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.   

 

NASA media briefing feat; Kate Calvin (Chief Scientist), Lindley Johnson (Planetary Defense Officer), Tom Statler (Program Scientist), Ed Reynolds (DART project manager), Lena Adams (DART systems engineer).

Couple things off the bat. First, these press conferences by NASA tend to be dumbed down. They're scared of being connected to the inevitable "Aliens-Confirmed" headlines and don't want to be left without an alibi. Second, they suck at reading teleprompters for nerves and lack of practice. They themselves usually wrote whats on the teleprompter but you can never be too sure. There for certain was editing involved regardless. This one was way better than say the Perseverance one, so on the higher end of panel-previews. 

This is a preview, and the impact happened last night. I'll put up a during-impact-vid below but there's more information in this one. Test results with the good stuff for this particular mission will come in the form of a scatter of astronomical observations in the next few weeks followed by a lecture which may take a year (depends on who publishes first.) Then the ESA Hera mission will follow up in 2024 and kind of absorb the DART mission, giving a bunch of quick images before a lull before anyone publishes and lectures. 

• Tom Statler, the skinny guy in the middle, drops some good info at 5:30. Most Reddit level questions will be answered in this bit.
• Lena Adams' bit starting 13:20 is pretty good, but possibly old news at the time I post this.
• At 15:40 public Q&A starts. It's pretty good. Partly because it's a mix of credited media reporters who do this full-time. There's a big difference between a press-conference and a press-release They aren't random reporters, they do NASA and they personally know the NAS'ites. These reporters know how to ask good questions and they usually compare notes prior so they ask different questions. 
• One thing I noted was that Dimorphos did in fact look a lot like Bennu, but there was a bit predicting it would not. That's not really a contradiction. They know the density of both and density is a bigger deal than albedo. They also know the spectroscopy and that gives them an average idea of what the rubble in the rubble pile is. So DART probably was stopped by Dimorphos but for sure there was a splody. The astronomers will have something to say today or soon.

This one is happening at LPI at the same time as the countdown to impact. So there are some wonky editing-presentation things that happen but in this day-&-age are actually normal for these kinds of live events. 

Edgard G. Rivera-Valentin from APL (the lab that's running this mission) gives a hype-lecture starting at 4:50 to kill time while we wait for impact. It's a lovely presentation, certainly informative, but mostly it's got a lot of great slides.

• At 30:00 it goes into Q&A
• At 39:30 the Q&A is interrupted to see the impact. There's no video but there is audio. 
• At 49:10 Ed reacts "With all those boulders It's definitely looking fluffy." Implying he suspects it would have deviated from orbit a lot and sent out a lot of debris.

Here's the gif for reference. And a link to Wiki which has some analysis at the bottom.

"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. 

 -Michael Zeilnhofer 

The Dawn mission is going to be putting out good data for a while, partly because it covered two divergent targets, Ceres and Vesta, but also because it carried a payload of data heavy equipment, from which a great many observations can be needled out. 

This LPI is an early attempt to categorize the full crater inventory of Ceres. Everything larger than a kilometer is surly an impact, while smaller craters may be ejecta. Therefore an effort to list and map large craters is a must, and here it is. 

• Check out these beautiful but enigmatic features on the slide at 3:35. 
• The very next slide at 4:10 shows another odd feature, a polygonal crater, and it's not the only one.
• Conclusions at 12:40, with a lot of simple charts between. 

Ceres has a few glaring mysteries included such as the geophysics of Ahuna Mons and these salt deposits. Now we are starting to see (because this more a trailhead of investigation than a one-&-done) that there seems to be a difference in regional crust strength on Ceres. Picture discrete patches of Ceres having totally different properties, but you can't see these patches at a glance. The implications are that all ice-worlds have similar traits. 

-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. 

"They open up doors and pull these suits out on gurneys, now that's weird. And particularly when your name is still there." -Harrison H. Schmitt

In light of Artemis I remembered this old LPI, and am pleased my memory could do that. On the other hand it's quite memorable. The speaker is a geologist and an astronaut and has worked and lectured in planetary science ever since. The context of this lecture though is part reminiscing, part mission report, so it has a unique feel to it, and I promise you if you watch it you will feel closer with the Artemis mission.

• Prior to 13:00 he speaks of the lead up, astronaut stuff you've seen before. After that time-stamp he starts speaking clinically of the landing site, which many have not seen these pictures with context before. 
• From 13:00 to 20:20 he describes the area-of-exploration quite simply and attainably, but also as though you were in the room as a part of the mission. Providing maps and stunning pictures (that he himself took, some became famous) of the study area. 
• Anecdotes and background stories carry you through the 31:00 minute mark. And it should be clear now that the images you have not seen are often the best of them. 
• From 36:10 on he steps up his lecture game at the cost of some anecdotes.

This lecture displays what Artemis astronauts will be doing, so on-point that you will be equipped to guess for yourself. It even implies what engineers have worked on between Apollo and Artemis. When you have this kinds of context the mission becomes much more valuable, like how a jeweler can determine precious stones better than the average rock-hound.

"I always have to think about why things are important nowadays, when I first started out it wasn't like that."-Virgil L. ("Buck") Sharpton

Buck Sharpton has retired by now, and that's a shame. He was always a good speaker with subtle humor and blunt details. 

This LPI is about crater morphologies. You may notice that crater morphology gets talked about often. That's because there is a lot to infer out of it. So much so that what you can infer is still expanding. Many if not most modern planetary scientists were taught directly or indirectly by Buck.

• Slide at 21:20, the interiors of crater rims display the target rock as uplift. I to this day am still wondering why Curiosity never tried to see the outcrop of Gale craters uplift zone. Another important detail on this slide is that crater ejecta isn't expected to be a voluminous as it used to be. This is a recent change in thinking, but the material that was thought to be ejected is actually mostly injected.
• At 39:00 he transfers to talk about Venus, underscoring how little is known about it, even now.
• At 49:00 you get to learn a little trick of Radar that comes in handy in places like Titan and Venus. Radar is very sensitive to angles, and because of this you can math out a line to do trig with. So you can get accurate scales even without a sun-shadow or laser. With radar bright = rough and dark = smooth.
• At one hour Buck brings it home. A lot of solid Venus facts are in the latter half of this vid, but it is widely assumed that Venus lost it's whole surface at once. It's possible it didn't, but to make that work, Venus has to be thought of quite differently. 

You can see that Buck was a very good lecturer. Note how much more dynamic his presentation of Venus is. Did you even know about those parabolic "guppies" before? When you hear about Venus it's almost always some pre-school level content. Retrograde, hot, pressure. Stuff every kid knows. At the college level, they know more stuff, but it too is repeated so much the students start to just mention it offhand, not appreciating that the general public has no idea. 

"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.

"I wouldn't be dwelling on this if I didn't think it was the dominant mechanism"- B.M. Jakosky

I want all readers to consider two important things. 1) Atmospheres are not round, and they aren't very tight. 2) Mars dust does a lot of weird stuff. It has no Earthly equivalent, not even in the driest deserts, and it is always a factor.

The MAVEN mission to Mars is one of the least understood (probably thee least,) yet most important Mars missions to date. This speaker was the PI of MAVEN till about a year ago, when MAVEN ended its science campaign, yet still serves as a relay for ground probes.

• Slide at 5:50, "The upper atmosphere changes with seasons by an order of magnitude. That means the loss rate changes by an order of magnitude." Basically what he's saying is that in the dusty season, the loss rate of atmosphere skyrockets. This is one of two great discoveries MAVEN made. The loss rate on Mars is not consistent even remotely. To this day, people on the outside looking in still seem to assume that it is. "You can't just multiply the current loss rate by four-billion years."
• Slide at 12:40 shows the second great MAVEN discovery; EUV losses were going at a much higher rate before three-billion years ago. They took a different rate when the atmosphere got small enough that Mars gravity could hold some of it. The start of hyper-fast-atmospheric loss is about as old as the oldest Mars surface, Noachian highlands. The end of that rate, and beginning of the current variable rate, seems to start deep inside the Hesperian. This means that whenever Mars lost whatever dynamo it had, the lions share of the atmosphere quickly followed, switching gears during Earths Archean Era. 
• Slide at 16:40, mostly because it's awesome. You get a really cool image of a big Coronal Mass Ejection (CME). CME's are the penultimate-reason you cant import or release a sudden atmosphere on Mars. 
• Final comments at 25:60. 

I don't know why, but MAVEN seems to be referred to a lot by persons whom have obviously misunderstood everything about it. Every MAVEN lecture I've seen is bits of this one, which I'm confident is the most modern. 

"Despite uncertainties, conclusions about significance of loss to space are robust." In other words the MAVEN team tied-a-bow-around-it, and are very confident that Mars started losing atmosphere the day the ground solidified.

 

Here's a book that is frequently cited as a classic, mandatory for all who aspire to be called literate, and it is. 

Curiously, it has been borrowed from so often since it's publish, that I can't tell if authors like J.K. Rowling borrow from it liberally and intentionally, or unintentionally because so many others have too. It was once far more original than it comes across now. At any rate, you can consider this J.K. Rowling for grownups.

Interesting that there are many literary tricks Eco used that have not been widely mimicked since, and they work. 

Elementary in a good way, this guide is appropriate for supervised children and passionate chefs with access to a thriving forest.

This book teaches well, but it leaves me with a few nitpicks. The images in chapter 3 seem more glam-shots, and there are too few of them. I would like to see mushrooms in various stages of growth and concealment. This goes triple for anything poisonous, where I would want to see diagnostic images. I feel it may be irresponsible to make a mushroom foraging guide that does not include psychedelics. If that's what your looking for give this book a hard pass because it has none. Nor is it comprehensive, so you cant guess a mushroom is psychedelic by process of elimination. You may run into something poisonous.

But this sets out to be a good rated-G guide, and it is. I can't help but believe there are better mushroom foraging guides out there, but this one does teach well. 

"By the end of 100 million years after the initial formation of the solar system, we've already had the full-fledged formation of all the major planets."-Roger Fu

The Solar System is 4.56 Billion years old. Life on Earth started at least 3.7 Billion years ago. So that 0.86 billion years had a lot going on in it. So much that if you leave it just to gravity to form and alter the planets, there isn't enough time. 860 million years is a long time, but every Late-Heavy-Bombardment object, including surviving planets, was formed then. Thea, the impactor that blew off Mercury's crust, Heles, the two impactors that shattered Vesta, the Saturn moon-object that was destroyed to make the rings, and the thing that hit it; all these things came and went. A force other than Gravity must be in play. Magnetism is a good suspect.

• Slide at 5:20, just like currents in an ocean, the gravity of Sol, and magnetic field of Sol, pull in debris until the solar wind can oppose the pull. But then rather than scatter the debris, it is concentrated along magnetic field lines, where the debris is able to accrete faster by its own gravity and magnetism.
• Slide at 13:30, so if all this is true, how do you test it? 
• At 19:30, just because it is awesome, the speaker shows us a new kind of microscope. One that observes magnetism to the nano-meter scale.
• At 25:10 he starts over for the outer solar-system. Explaining the differences for the more water rich particles outside Jupiter. Regardless of where Jupiter's orbit happened to be at that time.

So the spoiler is, yes, it does appear that magnetism had a lot to do with the speed at which the proto-planetary disk made planets. However, the implications are that there is some reason why the gas and ice-giants formed in the outer, not inner system, and that was not mentioned. Also, it's implicit that planetesimals had early inclined orbits. That's interesting, but left hanging. 

"Collisions, they inevitably lead to, dust ejecta to fragments."-Abedin Yussein Abedin

Kuiper Belt Objects (KBO’s) are among the most intriguing objects out there, largely because they are hard to see and get to. Only the New Horizons mission has truly tried. There are a great many KBO’s, but they are so small and so spread apart that they rarely contact each other. None-the-less they do collide, and this lecture is modeling what to expect during such events.

• Slide at 7:00, she has a X-Y scatter plot comparing space in terms of AU (so big as heck) to eccentricity of orbit. Eccentricity effects the odds of an impactor finding a target because objects in the same plane are likely going about the same speed and also might find a resonance between them. KBO’s that approach Neptune are more likely to change orbit than those that stay away, and most KBO's are close enough to be effected. So which force is greater; proximity to Neptune, or eccentricity?
• At 10:00 she shows a frank equation to calculate collisions between KBO’s. One might think it would be harder than that. 
• Slide at 12:00, turns out the equation is incomplete, so yeah.
• At 15:20 she compares probability to speed, hence, likelihood of a big one. However, also a small one. Keep in mind the KBO’s will merge at certain velocities or destroy each other. Her graphs can be used for either. 

Most collisions happen in the main KBO belt, about 30 AU outside of Netune’s orbit. When they happen they are usually low impact, and likely to merge most of the mass of the two KBO’s. One could infer the results of the collision if you could see dust in the vicinity, but that has been difficult. More dust would mean a more destructive collision, the area where the dust is found could give clues to time and angle.