egg|nomz|egg 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.
<soundnfury>
UmbralRaptor: this owl, is it superb?
<B787_300>
soundnfury: no that was last weekend
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<bofh>
B787_300: uh, working in a chemical lab?
<B787_300>
ah fun
<B787_300>
know any places that I can get about 30 L of LOX?
<B787_300>
for reason...
<B787_300>
for whatever reason places like AirLiquide doesnt want to sell me some
<B787_300>
s/doesnt/dont
<Qboid>
B787_300 meant to say: for whatever reason places like AirLiquide dont want to sell me some
<B787_300>
and i dont really want to make a rocket engine that runs on NOX
<B787_300>
because i can get that...
<B787_300>
I mean heck at this point I try to see if I can get my hands on h2o2
<bofh>
B787_300: so my instinctual response to hearing "where can I just, like, casually get 30L of LOX" is to run screaming.
<bofh>
before I say anything, you *do* realize how incredibly dangerous that much LOX is?
<B787_300>
Yes I do
<bofh>
and you know how to safely handle it and have equipment capable of doing so as well? (for instance it'll easily sustain metal-O2 fires)
<B787_300>
Not yet. But I ain't about to buy all the stuff I need before I know I can source it
<bofh>
okay, so the easiest way you can get LOX IMO is just condensing it out of the air via LN2 -- it's got a higher liquefaction point so this is actually a huge problem.
<awang>
Is LOX one of those things where you're like "Yeah, it's bad, but just gotta be careful, right?", but then you get it and are like "Holy crap this is touchy"
<bofh>
no, it's one of those things where it's stable, it just tends to make everything *else* unstable.
<bofh>
let's put it this way. fire is an oxidation reaction and takes place in a 30% O2 environment. when you have LOX turn to gas it locally creates 100% O2 environments.
<bofh>
this gives it the opportunity to support combustion of things that one wouldn't normally consider to be combustible, such as, uh
<bofh>
metal piping and PVC hose
<B787_300>
bofh: hey at least I ain't trying to do N2O4/ UDMH
<awang>
bofh: I guess the better question then is "What does LOX *not* react with?
<bofh>
B787_300: okay if you asked me about that I'd legitimately consider you stark raving mad.
<B787_300>
Particularly the udmh part
<bofh>
awang: so like, it's not chlorine trifluoride. it's still not going to react with things that don't normally oxidize in the presence of oxygen. it's just going to do so much, erm, faster.
<awang>
Ah
<awang>
Makes sense
<B787_300>
bofh: though I do wonder what a rocket using F2O2 would get as an isp
* B787_300
looks for the bofh shaped hole in the wall
<bofh>
on a tangent, speaking of topicquotes: <@bofh> My E&M was Griffiths for intro, then Jackson for... the Jacksoning. <- I almost forgot I said this, but it's still accurate. :P
<bofh>
so like, I don't think it would, to have a good isp you need the fuel to not, like, be hypergolic with the nozzle
<bofh>
that's how you get stuff like Akatsuki's failed initial orbital insertion, except far worse since it's on the ground and instead of being cracked, it's vigorously on fire.
<kmath>
<nascom1> For those wondering how we can determine spin rate of a spacecraft. Image has made it very easy to do by looking at… https://t.co/w8P5Hut2jr
<bofh>
B787_300: the JAXA Venus orbiter currently around Venus.
<B787_300>
Bofh you can also see spin rate in spacecraft just by the reflected light.
<bofh>
True but if you don't have a visible light telescope :P
<B787_300>
And tell if it is one axis or two or even 3 axis tumbling
<B787_300>
I dabble in astronomy like stuff on the side as UmbralRaptor knows...
<B787_300>
So I have access to 4 telescopes the biggest of which is a 16 incher
<UmbralRaptor>
ping
<bofh>
so like, you can do the same by looking at (sub)carrier doppler, particularly if your S/C does two-way ranging like all NASA stuff past Pioneer 10 do.
<bofh>
(conversely I dabble in amateur satellite RF communications :P)
<B787_300>
And bofh what is light except really high frequency radio waves
<bofh>
I guess :P
<B787_300>
Although you radio guys do have it nice with not having to worry about tiny (nm) sizes imperfections in your reflecting surface
<soundnfury>
heh yeah, you can make a yagi in a metalbashing shop
<soundnfury>
bend a few coathangers "bam! high-gain antenna"
<B787_300>
soundnfury: or even just a paperclip
<soundnfury>
clippy turns entire universe into antennas?
<UmbralRaptor>
Oh, right. This channel has lots of shouts of dismay.
<B787_300>
How is a GA witchcraft
<UmbralRaptor>
Consider: computers are basically deterministic, with various shenanigans needed to get useful randomness. Nonetheless, working with some parts of them feels downright occult.
<soundnfury>
programming _is_ sorcery
<UmbralRaptor>
*sourcery
* soundnfury
is an open sorceror
<soundnfury>
:)
<B787_300>
i mean my thesis is using a very Deterministic program to feed a stochastic program
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* soundnfury
gives B787_300 a stochastic scholastic Socratic sarchastic program
<soundnfury>
s/rch/rc
<Qboid>
soundnfury meant to say: /me gives B787_300 a stochastic scholastic Socratic sarcastic program
<B787_300>
and you give it to me sarcastically right?
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<B787_300>
so are most people in here actually working on advanced degrees?
<soundnfury>
don't think so
<soundnfury>
I'm in industry (since I got my BA)
<B787_300>
you got a BA and not a BSc?
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<soundnfury>
cambridge maths. All UG degrees are BA
<B787_300>
ah interesting
<soundnfury>
funnily enough one of my co-workers stayed on for fourth year and got his MMath... now I tell him what to do xD
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<awang>
B787_300: If the isp with FOOF is known I'd guess it's in Ignition!
<B787_300>
awang: it isnt
<B787_300>
FOOF is not something much research has been done with for obvious reasons
<awang>
Oh, it's not?
<awang>
I'm half surprised
<awang>
It's nasty, but there was some pretty nasty stuff in there too
<soundnfury>
don't think anyone's made enough to do a test run in a motor ;)
<UmbralRaptor>
awang: fluorolox ≠ FOOF
<awang>
Wasn't there at least one test fire with ClF3?
<B787_300>
there is nasty then there NASTY
<awang>
UmbralRaptor: ....Really?
<awang>
TIL
<B787_300>
FOOF is very much in the NASTY category
<awang>
And ClF3 is just nasty?
<awang>
Heh
<UmbralRaptor>
awang: fluorolox is just a mix of LOX and fluorine. Since it's at liquid oxygen temperatures, fluorine becomes a bit less terrifying.
<soundnfury>
yeah I don't think ClF₃ will spontaneously decompose...
<awang>
Googling "Fluorolox" yields two results from #RO
<e_14159>
I must admit, that radio bot is quite amusing if its assumptions on window width don't hold up and the ASCII-Art is all strange.
<egg|mobile|egg>
Awang : dunno, pinging everyone sounds like something I might do
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<egg|phone|egg>
!Wpn whitequark
* Qboid
gives whitequark a COBOL monopoly
<egg|phone|egg>
Whitequark : how is котя doing?
<whitequark>
no idea, i'm in hk
<egg|phone|egg>
Ah
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* UmbralRaptor
thought kotya was in hk for some reason.
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<oeuf>
whitequark: how is the mould doing then
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<whitequark>
i left the dehumidifier on for 3 months while i left
<whitequark>
no new mould
<egg>
yay
<B787_300>
whitequark: what is котя ?
<whitequark>
a cat
<whitequark>
котя is the name
<whitequark>
yes, i have a cat called "kitty"
<UmbralRaptor>
According to MERCURY6, 9.9d29 is an implausibly large number. >_>
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<whitequark>
whats that
<Ellied>
I wonder how you'd do with getting rid of these spambots if you just made the server instantly GZLine anyone whose first message is either all-caps or all non-language characters
<Ellied>
or uh, however you define the set that includes characters that aren't used in words in any language
<whitequark>
Ellied: then the first message will be something else.
<Ellied>
yeah
<e_14159>
Just ban everybody new?
<Ellied>
there are probably patterns you can recognize that spambots will always follow if they're effective spambots
<egg>
whitequark: MERCURY6 is https://github.com/4xxi/mercury by chambers et al., fairly standard solar system integration thingy for astronomers
<Ellied>
like some nick connecting for the first time, joining tens of channels, and immediately sending out messages to them
<egg>
whitequark: scott manley was involved in it iirc
<egg>
UmbralRaptor: clearly you should use principia instead :-p
<UmbralRaptor>
<_< >_>
<tawny>
this sort of spambot usually has three-letter nicks that aren't words, usually posts either text-art or ALLCAPS and a url in its first line, and starts posting messages immediately after joining, usually several at once or in very quick succession
<egg>
whitequark: do you have any new котяpics?
<e_14159>
I still prefer them to ian.
<tawny>
iirc the way some friends on another network solved it was with a script that blocks anyone who joins and immediately posts either a URL, or a message with several nicknames in it, or three+ lines at once in a certain length of time
<tawny>
filters for ALLCAPS, non-text content, and specific urls might help but I've seen messages that'd get around all three of those
<rqou>
saw
<e_14159>
egg: Remember ian?
<egg>
aaaaaaaaaaaaaaaaaaaaaa
<whitequark>
egg: nope
* e_14159
hands egg brain bleach.
<e_14159>
tawny: Might work, but is it worth it for a spambot every few weeks?
<tawny>
oh, on the other server it was showing up several times a day sometimes
<egg>
yeah I recall a lot of spam on ##openfpga a while back
* egg
pokes UmbralRaptor with principia
<egg>
and kozai
<Ellied>
Freenode already K-lines you if you say too many nicknames at once. I discovered this when I attempted to talk on ##electronics and for some reason there are like 90 people on that channel with nicknames that are common words >_>
<tawny>
pfff
<tawny>
did they un-ban you eventually or
<Ellied>
I just switched to the other wifi network lol
<Ellied>
and I guess that kind of k-line doesn't stick to your nickserv account
<Ellied>
presumably because it's a k-line and only server-wide?
<SnoopJeDi>
!wpn -add:adj singular
<Qboid>
SnoopJeDi: Adjective already added!
<SnoopJeDi>
!wpn -add:adj extragalactic
<Qboid>
SnoopJeDi: Adjective added!
<UmbralRaptor>
egg: admittedly I'm procrastinating on finding star catalogs… >_>
<kmath>
<arclight> Counterpoint: FORTRAN is forever, outliving its community. All the people are gone, only the software remains. https://t.co/vSVJog2E3e
<bofh>
"I don't know what the scientific programming language of the year 2000 will look like, but I do know it will be called Fortran" ~ Tony Hoare
<Ellied>
or apparently if you're the chair of my department, it looks like FORTRAN 77
<B787_300>
UmbralRaptor: fortran needs to die
<SnoopJeDi>
B787_300, why? it's lovely at what it does (if not much fun to write or read)
* SnoopJeDi
hugs numpy
<SnoopJeDi>
!wpn -add:wpn scipy
<Qboid>
SnoopJeDi: Weapon added!
<B787_300>
like i understand it if you need to for running old programs but certainly there are better modern programs that are better (and more user friendly)
<B787_300>
SnoopJeDi: i am sure Python with some extra packages is better than fortran at some things
<Ellied>
I very much doubt there's much that Python can do faster than Fortran
<SnoopJeDi>
B787_300, depends on what "better" means, but the scipy stack (notably numpy) certainly depends deeply on Fortran
<bofh>
^
<bofh>
like ultimately a ton of numpy is just LAPACK bindings.
<SnoopJeDi>
and LAPACK's age is a Very Good Thing
<SnoopJeDi>
it's a little like saying gcc is old therefore we should stop using it: it's a feature, not a bug
<UmbralRaptor>
Numpy's integrators outright say "based on LAPACK"
<bofh>
also QUADPACK.
<bofh>
SnoopJeDi: the amount of research that's gone into making LAPACK both fast and numerically precise is *insane*.
<bofh>
just the latter is enough reason to not try and roll your own impls.
<SnoopJeDi>
I'd love a lit review or other I'm-not-smart-enough-for-the-real-milk reading along that line
<bofh>
SnoopJeDi: I mostly read the release notes for the routines I care about.
<SnoopJeDi>
ahh
<SnoopJeDi>
I've never written a line of it myself, which is a shame
<bofh>
(which for me is decomposition to upper Hessenberg, SGETRF/SGETF2).
<bofh>
(also SPOTF2, aka Dense Cholesky).
<SnoopJeDi>
I *am* tempted to do a little playing with System 360, which would probably be F77 (I think?)
<SnoopJeDi>
just to get some flavor of what my dad cut his teeth on
<bofh>
I think so, but not sure.
<SnoopJeDi>
bofh, is that exposure principally from your experience with ffmpeg et al, or?
<SnoopJeDi>
or research perhaps? your travels are varied
<bofh>
For what it's worth, F77 is easy to call from C, just add an underscore to the function name and pass all arguments by reference (yes, this means you have to assign numeric constants to temporary variables).
<bofh>
mostly my work in computational chemistry, which was 75% just outright coding, about half of that in Fortran (the rest in Python, about half of *that* generating Fortran).
<SnoopJeDi>
oh neat I didn't realize you done chem but that makes a lot of sense
<bofh>
ffmpeg doesn't use lapack, lol. that'd be massive overkill (it does have PCA & Linear Least-Squares routines, but they're self-contained, which makes sense as they're only ever invoked on small systems).
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<SnoopJeDi>
ah okay, that makes sense for portability's sake
<bofh>
I did pure math -> computational/quantum chemistry -> condensed matter physics.
<SnoopJeDi>
I think it's usually called 'rehab' :P
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<bofh>
SnoopJeDi: also it's ffmpeg. using something off-the-shelf would mean they don't get to NIH something, which is anathema to one of the core philosophies :P (I'm only half joking).
<SnoopJeDi>
bofh, I told you about the MD simulation of a kinesin "walking" on a microtubule, right?
<bofh>
I've seen the animation a bunch, yeah. I have my reservations about its accuracy wrt reality, but it certainly is neat.
<SnoopJeDi>
oh?
<bofh>
so I don't know enough about MD to be able to ascertain its accuracy, but it's apparently slightly controvertial (in general, not that specific example)
<SnoopJeDi>
I found the resolution of conformational changes pretty compelling
<bofh>
(MD is well out of my knowledge, what I did was excited-state energies and transitions).
<SnoopJeDi>
but sure, it's a hairy subject in general
<SnoopJeDi>
I think the sim they did was all of a few 10s or 100s of μs heh
<SnoopJeDi>
we'll probably know that story better in the next decade considering the rate of development in the attosecond sector
<bofh>
*nods*
<bofh>
Yep, sounds about right.
<SnoopJeDi>
I bet I'll learn some neat stuff about LCLS-II in April at IPAC \o/
<SnoopJeDi>
(and maybe even understand any of it)
<bofh>
Nice!
<bofh>
IPAC sounds cool as hell.
<SnoopJeDi>
It was pretty cool in Richmond two (three?) years ago
<SnoopJeDi>
although surprisingly my favorite talk had very little to do with accelerators: a guy who helps run a (free!) risk management workshop through MIT gave a talk about their system for risk analysis
<SnoopJeDi>
lots of applications to accelerators, particularly medical contexts (rule #1: don't kill the patient), but it was very cool, they focus on interactions between systems in a very telescopic sense, rather than isolating systems and testing their behaviors against a spec
<kmath>
<JohnWomersley> (2/3) Big cuts to science in NASA, to fund new manned moon program: WFIRST is zeroed out. And proposed budget for… https://t.co/CufO1Fdn3z
<SnoopJeDi>
jfc what
<bofh>
The fuck?!
<SnoopJeDi>
WFIRST-AFTA is like, basically done innit?
<SnoopJeDi>
I mean, I guess there's probably a case (particularly in this admin) to be made that it duplicates Euclid in part, but still
<bofh>
And why on *earth* are we now somehow doing a manned moon program *again*?
<UmbralRaptor>
The current administration is big on showy empty statements.
<SnoopJeDi>
manned spaceflight in general idk ¯\_(ツ)_/¯
<UmbralRaptor>
On the up side, I can see value in sample returns from the polar regions, far side, mare orientalis, Aitken basin…
<UmbralRaptor>
Uh, WFIRST did show some issues in the last budget review. IIRC, the starshade and coronagraph are at risk.
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* UmbralRaptor
🔪 the lack of a complete catalog of Teff, logg, radius, metallicity, and vsini for stars within ~15-20 pc.
<B787_300>
UmbralRaptor: isnt WFIRST getting really close to a Nunn-McCurdy breach?
<UmbralRaptor>
Something like that.
<soundnfury>
bofh: it wouldn't be *again* anyway, since essentially none of the people (or even, really, institutional memory) that did it last time are still around