowing-up clathrates are very possible, on Europa the clay-clathrates are very likely. You can have more classifications of ice, but also salts and for sure there will be unusual clathrates few but the experts, such as our speaker, have even thought about. This is one of the most exciting things about ice-worlds to me. 
• Conclusions at 27:30.
  

Alright, lets get sci-fi for a second. If you want to live on a Galilean moon, where, specifically, do you want to live? I would argue wherever one bar is. Looking at Jupiter may sound nice, but Jupiter is brutal. You would not want to be where you can see it, and radiation can get you. So you dig, and you get so deep you are at Earth-like pressure; now where are you? What do you have? What does the ice taste like? 

 -Rachel Maxwell

A while back, during Cassini, when ocean/ice worlds were understood even worse than now, the idea that the "lithosphere" could be completely detached, ice-crust floating on water mantle, was just a hypothesis. It's a pretty strong theory now. Titan got good data to say it has such a thing going, but the best proof that detached crusts are a regular thing comes from Europa.  

• Slide at 1:00. A specific fracture individually named Rhadamanthys Linea. Along with the other linea don't they look like there is a pattern to be identified? Put a pin in that idea. 
• Slide at 2:30 demonstrates the mechanism by which Europa and Enceladus, probably Ganymede too, seem to get their linea patterns. Those arching tiger-stripes are curved with the ice surface on tidal-extension. When the floating crust moves over the more stationary core a different arc will form. The position of the crust changed, the position of the force did not. This is called tidal-walking.
• Slide at 3:40 has more to do with the speakers intended message. Specifically Rhadamanthys Linea as compared to Enceladus. Everything seems to line up nicely.
• At 4:50 Rhadamanthys expected tidal-walking is predicted.

These functions, tidal-walking and pull-apart basins, are going to come up again and again from now on in planetary science. One day someone will get brave enough to try it on rock, maybe IO. However Europa is the world in our system that by a huge margin is most likely to have life after Earth. And these functions are central to Europa. 

-Betzaida Aponte-Hernandez 

This LPI is about Rhea! Good, because we don't get to see Rhea very often.

One thing that disturbs planetary scientists is the concept of regelation. All icy bodies are deeply influenced by it, but regelation has only recently been studied in such a context. As probes are lined up for the outer solar system, post-grads are tasked with studying long ignored physics until they become an expert.  

Rhea is Saturn's second largest moon, but it's down a weight class from Titan, Triton, Luna, & the Galilean moons. It compares better with certain KBO's like Pluto, or Uranus's two largest moons, Oberon and Titania.

• Ever wanted to see a geological map of Rhea? Timestamp at 1:50. The focus will be obvious a minute later.
• At 5:10 concrete proof that sometimes speakers hand draw their slides seconds before starting their presentation.
• Slide at 10:00. In the slides preceding she is setting up a D value for Rhea. In this slide, she is comparing her D value to other D values other people made for other smallish ice-worlds. They vary a lot, because the ice of each world is different. This is one of the most interesting things to me. Ice-minerals, salinity, composition, internal heat. Look at how big a difference between Titania & Oberon even though they are both of similar size and moons of Uranus.

Here's the trick. Usually when we see a complex crater on an ice-world we think big impact. Maybe something that even punched all the way through. Then a simple crater would mean a smaller impact that displaced the source ice. However that doesn't always work. Sometimes it appears that a crater should have been big and complex, but relaxed into a simple crater. Often simple ice-craters look like a portion of their volume was injected instead of ejected like a rock-crater would be.

It's interesting because regelation works on even the coldest of ices, but seems to be effected by composition and salinity even when temperature is out of the equation. Water-ice is a hard mineral when cold enough, but regelation remains a thing. Imagine now, impact basins with stony and metallic debris. How deep can they sink into Rhea before the debris collects at a certain depth? What about Oberon? Our speaker has now put Rhea on that data-point map. 

"The Star formation rate in the region before our Solar System formed was ~4-5 times higher than the galactic average."-Emilie T. Dunham

Maybe you have heard that it's hard to see the Milky Way from inside it? It's true, and since it is, what are the many things that we would like to know, that we have a hard time seeing? Frankly astronomy isn't very helpful in these kinds of cases. What do geologists fall back on when they really want to settle their arguments? Isotopes and a mass spectrometer. Specifically, Beryllium, Boron, Magnesium and Aluminum isotopes. 

We don't get a lot of good lectures about galaxy formation, and this one lays it out quite simply.

• Slide at 3:45 is not the Milky Way, but the slide is meant to demonstrate that star formation is more likely to happen in the arms of a spiral galaxy rather than some space between or around them. But at what rate?
• Slide at 6:55 is a standard periodic table you may have seen already, but now you have context beyond the gee-wiz factor. Note that Beryllium and Boron are exclusively formed by fission of something bigger. What bigger? Could be a lot of things that divide down to H, He, Li, Bo, & B. The process is detailed on the slide at 8:00.
• At 21:50 she does something similar with isotopes of Beryllium and Boron, though with a twist, the half-lives involved are quite different.
• She brings it all together at 44:30, with a slide that implies the scale of change the Milky Way may have undergone.
• Summary at 48:25.

None of the math and chemistry in this lecture is particularity difficult if and only if, you have some college education in chemistry. However if you don't, what you are looking at is a lot of natural fission. Natural fission involves an element degrade to a different/lighter element, which on average, takes a predictable amount of time. Since she has time, all she needs is space. The element tells you how far it could have come from per that periodic table at 6:55. Be & B could have come from anywhere but Al and Mg for sure came from a point in space that was massive (there was a lot of it,) and energetic (big explody.) So a place in space that had a lot of dust, turned into a big star then later, then left that place in a hurry. In this way she can predict where old nebulae were, how big they were, and where they distributed their stuff on explody.

Now she knows when and relatively where (in our arm of the Milky Way), a thing in the Galaxy happened, as well as the rate of happenings.

 -Natalia Rossighnoli

Titan is irresistible. Pity that it's so damn far away. We now know that the Dragonfly mission, once launched, and then given sufficient travel time, will land adjacent the crater "Selk". This location will allow Dragonfly to study an area where heated and metamorphosed organics are likely. All set? Not quite, because why Selk and not some other crater and location? 

Image of Selk taken from 2nd link above.

• Slides from four minutes to eight minutes are very algebraic. Our speaker is making emphasis on Titans impact zones. Impactors land generally equatorial, generally high-speed and passing through the shortest routes of Titan's thick atmosphere. Generally finding the places where it presumably makes lakes least often, if only because that's where the least erosion seems to happen.
• Slide at 10:00 singles out a different crater than Selk. Melbourne crater (probably a caption-mistranslated "Menrva") seems to have a case to say it's the eldest of Titian's craters, perhaps primordial. One one hand, that's neat. On the other hand, what can you do with it if Dragonfly doesn't carry a drill? You would just see topical sediment.
• Conclusions at 12:10

In the end our speaker was emphasizing crater density on Titan. After-all, this talk was part of the Planetary Crater Consortium and not specifically a talk about Dragonfly. But it lead me down a bit of a rabbit-hole. I knew very little of Titan's various craters beforehand. And the answer to; "Why Selk and not (I'm pretty sure it's Menrva)" are in the links above. Though I find the topic to be fairly controversial.

"These images were such a delight to look at." -Emily Costello

Ganymede is one of my personal favorites. Partly because it has plate-tectonic activity that might be active, more similar to Earth than any other world. However the similarities don't go far, because Earth-like subduction and buoyancy differences between granite and basalt are off the table. Ganymede uses different rules to do different things than Earth thought to be related to ice expanding as it freezes. But there is a catch. The Sulci of Ganymede seem to take up more space than water freezing alone can explain. The simplest explanation is that the Sulci didn't rift at once, they took turns.

That's what this fantastic LPI lecture is doing, dating the relative ages of the Sulci by crater-counting.

• At 6:40 the speaker starts showing craters on trailing Sulci. Leading and trailing are important terms with moons. Jupiter is attracting impactors, and Ganymede's leading end will collect more than the trailing end. Since Ganymede is tidally locked, the leading end will always be the same.
• The slide at 7:00. Look at Tiamat Sulcus. Is it older or younger than Kishar Sulcus? The one that crosses the other is younger. Which one is younger in this image? There seems to be another Sulci inside Tiamat Sulcus that is the youngest, while Kishar is younger than the rest of Tiamat. But the youngest thing is that crater right on the intersection there, and there aren't very many craters in that image. See how fun Ganymede is?
• At 9:00 the speaker demonstrates the same law-of-superposition, (younger is on top), principal, just in a mathematically absolute manner.
• At 10:10 the speaker demonstrates a conflict between eyeballing the law-of-superposition and her mathematical model. In every case, the law-of-superposition wins. The likely explanation is that where they overlap, the newest Sulci wiped out the craters on the bottom Sulci, thus skewing the numbers. 

The bottom line is that Ganymede craters do make for an accurate method to date Ganymede's Sulci, and that the Sulci vary in age considerably. But there's another funny catch to consider going forward. Europa's double-ridges are thought to be related to where Europa's crust happens to be (since it's floating) when it pulls towards or away from Jupiter. The Europa ridges tend to come in arcs this way, and periodically appear with ongoing frequency. Ganymede has very different morphology, but the root cause may be similar. However Ganymede may not be gaining new Sulci anymore if the ice-lithosphere is thick enough to resist and insulate. Ganymede has internal heat, and the thermal expansion of ice may be in equilibrium.

"I'm not necessarily here to advocate for Neptune over Uranus but..." -Abigail Rymer

This LPI is about a misson proposal. A flagship budget to Neptune. Strictly speaking, it's less likely than a similar Uranus mission because Uranus will be in a better position for the next decade; they move slow and wide. 

This begs the topic though, so much of the outer solar system is so far and inaccessible, yet so baited with temptations, that I wonder if it will compel engineering in the near future. This, the age of probes, and so many targets are so far and separated that scientists are discouraged before they try. Wouldn't it be nice if we could get the probes to go faster, and still get into orbit around objects with scant gravity? Maybe two delta-V launches, the probe, then a bonus fuel tank for the probe. It's sad to realize many of these temptations cannot be reached in my lifetime, and I would like to be greedy.  

This short mission proposal LPI actually has it’s own time-stamps between slides. It's intuitive and needs little paraphrasing from me. Probes themselves begin to have personality at some point, and this is one I would like to meet one day.   

 -Sean O'Hara

Cryovolcanos are peculiar. If not for Triton I wonder if people would find the topic so interesting. However... Triton. Among the most active worlds in the solar system, and so far away a return mission isn't forthcoming. 

• The slides in this LPI are self explanatory, so I don't feel like I need to call attention to some choice timestamps, but at 12:00 the future of planetary science makes an appearance.

There are 5 cryovolcano suspects named.

1. Ahuna Mons on Ceres at 11:00
2. At 13:30, Hubble says there might be plumes on Europa, nothing confirmed. 
3. At 15:40, Enceladus' Tiger Stripes, the most studied Cryovolcano of them all. 
4. Triton at 17:20. With a mission teaser. 
5. Pluto’s Wright & Piccard Mons at 19:00. Not confirmed at all, but odd enough to take a hard look at. 

At 28:40 in the Q&A he shows you some of the "anti-freeze" chemistry in videos. Lab-lava in it’s cryogenic form. At 34:00 he models a volcano with chocolate. It’s even better than I’m making it sound.

If interested in more check out Fire & Ice by Natalie Starkey.

 -Rachel L. Klima

This is a really easy LPI to love. The slides are lovely and intuitive, partly because Europa scientists have had tons of time to salivate and trade graphics.

If you were an alien looking from a distance at this solar system, you could be forgiven for thinking Europa was the most likely place to find life. Mars life is just talk, Venus, Titan, Triton, Enceladus, sure maybe; but there really actually might be something going on inside Europa. The difference is huge because Europa has been going like this since longer than Earth has had a solid surface.

So why not fly a lander with a drill instead of Clipper? Because you don't know where to land, and how much of what kind of drill to bring. The range of what the crust thickness can be has kilometres of error involved. Europa Clippers primary mission is to find a good spot, which happens to involve collecting a ton of science anyway. 

This LPI is a very excited preview. The closer the mission gets the more enthused the scientists get. You can really feel it. Like they're planning their haul before they go trick-or-treating.  

• That slide at 10 is gif worthy by itself. Showing the IO flux tube aside Europa's induced magnetic field.
• At 16:30 the concept of "subsumptions". Basically a forced rifting in sort of a slip-strike sort of way. But that's awesome, because it's not a common thing on Earth, but may be a regular thing everywhere else.

We're driving over around Mars, and we're looking at all these sort of inorganic rock minerals,searching for any organic molecules that may be trapped inside them. Whereas on Titan, organics are everywhere -Melissa Trainer 

This LPI is more science and less engineering than the last one I put up. Which because the Cassini mission was so crazy good, and a little time has past, means this LPI is packed with good slides. 

Complex chemistry. If I tried to rank the complexity of atmospheres, Titan, Earth, and Venus, I couldn't because Venus hasn't been studied enough, but Titan has, and is more complex than Earth. This is a big part of why Titan is irresistible. It's un-Earth-like traits and Earthlike traits combine to make it attractive and scientifically usable. 

• Slides kick off early at 9:00. Pretty must every slide is lovely and informative.
• At 18:00 there is a simple slide, but it makes me think. Titan is the only world that rains to a surface aside Earth. It has winds comparable to Earth. Yet some worlds like Triton and Europa are cratered about as much.  
• Slide at 25:40 she repeats the bit about wanting to see what happens when an impact packs hot organics into Titans surface. I'm hearing that bit repeated a lot from the Dragonfly science team so we can take a flagrant-hint about where Dragonfly will be looking to go. At 33:20, the name of the crater is 'Selk'. 
• At 35:10 and after, Dragonfly's planned route is made explicit. 

In general, the extraterrestrial search for life does not inspire me much. I find it overplayed, but then when it comes to Europa and Titan, I can't help myself. Europa is almost more likely than Earth if you didn't know better. And Titan, far less likely, but there is so much possibility. 

One thing that sits in the back of my mind regarding Titan is the idea of a benthic environment. No doubt silt of Titan is different and follows different rules than Earth. With life, water sorts polar molecules and separates polar from non-polar, so you already have a basic organizing to start with. On Titan the seas are non-polar, not at all like water. But the dirt is polar. So the benthic layer, where nonpolar liquid emulsifies polar particles, is a place where some sort of basic sorting can occur.

I've never heard a proper planetary scientist talk about benthic Titan. Not the seas nor the soggy flood-plains. I hope to one day, but if it's going to happen in my lifetime, it will probably be the Dragonfly mission.