raptop changed the topic of #kspacademia to: https://gist.github.com/pdn4kd/164b9b85435d87afbec0c3a7e69d3e6d | Dogs are cats. Spiders are cat interferometers. | Космизм сегодня! | Document well, for tomorrow you may get mauled by a ネコバス. | <UmbralRaptor> egg|nomz|egg: generally if your eyes are dewing over, that's not the weather. | <ferram4> I shall beat my problems to death with an engineer. | We can haz pdf
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<mofh> egg|zzz|egg: it does seem to make sense to me, tho I'm not sure what justificiation I'd use here
<mofh> but it seems reasonable to me, at the least.
<egg|zzz|egg> mofh: the justification is that you want to eliminate short-period perturbations (those that recur every revolution), as they have a high amplitude and are by definition a distraction from the Keplerian behaviour and its evolution
<egg|zzz|egg> so you filter over a duration that's ~one revolution, for some definition of revolution
<egg|zzz|egg> the definition that is least affected by short-period oscillations ideally, so that you can start somewhere :-p
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<mofh> egg|zzz|egg: hrm, that makes sense.
<mofh> I keep forgetting short-period perturbations *recur*
<egg|zzz|egg> mofh: even if they didn't, you'd call them "noise" instead of "short-period", and a low-pass filter would still work :-p
<egg|zzz|egg> (but probably wouldn't work as well I guess)
<mofh> point, I guess at that point they are noise, I don't know why I was worrying about the inability to predict non-recurring perturbations
<mofh> unrelated but this hacking dry cough is AMAZING no actually it fucking sucks.
<mofh> thanks, neutrophils.
<mofh> theutrophils.
<whitequark> lol
<mofh> like the worst part is I know more adrenergics (specifically adrenergics) will help with the throat insanity or at least make it more tolerable but are a *terrible* idée to take in this weather
<mofh> since vasoconstriction is just about the last thing I want right now
<egg|zzz|egg> mofh: well, they ought to be highly periodic, which should make integration over something close to their period a decent filter
<egg|zzz|egg> that's how you end up getting a good e by integrating e sin ω, e cos ω (that was over many periods but iirc mean ω varies slowly and only with long-period cyclic variations, no secular ones, for TOPEX/Poseidon so it still worked)
<egg|zzz|egg> (even though osculating e is garbage at all times :-p)
<egg|zzz|egg> there's a pretty strong periodic signal there :-p
<B787_300> joke/pun for yall... why must all people who own a house have a cat?
<B787_300> because they are a hoMEOWner
<egg|zzz|egg> makes sense
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<egg|cell|egg> !wpn whitequark
* galois gives whitequark a horizon with a potato attachment
<egg|cell|egg> I should sleep
<whitequark> !wpn egg
* galois gives egg a shell
<whitequark> !wpn !wpn
* galois gives !wpn a switched grenade
<whitequark> 02:40 * galois gives egg a shell
<egg|cell|egg> !
<whitequark> ok can we talk about how appropriate this is
<whitequark> and the second one too honestly
<UmbralRaptop> Sometimes the bot is good
<UmbralRaptop> 🐈🏡
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<kmath> <✔Tesco> @mattyjstock Hi Matthew, I have had a response from my support team. They have advised the date code on the relish… https://t.co/PkPpZIJUjW
<UmbralRaptop> 2020-05-20T00:00:00Z is JD 2458989.5
<kmath> <jajohnson51> TIL that the artistic illustrations of the Milky Way make it look too blue. The Milky Way is probably a red spiral… https://t.co/9qjPf6XPkB
<SnoopJeDi> I wonder what astrobiology has to say (if anything as yet) about the age of a galaxy and life formation. Presumably you need some pretty good mixing to occur before you've got enough for what they'd call "interesting" chemistry
<UmbralRaptop> I'd guess that you want a complex star formation history. Lots early on for heavy elements, but then a moderate amount (small bursts?) later to exploit it without getting too many GRBs
<UmbralRaptop> Don't ask me about black hole feedback >_<
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<egg|cell|egg> Mofh: 喵
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<uovo> !wpn mofh, whitequark, et al.
* galois gives mofh, whitequark, et al. a harpoon
<egg|zzz|egg> UmbralRaptop: mofh: "type II frozen orbits"
<egg|zzz|egg> ah, this book calls frozen orbit type-I if they are frozen because critical inclination, type-II otherwise https://link.springer.com/chapter/10.1007%2F978-3-319-74373-8_12
<egg|zzz|egg> mofh: oh this is interesting: Precise Analytical Computation of Frozen-Eccentricity, Low Earth Orbits in a Tesseral Potential
<egg|zzz|egg> featuring capitán de fragata Martín Lara
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<uovo> mofh: topicquotes
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<UmbralRaptop> egg: which type of frozen orbit would have an event horizion in its future lightcone?
<mofh> egg|work|egg: what are the differences in frozen orbit type?
<egg|work|egg> mofh: at the critical inclination, the argument of periapsis is unconstrained, the inclination prevents its drift (you get oulitka orbits)
<egg|work|egg> the eccentricity is unconstrained as well
<egg|work|egg> mofh: otherwise, the frozen orbits need to have an argument of periapsis at 90 or 270 degrees; it is the frozen eccentricity (dependent on chosen inclination and semimajor axis) that freezes the orbit (usually the orbit is near-circular, but not always)
<egg|work|egg> mofh: type I freezing is by J2; frozen orbits around the moon are type II always because J2 does not dominate there
<mofh> so type II are just everything not type I?
<egg|work|egg> mofh: well yes, in a sense
<egg|work|egg> they are the ones that are frozen by omega being 90 or 270 instead of i being i_c
<egg|work|egg> mofh: I think both types form a 2-parameter family
<egg|work|egg> in the type I case, e and ω are free
<egg|work|egg> wait no a is free too
<egg|work|egg> mofh: okay so type I is a 3-parameter family (ignoring the mostly-trivial freedom in Ω and initial M, can't really call those different orbits)
<egg|work|egg> with i constrained to a mostly-fixed value (actually a function of a iirc but not that strongly)
<egg|work|egg> mofh: whereas type II is a 2-parameter family, as you get e(a, i) (occasionally multivalued), and ω is ±90° (I think its sign is constrained by i too)
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<egg|work|egg> mofh: meow
<egg|work|egg> !wpn mofh, UmbralRaptop, whitequark, et al.
* galois gives mofh, UmbralRaptop, whitequark, et al. a heptapodial tetrahedron
<UmbralRaptop> Alien geometry?
<UmbralRaptop> !wpn egg|work|egg
* galois gives egg|work|egg a discrete ordinary hexagon
<mofh> !wpn egg|work|egg
* galois gives egg|work|egg a arsenic iridium square
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<kmath> https://twitter.com/ClementSalviani/status/1143877161062948867 <ClementSalviani> J'ai fait mon premier clafoutis avec les cerises du jardin de ma moman. Hâte de le goûter. https://t.co/rRLo9q0fLE
<mofh> egg|work|egg: today's terrible hiding-from-the-canicule strategy: pavillion d'horloge, niveau -1, Pavillion Sully, Le Louvre :p
<mofh> (and by terrible I mean it's actually *really* pleasant down here)
<mofh> egg|work|egg: scrolling up,I
<mofh> egg|work|egg: scrolling up, I'm a bit confused why frozen-by-J2 is the 3-parameter family, it strikes me as that's the one that should have *less* degrees of freedom but it's not
<mofh> and I'm not sure I understand why
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<kmath> <LiaSae> “I’ll be honest, I don’t see how I could eroticize Léguman” - @BicheDuMarais
<mofh> on today's episode of "it's always a good sign when the weather station is posting this": https://twitter.com/MeteoMontsouris/status/1143986818750267397
<kmath> <MeteoMontsouris> Courage, la température baisse plus vite ce soir qu'hier soir… https://t.co/4WMdPrEzXT
<mofh> more of a breeze tonight too, mercifully
<B787_300> mofh: why is it important that the temp is falling faster
<B787_300> actually let me ask the better question... how many times in the past decade has that location seem temps above 32.5
<mofh> B787_300: uhm: A) not much of a climatological purpose, but it goes a long way into making it more livable, the temp didn't drop to livable levels until LATE last night and that didn't help, B) uhh very rarely?
<mofh> like I think we're forecast for a high ~2degC warmer than the record for tomorrow or Friday, not sure which.
<B787_300> and because its europe yall dont believe in AC
<B787_300> (tbf i dont think 34C is all that hot
<B787_300> like it will be 32.2 C high tomorrow where i am
<whitequark> B787_300: "34C is hot/not hot" is a meaningless statement
<whitequark> "34C with 85% humidity" is death
<whitequark> "34C with 30% humidity" is pleasant
<B787_300> fair point
<B787_300> looks like when we hit 32.2 C tomorrow RH will be around 50%
<mofh> B787_300: https://twitter.com/MeteoMontsouris/status/1143916309593374721 we hit 34.2degC, RH ~53% and of course no A/C.
<kmath> <MeteoMontsouris> À 18 h, il fait 34.2 °C, légère brise, humidité à 53%, pas de pluie. https://t.co/I6zc33hmlI
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<uovo> mofh: well, frozen-by-j2 is just "be in that plane", and you can have whichever orbit shape, size and orientation you want because ω' is 0 in that plane
<_whitenotifier-5dfc> [Principia] eggrobin opened issue #2222: Flight plan error message wording - https://git.io/fjrxS
<_whitenotifier-5dfc> [Principia] eggrobin labeled issue #2222: Flight plan error message wording - https://git.io/fjrxS
<_whitenotifier-5dfc> [Principia] eggrobin assigned issue #2222: Flight plan error message wording - https://git.io/fjrxS
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<UmbralRaptop> This is far too accurate http://phdcomics.com/comics.php?f=656
<B787_300> UmbralRaptop: gotta make room for all the other random shit you need to know
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<UmbralRaptop> Fair
<uovo> !wpn whitequark
* galois gives whitequark a bismuth linter with a question attachment
<whitequark> !wpn egg
* galois gives egg a bad bird
<whitequark> is that like a bad dragon
<uovo> what's a bad dragon
<UmbralRaptop> uh
<whitequark> enormous silicone reproductions of imaginary animal genitals
<uovo> whitequark: so would that be the same but with avian genitalia
<whitequark> i think so yes
<uovo> <insert something about ducks here>
<whitequark> like, animatronic duck penis.
<whitequark> pfff
<mofh> UmbralRaptop: I feel like that's the inverse of how I operate
<mofh> UmbralRaptop: like I could prolly function as a uni tour guide for most campuses I've been on for more than a week.
<UmbralRaptop> whitequark: so if we include airbag style explosives…
<whitequark> UmbralRaptop: BAD IDEA
<uovo> whitequark: most birds just have a cloaca though
<whitequark> well yes
<whitequark> but we're talking about *bad* birds
<whitequark> and ducks definitely qualify
<UmbralRaptop> whitequark: well, yes. It was an absurd idea because ducks
<uovo> explosive ducks?
<UmbralRaptop> mofh: it really doesn't help that the people asking seem to never have questions about where the buildings I actually work in are? >_<
<uovo> mofh: also it's too hot here too
<UmbralRaptop> Today's high was 305.
* UmbralRaptop refuses to believe that a nontrivial number of people lived within 40 degrees are the tropics before air-conditioning
<whitequark> they didn't stay up during the day, right?
<whitequark> more of a crepuscular lifestyle than diurnal
<uovo> are we talking about cats
<uovo> whitequark: but e.g. afternoon naps are very much a thing
<whitequark> ye
<uovo> !u е
<galois> е: U+0435 CYRILLIC SMALL LETTER IE
<uovo> I saw a black cat hiding from the sun under a car on my way to work this morning
<mofh> I ran into a grayish cat today hiding under a piece of construction equipment by one of the parks here.