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Comment by bwang29 | Hacker News Reader

To put things in perspective, the comet, 67P/Churyumov-Gerasimenko, is about 4km in diameter, moving at 135,000kms per hour. Rosetta's rendezvousing with the comet required travelling a cumulative distance of over 6.4 billion kms. Gravity assists were needed from four planetary flybys – one of Mars (2007) and three of Earth (2005, 2007 and 2009) – a long circuitous trip that took ten years to complete.

Now back to my Javascript callback bugs

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To be fair, people have been studying and predicting celestial movements for millennia, and boiled it down to unbelievably precise mechanical formulae. JS is poorly understood in comparison.

I say this to hope you feel better at work. I've been pressed into frontend web work and it's fractal complexity.

JS is poorly understood in comparison

This might be the most hilariously ridiculous true statement I've ever heard.

In javascript:

x == x _ is true. Good.

x == !x _ is also true. Oops?

And guess what:

Array(3)==",," _ is also true.

But

NaN == NaN _ is false.

Math.max()>Math.min() _ is also false!

but then again

Math.max()<Math.min() _ is true.

Madness, I tell you!

I just looked at the famous left-pad for the fastest way o implementing a pad function in JS.

I asked a friend that does web dev and it is apparently pretty idiomatic JS. Pretty appalling. I finally understood why people claimed it was "hard to get right".

NaN not being equal to itself is true in all languages with IEEE compliance: https://en.wikipedia.org/wiki/NaN

Nitpick: NaN is supposed to work like that: the rule is that every comparison of any value against NaN returns false.

At least x === x, right?

const x = NaN;

x === x; // false

:D Many more Javascript WTF's here: https://www.youtube.com/results?search_query=javascript+wtf

But they're close to getting two numbers to add together!

https://twitter.com/thomasfuchs/status/933447631514169344

They should use jQuery for that. I hear it's good for all the things.

Yes, but you're wading into the JavaScript weeds for what? More CRUD forms? Meanwhile...

"With a combination of large ground-based FORTRAN programs and small spacecraft-based assembly language programs, [Real Programmers] are able to do incredible feats of navigation and improvisation -- hitting ten-kilometer wide windows at Saturn after six years in space, repairing or bypassing damaged sensor platforms, radios, and batteries. Allegedly, one Real Programmer managed to tuck a pattern-matching program into a few hundred bytes of unused memory in a Voyager spacecraft that searched for, located, and photographed a new moon of Jupiter.

The current plan for the Galileo spacecraft is to use a gravity assist trajectory past Mars on the way to Jupiter. This trajectory passes within 80+/-3 kilometers of the surface of Mars. Nobody is going to trust a PASCAL program (or a PASCAL programmer) for navigation to these tolerances."

Those are impressive sounding achievements. I haven't heard of all of those, can you provide references or details about the stories?

I'd like to, but the original was from "Real Programmers Don't Use Pascal" by Ed Post: http://web.mit.edu/humor/Computers/real.programmers

You would be better off asking him about the veracity of the stories.

It's true. Some of the greatest minds have spent 20 fruitless years trying to discover a unified theory of object fields and elementary values in JavaScript.

Has everyone given up on string theory, or is there still hope another few hundred genius-years will bring progress?

At least it's not erlang's string-list of integers duality.

    Observable.of(rosetta)
         .map(rocket => gravityAssist(rocket,'Earth'))
         .map(rocket => gravityAssist(rocket,'Mars'))
         .map(rocket => gravityAssist(rocket,'Earth'))
         .map(rocket => gravityAssist(rocket,'Earth'))
         .do(rocket => land(rocket))
         .do(rocket => tweetVideo())
         .catch(error => kaput(error))

Or just simply:

npm install rosetta-67P-rendezvous

Then somehow get a completely incomprehensible error about Visual Studio executables.

Use yarn

Oops. The new probe smashed into Mars at 146 km per second.

It was a leftpad error.

>Now back to my Javascript callback bugs

Check to make sure you are running the right files... Spelling/Capital letter errors... Returning after selecting a case...

Just some horror stories that cost me 8 days...

Moving at 135,000 km/h relative to what? (honest question)

I presume relative to the solar barycenter, and Wikipedia says that speed is its maximum speed (at perihelion of about 1.3 AU).

For reference, Earth does a mean speed of about 107,000 km/h relative to the solar system's center of mass.

I guess relative to the stars in the image, using parallax.

No, relative to the stars it's going a LOT faster than that!

Most likely it's relative to the sun.

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