"And what we found, is not what we expected to find."-Ken Farley

JPL used to have a good monthly lecture called the Von Karmen lecture series. It still exists, but about three years ago they turned to dumpster juice, "discussions", severely dumbed down past the point of not being worth watching. The old ones are still good, though some seem to be missing. Currently however, they seem to be trying to compromise some sort of internal stressor by keeping aspects of the discussion (which inherently are a waste of time and are still a burden on the videos) but have someone actually show up with slides and information. So I'm willing to watch them, and I can tell you where the good timestamps are. 

This JPL however is a "news briefing" video, less risky than the current Von Karmen lectures. This one is from mid-September of this year.

• Skip ahead to 7:13. Just hype prior.
• At 10:00 Ken Farley mentions one of Percy's major finds so far; the Jezero floor is covered in Igneous, not Sedimentary material, implying that the most recent major deposition events in this basin were not water related. "Crystalized from a melt", consistent with one or several impact pyroclastic flows.
• KF also mentions a very important Mars thing... we don't actually know any dates on the ages of things. We can relatively date things, Law of superposition and whatnot. There is plenty of that, but all Mars dates have a ton of error involved currently. We need sample returns to constrain that, and that alone will settle a great many backoffice arguments.
• About 15:50 David Shuster referring to 'wildcat-ridge' mentions that this mudstone bears sulfates, and is salty "possibly in the lake evaporation stage." So Hesperian (because sulfates) and water is depleting. That's no revelation, but the twist is that while this kind of stone is a good preservative of biological organics, as opposed to chemical organics, anything that might be biological is much less likely in the Hesperian.
• Q&A at 37:35.

I have to admit that I personally am a tad frustrated with the Perseverance mission. It may color my impressions, but the Percy crew seems overly focused on astrobiology and tunneling on any organic finds. Organics are everywhere, and not by themselves remarkable. Titan gives no shits about Mars' organics. The sedimentary record is much, much more interesting to me, and the mission happens to be looking at sedimentary rocks, just not talking about them. Sedimentary layers in Jezero should have Noachian stuff included, and no successful missions have touched down on Noachian soil to date. I fear the best discoveries of the Percy mission will come years after it has concluded.

"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. 

 

There should be a book like this about every celestial body in the solar system. A book crammed with facts like a textbook, but serving them for delight instead of a textbooks obstructionist ways. 

I cannot think of anything to nit-pick. This is a superb example of what non-fiction should be.

"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.

"Permeability is key here."-Suzanne P. Schwenzer 

Skip ahead to 7:00. It's literally dead air up till then.

This video is probing reaction pathways on Mars, to paraphrase it is trying to find exact means by which exact species could live on Mars. 

Astrobiology is a peculiar field. When in the history of history has an 'ology become so robustly staffed long before the first sample is discovered? Such is the red carpet lain before the first alien we can find. Mars isn't among the more habitable places. Remember, 'habitable' for astrobiologists is "can you name a critter that can live there." Mars looks like you could have in the past, Europa however might have life right now and if it doesn't there is almost certainly something from Earth that could thrive there. Venus can't support life at any altitude, but it wouldn't take much investment to get it there. Mars, would take much more investment. Arguably all the frosty ocean worlds could be more habitable than Mars.

This LPI is only looking at Mars and primarily set to ID 'fossils'. Anything that could have lived on Mars had to eat, but what? And had to leave a trail of waste, also unknown. But what is even possible? This LPI narrows it down. 

Our speaker relies heavily on her argument and didn't bring the best slides. The better slides come around 33:10.

• About 34:00, impact sites on Mars are one place where the heat to drive life could be after the very beginning era of Mars. But not in the middle of the crater. At the lowest places, where liquid could pool and the basin could be permeable. This will also Apply to Titan and the Dragonfly mission.
• 39:40 She doesn't really call it out that I noticed, only because her assumed audience would already know it, but the chemicals she names have enough chemical energy to drive some sort of metabolism.
• 40:40 the slide is... not showing you outright, but proving the chemical reaction paths that microbes could capture energy from. 

All planetary scientists have come to note that Mars history is very episodic with a background trend of cooling. In other words Mars climate change has been constant cooling, no decadal period had the same habitat. However in local environments, say an old melt-dyke, or an impact crater (Gale craters development is wholly explained using the heat of impact alone,) you really could have a stable environment for a while, centuries, and this LPI is showing that you could have the food too.

"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.