little free library stan account

Tess wtf do you mean this is easy there is so much math

There is no version of this that does not involve math. I love you! You can do this!

The other (more accurate!) option is modeling your planetary bodies as a point-mass system/solving a 2-body problem using vectors (see section 8.3.1; also chapter 6 of this book, also a lot of other places, probably). Dr E M Standish of JPL is giving you a way to do it that is already mostly-solved and involves practically zero required knowledge of vectors and shockingly little calculus; JPL publishes the constants you need so there's no need to calculate them yourself. In using them, you're standing on the shoulders of everyone from 18th-century astronomers like Johannes Kepler to the people behind modern crewed and uncrewed space missions. We have been working on the problem of increasingly accurate orbital determination for centuries and that is so cool.

2. How does this work?

Basically, orbital elements are numbers that define an orbit, like how three points define a plane or two points define a straight line. Orbits change a little bit over time, which is why JPL is also giving you their derivatives (to tell you how fast they're changing, and in which direction). Keplerian elements are the traditional way to do this. You can calculate them from observational data (chapter 7; Wikipedia), but JPL has done this, so you don't have to. All that's left is more or less just geometry.

3. Okay so what do I do?

Since your orbital elements change over time, you first need (a) a time in the correct format and (b) the orbital element at that time. (It is also not a bad idea to write out what all your orbital elements are.)

JPL calls (a) T_eph. It can be calculated using T, the Julian Date, and there are pretty good explanations of how to get that here, plus another explanation of this whole method here.

Once you have that, in order to get (b), multiply the orbital element's derivative by T_eph and add it to the orbital element JPL gives you. (These are all the elements in the year 2000, which JPL is using as a reference.)

After that, plug & chug!

4. Newton iteration?????? Kepler's equation??????

This is Kepler's equation:

Everything else is pretty easy if you're carefully plugging in numbers where the steps tell you to. This one's tricky because you're trying to solve for E, which is both inside and outside the sine. e* is just e in radians (they initially give it to you in degrees).

Once you have that, the website shows you how to do the Newton iteration bit: solve those three equations, over and over, until E stops changing very much. (Dr Standish suggests an acceptable amount of error.) If you poke around online a bit, you'll find lots of code to do this; since it's astrophysics, you'll probably find versions in Fortran and BASIC. (<3!!)

Once you've got E, keep going!! You're almost there!!

5. Reference frames

Once you get x', y', and z', you have a planet's position!! It's just not in a super useful reference frame.

In order to talk about where anything is, ever, you need a reference frame—"where something is" is impossible to talk about if it's not "where something is in relation to something else." "The store is 5 miles" <- a nonsense sentence that means nothing. "The store is 5 miles north from here" <- helpful!!

The reference frame we have right now is Cartesian—good old familiar x, y, z coordinates—and the origin, (0, 0, 0), is the sun. You'll notice z' = 0, which is because the bottom plane of this reference frame is defined by this planet's orbit. You'll also notice we haven't used I, the inclination aka orbit tiltedness element, yet.

In order to see how tilted the orbit is in comparison to Earth's, and therefore what angle the planet is at in comparison to Earth, we want it in a reference frame where the bottom plane is defined by Earth's orbit instead. It's still Cartesian and the origin will still be the sun.

To get there, this method has you do a bog-standard vector rotation (you still don't need to care about vectors, but your new planetary coordinates are a vector that needs to be rotated in order to account for the orbit tiltiness; that Wikipedia page gives you the math in 2d, but space is 3d, so this is a 3d rotation). You can plug your numbers into the trig equations the JPL page gives you and it will rotate them for you!

NOW you are done and you have your planet coordinates!!! Yay!!!!

6. (Asiatic Clam Guy Voice) Never Give Up

I know I said this was easy, but it's okay to be confused or frustrated, it's okay to make time-consuming mistakes—everyone does at some point when doing physics. (Also, I have a terrible cold and am running on Dayquil and caffeine right now so I don't know how coherent any of this is; I just wanted to hit the interesting bits and cover the parts that I personally found confusing.)

And so the two surgeons filmed a handover after heart surgery and sent it to the Ferrari pitcrew who were told to critique and improve handover process

And from this:

we got this:

The error rate during patien handovers dropped from 30% to 10% with the F1 informed protocol.

I love this!

And it that it wasn't a one and done.

The doctors went to the race tracks to watch the car changes and the pit crews went to the hospitals and watched a live transfer and offered suggestions and they kept working with them to improve.

After there was a successful improvement of the most vital metrics of a handover of a patient from surgery to ICU, the pit crews also worked with other hospitals for other procedures and it's now a whole thing of trying to apply the specialized, streamlined and speedy teamwork and nonverbal coordination of pit crews to other high-risk fields.

to explain what i mean by "coerced":

i think doing things that are morally bad is also bad for the individual. people shouldn't be forced to do things in general, but its especially bad to force someone to do something morally bad. its also bad to coerce them into doing that. and its quite horrific for a system to embed within someone a worldview which habitually leads them to do bad things, and a social system which incentivizes people to do bad things.

this post is in part inspired by reading the book Dirty Work which talks about moral injury & people (largely marginalized people) who do work that is seen as morally "dirty" in society. and specifically the chapter on people who work with drones for the US military (in a variety of ways). one of the major figures was a woman who grew up in poverty and was terrified of dying that way, went to join the military to get to see the world, and ended up working a job requiring her to watch hours and hours of drone footage, including hours of people living their lives, their gruesome deaths, and their families trying to collect their body parts in the aftermath. she recounts how much this weighed on her psychologically and morally, but not only her fear of poverty but also being court-martialed or otherwise subject to punishment if she spoke out or did anything, and her anger at protestors who seemed to be largely middle-class women who directed their protests at individual workers like her. she eventually did become a whistle-blower and says she experienced backlash from the left as well as the right because of her job.

now, this was a difficult read for me. it can be frustrating to read a whole chapter on the suffering of drone operators when so many people in the US don't give the beginning of a fuck about the people who have been getting bombed for years. the trauma of entire countries doesn't outweigh the trauma of a single US soldier. how can we talk about her anger at women protesting drone warfare because it hurts her feelings when we are still having to protest drone warfare that destroys entire families?

and yet. i think that reaction is partially an attempt to avoid the discomfort of how fucked the situation is holistically. the woman clearly had internalized plenty of dehumanizing, imperialistic, racist, and likely Orientalist beliefs and values. but this was hardly something she consciously chose. its easy to say "never join the US military" when you are someone who 1. already had the time and chance to develop a sense of how evil the US military is (not everyone necessarily does) 2. was not and is not in the position of being 17 and worried you'll die of a fentanyl overdose in the next five years like multiple of your classmates and desperate for any opportunity out.

does it make her decision better morally? i don't think so. but why was it a decision she had to make? why did she have so few options? why did things feel so desperate? why did a certain decision seem better and more accessible than others? if we are going up the line of responsibility here, the reason this harmful, morally bad action took place at all is because of the system of US imperialism and capitalism.

the problem is, that answer does not give us A Person To Punish. which we, as people socialized into a worldview of punitive justice, have been taught to want. transformative justice isn't just switching to A Person To Fix, its directing our energy towards social change and collective thinking and acting. that doesn't ignore the individual, but it always sees the individual through a social lens. the ultimate goal is a system which incentivizes the morals we want to see just as much as the current one incentives individualism and authoritarianism and puritanism and imperialism.

i think the perspective that we are coerced, by social systems like imperialism, patriarchy, capitalism, white supremacy, etc. into acting immorally and harming others and ourselves, more naturally invites people to see their own racism, sexism, orientalism, classism, etc. as both morally bad and yet not a sign they are bad. it directly counters the idea that saying "the thing you did is racist" means "YOU are racist and EVIL and CONSCIOUSLY DESPISE PEOPLE OF COLOR"*; the point is that the thing you did is racist, and if you don't want to do racist things, then you have to unlearn the shit you were socialized into believing. "coerced" keeps in mind that there are people who benefit from keeping this status quo. if racism is evil, and white supremacist culture means everyone has internalized racist beliefs, that doesn't mean everyone is evil. it means we have all been coerced into participating in evil, and we are demanding an end to that coercion; that is (one form of) accountability.

this perspective can't exist alone, either. it must be paired with a devotion to the victims of these systems. this is why it is a process. the back-and-forth has to be put into action to get a balanced solution. what is best is what practically creates system change, and having process for (again, social) forgiveness is a practical necessity.

see this is even worse than oranges. pears and apples are like the most comparable things ever. france takes another L

ok so this is what i mean. these are measures of temperature and texture and are in fact not very comparable. молодцы ребята продолжаем в том же духе.

colombia wins most vivid image invoked hands down. would not want that to happen to me.

this turned into a fic rec/meta post about how hockey is sex but it's taboo to acknowledge that it's sex but also that taboo is itself can be sex. but i'm putting it under the cut bc some of the screenshots include homophobia including slurs, racism, and allusions to sexualized violence in the form of hazing. and also this is just long as hell.