Over 150 new families of Newtonian periodic planar three-body orbits - <AUTHOR> https://arxiv.org/abs/1705.00527 <comment><USER2> Has anyone explored the computational nature of Newtonian gravity? That is, if you carefully setup a set of masses in some manner, and let them interact though their gravitational pull, what kinds of things can you compute? Is gravity Turing complete? Is it a push down automata? Finite state machine? Can you use choreographies like these, coupled together to create register machines, or simulate cellular automata?

<comment><USER3> Not quite a computation, but there is a striking example (due to Xia) where 5 particles interact and "kicks" off one particle to infinity in _finite_ time. Further details can be found in

[http://www.ams.org/notices/199505/saari-2.pdf](http://www.ams.org/notices/199505/saari-2.pdf)

<comment><USER4> Of course, that is physically impossible.

</comment></comment></comment><comment><USER5> This paper seems to be missing some related work, for instance Carles Simó.

Greg Minton created a computer-assisted proof system for showing that there must exist a choreography with parameters within a certain distance of some given approximate parameters. This isn't just a matter of more floating point precision; it certifies that there is a critical point for action of the right kind. [http://gminton.org/#gravity](http://gminton.org/#gravity) and [http://gminton.org/#cap](http://gminton.org/#cap)

Greg Minton also has a bunch of proved choreographies at [http://gminton.org/#choreo](http://gminton.org/#choreo)

<comment><USER6> Simó work was presented beautifully here, in Java: [http://www.ams.org/samplings/feature-column/fcarc- orbits1](http://www.ams.org/samplings/feature-column/fcarc-orbits1)

<comment><USER7> Note: that only works in Internet Explorer (not Edge, of course), since all other browsers have disabled support for NPAPI plugins, including Java. I guess it shouldn't be too hard to implement a JVM in JavaScript that's good enough to run simple applets like this, but sadly nobody is doing it.

<comment><USER6> Yes, I guess you can, alternatively, still download a JRE with an "appletviewer" app.

<comment><USER7> How can you run an embedded applet in an external viewer? Also, how is that more secure than just running it in the browser?

<comment><USER6> [https://en.wikipedia.org/wiki/AppletViewer](https://en.wikipedia.org/wiki/AppletViewer)

"The applet viewer operates on HTML documents, but all it looks for is embedded applet tags; any other HTML code in the document is ignored. Each time the applet viewer encounters an applet tag in an HTML document, it launches a separate applet viewer window containing the respective applet."

As far as security goes, I don't think appletviewer claims to be more secure that the browser. It has a similar security policy/sandbox.

</comment></comment></comment></comment></comment></comment><comment><USER2> Here's an older visualization for other interesting planar n-body choreographies:

[http://www.maths.manchester.ac.uk/~jm/Choreographies/](http://www.maths.manchester.ac.uk/~jm/Choreographies/)

...plus a link to the animations for the linked paper:

[http://numericaltank.sjtu.edu.cn/three-body/three- body.htm](http://numericaltank.sjtu.edu.cn/three-body/three-body.htm)

<comment><USER8> We live in a boring planetary system. Can you imagine if we lived in one of those choreographies how difficult would it be for Kepler to devise the laws of planetary motion?

<comment><USER9> There is a popular (but IMHO terrible) Chinese science fiction book called "The three body problem" which tackles this exact issue.

<comment><USER10> I'd be interested to hear why you think that book is terrible

<comment><USER9> For one, the science is dead wrong. Just because the three body problem doesn't have an analytical solution that doesn't mean that orbits are chaotic. Case in point: the very solar system in question is now known to have at least one planet in a very stable orbit. Nor does it mean that they are particularly difficult to calculate in many circumstances. You just can't use algebraic methods. So I was turned off because the what-if proposed was fantasy not science fiction. Fwiw I had the same response to the movie Arrival, which many people seemed to love.

Second, the proposed solution that allows for the aliens to predict future seasons and therefore develop culture and technology reflects human problem solving. This is intellectually lazy and wrong. A more realistic solution, of the type I prefer to read about, would have the aliens evolve different ways of thinking that are more compatible with iterative methods than algebraic manipulation. To such a mind abstract reasoning would be really difficult, but it would be entirely natural to specify initial conditions and solve iteratively. Such a mind would find solving ordinary differential equations as easy as breathing, but solving x + 3 = 4 would need a computer. Even more interestingly, how would those differences in mind structure reflect the development of their language, culture, and societal structure? These are all very fascinating questions that seemed extremely obvious to me from the setup, and the sort of thing many hard sci-fi authors like Raynolds or Clarke would tackle. It's a book I would read and rave about. But instead we get the same old trope of basically human aliens invading earth because it is "habitable", never mind that habitability should be a non-concern to any self-respecting interstellar species, for whom climbing down a gravity well is probably a net negative. Planets are in fact shitty places to live in terms of galactic real estate, even more so when they are infected by foreign biology.

Finally, the behavior of humans across the entire books is utterly unrelatable. I'm limited in how much I can say without spoiling the story. But in short every scientist is portrayed as incurious (wtf?) nihilist easily swayed by the suggestion to kill all humans. And the rest of humanity hardly dares better -- they willingly and dejectedly walk to their own execution when they are told to later in the series. I have no explanation of this other than bad writing.

It was, in short, a really bad book.

</comment></comment></comment></comment></comment><comment><USER11> How stable are these orbits? Do they tend to degenerate into simpler forms over time? If they're stable, do we see any asteroid triplets in such configurations? Why not?

</comment><comment><USER12> Reminds me of Cixin Liu's 'Three Body Problem', about alien invaders that want to escape their own chaotic three-body planetary system by taking over ours... The first two books of the trilogy are just spectacular science fiction.

</comment><comment><USER13> Guess I have some work to do to update my mobile app Three Body! (It presents galleries of solutions up to those found in 2013, and lets you explore your own initial placements)

iOS: [https://itunes.apple.com/us/app/threebody- lite/id951920756?m...](https://itunes.apple.com/us/app/threebody- lite/id951920756?mt=8) Android: [https://play.google.com/store/apps/details?id=com.nbodyphysi...](https://play.google.com/store/apps/details?id=com.nbodyphysics.threebodylite)

The authors of the new solutions have published all the initial conditions - so hopefully it won't be too hard. (Although they use an 8th order RK integrator and the one I have is a regularizing Bulirsch-Stoer integrator).

</comment><comment><USER14> I wonder how can authors claim such great certainty in their results, after all, it is all based on number crunching. Some floating point error, and similar is bound to creep in...

<comment><USER15> The numerical methods used for this kind of calculations are engineered to compensate numerical errors (floating point and errors inherent to integrators).

They take advantage of a priori knowledge about the laws of physics, in particular the conservation of mechanical energy and angular momentum. Predictor-corrector is one family of methods. Other methods rely on convergence as timesteps change.

There is a lot of literature on numerical integration applied to celestial mechanics and new methods being released every year. These methods are tailored to this problem space.

<comment><USER16> When I looked into making a solar system simulation awhile back, I actually found it shocking how much goes into monitoring and ensuring conservation of energy/momentum in these models.

Once I was aware of this issue though, even more shocking to me was that many papers on climate models I came across do not even mention they monitored adherence to conservation laws. There is a disconnect there, I would think this adherence either is a big deal (as would be suggested by the practice in astronomy) or not (as would be suggested by climate research), not that it would change by subfield.

<comment><USER17> When just doing point gravity dynamics (no friction, collision etc) energy and momentum take care of themselves as long as the math is clean. I say this confidently because I made a solar system simulation[1] with no attention to conservation of energy at all. In practice Star systems also shed large amounts of angular momentum through solar wind[2], but I expect this is often not modelled.

Climate models are an entirely different matter and with respect, there is a disconnect with your scepticism of them for this matter.

[1] [https://strainer.github.io/fancy#00](https://strainer.github.io/fancy#00)

[2] [http://farside.ph.utexas.edu/teaching/plasma/Plasmahtml/node...](http://farside.ph.utexas.edu/teaching/plasma/Plasmahtml/node69.html)

<comment><USER16> It says in your readme[1] though that your solar system simulation simulation is off by 70k km (regarding Earth orbit) after only 1 year relative to the JPL ephemerides, for "unknown reasons". I don't see how you can use that to justify not checking for conservation of momentum/energy.

I also do not understand your final sentence.

[1] [https://github.com/strainer/fancy](https://github.com/strainer/fancy)

<comment><USER17> Come on it doesnt say "unknown reasons" it says the "It is possible the discrepancy is due to the limitation of javascripts 64bit FP numbers rather than subtle algorithmic or physics error"

70k km / a year (on a billion km long orbit) was a lot closer than I had hoped for, considering its a 64 bit newtonian model. But this is beside the fact that having worked on the project a fair bit, I understand that any model adjustments to conserve energy or momentum are non-physical 'fudges' to correct deficiencies of the model. There are no laws of physics dedicated to adjusting energy, momentum, information in order to conserve them. They are conserved by a mathematical correctness of every physical law - a proper account of that eludes me, but it is certainly explained somewhere.

<comment><USER16> Right, you don't know how much error the floating point error accounts for. You also brought up loss of angular momentum to solar wind, etc. These are all just speculations. That may be fine for the purposes of your simulation, but not for predicting if asteroids will impact the earth or the influence of human activity on Earth's climate.

Also, I know you are supposed to use a symplectic integrator to ensure conservation of energy when doing these simulations, so it is not somehow hardcoded into the laws, eg: [https://en.wikipedia.org/wiki/Leapfrog_integration](https://en.wikipedia.org/wiki/Leapfrog_integration)

<comment><USER17> We could certainly calculate how much error was introduced by rounding, if we had the time and inclination. It is useful to understand that about numerical modelling, it should not be necessary to accept any indeterminable discrepancies.

Conservation of energy, momentum, information _is_ hardcoded into all known laws of Physics. It is our integration algorithms which do not all ensure conservation of information - but that is carefully achievable with basic first order schemes, such as Verlet and leapfrog integration.

<comment><USER16> >"Conservation of energy, momentum, information is hardcoded into all known laws of Physics. It is our integration algorithms which do not all ensure conservation of information - but that is carefully achievable with basic first order schemes, such as Verlet and leapfrog integration."

I am not sure about "conservation is encoded" part, but I can believe it. Either way, in practice the simulations will encounter issues along these lines if they are not careful. For example, I left your simulation running for what amounted to ~120 yrs and saturn lost all her moons. This is the best pic I could get, sorry (hopefully it is reproducible): [https://i.imgur.com/C7emd28.png](https://i.imgur.com/C7emd28.png)

Since you do not report anything about conservation of energy/momentum, how do we know that isn't the problem?

<comment><USER17> >For example, I left your simulation running for what amounted to ~120 yrs and saturn lost all her moons.

Thanks! heh, it is rather complex there are all sorts of things... most likely the new gravity function set for that model messed up, which can apply attraction between groups of objects if they are distant and weak enough.

But honestly I am certain that it is something in particular and not something mysterious about conservation of energy/momentum which i have not come across yet, because there is no formula in that gravity simulation which _should_ be able to destroy momentum. In the other models, there are quasi-physical friction and pressure functions which do destroy momentum and do have some rough adjustments to compensate for that somewhat, but accuracy is lost whether things are compensated for or not. Tracking energy and momentum can be a good way for tracking accuracy of a model, but if you do any adjustments to _correct_ it, that is a kind of fudge not based in true physics. It is poignant that you expressed scepticism of climate models because of a perceived lack of such adjustments, while the opposite is actually true. Climate models have to include a lot of calibrated adjustment and quasi- physics, because the whole system is too complex to represent at all relevant scales. This should not condemn the work of computer scientists specialised in climate modelling to undue scepticism.

<comment><USER15> > But honestly I am certain that it is something in particular and not > something mysterious about conservation of energy/momentum which i have not > come across yet, because there is no formula in that gravity simulation > which should be able to destroy momentum

It's a well established fact that numerical integration methods either gain or lose energy (in particular, the Runge-Kutta family is known to lose energy over time). For celestial mechanics simulations, a special class of numerical integration methods called "symplectic integrators" are used and their purpose is to conserve energy and angular momentum.

> but if you do any adjustments to correct it, that is a kind of fudge not > based in true physics.

When you are numerically integrating differential equations that model physical phenomena, you're not doing "true physics" but an approximation thereof.

And an approximation that makes Earth drift 70 km per year or Saturn's moons drift out of orbit in a few hundred years is a very bad approximation by scientific standards.

The methods used for celestial mechanics calculations need to be precise over thousands to millions of years. And the way they work is to "fudge" with the numerical methods to preserve energy and angular momentum. It's a much better approximation of "true physics" than your toy simulation.

Your assumption that the issues are due to floating point errors is incorrect. 64 bit double precision is millimeter accurate to the orbit of Neptune. That's good enough for scientific applications.

If you're interested in this, you could take a look at this scientific grade N-body simulator and the methods it uses: [https://github.com/hannorein/rebound](https://github.com/hannorein/rebound)

<comment><USER17> > Your assumption that the issues are due to floating point errors is > incorrect.

Its not as easy as declaring the resolution of absolute position. If you really want to spend the time on figuring it out, then examine the difference in scale between the bodies positions, velocities, accelerations given different model timestep values, what happens during the squaring summing and rooting, multiplying by G of those values and also even (because i _have_ looked into this before) the subdivided timestep values involved in tempering this models data, so it becomes a perfectly stable quantised version of its anologe values (with no need for the kind of corrections Runge-Kutta is notable for)

That link is very intresting to me thankyou. You can notice that it includes some quite simple integration schemes as 'symplectic' (basically means stable without need for gross correction)

</comment></comment></comment></comment></comment></comment></comment></comment></comment></comment></comment></comment><comment><USER18> What are the implications of this?

Until 2013, only 3 or so solutions to the 3-body problem are known. Now we have over 150 solutions. This sounds incredible, given how fundamental the problem is, but So what?

Will this change astrophysics - for example - in any way?

<comment><USER19> 3-body problem is unsolved math problem. There is equation, but no one knows how to solve it, and the only way to deal with it is number crunching. Stable orbits are solutions to the problem, but partial ones. The more solutions are known there more possibility to find more generalized solution. Maybe even the general solution for the problem.

I do not know how it can change astrophysics (its just newtonian gravitation, not einshteinian), but it can bring new methods/ideas to mathematics, then improved math will change everything. Maybe.

<comment><USER20> The problem isn't unsolved. It just doesn't have analytical solutions. But the mere fact we can simulate trajectories means we can solve it.

<comment><USER19> From engineering point of view, maybe the problem is solved. From maths point of view it isn't. For example, one cannot say for sure, are these trajectories periodic or no. 100-digit precision says "yes", but there is no guarantee, that 101-digit precision wouldn't say "no", they are not periodic.

</comment></comment></comment></comment><comment><USER21> It'd be fascinating to see a harmonic analysis of these orbits. They seem (qualitatively) to exist on some edge of order and chaos.

</comment><comment><USER22> Holy cow, some of those are complex. The equations of motion must be arcane.

<comment><USER23> There very likely won't be any "equation of motion."

</comment></comment><comment><USER24> I, for one, welcome our new Trisolarian overlords!

<comment><USER25> For anyone wondering - [https://en.wikipedia.org/wiki/The_Three- Body_Problem](https://en.wikipedia.org/wiki/The_Three-Body_Problem)

I'm just in the middle of the third book now, the series is well worth reading.

<comment><USER26> I cannot wait to see the movie, subtitles or dubs, the story was really interesting.</comment></comment></comment>


Campaign (+ helpline) setup to find missing Blockstream co-founder Greg Maxwell - <AUTHOR> https://gregismissing.com <comment><USER2> So I called the helpline. Tips are submittable. Hilarious.</comment>


Ask HN: Advice for a new Tech Lead? - <AUTHOR> Good evening everyone,
I am a senior software engineer working at a company that develops SaaS B2B products for hotels and the hospitality industry in general.
I got promoted this month to the position of a Tech Lead on a team other than than the team I was in last year.
A bit of background, my work last year was involved in Full Stack software development for the product lines. My new team, now, develops data intensive APIs that our partners use to setup their hotels in the mass markets on our products.
The team size is 5 engineers, we report to the VP of Engineering directly. The scope of my work is to lead the team technically and be involved in the software development responsibilities as well.
What advice can you give me? What are the characteristics of the best Tech Leads that you have ever worked with? What do you wish your current/previous Tech Lead did for the team to make things better? How do you enable your team for better productivity and efficiency?
Thanks a lot! <comment><USER2> Past posts:

[https://news.ycombinator.com/item?id=10395046](https://news.ycombinator.com/item?id=10395046) [https://news.ycombinator.com/item?id=13432331](https://news.ycombinator.com/item?id=13432331)

<comment><AUTHOR> Thanks a lot for sharing these threads.</comment></comment>


Every solar eclipse in your lifetime - <AUTHOR> https://www.washingtonpost.com/graphics/national/eclipse/?tid=ss_tw&utm_term=.7d131b2e9fd3 <comment><USER2> Discussion: [https://news.ycombinator.com/item?id=14739638](https://news.ycombinator.com/item?id=14739638)</comment>


Flatshare bias: room-seekers with Muslim name get fewer replies - <AUTHOR> https://www.theguardian.com/uk-news/2018/dec/03/flatshare-bias-room-seekers-with-muslim-name-get-fewer-replies <comment><USER2> This is just people being culturally sensitive.

I would chose not to share a flat with Muslims, or Jews, because I love eating pork, and I'm well aware that they're very uncomfortable about sharing a kitchen in which I cook it.

<comment><USER3> Though many are non-practicing. Only about 5% of the Jewish people I know keep kosher in any sense, and maybe half of those are strict enough to ask a roommate to avoid pork in the kitchen. (Pretty sure that's lower than the proportion of vegetarians I know who would care about a roommate eating meat.)

Some might allow it in the kitchen but ask you not to cook or consume pork using shared dishes and utensils.

Those who are glatt kosher - who care that much - often will customize a kitchen with dual sinks, ovens, and dishwashers in order to accommodate the need to keep meat and dairy separate. If you need that, you're probably not looking for a typical apartment share in the first place.

<comment><USER2> In my first year of university I ended up in a shared accommodation with two muslims and a jew, and two other people. I made the innocent mistake of cooking a pepperoni pizza in the oven.

After hearing them swear at me in Arabic and Hebrew (I understand neither), I cleaned out the oven and kitchen and told them I wouldn't cook pork again.

Didn't help. They would not speak to me again. They didn't use the kitchen (I have no idea where they ate). In the end I just started cooking pork again because they weren't using it anyway.</comment></comment></comment>


The share of Americans not having sex has reached a record high - <AUTHOR> https://www.washingtonpost.com/business/2019/03/29/share-americans-not-having-sex-has-reached-record-high <comment><USER2> This is an interesting graph - the proportion of men aged 18-30 who were celibate for the past year doubled in the past decade: [https://www.washingtonpost.com/resizer/Qalq8rTTOBvGnlWtfAt_R...](https://www.washingtonpost.com/resizer/Qalq8rTTOBvGnlWtfAt_RiXagMo=/480x0/arc- anglerfish-washpost-prod- washpost.s3.amazonaws.com/public/4C7SSBIXSNFCLOJIGCWUOKDYTY.png)

My first thought is that the "incel" crowd will grab on to this, and I wonder if they have a point. My next immediate thought is to wonder if the online social networks that have risen catering to that group might actually be the causative factor - men who feel unable to attract a partner instead find some level of companionship in these groups, creating a self-reinforcing cycle.

I suspect the answer is a bit of both, though. Tech has likely had a profound impact on the dating scene for this generation, and it likely _is_ more difficult for less attractive men to find companionship.

For the purposes of disclosure, I'm a 36-year-old male who met his wife at 14 and married her at 21. My experiences are atypical for my generation, and I feel like I see these issues from an external perspective.

<comment><USER3> There are roughly as many men per women per age cohort, no? That implies that some people are just too restrictive in their attractions.

<comment><USER4> Unattractive men aren't entitled to anything, sorry. I don't think the numbers mean people are too restrictive. Honestly, I'm surprised it's not more polarized.

<comment><USER5> Disclaimers: I have no sympathy for the plight of the incel community, and anyone who even jokingly desires forced/unwanted relationships or rape deserves way worse than just ostracism.

Still, I take issue with how the word _entitlement_ weaves itself into such debates. What is due is due — how much a certain group yearns for it, or doesn't, is a distraction from whether the group should be granted its desire. It comes with an awful implication, which incels weaponize, that men who are having sex constantly _are okay_ , possibly because they don't feel entitled to it.

This raises nonchalance to a virtue. It simply convinces incels they should become more like the misogynists (like them) who, unlike them, are getting laid. It makes them want to have the eyes of a successful rapist [0]

Nobody is entitled to anything. What few human rights we have were established through social consensus — sometimes as a concession to prevent wider unrest. Sex isn't a human right (though the choice to have it consensually is), mental health is.

[0]: [https://en.m.wikiquote.org/wiki/Wyndham_Lewis#Quotes_about_W...](https://en.m.wikiquote.org/wiki/Wyndham_Lewis#Quotes_about_Wyndham_Lewis)

<comment><USER6> Sex is not a human right, but a _reasonable_ pursuit of sex, relationships, marriage etc. very much is. Entitlement has no legitimate place in such a pursuit, simply because it incredibly counterproductive. There's a very real dynamic where being nonchalant about these things makes you more likely to be successful at them, and we shouldn't be dismissing it so quickly.

<comment><USER7> >Entitlement has no legitimate place in such a pursuit, simply because it incredibly counterproductive.

Entitlement has no place in such a pursuit because entitlement implies a right of ownership, but a human being is not an abstract concept like "liberty" or "happiness" or an inanimate object like a plot of land that lacks agency or can be owned by another person.

No one, regardless of gender, stats or status, is entitled to _anything_ in regards to a relationship with other people. Certainly not to sex.

</comment></comment></comment></comment></comment></comment><comment><USER8> Seems like a pretty obvious symptom of increasing loneliness and isolation.

</comment><comment><USER9> There could be economic and government factors here. Almost any form of birth control or medical procedure costs money (and kids _really_ do), while many people are trying to just pay rent and eat. And governments seem to have been...motivated...to interfere as much as they can in matters of sex, abortion rights, etc.

<comment><USER10> Yeah actively going against birth control is the dumbest thing a country can do. I'm talking about some US states that are still backward.

</comment></comment><comment><USER11> When you're as busy as everyone is now, who has time? Can barely keep up with everything as it is.

Luckily I'm already married, but it would be a problem otherwise.

<comment><USER12> Yup. Pretty sure I had far more sex 15-19 than 20-32. Jobs and school and marriage and kids. I think sex and intimacy are critical to the health of my marriage and yet we struggle to make the time.

<comment><USER10> Kids eat most of your time, that you're too exhausted to do anything other than sleep.

I'm pretty sleep deprived since our baby was born. Averaging about 6 hours of sleep a day, with interruptions every 2 hours.

</comment></comment></comment><comment><USER13> I like how cultural panic over people and especially youngsters being too causal with sex and having too much of it flopped directly to cultural panic over people and especially youngsters not having enough sex.

<comment><USER14> I think editors just demand a certain percentage of "X having sex Y" headlines for traffic purposes, and leave it up to the writer to fill in X and Y so that the headline can be justified.

</comment></comment><comment><USER4> Sad</comment>


Apple removing all vaping apps from App Store - <AUTHOR> https://9to5mac.com/2019/11/15/vaping-apps/ <comment><USER2> At this point no one can be surprised when Apple decides to censor legal content on highly questionable whims. Facebook, Google, etc can collect and misuse every detail of our lives, but don't worry, Apple will protect the public (and especially the children) from the scourges of pornography, nicotine, Hong Kong protests, and web browser extensions.

<comment><USER3> What do you mean when? They already did with HKmap.live.

Also, its important to note that unlike Android, there is no way to download the app and sideload it.</comment></comment>


Ask HN: Is anyone using spaced repetition with LeetCode? - <AUTHOR> I started using LeetCode a couple of months ago to prepare for my upcoming university internships and I found myself using Trello or similar apps in order to organize my learning.
Eventually, I made a chrome extension for reviewing old LeetCode questions using spaced repetition. The goal is, of course, not memorizing the question but rather making sure that the question's pattern "sticks" in my memory.
So I'm wondering if any of you have used this method while preparing for interviews and whether you found it helpful or not. <comment><USER2> I tried before, but it was quite demotivating to go back to the same questions and still not remember the answer. I'd rather just go and do new questions instead of repeatedly failing at an old one. It's probably not a good approach but better than nothing.

</comment><comment><USER3> I did this with Anki when preparing for my last round of interviews.

After completing a question (working through on a whiteboard while imitating a coding interview session), I would make a card for it. General pattern and general algorithm to use to solve, then review it whenever Anki told me to. I found that it was better to focus on higher level concepts than worrying about exact algo implementations (though I did the exact implementations when first working through a problem).

I think this worked well, but I also probably have confirmation bias.

I've also used this technique for math/CS problems, and it has seemed to work well.

<comment><AUTHOR> I did use Anki for scheduling my math problems' reviews and the results were pretty satisfactory.

Do you think I should publish the chrome extension that I made for LeetCode or does Anki do the job?

<comment><USER3> I think you should do it to learn and try something new (publishing a Chrome extension). I'm sure you could also write an interesting blog post about how you chose and implemented the spaced repetition.

Worst case scenario no one download it, but it's like most side projects, where doing it for your own growth is the important part.

<comment><AUTHOR> Well, I published it :D

[https://spacedleet.imedadel.me](https://spacedleet.imedadel.me)

</comment></comment></comment></comment><comment><USER4> Leetcode is a disease. I know many people memories answers and test cases.

</comment><comment><USER5> Why would you do that? It's not about memorization. It's about understanding the problem so if you saw it reshaped differently, you can still come up with a valid solution.

<comment><USER6> It's not about memorizing a particular solution, but the specific solution is only one piece. You should be able to look at the same or similar problem and identify the particular pattern. If you don't remember the pattern, you're doing a disservice to yourself by memorizing the solution. It means you need to rework that problem and work on other problems that rely on a similar problem solving approach. The goal is mastery of that specific pattern so it's readily available in your toolkit.</comment></comment>


"The Depressed Person" by David Foster Wallace (1998) [pdf] - <AUTHOR> http://harpers.org/wp-content/uploads/HarpersMagazine-1998-01-0059425.pdf <comment><USER2> My understanding is that David Foster Wallace wrote this about Elizabeth Wurtzel and it was meant to be a kind of slam of her as not being depressed but merely narcissistic.

[http://www.rollingstone.com/culture/news/six-things-you- didn...](http://www.rollingstone.com/culture/news/six-things-you-didnt-know- about-david-foster-wallace-20120827)

There's probably a better source but that's the first one I found on google.

<comment><USER3> I have no idea what is the context of this or who this woman is, but narcissism is a mental disorder as well so I'm not sure why anyone would try to belittle someone for being narcissistic.

This whole "my disorder is better than your disorder" doesn't impress me, neither does the universal adoration of DFW.

<comment><USER4> The question is a bit more complicated than just belittling someone's disorder.

Wurtzel wrote _Prozac Nation_ , which was nominally an account of her own depression and a broader reflection what personal struggles with depression look like in America. It was widely seen as revealing but unpleasantly self- indulgent and unreflective of common experiences with depression.

That might clarify why DFW, struggling with depression himself, was rather less than kind to Wurtzel and her book. Narcissism is something to sympathize with, certainly, but seeing a popular book portray narcissism and a rather entitled life as representative of depression put a lot of people's hackles up. The context, and the move from "disorder" to "book about having a different disorder", are vital.

None of which is a simple endorsement of DFW, but it's at least worthwhile context for the piece.

</comment></comment></comment><comment><USER5> Every time I read "Infinite Jest", i wonder how much of it is basically autobiographical with a thin veneer of difference and a heap of really, really tight prose.

The recursive spiral of recursion is really hard to avoid with DFW to the point you think it is the point, which, of course, is itself recursive.

<comment><USER6> I took a whack at IJ and got bogged down after ten pages or so. This is from TDP, not IJ, but it's illustrative:

"And the depressed person always took care, when as an adult she attempted to describe to a supportive friend the venomous struggle over the cost of her orthodonture and that struggle's legacy of emotional pain for her, to concede that it may well truly have appeared to each parent to have been, in fact, a matter of "principle," though unfortunately not a "principle" that took into account their daughter's feelings at receiving the emotional message that scoring petty points off each other was more important to her parents than her own maxillofacial health and thus constituted, if considered from a certain perspective, a form of neglect or abandonment or even outright abuse, an abuse clearly connected-here she nearly always inserted that her therapist concurred with this assessment-to the bottomless, chronic adult despair she suffered every day and felt hopelessly trapped in."

That was one sentence. There are many favorable adjectives one could reasonably apply to it, but IMHO "tight" is not one of them.

(BTW, that sentence is not an isolated example. Here's the very next sentence:

"The approximately half-dozen friends whom her therapist-who had earned both a terminal graduate degree and a medical degree-referred to as the depressed person's Support System tended to be either female acquaintances from childhood or else girls she had roomed with at various stages of her school career, nurturing and comparatively undamaged women who now lived in all manner of different cities and whom the depressed person often had not laid eyes on in years and years, and whom she called late in the evening, long- distance, for badly needed sharing and support and just a few well-chosen words to help her get some realistic perspective on the day's despair and get centered and gather together the strength to fight through the emotional agony of the next day, and to whom, when she telephoned, the depressed person always apologized for dragging them down or coming off as boring or self-pitying or repellent or taking them away from their active, vibrant, largely pain-free long-distance lives.")

<comment><USER7> Existentialist prose is agonizing to read no matter the person in which it's written. It leaves me flabbergasted that anyone could possibly describe as 'tight' such stacks and piles and reams of words, whole paragraphs at a time of them without the leaven of a period and barely even a comma as a kindness to the reader, until one feels one's head is being slowly shoved through wallpaper paste - and in both cases one eventually comes to feel that to finally suffocate would be a mercy.

Having not looked closely before now into _Infinite Jest_ , I think I better understand why it serves as such a _pons asinorum_ for literary fiction in general. It takes a more than ordinarily diligent and accommodating person to get through it at all without her eyes glazing over, much less to come out the other end with any sense of what actually happened between front cover and back.

(Oh, also: "ghastlily"? _Really?_ Far be it from me to speak ill of the dead, but...)

<comment><USER6> Now _that_ was some well-written prose! I wish I could upvote you ten times.

<comment><USER8> i nearly posted an almost identical comment as you; then i thought, well this person is probably chair of the Contemporary Literature Dept at Amherst, etc. so one should expect insight like this

<comment><USER7> Not that I don't appreciate the thought, but given what I know of academia, I think I'm more horrified than flattered. The banal enormities one must no doubt both suffer and inflict, to achieve tenure in the humanities...no, thanks. If I'm to wind up in a hell of my own devising, I should at least like to hope I've the wit to make it a livelier one than that.

<comment><USER9> You do have a very, uh, 'Literature Department' way of communicating though, surely you're aware of that? I figured you were doing it to make a point...

But so anyways, by all means write exactly as you feel like writing. I'm a huge fan of DFW, for example, precisely because he is all fancy and colloquial at the same time, which happens to tickle my fancy quite a bunch. I just wanted to point it out.

<comment><USER7> Do you mean by that to say I write like a pretentious ass? Because if so, well spotted! I'm absolutely a pretentious ass. Like any such, I thrive best well away from others of my ilk, because we can't help striking sparks off one another; based on what I've seen of Eng lit academia, I tend therefore to think it is the wrong hothouse for me.

<comment><USER9> I still don't get how being a pretentious ass and wanting to distance yourself from your ilk is best achieved by emulating their style.

Either you don't give a shit about 'them' and write as pretentiously as you desire, or, like myself, you adjust your style to distance yourself from 'them' because you dislike the association.

As it is, it's rather confusing to me because I can't tell the difference between you and the 'Eng lit academia' you seem to wish to avoid.

All that said: I don't think you write like a pretentious ass and I feel anyone should communicate however they want as long as the message comes across. And personally I like your style. So rock on, I guess :). But it's essentially what DFW is doing too, I think.

</comment></comment></comment></comment></comment></comment></comment></comment></comment><comment><USER10> DFW's writing comes up from time to time, and I always react by venting the frustration I feel with his work, which I promptly destroy because it seems wrong to criticize a (relatively recently) dead man.

But I'll say it: his writing style is incredibly self-indulgent and dreadfully dull. I guess it's a matter of taste, but it takes a unique talent to attend a pornography award show and afterparty, and churn out something as soulless, humorless, and completely devoid of a point-of-view as "Big Red Son."

I'll probably delete this soon -- I feel like an awful person for writing it, although I'm not entirely sure why.

<comment><USER2> I thought "Big Red Son" was hilarious. Humor comes from the clash of high culture with low culture. I'm not sure what the point of view was but I'd guess it's "we're all human here" which is a common POV of Wallace's work.

<comment><USER11> The humor is so dry it makes the pages all dusty. I liked Big Red Son very much, too.

</comment></comment></comment><comment><USER12> Aaron Swartz's explanation of Infinite Jest's ending comes highly recommended- not to mention their convergent trajectories. Their deaths greatly impoverished the public intellect.

</comment><comment><USER13> I'm really trying to start and finish Infinite Jest but the sheer girth of the book is discouraging me from bringing it on my commute.

<comment><USER14> Taking on _Infinite Jest_ as your introduction to David Foster Wallace is a little like getting started in rock climbing by tackling Mount Everest.

A much friendlier/more accessible place to start is _A Supposedly Fun Thing I 'll Never Do Again_ ([https://www.amazon.com/Supposedly-Fun-Thing-Never- Again/dp/0...](https://www.amazon.com/Supposedly-Fun-Thing-Never- Again/dp/0316925284)), a collection of his essays. They're shorter, tighter and generally much better commute reading.

<comment><USER15> I actually find his non-fiction in general to be much more satisfying than his fiction. He was such a gifted guy, and so funny, but when writing fiction I just feel like he was un-grounded to anything relevant to me, just wandering in the depths of his pyrotechnic writing-for-its-own-sake. For example in _The Pale King_, as an English major with lots of experience deconstructing and analyzing texts, I can see how subtle and clever his portraits of the characters are, but after a while I find I just don't care, because the story isn't interesting me as a story. Reading his non-fiction, I feel like he's always getting somewhere, and it's usually much more interesting to me.

<comment><USER16> Not to detract from your overall argument, but dinging The Pale King for not getting anywhere is a bit unfair, what with him dying before completing it.

</comment></comment></comment></comment><comment><USER17> why are depressed ppl always shown to be hanging out with cats. Maybe cats are depressing them [1]

[http://www.huffingtonpost.ca/2014/02/20/cat-bites- depression...](http://www.huffingtonpost.ca/2014/02/20/cat-bites- depression_n_4823339.html)

</comment><comment><USER18> Anyone have a link to this in plain text?

<comment><USER19> curl [http://harpers.org/wp- content/uploads/HarpersMagazine-1998-0...](http://harpers.org/wp- content/uploads/HarpersMagazine-1998-01-0059425.pdf) > depressedwallace.pdf

pdftotext depressedwallace.pdf > depressedwallace.txt

</comment></comment><comment><USER20> Explaining depression with childhood trauma always makes me uncomfortable. What are those without vestigial wounds to make of their own misery?

<comment><USER9> Why would one exclude the other?

</comment></comment><comment><USER21> I don't get it why would anyone read something like this. I mean it is not bad but simply hurts my brain.

<comment><USER22> To gain insight into minds like the Depressed Person's - not just as described dryly, but actually experienced first-hand as a result of the way it is written.

<comment><USER21> I understand the purpose of the writing style. And it works on me. That's why my brain hurts. My question was why anybody would do this to himself? Masochism?

<comment><USER22> Probably the most important thing that literature can do, in my opinion, is transport us into someone else's mind. Even if it isn't necessarily pleasant, it can still be broadening.

I feel the way you do about Eraserhead, to some extent. It's an amazing work of genius that I'll never watch again, because it made me feel physically il. I'm still glad I watched it once.

<comment><USER21> Ok, that's a valid point. I putted the movie on my to do list.

</comment></comment></comment></comment></comment><comment><USER23> It's our parents' fault we're fucked up. But it's our fault that we stay fucked up.</comment>


The Product Hunt Global Hackathon, with Over $250k in Prizes - <AUTHOR> https://blog.producthunt.com/the-product-hunt-global-hackathon-join-us-1cdee25c9608 <comment><AUTHOR> It's been a loooong time since we hosted a hackathon. The last one took place at YC HQ in Mountain View three years ago.

So far we have 1,000+ makers signed up and awesome group of judges, including YC's very own Michael Seibel, participating.

<comment><USER2> Hi Ryan. Do you send a confirmation email after signup? I can't find one in my inbox, so I'm unsure if my signup was succesfull or not.</comment></comment>


Nasa Releases Dozens of Patents into the Public Domain - <AUTHOR> http://technology.nasa.gov/publicdomain <comment><USER2> Some confusion here about government research and patents. As a government researcher with patents, I will weigh in with an approximation of our patent criteria:

1\. Increases the potential for commercialization of the technology. If you have an invention which will take effort to commercialize, companies are less likely to spend that effort without any patent protection. Offering an exclusive license on the patent can increase the chance of anyone doing anything with it.

2\. Fulfill the goals of a collaborative research agreement between the government and a private company.

3\. Further US manufacturing. The taxpayers pay us to do research to fuel industry in the USA, not Germany or China.

4\. May lead to commercialization license. This is way down on the list, and total patent royalties amount to <0.1% of our budget.

I would guess that the NASA patent set represents cases where the patent did not end up fulfilling one of those goals, and they are releasing it into the wild to see if it does better on its own.

<comment><USER3> > 1\. increases the potential for commercialization

I don't get this. If an idea is good, monopoly is icing, but not required for its adoption. If say NREL comes up with a something that increases efficiency of something by 2%, I'd want all of America and potentially the world to use it. If NIST finds a cheap way to make welds more robust and void free, I'd want every bridge, building and car to use these new techniques, not trapped in a patent monopoly.

> 3\. Further US manufacturing

Do US Gov patents require that manufacturing be in the US? Is government sponsored research an R&D arm of industry or is it to undertake projects that _don't_ have a direct economic payback or are too large or too risky?

What you say might be the "correct answer" but it isn't one I find palatable. The majority of government sponsored research should be open to all. In some circumstances I can see limiting it to people in the US and under even narrower circumstances, limiting it via a patent.

<comment><USER4> If the new welding method is developed enough to patent, but possibly not enough to mass produce new welding equipment, then it will require an investment from someone to get it into use outside the laboratory. Being able to license them a patent provides a greater incentive to make that investment. It's possible for an idea to be simultaneously an improvement, cheap in the long run, and also require an up-front investment that might never be made back without a guarantee of monopoly.

I can't judge how frequently this occurs, but it seems reasonable.

<comment><USER5> _Being able to license them a patent provides a greater incentive to make that investment._

In theory. But that's not the only way things can play out. It's just as likely that if such an innovation is offered freely to everyone, that everyone will feel compelled to adopt it, exactly because of the fear that their competitors will. And nobody wants to get left behind.

Given that it's basically impossible to know how a given scenario will play out ahead of time, I don't buy this whole "grant patents on government sponsored developments and then sell them" based on some hypothetical scenario that lacks any real justification.

</comment></comment></comment></comment><comment><USER6> To those asking the question "why aren't patents automatically in the public domain?", the question received a decent answer on Stack Exchange two years ago:

[http://patents.stackexchange.com/questions/9994/are- patents-...](http://patents.stackexchange.com/questions/9994/are-patents- granted-to-the-us-government-public-domain)

"No, they are owned by the U.S. and controlled by the specific agency where the inventing happened. However, there is a policy of licensing. It is covered in 35 USC 209. The logic behind this is that the U.S. would like the public to benefit from the invention and if anybody can do it, it may very well be that no one actually does it. Without some exclusivity it may be that no one will be able to justify the investment to enter the market." -George White

One of the comments to that answer also suggests inventors of government patents also get a fixed percentage of revenue, which wouldn't surprise me as an incentive to drive government employees to come up with novel inventions on the clock.

<comment><USER7> A similar argument could be made for copyrighting government works: maybe no one would publish them if not granted a monopoly, and maybe getting a kickback would incentivize government employees to create copyrightable works.

... I'm glad it isn't, and am inclined to view government patents in the same way most of us view crown copyright.

<comment><USER8> The cases are pretty different. The government isn't generally creating copyrightable works with the hope of turning a profit on them. They're creating them, e.g. as part of the mission of an agency. Think NASA photographs for example.

To be copyrightable, the work needs to exist in more or less final form. That's what is copyrighted.

By contrast, while what's patented goes beyond an idea, it may not be usable for anything until someone has spent significant money to commercialize it-- and maybe not even then.

</comment></comment></comment><comment><USER9> Finally! I can build coils for my plasmoid thrusters[1] and not worry about NASA coming after me. :-)

More seriously, this is something I really like about NASA and their mission, they are excellent at technology transfer. They did a lot of work on Lithium batteries that got widely licensed for little to no money and that has made for an explosion of battery applications (no pun intended)

[1] [http://technology.nasa.gov/public_domain/MFS-32364-1](http://technology.nasa.gov/public_domain/MFS-32364-1)

<comment><USER10> Here's a better view of the same thing: [https://www.google.com/patents/US7808353](https://www.google.com/patents/US7808353)

Note that this coil essentially _is_ the thruster. You put gas (from a compressed tank) in one end and it fires out the back, creating thrust from electricity + the gas. It's not quite a massless thruster, but very close!

This represents a major improvement over the ion propulsion on Deep Space 1.

<comment><USER9> In my case I've modified it to be an Plasmoid overthruster. :-)

</comment></comment></comment><comment><USER11> The government using tax money to develop things, patent them, then charge license fees for them seems quite at odds with the Constitutional purpose of patents:

"To promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries;"

<comment><USER3> Analogously, the FCC auctioning off spectrum to the highest bidder instead of leasing it to the provider who will provide the best or cheapest service using that spectrum. Seems like an effort to ensure that the citizens get gouged.

<comment><USER12> There is a deep body of economic theory that argues that it's much more efficient to simply auction off spectrum than to have a government agency make decisions about "who will provide the best or cheapest service" using that spectrum. Indeed, the old model of licensing spectrum to who the FCC thought of as the best users resulted in the current problem of prime spectrum being allocated to low-value uses like broadcast television.

Tom Hazlett's papers are a good introduction into the orthodox view of spectrum economics: [http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1583098](http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1583098).

<comment><USER3> You have got to be kidding me, is this writing typical of economic publishing? This is a circle jerk echo chamber of cliche and truism.

Low-value broadcast television is a by product of auctioning spectrum and maximizing profit. If something is a public good, it isn't in the publics good to maximize the profit. The fitness function of the whole thing is flawed. In what measure of efficiency does the duplication of poor cellular service and capability rank? How far into the future will such byzantine structures exist?

[https://en.wikipedia.org/wiki/Ronald_Coase](https://en.wikipedia.org/wiki/Ronald_Coase)

<comment><USER12> > Low-value broadcast television is a by product of auctioning spectrum and > maximizing profit.

Broadcast television spectrum wasn't allocated by auction. It was allocated by government bureaucrats deciding what was most important.

> If something is a public good, it isn't in the public's good to maximize the > profit.

It's in the public's interest to maximize the economic revenues generated from the resource.

</comment></comment></comment></comment></comment><comment><USER13> Can anyone explain: why are government works automatically public domain (not copyrighted) but government inventions are not unless explicitly stated?

<comment><USER14> Probably because copyright is automatic and patents aren't. You have to actively patent an invention to make sure nobody else patents it, but the same risk (someone else copyrighting the government's work) isn't really applicable on the other side.

<comment><USER7> I don't think that's the case: an unpatented invention (that is disclosed) becomes prior art, which protects the invention from being patented by someone else.

Theoretically. The US patent system is a mess, from the rubber-stamp examiners in DC to the ridiculous judges in East Texas.

<comment><USER15> _I don 't think that's the case: an unpatented invention (that is disclosed) becomes prior art, which protects the invention from being patented by someone else._

If an unpatented invention is disclosed publically (not through a patent application), then it becomes public domain and nobody can patent it.

Also, the US is no longer "first to invent", but rather "first to file". You could have a claim that you invented it first, but if someone files before you, you are SOL.

</comment></comment></comment></comment><comment><USER16> Are these parents as useful as all other patents, where you require a lawyer to English translator to get a gist, and almost reinvention to get it to actually work from the description?

</comment><comment><USER17> Someone let Walt Kerman run with his strategy again. :)

[http://wiki.kerbalspaceprogram.com/wiki/Strategies#Open- Sour...](http://wiki.kerbalspaceprogram.com/wiki/Strategies#Open- Source_Tech_Program)

</comment><comment><USER18> Misread as Dozens of Planets.

I was confused.

</comment><comment><USER19> At risk of a downvote, I have to ask: am I the only one who read the headline thusly,

"NASA Releases Dozens of _Planets_ into the Public Domain"

"Wow," I'm thinking, "that's way cool of them..."

Whereas the _correct_ title is probably just as cool, if not cooler.

</comment><comment><USER20> > Nasa

NASA is an acronym and not a word

<comment><USER21> Some style guides recommend that word-like acronyms (i.e., pronounced as a word, rather than its individual letters) be capitalised as though they were normal words (cf. BBC vs. laser).</comment></comment>


Startup explainer videos can cost $50k – $500k  so we made a game instead - <AUTHOR> https://medium.com/matter-app/startup-explainer-videos-can-cost-50k-500k-so-we-made-a-game-instead-585387afa607 <comment><AUTHOR> $500k, really?</comment>


Ask HN: Would you solve programming puzzles to apply for jobs? - <AUTHOR>

Imagine a website like http://jobs.37signals.com/ where instead of applying by sending an email, you were given a programming quiz to transform a randomly generated data set to a result set given some parameters (testing algorithm comprehension, implementation and such up front). You upload your result set and code used to generate the result along with your resume for consideration. Based on how fast you generated the result and how good your code is, this process could streamline your application process and show off your talents.   For those rockstar programmers that are looking to upgrade jobs, this could set you apart from your competition and be a fun exercise to keep you fresh. For those programmers that are working towards rockstar-ness, you need not apply to jobs to take the quizzes and improve your programming skills with practice.
If the quizes you pass happen to be the type that a company wants to post a job for, the site will let you know that you should send in your results for consideration since the job might interest you.
This system would be completely language-independent since as long as the generated result set is correct then the code is assumed to work and someone at the company will review your code in more depth anyhow.
Assuming the obvious cheating methods are stifled with sophisticated code comparison techniques and google searches, thus making the system difficult to game and relatively fair, is this a site you guys would use?
If not, why not? Thanks for your feedback! <comment><USER2> It'd be cool, but there are a few things to worry about:

\- Bugs in the system are dangerous; for instance, if I did my quiz in an hour but it got submitted as two, my job opportunity could be lost

\- People will get around your anti-cheating methods

\- People will practice or memorize solutions to your quiz (while there's no problem with practicing, this allows people who are good at solving your quiz but bad at programming in general to get through)

\- Code comparison may not be useful, especially since a lot of tasks will lend themselves to being expressed in just a few ways which most code will use

\- Defining a useful metric for "how good your code is" is tricky, possibly impossible

It'd be especially good if your quizzes asked for things that needed to be implemented anyways. It'd be a nice, cheap way to build up an open-source code repository.

Honestly, I'd probably do the quizzes just for fun. Now that I think about it, something similar already exists which I do play for fun: <http://projecteuler.net/>

Altogether, it sounds like a good idea if you can get the details right.

</comment><comment><USER3> Something like this already exists: TopCoder. They are pretty well known and have a good reputation, so they will be hard to compete against. With that said, however, there are a lot of things that can be improved: (like what you hinted at) you can have each company submit their own problem and make it more open, etc. If you are going to run with this idea, good luck!

<comment><AUTHOR> Does TopCoder have a job posting feature? I can't find it.

</comment></comment><comment><USER4> Strikes me as pretty easy to game, as Google's MY friend... Might have some use for hiring fresh-from-school, but anything more senior's best done by reputation rather than brain teasers. True rockstars would not stoop to proving it - imagine asking Linus to play such a game.

<comment><USER5> Who knows? He might do it, if it's fun.

</comment></comment><comment><USER6> It sounds like a good idea, but it probably would only work well for junior programmers. I'm working on something similar in a couple ways, but not related to programming.

</comment><comment><AUTHOR> But assuming I figured out a way to make it hard to game

<comment><USER7> I hate to sound discouraging, but when it comes to job interview techniques, making it hard to game is the entire problem, not just a detail.

<comment><AUTHOR> This is true, but I don't want to describe the details in public which would only make it easier to game. I am just wondering if hackers would use the service if it was available.</comment></comment></comment>


Julia Ferraioli's account of casual sexism in tech - <AUTHOR> http://www.blog.juliaferraioli.com/2014/08/do-you-even.html

<comment><USER2> It may have been his akward attempt at hitting on you. A lot of computer guys have no idea how to talk to females. Also this is not limited to tech all over the world racism, sexism, ...ism exist.

<comment><USER3> I'll dust off my account to reply here.

The point isn't to find an explanation for it. This sort of behavior drives people out of technology (or pick your industry). I wouldn't dream of going up to someone, with or without cause, insulting them and questioning their capabilities based on some irrelevant detail -- in my case, gender. Let's communicate that this sort of behavior is unacceptable, and let's do it by calling it out. People won't learn unless we tell them.

The insidious aspect of this idiocy is that any attempt to educate by myself and my colleague is undermined by the individual's bias, so no matter what we say, it won't be taken seriously or given any weight. This is why good allies are invaluable.

Also, I take issue with the idea that hitting on someone is the primary reason to "[talk] to females." Hey, I'm a person with interests and expertise. How about talking to me about that?</comment></comment>


What did Jesus really look like? (2015) - <AUTHOR> https://www.bbc.com/news/magazine-35120965 <comment><USER2> I've been fascinated with how the countenance of Christ has been a tool for racial (and racist) propaganda. As a Jew from the Middle East, He certainly wasn't the fair-skinned, blue eyed, blond hair rock star depicted by some Christian denominations. I also doubt He was black, although some Rastafarians believe He was because it says so in Jeremiah 8:21.

I discussed "Black Jesus" and the Rastafari on my podcast : [https://soundcloud.com/jesusinbooks/black_jesus_rastafarian_...](https://soundcloud.com/jesusinbooks/black_jesus_rastafarian_religion) and for those who want to deep-dive into the topic, I highly recommend The Color of Christ by Paul Harvey and Edward J. Blum. It's a knockout book.

<comment><USER3> > I also doubt He was black, although some Rastafarians believe He was because > it says so in Jeremiah 8:21.

That's an odd interpretation. The word in Hebrew stems from qadar, which does mean dark, but is often used to indicate mourning ([https://biblehub.com/hebrew/6937.htm](https://biblehub.com/hebrew/6937.htm)). And that follows the context of the verse: "Since my people are crushed, I am crushed; I mourn (qadarti), and horror grips me" (NIV). As far as I recall, the Bible never uses skin color to indicate race. It always goes by ancestry ("Abraham was the father of Isaac, Isaac the father of Jacob, . . . "). Speaking of which, it spends a great deal of time, across several books, to tell us that Jesus is Jewish. Most Jews I know of are fair skinned. Skin color doesn't mean any kind of superiority to me. I'm just talking about the accuracy of paintings.

> He certainly wasn't the fair-skinned, blue eyed, blond hair rock star > depicted by some Christian denominations.

I've been a Christian all my life, and visited churches of many denominations. Most depictions show him with brown hair and brown eyes. I can't remember seeing any depiction with blond hair. Now blue eyes I have occasionally seen, but isn't it possible for any race to have any eye color?

<comment> village-idiot > Most Jews I know of are fair skinned.

It has been a while since Jesus' time, and chances are most Jews you know work inside, unlike Jesus.

Sarcasm aside, all of the Jews I know can trace their lineage through Europe after the diaspora in the early second century. One would expect that a pre- diaspora Jew in Judea and a modern Jew who's family had traveled through Northern Europe for 1800 years would have significantly different skin tones.

<comment><USER4> When you look at natives of the Levant they pretty much look like the depictions of an Mediterranean Jesus you will find most commonly in churches around the world. Fair skin and light eyes are not a unheard of trait in that region either. I have a Jordanien friend who has the bluest eyes and blonde hair. The Levant is not Saudi Arabia or Pakistan, these people are well in the phenotypical spectrum of most Mediterranean people, like Greeks, Italians, Turks or Lebanese people.

</comment></comment></comment></comment><comment><USER5> Bart Ehrman, a professor of religious studies at UNC Chapel Hill wrote a decent book on the question of whether or not there was a historical Jesus. He does a good job talking through the arguments on both sides, and covers the history of the argument. He did an interview about the topic on NPR a few years ago: [https://www.npr.org/2012/04/01/149462376/did-jesus-exist- a-h...](https://www.npr.org/2012/04/01/149462376/did-jesus-exist-a-historian- makes-his-case)

<comment><USER6> I'm currently reading Zealot by Reza Aslan, which doesn't really debate whether or not there was a historical Jesus, but discusses the differences in fact vs the bible.

I highly recommend it.

<comment><USER7> I read it, and was disappointed. The book could only get so close to Jesus as to speculate what a person living during that time period might have been like, and what some of the prevailing social issues were.

<comment><USER8> I thought it was a good book, as he says, he's not presenting anything new or controversial to biblical scholars, but I (as a layperson) learned a lot about Christianity, and now understand it better - how it went from being a weird Jewish sect to the imperial religion of Rome.

Just finished The Darkening Age: The Christian Destruction of the Classical World by Catherine Nixey, which documents the destruction of statues, temples and artworks by Christians in the years 300-500AD in Europe. Also recommended!

<comment><USER9> Unfortunately Nixey's book is terrible. As a classisist she should know better than to regurgitate ideas from Gibbon, ignoring 200 years of scholarship. Instead she goes for sensationalism, "evil Christians destroying classical culture" and links to ISIS and such. Which isn't needed because the period she describes is interesting enough on its own.

The book is so terrible a collection of reviews from historians can be found here: [https://gegrammena.wordpress.com/2017/10/22/reactions- review...](https://gegrammena.wordpress.com/2017/10/22/reactions-reviews-to- catherine-nixeys-the-darkening-age-eeuwen-van-duisternis/) .

I especially like this article ([https://www.roger- pearse.com/weblog/2017/10/21/hunting-the-w...](https://www.roger- pearse.com/weblog/2017/10/21/hunting-the-wild-misquotation-again-the-perils- for-the-author-of-not-verifying-your-quotations/)), focusing on how she misused a quote from Chrysostom by removing all context, which completely changed the meaning to fit her narrative. Not only that, she clearly didn't read the original source but borrowed the interpretation from another author, who also misread it.

</comment></comment></comment></comment></comment><comment><USER10> Isn't it fascinating how _little_ Paul refers to Jesus' own biographical life though? We know that the gospels are likely younger than Paul's letters and that Paul is one of the earliest missionaries to the Gentile world. And when we read Paul's letters, they're far more direct and practical in content than everything else in the NT. So is it that over time, as early Christian's earliest leaders died out, a fascination with just _who_ this Christ was vivified? As well, wouldn't this dating make Paul's letters the most authoritative liturgical documents?

<comment><USER11> > Isn't it fascinating how _little_ Paul refers to Jesus' own biographical > life though?

This comes to mind. In my early school years, a bunch of us kids were really close. We did so many things together at school and all summer in our neighborhood. However it is fascinating to me now that we didn't share anything about our Moms, Dads or Grandparents, the people in our background we were closest to. All of that was implicit, there were no need to discuss the daily lives of ones we knew intimately and loved us so much. So with Paul, I'd think. After all Paul studied under Gamaliel and he would have known how to research and share with the world the biographical details of a subject beyond what people just knew from the Gospels, or word of mouth, at least (they must have known more as they all lived closer to the events). What I am getting at is, he just preached what that really mattered for him.

</comment></comment><comment><USER12> Considering there's plenty of traditional depictions of Jesus from middle eastern churches that date back to Greco-Roman Palestine, I don't see why we shouldn't assume those are relatively close to what he would have looked like, considering that's the culture and region he came from.

Example: [https://commons.wikimedia.org/wiki/Church_of_the_Holy_Sepulc...](https://commons.wikimedia.org/wiki/Church_of_the_Holy_Sepulchre#/media/File:Jerusalem_Holy_Sepulchre_BW_15.JPG)

Slightly curly hair, dark hair, dark eyes, beard, seems about right for a Jew living in 1st century Greco-Roman Palestine.

<comment><USER13> Because not all art is intended to be accurate — it might be symbolic. The linked example shows blue/purple clothes, which were limited to the elite. Like the article says, this is used to show a royal status, not that it was what he actually wore.

<comment><USER12> And the earliest Christian art was almost entirely symbolic - fish, lambs, wheel cross, chi-rho, etc...

Even if elements of iconography are symbolic, they could have easily made Jesus look any way they want, yet the standard 'Byzantine' Jesus icon gives him dark features and slightly curled hair. Seems close enough, and none of the earliest art (either purely symbolic or very Roman - possibly to hide from persecution) seems any more accurate.

</comment></comment></comment><comment><USER14> Fun google - "jesus magic wand" because... for early Christians Jesus often had a magic wand!

<comment><USER15> "On the eve of Passover Yeshu was hanged. For forty days before the execution took place, a herald went forth and cried, 'He is going forth to be stoned because he has practised sorcery and enticed Israel to apostasy. Any one who can say anything in his favour, let him come forward and plead on his behalf.' But since nothing was brought forward in his favour he was hanged on the eve of Passover. Ulla retorted: 'Do you suppose that he was one for whom a defence could be made? Was he not a Mesith [enticer], concerning whom Scripture says, Neither shalt thou spare, neither shalt thou conceal him? With Yeshu however it was different, for he was connected with the government."

<comment><USER16> Where is that quote from?

<comment><AUTHOR> A quick web search reveals that it is from the Babylonian Talmud, Sanhedrin 43a.

</comment></comment></comment></comment><comment><USER17> > That Jesus was a Jew (or Judaean) is certain in that it is found repeated in > diverse literature, including in the letters of Paul. And, as the Letter to > the Hebrews states: "It is clear that our Lord was descended from Judah."

True enough, it seems.

But what about Muhammad? From what little I know, he was neither Jewish nor Christian. Before founding Islam, I mean. But it seems pretty clear that he worshiped the same god.

In other words, what was the main Arab religion before Islam? I'm guessing that it was something like Judaism. Indeed, maybe there were many forks.

<comment><USER18> > In other words, what was the main Arab religion before Islam? I'm guessing > that it was something like Judaism. Indeed, maybe there were many forks.

Pre-Islamic Arab society was largely polytheistic, with pockets of Jewish tribes and smatterings of individual Christian and Zoroastrian priests representing the monotheistic element, the latter largely either as immigrants to the Arabian peninsula or via the influence of foreign traders, etc.

When the prophet Muhammad emigrated from Makkah to escape economic and physical persecution at the hands of the Quraish Arabs, he moved with his followers (or rather, having already his sent his followers ahead of him) to Madinah (then known as Yathrib) which was home to, among others, two Jewish tribes.

<comment><USER17> Ah, this is exactly what I wanted to know!

From Anwar-ul-Quran:[0]

> Quraish was the name of our Holy Prophet's tribe. Makkah did not possess > cultivable land. It lay in a valley surrounded by barren hillsides — a land > that was devoid of food and so its livelihood depended on trade. ...

> As they were the guardians of the Ka'bah they were treated with great > respect by all Arabia.

And from Wikipedia:[1]

> Ibn Kathir, the famous commentator on the Quran, mentions two > interpretations among the Muslims on the origin of the Kaaba. One is that > the shrine was a place of worship for Angels before the creation of man. > Later, a house of worship was built on the location by Adam and Eve which > was lost during the flood in Noah's time and was finally rebuilt by Abraham > and Ishmael as mentioned later in the Quran. Ibn Kathir regarded this > tradition as weak and preferred instead the narration by Ali ibn Abi Talib > that although several other temples might have preceded the Kaaba, it was > the first "House of God", dedicated solely to Him, built by His instruction > and sanctified and blessed by Him as stated in Quran 22:26–29. A Hadith in > Sahih al-Bukhari states that the Kaaba was the First Mosque on Earth, and > the Second Mosque was the Temple in Jerusalem.

> While Abraham was building the Kaaba, ...

So yes, they and the Hebrews were siblings.

0) [http://www.muslim.org/islam/anwarqur/ch106.htm](http://www.muslim.org/islam/anwarqur/ch106.htm)

1) [https://en.wikipedia.org/wiki/Kaaba](https://en.wikipedia.org/wiki/Kaaba)

</comment></comment></comment><comment><USER19> I remember National Geographic Magazine had an article on exactly this, and reach the same conclusion, a decade or two ago. I'm not a subscriber so I can't search their archives (anyone?). However, they do have a nice list of depictions of Jesus:

[https://www.nationalgeographic.com/magazine/jesus- portrayals...](https://www.nationalgeographic.com/magazine/jesus- portrayals/grid/)

</comment><comment><USER20> Do we even know he was a real person and not combination of 2 or 3 men with similar fate?

<comment><USER21> No, although typically the opposite claim is made. That people named "Joshua son of Joseph" lived at that time, that various revolts and religious upheavals occurred is pretty certain. That one guy fitting the rough description of Jesus was behind it is not. The history of Christianity doesn't really start in earnest for hundreds of years after the supposed death of Christ in any case.

People today can't even agree on the details of Elvis' life... now imagine if Elvis had lived a few hundred years ago, and we're all working from quaternary+ sources. Then fast-forward a thousand or so years of very intentional document editing and re-editing, translations and re-translations, and all of the incredible wealth and power hinging on it for centuries.

How accurate would accounts from those times be expected to be?

<comment><USER22> >although typically the opposite claim is made. That people named "Joshua son of Joseph" lived at that time, that various revolts and religious upheavals occurred is pretty certain. That one guy fitting the rough description of Jesus was behind it is not

That doesn't seem quite fair because it's almost certain that the guy named Jesus was not behind the upheavals of that time. That was about the Jewish revolt against the Romans which Jesus was not involved in at all. Also, while Christianity didn't start in earnest until about two hundred years after Jesus' death, stories of his life were written down as early as 60 years after his death.

It's very difficult in a society like ancient Israel to fake the existence of a person, people had clan allegiances, they kept track of genealogies and would be able to tell right away if the writings concerned someone who didn't exist.

There were translations but that's irrelevant because we have the original dead sea scrolls with the earliest ones dating to a few decades after his death. A time when wealth and power did not hinge on this. We're not solely working with edits and re-translations.

I think there's a bias against religious figures that inform people's arguments when they say it's all uncertain - when in reality the evidence is pretty good that he did exist.

<comment><USER21> Details of his life may have been written down then, but the sources we have aren't those sources, just edited and translated retellings of those supposed stories with about 1800 years of politically and religiously motivated games of telephone between us and them. I have to ask, the Dead Sea Scrolls date from between about a century before Jesus' purported life, to about a century after his death and as far as I know make no mention of him. I wasn't claiming that the language is somehow untranslatable, but that we don't have anything like contemporary sources, only people who hundreds of years later claim to have access to those sources.

</comment></comment></comment></comment><comment><USER23> Probably looked more like Osama bin Laden than white Jesus.

<comment><USER24> I had a white blonde hair, blue eyed student ask me what I thought Jesus looked like the other day. After first clarifying that Jesus wasn't a Christian, but a Jew, I proceeded to say he probably looked more like bin Laden than the student. Needless to say, this student from the backwoods American South was _not_ happy with that, but I thought it was hilarious.

</comment></comment><comment><USER25> A more important question is whether or not there is a historical Jesus at all. Richard Carrier has done some of the best work on questioning this: [https://www.youtube.com/watch?v=LTllC7TbM8M](https://www.youtube.com/watch?v=LTllC7TbM8M)

Did Christianity really begin without a Jesus?

</comment><comment><USER26> Is it just me or does that last Jesus look like Shia Labeouf

<comment><USER27> He (Shia) is half-Jewish as well, and has several middle-eastern traits, so it makes sense a depiction of what people looked/look like in the region to have some common elements.

</comment></comment><comment><USER28> "What Jesus could have looked like?"

</comment><comment><USER28> I never understood why people are so fascinated by some theories and spend so much time on it.

Bermuda triangle, jesus and loch ness monster don't become more interesting when we decorate those stories with more theories which can't be proven.

I'm always thinking that this might just be the reason why those stories are still around. People just don't stop. they continue to extend it small little piece by piece.

<comment><USER29> I'm not sure what you're trying to say.. that Jesus is comparable to the Loch Ness monster (an urban legend)? No serious historian (secular or otherwise) doubts the historicity of Jesus Christ of Nazareth. His divinity is obviously a matter of faith, but Jesus was certainly a real human being that was born and eventually was crucified around 30 AD.

<comment><USER28> Yes he is. There is no proof that the Jesus existed.

We have more effidence on thousand real existing people. Less fames perhaps but propper people.

<comment><USER9> There is no reason to assume Jesus was not real. This issue was closed by historians over a hundred years ago and never has there been thrown any new light that puts it into doubt. It's only fringe people with specific agendas, who always seem to lack the skills and knowledge to work with the sources, who claim otherwise.

For a good overview of why historians know Jesus existed you should read John P. Meier - A Marginal Jew: Rethinking the Historical Jesus, Volume I: The Roots of the Problem and the Person.

</comment></comment></comment></comment><comment><USER30> Anyone interested in this should check out the podcast series Historical Jesus from Stanford:

[https://itunes.apple.com/us/podcast/historical- jesus/id38423...](https://itunes.apple.com/us/podcast/historical- jesus/id384233911?mt=2)

tldr; there probably wasn't a Jesus and there is no evidence to support his existence.

<comment><USER31> That seems to contradict the consensus among historians [1]:

> Virtually all New Testament scholars and Near East historians, applying the > standard criteria of historical investigation, find that the historicity of > Jesus is effectively certain although they differ about the beliefs and > teachings of Jesus as well as the accuracy of the details of his life that > have been described in the gospels. While scholars have criticized Jesus > scholarship for religious bias and lack of methodological soundness, with > very few exceptions such critics generally do support the historicity of > Jesus and reject the Christ myth theory that Jesus never existed.

Can you point to where the podcast makes such a claim?

[1] [https://en.wikipedia.org/wiki/Historicity_of_Jesus](https://en.wikipedia.org/wiki/Historicity_of_Jesus)

<comment><USER32> This is one of those times trusting Wikipedia is laughable.

Wikipedia is not the absolute authority on everything. No, really. Impressive, yes, but it's not correct 100% of the time. In fact sometimes it's crazy how wrong it is. [https://en.wikipedia.org/wiki/Wikipedia:List_of_hoaxes_on_Wi...](https://en.wikipedia.org/wiki/Wikipedia:List_of_hoaxes_on_Wikipedia)

<comment><USER33> What, then, is the consensus view among New Testament scholars and Near East historians of the historicity of Jesus?

<comment><USER34> What's the consensus view of homeopathy scholars on the efficacy of homeopathic "medicine"?

A group of people with an agenda writing volumes of tautological speculation doesn't make it credible.

<comment><USER33> > What's the consensus view of homeopathy scholars on the efficacy of > homeopathic "medicine"?

Near East historians have an agenda? News to me. What's the proportion of Christians versus non‐Christians in that field?

Even if that group is replete with biased theists (something you seem to be suggesting but haven't presented any evidence for), surely there is some scholarly group whose views on historical science you can agree would be worth listening to. So what's _their_ consensus on the historicity of Jesus?

<comment><USER30> Did you listen to the history podcast in my original comment? He presents a very strong case for there not being a Jesus. Everyone keeps saying there's some sort of consensus on his existence yet I've posted a very thorough argument that argues the opposite. Last I checked, Stanford was pretty reputable.

<comment><USER31> See my top-level comment. There _is_ a historical consensus on Jesus' existence and some basic facts about his life (with wide disagreement beyond that).

And Thomas Sheehan, the philosopher and presenter of the podcast you linked to, accepts the historicity of Jesus.

<comment><USER25> This article does a great job of explaining why you should question that consensus.

[https://www.richardcarrier.info/archives/5553](https://www.richardcarrier.info/archives/5553)

</comment></comment></comment></comment></comment></comment></comment></comment></comment><comment><USER35> Not sure what he looked like, but it doesn't matter to me. I see him as a philosopher before the Gutenberg press that was not associated with the Pharisees (established philosophical order). There have been many Jesus personalities throughout history, every religion has one as a voice to convey useful advice.

He gave such good advice about how to navigate hardships without the pressure of tithing that he has since been revered as supernatural.

\--5,000 fed with 5 loaves and 2 fish:

I used to think everyone was fed "magically" with whole portions. Now I realize it was a communal exercise, and the lesson learned was how to share and make sure everyone gets an equal piece (even though everyone just got a small crumb).

\--Water to wine

Once again, as a child I thought he violated laws of physics. Alcohol is a depressant and excessive use can hinder productivity of the citizenry. Under the advisement of Jesus, the man without ties to the Church, word spread to replace wine with water. Water to wine; pez to Xanex.

\--The poor woman and the blind man

I recall one story where there was a poor woman without food, and Jesus was able to scrounge up enough flour from her own storage containers to produce a meal. Once again, thought it was magic. But he came into her home and helped her assess her resources.

Mud on the blind mans eyes? Impossible to cure blindness like that - but he wasn't literally blind. Unfortunate circumstances likely provoked a depression that pushed him into pretending to be blind and beg - free money. Not the way an able bodied citizen should behave. The revered Jesus came to him and performed a ceremony with the audience consisting of locals that had walked by the blind beggar every day. Now he is "cured" in front of all and he can end the act safely using Jesus' supernatural status as a catalyst. Probably got a job the same day - no more begging. Productivity of the village slightly improved.

Lazarus "raised from dead" is another example of this - a depressed guy shutting out the world could be considered dead. Jesus brings him back to the tribe. Another able-bodied person returning to the economy.

If we assume religion is an early form of software engineering used to instill practical economic ideals and morals into society through simple parables and metaphors: Jesus was the software update everyone was ready for, but had to be killed off because embezzlement-prone-tithing-proceeds were probably being threatened. This kind of sacrifice effectively locked in his doctrines.

<comment><USER36> you read those passages and reimagined their intent and delivery? I don't think any christian I've ever met has come to such conclusions. I think generally they see the miracles as proof of his divinity

<comment><USER35> The intent and delivery of my interpretation is to take a familiar person that is particularly sought out this time of year and bring up issues I've been noticing in the region I am currently exploring.

</comment></comment></comment><comment><USER37> Not a historical figure, so good luck.

</comment><comment><USER38> I think depicting Jesus as attractive is a reasonable assumption. A young, charismatic leader seems more likely than the average person to be attractive, or at least distinct looking.

But of course, not the blond hair blue eyes thing.

<comment><USER39> For what it's worth, I agree. Siddhartha is said to have been attractive, there's no reason to think his analogues like Muhammad or Jesus weren't.

</comment></comment><comment><USER40> Richard Carrier has made a decent case against a historical Jesus, but I'm not a scholar. On the other side, Bart D. Ehrman is an atheist who backs a historical Jesus. If he was based on a real person, The Jesus we know is like a Hollywood biography where the story was 'based on actual events' but was exaggerated beyond recognition for rhetorical impact. It's allegorical fiction.

<comment><USER40> I am not sure why I got downvoted. Mark is the oldest of the Gospels. The others, especially Matthew and Luke are just derivative works. They are anonymous embellishments of anonymous writing that was never meant as historical record. They were meant to convey the basic ideas to a non- christian populations.

<comment><USER25> People fighting back because the truth hurts.

</comment></comment></comment><comment><USER41> According to John Allegro, of Dead Sea Scrolls fame (among other more recent scholars), he looked like this:

[https://en.m.wikipedia.org/wiki/Amanita_muscaria](https://en.m.wikipedia.org/wiki/Amanita_muscaria)

<comment><USER42> From Wikipedia:

Allegro argued that Jesus in the Gospels was in fact a code for a type of hallucinogen, the Amanita muscaria, and that Christianity was the product of an ancient "sex-and-mushroom" cult. Critical reaction was swift and harsh: fourteen British scholars (including Allegro's mentor at Oxford, Godfrey Driver) denounced it. Sidnie White Crawford wrote of the publication of Sacred Mushroom, "Rightly or wrongly, Allegro would never be taken seriously as a scholar again."

<comment><USER43> much more probable than what various religions tell us.

</comment></comment></comment><comment><USER44> He looked like a mushroom, obviously. [https://en.wikipedia.org/wiki/The_Sacred_Mushroom_and_the_Cr...](https://en.wikipedia.org/wiki/The_Sacred_Mushroom_and_the_Cross)

But an actual mushroom, not a human shaped mushroom like Lenin became. [https://en.wikipedia.org/wiki/Lenin_was_a_mushroom](https://en.wikipedia.org/wiki/Lenin_was_a_mushroom)</comment>