Why We Created Julia (2012) - <AUTHOR> https://julialang.org/blog/2012/02/why-we-created-julia <comment><AUTHOR> I noticed that today happens to be the 6th anniversary of this blog post being posted to HN, reddit, etc (previous HN discussion at [https://news.ycombinator.com/item?id=3606380](https://news.ycombinator.com/item?id=3606380)). I think it's fair to say that that event marked a major turning point in the development of Julia, probably doubling or tripling the contributor base overnight, many of whom (myself included) are still actively involved in the community. It's a little funny to see the blog post talk about 1.0 (that release would eventually be called 0.1), since that's still not out 6 years later (though this time around it is actually soon to be released). The blog post says julia was 90% done at the time - I guess it's true what they say, 10% of the work takes 90% of the time.</comment>


Thirsty: Intellectual Curiosity and Success - <AUTHOR> http://sethgodin.typepad.com/seths_blog/2009/11/thirsty.html

<comment><USER2> "I wonder which comes first, the curiosity or the success?"

That's a weird question to ask at the end. Children aren't born successful, but they can be born curious.

</comment><comment><USER3> I reblogged this one as Hungry.

It's tough to remove my bias from this observation. Of course I want curiousity and success to be highly correlated. But Seth did skip over execution. Do curious folks learn how to execute as well?</comment>


UX Myths (2014) - <AUTHOR> http://uxmyths.com/ <comment><USER2> I wish more websites, especially those actively writing about UX, would style visited links differently.

When you're reading one of these myths, there is no link to go to the next one ; you need to go back to the index. But since visited links are not differentiated, it's difficult to know which item you've just read, and where to go next.

Just using "a:link" instead would yield a more satisfying design: [http://i.imgur.com/oz6Hznw.png](http://i.imgur.com/oz6Hznw.png)

<comment><USER3> I didn't know they were links until I read this comment!

No hover on mobile.

<comment><USER4> I'm not too sure what the solution is. You could make the links blue and/or underline them, but that could harm readability and aesthetics.

I suppose some sort of icon (like an arrowhead) next to each link could help them to afford clicking.

<comment><USER5> _You could make the links blue and /or underline them, but that could harm readability and aesthetics._

I doubt it, blue and underlined is pretty much a standard. I think it looks perfectly fine and clear. There's a reason most browsers' default stylesheet will make links look like that.

<comment><USER4> It might be an improvement in this case, though it's common advice to limit the colour palette to a handful of colours. Blue text also doesn't always stand out against certain background colours.

Underlining links (particularly where there are many of them) can harm readability, which is why many popular websites do not do it, including the major search engines, Wikipedia and even Hacker News.

</comment></comment></comment></comment></comment><comment><USER6> I'll take serious issue with #12. There's undirected scatterbrained interfaces and that's bad sure.

But there's the other extreme. Like in Google mobile search, you can't do custom date ranges... they've removed one menu item just on mobile.

On SoundCloud mobile you can't delete your own uploads. On reddit mobile you can only do text posts. Or that new version of gas buddy or Google maps or in Google photos on mobile they removed the download option (but then put it back in).

What this process has morphed into is supporting a narrowing and increasingly specific user narrative.

Instead of seeking genericity, it's specificity. This is manifested as removing ports, keyboard keys, headphone jacks, save as menu options, disabling highlighting of text, or an ability to edit the spelling of a word without having to retype it, or an assumption that you want to tag a person and want a drop down menu of your friends instead of type something...

This is done supposedly in simplifying the product but it would be like making a paintbrush that only strokes vertically and only in primary colors...or a microwave with the number pad removed and only 6 auto cook buttons...

I mean what on earth

<comment><USER7> > in Google mobile search, you can't do custom date ranges...

In fact you can. Just swipe the menu bar to the left to access Search tools. (I admit it took me a while to discover this)

<comment><USER6> Nope. Still not possible. Here are screen shots showing what I'm talking about in this Twitter account I save for just the proper occasion: [https://mobile.twitter.com/FuckYourUI/status/753547054236872...](https://mobile.twitter.com/FuckYourUI/status/753547054236872704)

<comment><USER7> Ah yes, same here. (Note to self: do not read HN with a hangover)

</comment></comment></comment></comment><comment><USER8> Agree with so much of this, but definitely not with #28. White space has become a design curse. I know how to manage information; I'm not bewildered if I see a lot of it in one place, and I don't need to be guided through it.

And I'm truly tired of clicking ellipses to 'see more' Just load the damn page, load the damn comments and paginate. Abandoned Gawker for this reason long ago.

<comment><USER9> White space is super important. It can serve as a delimiter between pieces of your UI for example. It can serve as an emphasis on content or an important UI element. It has a ton of different uses you are completely disregarding... because

> _I know how to manage information_

But you really don't, though. If I replied with a 20 lines efficiently-packed wall of text with no paragraphs or linebreaks, you'd complain. If you were looking at a UI that was simply packing UI elements like the lego set for a giant cube, you'd be the first one commenting on its poor usability.

 _This_ is what it's like to have no whitespace: [http://www.milliondollarhomepage.com/](http://www.milliondollarhomepage.com/)

\--

You know, this exact attitude pisses me off. The #1 complaint in open source software is how poor the UX is in most of it. Famously, the software is "designed for its programmer", with the interface built to be as simple to code as possible.

It doesn't change because the community is full of devs arrogant enough to think that their users "know how to manage information" and will make sense of it all. They "don't need to be treated like children" because, obviously, intuitive interfaces are for kids.

OK, I get it, you've had bad experiences with whitespace. The G+ homepage is an abomination. Author isn't arguing a tiny column of text surrounded by two giant white columns is good design. Doesn't mean it's always bad.

<comment><USER10> >> _I know how to manage information_

> _But you really don 't, though._

No, I really do, you know. Sure, if there's a logical structure in information, you'd do well to highlight it - as well as any relative relevance of pieces of info ( _IFF_ you know what task I'm solving). But I'm not 3 y.o. anymore, I can handle more than 5 lines of text on a page. Please don't _hide_ information from me just because you think it's not relevant to the most basic use case.

I'm strongly with Tufte on this one. Presenting information is about dumping it all on the person with minimum artsy bullshit, and helping the viewer make sense of it efficiently. Modern UX paradigms however go in the completely opposite direction - hide everything, remove features, decrease information density.

There's a reason NASA mission control look like this:

[http://www.collectspace.com/images/news-090313a-lg.jpg](http://www.collectspace.com/images/news-090313a-lg.jpg)

and not this:

[https://i.imgur.com/4CqzSb4.png](https://i.imgur.com/4CqzSb4.png)

even though the latter is exactly what modern UX guidelines would call for.

If you want to build tools to help people solve problems efficiently, make tools. If you want to make a safe-for-work mental masturbation art piece, which is what most mainstream UX guidelines boil down to, then by all means. I just don't want to have it anywhere near me when I have problems to solve.

\--

> _intuitive interfaces are for kids_

There's only one intuitive interface in the world, and that's the nipple. Everything else is learned.

<comment><USER9> Are you seriously comparing NASA interfaces, which require months/years of training, to interfaces which are meant to be as intuitive and immediately- useful as possible?

<comment><USER10> It was a hyperbole, yes, but the general point stands - a proper tool will present all the things you need (or may need) to know in an organized fashion, to let you work efficiently. What we currently have in UX is a trend of making your work as _inefficient_ as possible, by hiding everything behind interactions or removing it altogether, because... well, because what exactly? Does someone really believe that e.g. people are too dumb to understand "2015-01-01 - 2016-10-30" and need to be limited to the choice of _only_ "Today", "Yesterday", "Last month" and "Last year"?

As for months/years or training - sure, there maybe (or maybe not even training in the tool per se, but more like general education; you need to know what the data shown actually means). But in a typical tool, 10 seconds or even 5 minutes of training won't kill anyone and would vastly improve efficiency. Want a proof? _Video games_. Each one has a custom, specific UI. RTS games have so many stuff on screen that they often have tutorials and in-game help. And 8-year-olds have zero problems with understanding all that in under 5 minutes. Outside of gamedev, people seem to have forgotten the concept of introduction, tips and tutorials.

<comment><USER9> You're literally just saying "a proper tool should have good UX".

Please backtrack a minute: What we're trying to debunk is that "Whitespace is always bad". The rant you're going into, here, is that some tools are oversimplified or don't give you immediate access to functions you need. That's the tool not doing its job - it's bad UX. Nobody will argue against that.

It also has nothing to do with whitespace.

> _Outside of gamedev, people seem to have forgotten the concept of > introduction, tips and tutorials._

SMB 1-1 is often praised as having outstanding video game level design. One of the reasons is exactly _because_ it doesn't use "tips and tutorials". It intuitively teaches you to run towards the right, to jump, how to kill enemies and discover secrets without ever popping a tooltip on the screen. Not that those are always bad, mind you, but intuitiveness is game design by excellence.

</comment></comment></comment></comment></comment></comment><comment><USER11> pretty straight forward and sensible, bar myth 18.

Praising flash is dangerous, ignoring all of its security flaws and the fact it's a cpu hogging, battery draining security risk. the fact it's easy to get up and running means little when it can actually hurt your users.

unless it's not as evil anymore? can anyone help me out here, did flash become secure while i wasn't paying attention?

<comment><USER12> > Note, this post was written more than 4 years ago.

The post seems out of date. Even in the post, the paragraph right before the section on "fun facts" emphasizes lack of mobile platform support.

Edit: Humorously, they address this with the Myth #0 reminder :-)

> ...and myth #0: If you read lists like this one, you don't need to do > research

<comment><USER11> yeah that made me think the guy who made the list is taking the list :p just that some of the points he made are in the UX book. it's very similar definition of what UX design is since it's about improving user experience, rather than streamlining user productivity.

but that #0... cheeky.

<comment><USER11> taking the piss _

</comment></comment></comment></comment><comment><USER13> I really want to go back and mention "The Design of Everyday Things" by Don Norman because the book lives and breathes what any designer and developer should strive for when designing (and developing) a web, mobile, or desktop app. Seriously, go read it.

</comment><comment><USER14> "Myth #18: Flash used to be evil...A Flash site can meet virtually all web accessibility criteria" \--UX Myths

"The majority of Flash content cannot be made natively accessible to screen readers. At this time, only modern versions of the JAWS and Window-Eyes screen readers that are using the Flash 6+ player within Internet Explorer on Windows can provide even marginal access to Flash content." \--WebAIM

</comment><comment><USER15> I thought presenting a list like this was sub-optimal, because people see it and remember the written statement, not the myth.

Thus, people remember "stock photos enhance user experience", and not "stock photos harm user experience".

</comment><comment><USER16> Flash is evil is a UX myth? I guess I am mything out on this one, as I don't even have it installed on my mac.

<comment><USER17> Open it up and the first sentence says this article is 4 years old. Then you probably realise you are not the first to mention that point. Yes, in nearly 2017 Flash is (almost) dead.

</comment></comment><comment><USER18> Hmmm take issue with this one - [http://uxmyths.com/post/99302792550/myth-33-mobile-users- are...](http://uxmyths.com/post/99302792550/myth-33-mobile-users-are- distracted)

A key point in mobile app UX is being transactional. If you require any input from a user such as a signup form, design it in such a way that it can be done as quickly as possible e.g. in under 60 seconds. That's because that's how long you have until they are distracted by something more interesting. That would mean not asking users to provide 50 data points all at once but do it in stages over multiple sessions.

<comment><USER19> If you read the page about the myth, I think the main takeaway is not "mobile users aren't distracted" it's "mobile users are no more distracted than non- mobile users." Therefore, don't require any user in any context to provide 50 data points all at once; design a signup form that can be completed in under 60 seconds regardless of device.

The secondary takeaway is mobile users are more likely to be at home or work than roaming around. I'm not sure what affect that has on UX, maybe as counter to the above, giving users the option to put more time in to a task and/or do one that's more complex.

</comment></comment><comment><USER20> This page was last archived 3 years ago [http://archive.is/u2d8Y](http://archive.is/u2d8Y)

</comment><comment><USER21> Everyone is saying not to use hamburger menus. What is a good alternative?

</comment><comment><USER22> Love the site, love the fact that it was created by two guys named Zoltan. Pocketed the first 10 articles and will be reading them later.</comment>


Vahan (YC S19) is helping low-skilled workers in India find jobs on WhatsApp - <AUTHOR> https://techcrunch.com/2019/07/29/vahan-yc-india/ <comment><USER2> On a different note, this everyone-jumping into the gig-economy of driving/riding for these services seem to be scary for their personal growth. Assume, I'm a bike-driver for Uber Eats (Today @ 2019), What would be I'm if i continue doing this after 5 years? It's the same Uber Eats driver. But if in a corporate set up, At least I can become something like a junior Accountant to Account or there's a career growth.

This growth seems completely invisible in this gig economy and during my conversation with a lot of recently joined Uber Drivers (in Bangalore, India) pretty much many are frustrated and trying to get into a different business that offers growth and stability.

Will this gig-economy destabilize global economy? I don't know. But I don't think a full-time Uber Eats driver is getting any benefit in long term.

<comment><USER3> I think the way that a lot of these companies (at least Uber, Doordash, Fiverr, ...) are positioning themselves is that this isn't supposed to be a full time job. It's either a side gig that can give you a bit of extra money to save/spend, or a launchpad to help get you to the next stage of your life. That's why I can't really empathize with everyone asking for better employee benefits and full time employment status because a gig is not supposed to be a job.

<comment><USER4> ...but it is. For a lot of people it's the only job they _can_ get. They don't have other options.

<comment><USER2> It's a fallacy. A lot of people who fall into this finds it lucrative. They are left-behind in the time of upskilling which they might have otherwise done had they weren't delivering food / driving uber. This way, they aren't up for the next game when this fails them (like Drones / Automated Cars). And I think that'll hit the economy.

</comment></comment></comment></comment><comment><USER5> Indian talents attracting foreign investors since last decade, combined with Jio reign to grow internet consumer by ten fold make me so much hopeful for success of startups of India. There were tons of talented "web era startups" 10 to 15 years ago that failed because of lack of affordable internet. Not now. I hope someday these startups go deeper to database, OS and hardware technology to make indigenous solutions.

</comment><comment><USER6> Do WhatsApp's Terms of Service allow companies to build "unofficial" chatbots like this? Or is there an undocumented API available for select customers? How does one get access to this?

<comment><USER7> Yes, via the WhatsApp Business API explicitly mentioned in the article.

<comment><USER6> It looks like WhatsApp is providing APIs via these companies:

[https://www.facebook.com/business/partner- directory/search?p...](https://www.facebook.com/business/partner- directory/search?platforms=whatsapp&solution_type=messaging#)

</comment></comment></comment><comment><USER8> one has to wonder why whatsapp is not following a "wechat" model in India and take control over the Internet based services industry. Yes they are touting their "Payment" options, but a catalog of services all inside Whatsapp should be possible right?!

Also to note that whatsapp has around 400 million users in India which is like 80-90% of Indian internet population which gives them enormous opportunity to become market leaders ...

<comment><USER3> If they can't find a foothold in the payment option, how can they expect people to use it for anything else? I don't think the shotgun approach is right or efficient in this case.

<comment><USER8> yeah, my question is more about , why being lethargic in the approach..

<comment><USER9> Their payments offering needs to roll out better before they can try anything more.

It just got cleared by the RBI and will take another year of adoption (my prediction) before WhatsApp gets more serious about businesses and apps.

Their E2E promise also bites them a lot (So thankful that Bryan did this before getting acquired).</comment></comment></comment></comment>


Django 3.1 - <AUTHOR> https://www.djangoproject.com/weblog/2020/aug/04/django-31-released/ <comment><USER2> JSONField has been an absolute godsend in combination with Django's ORM. I had been using it with Postgres and will likely keep our backend the same, but I cannot recommend it enough. You will have to write some validation and schema code on top if you want your data to have similar (but weaker) guarantees to the usual typed fields; the benefits from the flexibility you get are immeasurable though.

<comment><USER3> Can you give some examples where a relational schema isn't suitable?

<comment><USER4> Sparse data.

For example, if there are 1000 possible attributes, only 5% are populated for any given row. If you have 1000 columns you are going to have a ridiculously wide and mostly empty table.

<comment><USER5> In Postgres, NULL values take one bit of storage as far as I understand. So a table has to be very, very wide before this becomes a benefit. Of course if you have attributes that you don't control but are e.g. user-specified, JSONB column are a good choice.

</comment></comment></comment></comment><comment><USER6> I'm surprised the discussion has derailed into whether or not to use JSON fields... Certainly you don't have to, but they've been in Postgres contrib for a long time.

Async views have dropped, and that is genuinely exciting. It's taken a lot of work, and there's still a ways to go before Django is truly async native, but this is one of the big steps, and being able to do some concurrent IO on a few routes could be a huge saving for some projects that call out.

Otherwise a lot of stuff has to be done in event queues, to avoid blocking the main thread, and sometimes that means a bad UX when users take actions and aren't offered the guarantee that they are complete - in times where that might be the best option, were you not risking blocking thread.

<comment><USER7> As an FYI: Using a gevent monkey patch has been a way to get async Django for years. Overhead is inefficient in CPU cycles and you need to stay away from doing CPU bound things like Numpy manipulations, but for an app server that's bound by external API call latency, it practically gives infinite concurrency compared to a thread-per-request model. And no need to worry about event queues. You can feel free to synchronously call requests.get with a 10 sec timeout and still serve prod traffic from a small handful of threads. And most days we don't even worry about async from a coding perspective. Anyone can email me with questions.

<comment><USER8> I'd add that crucially, DB ORM operations just work with gevent. It will be a while before async database operations are supported natively by Django. For me that is a complete blocker.

<comment><USER9> > DB ORM operations just work with gevent

My impression was that django+gevent requires some care for the db part. The psycopg2 docs state, for instance

"Psycopg connections are not green thread safe and can't be used concurrently by different green threads." [1,2].

In addition, gevent cannot monkey patch psycopg2 code because it is C and not python. This is handled by calling psycopg2.extensions.set_wait_callback() [1,3,4]

I just now realize that you're probably referring to making the ORM itself async capable which is on the roadmap [https://code.djangoproject.com/wiki/AsyncProject](https://code.djangoproject.com/wiki/AsyncProject) in which case I totally agree.

[1] [https://www.psycopg.org/docs/advanced.html#support-for- corou...](https://www.psycopg.org/docs/advanced.html#support-for-coroutine- libraries) [2] [https://stackoverflow.com/questions/12650048/how-can-i- pool-...](https://stackoverflow.com/questions/12650048/how-can-i-pool- connections-using-psycopg-and-gevent) [3] [https://github.com/gevent/gevent/blob/master/examples/psycop...](https://github.com/gevent/gevent/blob/master/examples/psycopg2_pool.py) [4] [https://github.com/psycopg/psycogreen](https://github.com/psycopg/psycogreen)

<comment><USER7> In practice this is just a one-time setup. We use [https://github.com/jneight/django-db- geventpool](https://github.com/jneight/django-db-geventpool) which uses psycogreen under the hood. It isn't perfect (we're currently tracking down some rare cases where connections aren't properly returning to the pool, though we believe this to be error on our side) but it's more than sufficient.

While making the ORM async capable would be great, I'm not sure it will ever make sense to migrate towards sprinkling "async" explicitly across our codebase. We'll see, of course.

</comment></comment></comment></comment></comment><comment><USER10> As someone that has an active app still written in Django 1.6. The larger my project and more complicate the more I wanted to ditch the model/view/template separation. And attach methods to the model so that it can be called from everywhere, returning html code in a string directly.

Other times, I wished Django had something analogous to a component, where everything is just encapsulated in a single file. I don't want to separate javascript/html/css view/template. I want a single file I need to update and an easy way to call to render.

The template system is also difficult to use, if you get complicated scenarios.

I needed to show event details in a modal if that was the user preference. But the page could also be embedded. This lead to me having to render differently depending on the device, whether it was embedded and if it was a popup or not. This lead to an explosion of possibilities, a total 2x2x2 = 8 different views for the same data in the same template.

The most practical way was with if / then statements but that still lead to me repeating html code. And being difficult to reason about and test.

I also got into situation where the template wasn't parsed and updated. Probably because of too many includes or inheritance in the template. For example, I wanted to write a custom css file that would use google fonts that the user selected in the UI. The only way I found to work was to bypass the template and write a function in the view that would render_to_string the css file.

<comment><USER11> > I don't want to separate javascript/html/css view/template. I want a single > file

This was always possible.

<comment><USER12> >> I want a single file > This was always possible.

Any good (code/github) examples of this??

<comment><USER11>
        <body>
            <style>...</style>
            <script>...</script>
            …
        </body>

</comment></comment></comment></comment><comment><USER13> I've been using 3.1 alpha/beta for a while and it's got some pretty nice improvements. "JSONField for all databases" is a huge deal IMO, as it simplifies a lot of fairly common use cases.

</comment><comment><USER14> Cool, they've implemented async views.

ASGI has kinda passed me by. For some small project's I use Gunicorn.

What's the setup for ASGI that's popular?

<comment><USER15> They support Daphne/uvicorn [https://docs.djangoproject.com/en/3.1/howto/deployment/asgi/](https://docs.djangoproject.com/en/3.1/howto/deployment/asgi/)

I think in python world uvicorn is more popular choice, might be wrong tho

</comment></comment><comment><USER16> Pardon the rant, but I feel that the advantages don't outweigh the fact that with each release some of my stuff gets broken and I need to adjust. Django puts DeprecationWarnings basically everywhere and it's a hell to maintain projects that had been alive for a few years. God forbid you do anything with the interfaces they expose. The problem is only getting worse when you consider your dependencies, which in many cases don't keep up with the release cycle of Django. It's a mess.

<comment> WD-42 I'm sorry, but this is just programming. You have two choices: 1. Never upgrade and keep everything stable but go through hell when you inevitably must update something or 2: keep up with the latest and go through some minor pain with every release.

It's a lot like taking care of a house or car.

The world does not stand still, much less programming frameworks.

<comment><USER17> Hmmm, with well chosen, thought through abstractions, which only presume the minimum they need to presume about their usage, the frequent changes you describe are not a given.

The question is, what it is, what frequently needs to change and why no appropriate abstraction has been found to reach stability.

<comment> WD-42 We're talking about a huge web framework here. Your comment might apply to small isolated pieces of code. But Django is built on top of thousands if not millions of abstractions. It's absolutely unreasonable to think that it won't change.

</comment></comment></comment></comment><comment><USER18> Slightly OT:

How does HN feel about the recent craze to make web python asynchronous?

To me, the performance gains are dubious in many cases and the complexity overhead of handling cooperative multitasking just seems like a step back for a language like python.

<comment><USER19> Well, if you have external API calls in your Django app and you are running sync (which I would absolutely advice, with running async it is really easy to get an unpredictable performance which is sometimes hard to track down) having the ability to run some views async is really crucial.

Otherwise your application might me humming along smoothly at some point and coming to a sudden complete standstill or performance plummets when a random external API endpoint starts to time out. Yes I have been bitten by this :-)

To fix this while running sync I have dedicated separate application processes for the views that do external calls, but this makes the routing complex. Alternatively you can juggle timeouts on the external API calls but this is hard to get right and you need to constantly keep track if calls are not timed out just because the external endpoint is a bit slower at some point.

So I think this solves a very real-world challenge.

<comment><USER20> > plummets when a random external API endpoint starts to time out

You should add something like [https://pypi.org/project/circuitbreaker/](https://pypi.org/project/circuitbreaker/)

Continuously failing external requests should not make each one of your responses slow.

<comment><USER19> Interesting, will certainly try it out, thanks!

> Continuously failing external requests should not make each one of your > responses slow.

It is not really a matter of the responses becoming slow, the problem is that if you are running sync with i.e 6 application server processes and you have just 6 hits on an endpoint in your app that is hung up on an external API call your application stops processing requests altogether.

<comment> WD-42 Exactly this. I see the whole django async stuff being far more relevant for applications with lots of traffic or high request rates where you are already running on beefy infrastructure with a ton of workers and any small improvement in performance translates into huge real world cost savings. Your standard blog, no so much.

</comment></comment></comment></comment></comment><comment><USER21> I hope they prioritize some support for ROLLUP and friends.

I'd never used it before and it was fantastic but I had to drop down to raw sql to do it. SQLAlchemy has had support for well beyond a year.

I've used Django since 2008 and I love it with all its warts but I've really grown to prefer SQLAlchemy.

<comment><USER22> Adding new SQL support to the Django ORM is tricky. There isn't a nice low level abstraction for generating and composing SQL. It's mostly a bunch of lists containing different kinds of data (strings, Col, Expression) and they don't compose well.

On top of that, you'd need to come up with a decent frontend syntax that aligned with the existing methods.

I think Django made a mistake when first defining the language of aggregates by overloading the values() method and not using group(). To support rollup, values() would need to support it but only when used after an annotate. Not nice.

I often think about what it'd take to use alchemy for the sql building beneath the Django frontend. That would open up so many more possibilities and features.

<comment><USER21> Yea I started to bring up the existing ticket for grouping on the dev list and ask what people thought about it.

I also ended up writing a very tiny transformer function and using that directly because core only has a couple supported casts and I needed Postgres timestamp types so I could extract and rollup on the year / month / day. That gave me some insight in to some of the patterns in use in "lower level" Django differ from the expressiveness / composability of SQLAlchemy.

<comment><USER23> SQLAlchemy has a great architecture, but it comes at the expense of being tied to the use case of accessing a relational database.

Django models are more abstract and anemic in querying, but it means you can use the same API and write access layers for non SQL databases. At work, we have an in memory database, and Elastic Search all queried in an identical way to the Postgres models.

<comment><USER22> I'd be super keen to see your ElasticSearch model implementation if you're allowed to share it?

For what it's worth, I dislike the unit of work model that SQLA uses, but the layered architecture is enviable.

</comment></comment></comment></comment></comment><comment><USER24> OT Question : When choosing a stack for creating sites, would you choose Django over ASP.NET Core or PHP?

If so, why?

<comment><USER25> Does the backend language of a CMS matter?

We are a .NET shop, we'd love to use Django, Drupal, etc. But does that also mean we need a dedicated Python resource to support these CMS'?

Or could we use these CMS' out of the box?

Or would we just be better off with a .NET CMS like Umbraco or Orchid?

<comment><USER24> Once you have an app deployed, it takes a life of its own. Absolutely, the whole stack matters a lot.

<comment><USER25> So the backend language of the CMS does matter, because we'll eventually have to modify it to fit business needs?

</comment></comment></comment></comment><comment><USER10> Something I wish that Django did was user defined functions in the template. It has for loops, which is good but it forces you to write the html in top to bottom procedural manner.

It would be far better to be able to define a function that you can call for bits of html code that might repeat in the same template.

Since I stopped using Django at 1.6 does the new version let you define functions in the templates?

<comment><USER26> It has blocks for this [https://docs.djangoproject.com/en/3.0/ref/templates/builtins...](https://docs.djangoproject.com/en/3.0/ref/templates/builtins/#std:templatetag- extends)

<comment><USER10> That isn't as nice to having a function inside the same file you can call over, IMHO.

Also lets say you define a block for rendering a button with a different color. Then use 20 different buttons on one page.

Does that mean that the block code would need to be loaded from a file 20 times and parsed each time. Seems like huge performance hit to do it that way.

Is there a technical reason why you can't have a function in the same file.

Am I misunderstanding how it works?

</comment></comment></comment><comment><USER27> Does the ORM still write horrendous cursor based loops where simple joins would suffice?

<comment><USER28> By default yes, but you can configure queries fetching behavior using select_related/prefetch_related to avoid the N+1 queries problem.

<comment><USER29> Sadly not so many people know how to use those. From the Django projects that I have inherited at least.

<comment><USER30> Django ORM mainly hides the SQL from the developer (which is kind of the idea of any ORM). But if a developer does not understand the underlying SQL concepts, they will soon write performance wise horrific code. But, if you remove the ORM from that equation, I don't see how that same developer doesn't make the same mistakes. So in the end, I don't think that Django ORM (in its core) can help much in this area.

There are of course tools that can help with that (django-debugger and others).

<comment><USER31> This is a hot-take from Aaron Patterson, Rails and Ruby core team dev, in his keynote this year where he addressed a very similar idea on a perhaps related query generation topic...

[https://youtu.be/9JEEabL90AA?t=1360](https://youtu.be/9JEEabL90AA?t=1360)

To give you the tl;dr (he goes through profiling and a great deal of data to help show what a core dev needs to do in order to help us solve this one specific case, and...)

Aaron comes to the conclusion that there is a "performance pro-tip" which many Rails devs have learned, similar to what y'all are discussing in this thread for Django, and in this one specific case he outlines in some detail, Aaron considers that there is a bug where the programmer needs to know this "pro- tip."

As there was really no reasonable way for the Rails engine to interpret this instruction from the programmer as to mean "do it the slow way" when there's a better way to do the same thing with no drawbacks, and it would have been possible for the engine to safely do the smarter thing (it was IIRC to precompile some better-shaped SQL, bringing back the same result set in fewer queries, (making up the most runtime performance by spending less time in the SQL compiler overall, in the worst performing pathological case, all this is shown with data)...) and that having this behavior here is actually much better for a novice programmer's behalf, in order to make that better performance happen without requiring a developer to manually build such hints into the application code, at abstraction layers where they really shouldn't have to be thinking about those things anyway.

<comment><USER32> While a good point, I would say the problem is caused by ORMs existing. Somehow somewhere we decided that a person who thinks SQL is too difficult should be using a database.

<comment><USER33> Nobody who builds an ORM thinks that.

An ORM saves experienced SQL users from having to write boilerplate SQL and hack on their own garbage ORM, which is what any large project ends up doing, attempting to compose queries and filters in vain.

I have never ever heard of ORMs as an argument to avoid learning SQL, and AFAIK no author of well-known ORMs holds that opinion.

<comment><USER27> "boilerplate SQL" is an oxymoron...

Literally every pro-ORM dev that I've ever worked with was so incredibly weak with basic SQL fundamentals that I must conclude that they preferred ORMs simply due to a reluctance to learn SQL.

<comment><USER31> There is a strong argument for conceptual compression, the idea that every component has an optimum abstraction layer to understand it at, and with that, less-optimum layers for understanding. An ORM that does its job well allows you to take the complexity and pack it away for another day. We can unpack it later when we need to understand those details, but most of the time we'd rather be focused on the details of a domain-specific problem that we're trying to solve, with intricacies that are specific to the domain, that ideally need not become compounded against problems introduced separately by (for example) a persistence layer such as a database, as that makes it harder for the domain experts by introducing another layer of complexity that they must grok in order to build or spec an appropriate solution.

</comment></comment></comment></comment></comment></comment></comment></comment></comment><comment><USER34> I'm closer to a hobbyist than a professional dev, but the async views seem like a big functionality. Having done some Django apps, getting a synced up view for some changing variable was always a bit painful.

<comment><USER35> I'm not sure you're talking about the same thing, this is about asyncio/green threads.

<comment><USER34> re-read the documentation but I'm not following. This example:

      async def current_datetime(request):
          now = datetime.datetime.now()
          html = '<html><body>It is now %s.</body></html>' % now
          return HttpResponse(html)

seems like an example that I was thinking of.

<comment><USER35> I don't know what you're thinking of, unfortunately, but that piece of code just returns the current date when you visit the page.

<comment><USER34> After taking a uninterrupted reading slot to understand the async views, you're right, and I had the concept understood wrong.

<comment><USER35> Yeah, I think you were thinking some sort of auto-refresh.

<comment><USER34> That was exactly what I was _hoping_ this to be.

<comment><USER36> Perhaps django-reactor would be of interest to you? [1] It's targeting LiveView-like functionality for Django. I haven't used it (so I can't vouch for the claim).

1: [https://pypi.org/project/django-reactor/](https://pypi.org/project/django- reactor/)

</comment></comment></comment></comment></comment></comment></comment></comment><comment><USER37> What would be a typical use case for "Asynchronous views"?

<comment><USER38> async is cool for I/O bound operations. You don't have to wait the request/response to finish in order to start processing another request.

Talking with a db, or doing http requests are IO operations, so instead of blocking the process, django can now start processing another one. When the IO operation is done, it continues where it stopped.

<comment><USER37> Why would Django not be able to process other requests while one process is waiting for IO?

I don't know much about Python, but in a typical PHP/Apache setup, Apache simply starts as many processes as needed to answer all requests.

<comment><USER39> Apache or FCGI?

In python world you have few Django processes spawned by WSGI/ASGI app container, and those processes spawn python threads to handle requests. Because python uses GIL, no more than single thread is executed at single time per process. At specific times GIL stops running bytecode for one thread and moves to next one (eg when you do IO). This means other threads keep running, but in theory you can run out of threads.

In async you use tasks instead of threads for http requests, so single process can handle multiple requests at same time, only spawning threads at limited number of situations.

</comment></comment></comment></comment><comment><USER40> I wish, there is something equivalent like this in golang world. Django has been one of the best well maintained open source projects.

</comment><comment><USER41> can the async functionality replace celery?

<comment><USER42> No. Celery can execute tasks after your view returns. Async can't do that.

<comment><USER43> Would you please elaborate? If all of a task is encapsulated in a django async view, would this not be the same thing?

<comment><USER42> To run async code, you use 'await' in python. That right there tells you that you have to wait for it to finish. You want to receive the result. The view will wait for a result before returning the http response.

Celery and all task queues are fire-and-forget. You tell it to do something for which you don't want the result, so you can continue executing your code right away. The task queue can even take an hour to process, for example. Or you can schedule it to run later.

<comment><USER41> thanks</comment></comment></comment></comment></comment>


Thingiverse (site for sharing 3D printed designs) recieves its first DMCA notice - <AUTHOR> http://blog.thingiverse.com/2011/02/18/copyright-and-intellectual-property-policy/

<comment><USER2> Defenitley a milestone, although I'm not sure how someone can copyright a "triangle illusion". I wonder how long it will be before companies realize how much trouble they will be in when people can download pirated designs an print out their own 'stuff'. Is thingverse going to be the new piratebay?

<comment><AUTHOR> Probably not, since actually took the design down. I wouldn't be surprised to see it show up on the pirate bay though. Interesting times lie ahead.

</comment></comment><comment><AUTHOR> They posted an update about it as well.

[http://blog.thingiverse.com/2011/02/18/this-is-why-cc- licens...](http://blog.thingiverse.com/2011/02/18/this-is-why-cc-licenses-are- important/)</comment>


Gyroscope Annual Report 2015 - <AUTHOR> https://gyrosco.pe/2015/ <comment><USER2> This was a really fun project. We weren't actually planning to do any annual reports, but over the break I was digging through my own data and there were a few things I wanted to see.

Few days later we had a basic page and figured might as well release it for everyone. Hopefully you will find it interesting.

We were very inspired by things like the Feltron Annual Report & Jehiah's Annual Report. Seems like something people and companies have been doing for a long time already, so lots of examples to continue from.

</comment><comment><AUTHOR> If anyone has questions about data we collect and how you can use it to improve your year let me know.

<comment><USER3> Do the "Top Albums In 2015" come from RescueTime? If so, how can that be enabled from within RescueTime?

<comment><USER2> No, that music listening we are getting from Spotify through Facebook. The app info is from Rescuetime though.</comment></comment></comment>


Database with 4 Nvidia Gaming GPUs 43X Faster Than CPU Clusters - <AUTHOR> http://tech.marksblogg.com/billion-nyc-taxi-rides-nvidia-titan-x-mapd.html <comment><USER2> It looks interesting, and powerful, but I'm not seeing anywhere about how much MapD costs. I've got a DB of 6B+ records that would be great to do more flexible queries on.

<comment><AUTHOR> Hi please write us at info at mapd dot com for more info. We'll also be rolling out cloud instances soon if on-prem deployment doesn't make sense.

</comment></comment><comment><USER3> you already posted this earlier:

[https://news.ycombinator.com/item?id=12054605](https://news.ycombinator.com/item?id=12054605)

<comment><USER4> seems like a valid repost to me. only one other post a few days ago (as far as I can tell), with no comments and <10 points.

<comment><USER3> I don't think so:

[https://news.ycombinator.com/from?site=marksblogg.com](https://news.ycombinator.com/from?site=marksblogg.com)</comment></comment></comment>


Geocities - "Under Construction" gif archive - <AUTHOR> http://www.textfiles.com/underconstruction/

<comment><USER2> On the topic of Geocities shutting down, I found an option in wget which ignores existing files - because Yahoo has a 503 error if you try to spider too many pages.

It's -nc which means 'no clobber' - which is the least helpful phrase considering you could say 'ignore existing'...

When you get a 503, wait about an hour, and then run wget until it fails, then wait an hour, etc, until you've got all 10mb of your webspace.

Also -np to only spider below your page on Geocities.

<comment><USER3> "no clobber" matches the shell option of the same name.

</comment></comment><comment><USER4> So all we've really done is replace that lot with the word "Beta".

<comment><USER5> I'm waiting to see what next big advancement in web development the angled beta graphic changes into.

</comment></comment><comment><USER6> It would be interesting to see the trend of using "under construction" graphics over time. At some point it just clicked that web pages are -always- under construction, and we didn't have to be as explicit about it anymore.

</comment><comment><USER7> Web 0.9 was awesome.

<comment><USER2> I guess you could call it HTML 1.0...

</comment></comment><comment><AUTHOR> I know this isn't news, the news would be that they're taking Geocities offline, but I thought this animated gif "Under Construction" archive was hilarious.

<comment><USER8> It's sort of poignant, in a way. Like, "For sale, baby shoes, never used."

<comment><USER9> [http://www.thesixtyone.com/abledanger/song/For+Sale%3A+Baby+...](http://www.thesixtyone.com/abledanger/song/For+Sale%3A+Baby+Shoes%2C+Never+Worn/61912/)

</comment></comment></comment><comment><USER10> Time to start collecting the millions of variations on the "standard" orange RSS logo, and 80x15 badges, and social network follow buttons, et cetera.

</comment><comment><USER11> I think he did a grep for " _construct_.gif". This image:

[http://www.textfiles.com/underconstruction/SiSiliconValleyVi...](http://www.textfiles.com/underconstruction/SiSiliconValleyVista2013constructor- index.gif)

Is from an ancient version of JavaDoc if I remember correctly.

</comment><comment><USER12> Film noir under construction:

[http://www.textfiles.com/underconstruction/CaCapeCanaveralOr...](http://www.textfiles.com/underconstruction/CaCapeCanaveralOrbit1801Construction.gif)

Classy.

</comment><comment><USER13> What is up the the guy at the end with the bulging crotch?

<comment><USER9> That's what you'd call laying pipe.

</comment></comment><comment><USER14> Dialup users beware!

</comment><comment><USER15> be thankful. history we can laugh at is rare.

</comment><comment><USER16> Good gawd, y'all!

Why do I think of MTV when I see all that? Dire Straits!

</comment><comment><USER17> Nostalgia overload.

</comment><comment><USER18> <MARQUEE><BLINK><FRAMESET>THESE ARE AWESOME!

<comment><USER19> You forgot such gems as <font effect=emboss> and <audioscope>, which I was blissfully ignorant of until seeing Kibo make fun of them a decade ago.

[http://groups.google.com/group/alt.fan.warlord/msg/dc569dfec...](http://groups.google.com/group/alt.fan.warlord/msg/dc569dfec8f204bd)

</comment></comment><comment><USER20> My childhood coming back to me !

</comment><comment><USER21> who else wants a "web 1.0" holiday?</comment>


Avoiding fake clicks on your Facebook ads - <AUTHOR>

From an email I got:<p>"Inspired by the viral video explaining issue of fake accounts clicking facebook ads, we have created a tool called Fan Harvest where we let you target your ads at people who have been actively engaging, a trait that only belongs to genuine accounts, with your competitors. Try us at http://fanharvest.com/ and let us know what you think."<p>Looks legit and I know the team is strong behind this one. <comment><USER2> Doesn't seem to be working. I input page name (has over 1 mil fans) and upon submit nothing happens? Am I missing something

<comment><USER3> I tried the same thing, It takes a few (5-10) minutes to process a page that size I figured. The CTR was through the roof went from just under 1% to over 5% CTR.</comment></comment>


Smooth Javascript Image Zooming For Your Web Pages - <AUTHOR> http://www.cabel.name/draft1/2008/02/fancyzoom-10.html

<comment><USER2> I love Cabel's FancyZoom. It's the only Lightbox script I would ever use. Most of the other Lightboxes that take like 5 seconds to fade and autoadjust the dimensions of the frame are just inane.

<comment><USER3> The only issue that I have with it is size. Cabel basically wrote his own proto/jquery in the process of writing this so it's pretty big. I'd suggest to people who use proto/scripta or jquery to look for a lightbox that uses that lib and is much more manageable in size.</comment></comment>


Emergent Gravity and the Dark Universe - <AUTHOR> https://arxiv.org/abs/1611.02269 <comment><USER3> Also, a simple explanation for the layman: [http://www.alphagalileo.org/ViewItem.aspx?ItemId=169788&Cult...](http://www.alphagalileo.org/ViewItem.aspx?ItemId=169788&CultureCode=en)

<comment><USER4> Thanks for the link (+1) but it's very far from being an explanation for the layman.

> In the same way that temperature arises from the movement of microscopic > particles, gravity emerges from the changes of fundamental bits of > information, stored in the very structure of spacetime.

It doesn't explain how gravity emerges from bits of information. I'd love to understand how those bits make apples move from trees to the ground, the equivalence between gravity and acceleration and the weightless free fall experience. That should be one paragraph for the general principle and one for each example. Then it's for the layman, and me too :-)

<comment><USER5> It's funny how scientists always reference time in relation to gravity and yet separate out gravity from other forces of motion when the implicate order would be to have gravity always playing a role in motion whatever the axis or motion of travel.

The other thing to know is that for a wave, there are more motions of travel than upon a triune 3-dimensional axis. The common thought process of a pondering individual is to simply add singular 3-dimensional particles to a 4, 5 or more dimensional time-space environment and try to peer into the behaviors of a hyperspatial-capable environment.

This is ridiculous because in a hyperspatial environment, so-called objects have a tendency to be in more of a wave-like state and even more-so than the waves of an ocean. These waves would be more like a fine-cotton tuft which is being pulled by electrostatic strands in multiple directions at once and wherein the "identities" of each may out of behavior dynamics be considered as singular with multiple locations because of a tendency to collapse at the same time or leave one the strongest through a matrix interconnections consisting of concepts of "Tensegrity." <wiki it.

Then you have photons which are thought to be low-mass or perhaps even zero or negative in mass. This seems to correlate nicely with their high-speed velocities.

In a Universe which has hyper-spatial dimensions not only overlaying reality but also underpinning it via multiple directions (like the gravity of multiple stars, planets, and moons affecting each planetary body), the hyper-spatial arenas would seem to be more elastic and able to slip and slide over and around the greater reality. Mystics and even scientists talk about these other dimensions as a deeper reality but it might be fair to take it with a grain of salt and see our current average reality as the "deeper reality."

So gravity is the "sums" of multiple affecting bodies. The datastreams coming in from the Sun, Moon, and other planets all affect life on Earth. The Moon mostly contributes to water while other elements likely have greater response to other planetary bodies, depending on their molecular and nuclear composition. (although this has not been published in the traditional manuscripts of current science)

Anyway, to answer the question in the way I think of it, gravity is related more closely to time than the way in which science usually connects time to gravity. Scientists usually act like a photon travels at the 299 792 458 m / s rate.

It would seem that whatever forces of information flow (entropy...and some would say proto-consciousness) are behind gravity - are also interrelated with time itself.

Here's the kicker. People assume everything falls to Earth. Why? Because most things do? What about balloons filled with Helium? What about light which reflects to the astronauts in space? What about the electrical currents flowing to the Sun and back in the chains of ions? How much mass is held in those ions?

And that's just talking "vertically" without reference towards the hyper- spatial dimensions which the common man has even less experience with - <USER2> though we are experiencing the interactions with these dimensions all the time.

Let me make an important note before I forget: Electromagnetic forces may very well be different enough from "gravity forces" to be differentiated but there may also certainly be some overlap at various scales or in high-voltage or highly-sophisticated quantum situations.

Whichever ways in which time is generated/observed/transmitted, both gravity and electromagnetic forces are bound to be related with the flow & effects. ____If information is practically as important as energy and gravity, how much information leaves Earth through light or ionic currents which flow to the Sun (or other stars?) __ __

Also, to the person who also answered here and said electromagnetism can never be related with gravity, how do they imagine ions are moving through a wire or exchanged in an electrolyte solution of a battery or a hydrogen-production system? Again, to change the angle to "vertical" rather than horizontal is a weird way to classify an entirely different force.

Oh...as I was saying, :) it's all about the timing. In a coherent stream of information like a flow of photonic light or the flow of electrons in an electromagnetic current, the forces of motion are resistant to changes in the flow of time within their area of influence. Next move your attention to the heat we can "see" radiating from the smokestack of a semi tractor. This thermal emission is a form of energy which is slightly more disordered and "dispersed" than the kinds of "motion" we "see" elsewhere.

One would possible assume that if we get so close to Earth where we are essentially at "ground-level" and we allow the gravity well to exert its influence on an object, that the strong effect we see is because there is a very "unified" pull of forces. But this is just as false as if we get closer to a cable being weaved from dozens of smaller diameter threads. We begin 'seeing' the smaller threads are spread further apart as we change our perspective to a smaller and closer entity.

Why do we see water swirling different rotations into a drain on different places upon Earth? All to due with the nature of time, gravity, and space itself being shaped and molded by a force which is positional and situational and thus inherently "proto-conscious."

Link: Implicate Order: [http://www.bizint.com/stoa_del_sol/plenum/plenum_3.html](http://www.bizint.com/stoa_del_sol/plenum/plenum_3.html)

<comment><USER6> I don't have time to go over all your post, but you seem to be very very confused about several things. I suggest you try to read a science communication book, like Carl Sagan or the sort.

</comment></comment></comment></comment><comment><AUTHOR> An explanation by the author: [https://www.youtube.com/watch?v=ynRVnIh6wq4](https://www.youtube.com/watch?v=ynRVnIh6wq4)

</comment><comment><USER7> There is a great deal of observational evidence favoring Lambda-Cold-Dark- Matter, ie the status quo of cosmology with dark matter. The bullet cluster [1] is evidence for two colliding galaxy clusters where the luminous matter ran into itself but the dark matter kept going. The total mass (luminous plus dark) can be mapped out with the gravitational lensing of background galaxies and can be done very accurately. This was essentially the nail in the coffin for the leading alternative theory modified newtonian dynamics (MOND).

Dark matter is so deeply embedded into cosmology and modern astrophysics, you would have to explain a host of solidly observed phenomena to be a compelling alternative (baryon acoustic oscillations, the cosmic microwave background, primordial abundances, the evolution of structure or the "cosmic web"). Comparing to those things would probably take man-decades of work and also require computationally expensive cosmological simulations on super computers, so I'm skeptical we will see the kind of theoretical/observational comparison that would make you sit up and take notice.

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

</comment><comment><USER8> I love this, it feels cleaner and more elegant a solution than dark matter particles. However, nature doesn't care what we like, so that doesn't make it more likely to be true.

<comment><USER9> I agree that it sounds elegant, especially since it puts entropy/information into the core ontology so as to explain the arrow of time and thermodynamic behavior _as part of_ the same theory that can account for Einsteinian space- time.

I just wish I understood enough physics to tell this paper from elegant- sounding word salad!

</comment></comment><comment><USER10> If you're wondering how this isn't some weird form of MOND, which is basically dead as an explanation, here's an important paragraph from the paper:

> We like to emphasize that we have not derived the theory of modified > Newtonian dynamics as proposed by Milgrom. In our description there is no > modification of the law of inertia, nor is our result (7.43) to be > interpreted as a modified gravitational field equation. It is derived from > an estimate of an effect induced by the displacement of the free energy of > the underlying microscopic state of de Sitter space due to matter. This > elastic response is then reformulated as an estimate of the gravitational > self-energy due to the apparent dark matter in the form of the integral > relation (7.40). Hence, although we derived the same relation as modified > Newtonian dynamics, the physics is very different. For this reason we > referred to the relation (7.43) as a fitting formula, since it is important > to make a clear separation between an empirical relation and a proposed law > of nature. There is little dispute about the observed scaling relation > (7.43), but the disagreement in the scientific community has mainly been > about whether it represents a new law of physics. In our description it does > not.

</comment><comment><USER11> [https://news.ycombinator.com/item?id=12526559](https://news.ycombinator.com/item?id=12526559)

</comment><comment><USER12> There seems to be considerable disagreement in the field. Why is it news (I really would like to know!)?

\+ Kobakhidze explaining neutron experiments: [https://arxiv.org/abs/1108.4161](https://arxiv.org/abs/1108.4161)

\+ [http://physics.stackexchange.com/questions/4289/is- gravity-a...](http://physics.stackexchange.com/questions/4289/is-gravity-an- entropic-force-after-all)

\+ Lubos Motl: [http://motls.blogspot.nl/2010/01/erik-verlinde-why- gravity-c...](http://motls.blogspot.nl/2010/01/erik-verlinde-why-gravity-cant- be.html) and [http://motls.blogspot.nl/2010/01/erik-verlinde-comments- abou...](http://motls.blogspot.nl/2010/01/erik-verlinde-comments-about- entropic.html)

It's nice to see that also experts in these highly specified fields quarrel about what it means to be "entropic" and "irreversible", etc.

</comment><comment><USER13> > The central idea of this paper is that the volume law contribution to the > entanglement entropy, associated with the positive dark energy, turns the > otherwise "stiff" geometry of spacetime into an elastic medium. We find that > the elastic response of this 'dark energy' medium takes the form of an extra > 'dark' gravitational force that appears to be due to 'dark matter'.

</comment><comment><USER14> Discussion in Dutch: [http://www.volkskrant.nl/wetenschap/ineens-klopt-het- univers...](http://www.volkskrant.nl/wetenschap/ineens-klopt-het-universum- zwaartekrachttheorie-erik-verlinde-in-zes-lekenvragen~a4411221/)

</comment><comment><USER15> I think it helps a lot to try to understand the universe from an engineering perspective, thus by posing the question "How would I build a universe?" The apparent obvious answer is : as an N dimensional matrix where each cell executes some code.

With such a setup, effects like gravity, are more probable to be emergent effects.

Another consideration is that in such a setup the only thing that matters is the state of the matrix, in other words there is no time, just iterations.

So my 2 cents are: gravity should be explained as an emergent phenomenon, and time should be removed from all equations that try to explain the underlying fabric of reality.

</comment><comment><USER16> > According to the holographic principle, all the information in the entire > universe can be described on a giant imaginary sphere around it. Verlinde > now shows that this idea is not quite correct: part of the information in > our universe is contained in space itself.

I thought the holographic principle just said the _amount_ of information in any physical structure (up to the whole universe) was such that it _could_ fit on a 2D surface the size of the event horizon of the structure, not that it actually is contained on the surface. Does this theory change that?

</comment><comment><USER17> Gravitons always struck me as a goofy half-baked concoction (even though we've supposedly observed them now), and so did dark matter. Emergent gravity theories are very interesting.

<comment><USER18> > even though we've supposedly observed [gravitons] now

Source? Or are you saying that the existence of gravitational waves constitute a proof of the existence of gravitons, due to wave/particle duality?

I'm not a physicist, but all I thought we had detected were gravitational waves.

<comment><USER19> > _the existence of gravitational waves constitute a proof of the existence of > gravitons, due to wave /particle duality_

I always thought this is the case. But IANAP either. Could anyone with actual knowledge chime in?

<comment><USER20> No, a gravitational wave has mass (carries mass is more accurate), but a graviton does not. They are not two aspects of the same thing.

<comment><USER21> In a quantum field theory, a wave implies a force carrying particle, does it not?

<comment><USER22> To be precise, particles (with precise momentum) are certain modes or excitations of a quantum field which is often governed by something like a wave equation. However, not all quantum fields (and their associated particles) are force carriers. These are usually just the gauge bosons.

In any case, though, noone has managed to quantize gravity yet (i.e. describe gravity as a quantum field theory with gravitons as force carriers), so we've detected just gravitational waves but no gravitons.

<comment><USER23> Well, we've quantized gravitation extremely well - it's just perturbative quantum gravity, of which there are a couple flavours. In weak gravity it makes predictions identical to General Relativity, but is taken to be an effective field theory (in the Charles Wilson sense of "effective) in that we do not know how to deal with Feynman diagrams with more than a loop or two of gravitons, which only happens in strong gravity.

In these theories, gravitons are quantizations of the weak-field perturbations.

The non-renormalizability by power-set counting of gravity because it is a long-range force is a good result of perturbatively quantized gravity. Who knows if there is a workable way of renormalization by other methods? Not me.

Since we don't get strong gravity except close to a black hole singularity or in the extremely early universe, it's unfair and premature to say that the EFT approach has been unsuccessful.

</comment></comment></comment></comment></comment></comment></comment><comment><USER24> So I too love the idea that we don't need dark matter to explain all the gravitational effects we observe in the universe. However, is it just me or does the falsification of this seem a bit sketchy: if we find a dark matter particle...then my theory is false. That's a bit like saying...oh yeah if we find a different way to unify general relativity and quantum mechanics...then String Theory is false. It seems like there should be a 'smaller' way to falsify it.

<comment><USER25> I think you will find all the models are false to a degree. A model is only an approximation of the real thing. Quantum mechanics and General relatively cannot both be right. The obvious answer is that they are both wrong.

<comment><USER26> A thought experiment of mine.

Assume that all possible hypothesis or theories (explanations in general) form part of an "explanation space." Some explanations are good (theories), some have no evidence (hypothesis) and some are false (we are riding a giant turtle). Given the number of false explanations, the overall space is infinite. Hypothesis spaces would be islands within the false explanation space, theories islands within hypothesis and the truth as a single point within one of those theory spaces.

The question is, does that mean that the theory space is infinite? _If_ so, that would mean that it would be impossible to know that we've found the truth (as a single point within this infinite space) - we'd only ever be able to conclude that we've found a closer approximation. Scientists may never run out of work.

<comment><USER9> >The question is, does that mean that the theory space is infinite? If so, that would mean that it would be impossible to know that we've found the truth (as a single point within this infinite space) - we'd only ever be able to conclude that we've found a closer approximation. Scientists may never run out of work.

The theory space is _definitely_ infinite, in either the interesting sense of something like "the space of all possible programs, treated as causal or directed-generative models" or in the trivial sense that you can take any simple, well-supported theory and come up with mathematical elaborations that don't change any of the pre-existing empirical predictions.

In a certain sense, "the truth" may constitute an infinitely small point in a space that's more continuous than discrete.

</comment></comment></comment></comment><comment><USER27> In the summary, it says that these theories are "best understood in Anti de Sitter space...". I thought current observations ran against a spacetime that had a negative curvature. Are they just saying the math is easier in that geometry, but that it still applies to flat (or ever-so-slightly-positively curved) spacetime? Or are they arguing in favor of a "saddle-shaped" universe?

<comment><USER28> Spacetime has a positive cosmological constant, so it's closer to de-Sitter than Anti de-Sitter. It doesn't really have to do with curvature exactly, which is given by the Riemann tensor (so it doesn't make sense to say it's positive/negative).

<comment><USER22> But you certainly can talk about curvature scalars being positive/negative which are derived from the Riemann tensor.

</comment></comment></comment><comment><USER29> Imagining gravitational waves inevitably leads me to believe that gravity is a force that varies (in a cycle) over spacetime. But.. what exactly does it mean to propagate over a cycle in spacetime? (particularly the time aspect confuses me since something propagating in space remains constant in time (either accelerating or decelerating)

</comment><comment><USER30> Does this in any way match with Lipinski's gravity discussion ([http://adsabs.harvard.edu/abs/2008AcPPB..39.2823L](http://adsabs.harvard.edu/abs/2008AcPPB..39.2823L)) that was mentioned here just recently (unifiedgravity.com)?

</comment><comment><USER31> I do not understand this stuff, but the connection between gravity and horizont sounds like this [quantized acceleration theory]([http://physicsfromtheedge.blogspot.de/](http://physicsfromtheedge.blogspot.de/))

</comment><comment><USER32> I'm currently reading The Confusion [0] and just got through Leibniz's explanation of monadology [1][2]. Summarized very very briefly, the idea is that every particle in the universe is a sort of computational device, and their actions/reactions are determined by their "perception" of all the other particles in the universe.

Does this research suggest that he may have been semi-correct??

[0] [https://en.wikipedia.org/wiki/The_Confusion](https://en.wikipedia.org/wiki/The_Confusion) [1] [https://en.wikipedia.org/wiki/Monadology](https://en.wikipedia.org/wiki/Monadology) [2] [https://quantummoxie.wordpress.com/2014/09/09/neal- stephenso...](https://quantummoxie.wordpress.com/2014/09/09/neal-stephenson- on-leibniz-monads-and-more/)

<comment><USER33> Frankly, I'd be surprised if anything ever suggested that Leibniz's colorful metaphysics was correct, even or incorrect.

Leibnizian monads are unextended and unable to act on one another (from §1 and §7 of the Monadology), which is to say that they're non-physical. On the other hand, as they're somehow supposed each to have a complete picture to the world (§56), they imply some form of non-locality. Which is to say that they're some very _spooky_ things.

The thing that comes closest to Leibniz's monadology is the idea that the world is a simulation running inside a computer. But Leibniz's idea was more like that there is an arbitrarily large number of computers running the same simulation, while some of them also run artificial intelligences which just watch the simulation unfold.

Which is an idea I think can be fairly described as "completely nuts".

<comment><USER34> > But Leibniz's idea was more like that there is an arbitrarily large number > of computers running the same simulation, while some of them also run > artificial intelligences which just watch the simulation unfold.

I think this was just Leibniz awkward attempt at explaining modal realism. The idea of many possible worlds is much more mainstream now in physics, so I wouldn't call it "completely nuts".

<comment><USER33> I wasn't previously acquainted with the term "modal realism" (been avoiding contemporary philosophy for a while now), but there doesn't seem to be an immediate connection in this case. There aren't actually many worlds being simulated here, as each computer simulates the same world and they all get the same results. Leibniz does introduce the idea of many possible worlds (§53), but as a set of designs for this whole thing (computers plus the stuff running inside them) from which God draws one particular design to be the actual world.

He might be closer to modal realists in other regards, though. I don't know.

</comment></comment></comment></comment><comment><USER35> Does entropic gravity explain the lensing phenomenon attributed to dark matter?

</comment><comment><USER36> To what degree does this contradict Einstein's theory of gravity?

<comment><USER37> It does not contradict Einstein's theory of gravity, just as Einstein did not contradict Newton. All three are different models explaining progressively more thorough levels of observation.

Don't think of a theory so much as "what is true" but rather as a set of propositions and equations which are designed to model the way physical processes are observed to occur.

Theories exist within their own provenance of observation. Both Einstein and Newton's theories reflect reality within certain limits, but outside those limits they do not. To allow Einstein's theory to apply at larger scales, we proposed dark matter because Einstein could not account for the behavior of galaxies unless there was some hidden element involved. Thus we proposed dark matter. It is a reasonable accommodation, but one that has defied confirmation.

The emergent theory embraces both Newton and Einstein, eliminates any need for dark matter, and attempts to explain all current observations within a single framework.

Einstein's theory made testable predictions which were later proven to be true. The emergent theory lacks such confirmation, and so time will tell whether it reflects reality.

<comment><USER9> >Einstein's theory made testable predictions which were later proven to be true. The emergent theory lacks such confirmation, and so time will tell whether it reflects reality.

The author claims to be making a few novel predictions which, he claims, astronomers can go check. He also retrodicts several things we observe, though I'm not enough of a physicist to say if he's using a simple enough model for that to be interesting.

</comment></comment></comment><comment><USER38> How does the theory explain unaccountable 96% of the universe which we cannot observe/detect? Is there a thing such as antibaryonic matter?

</comment><comment><USER39> Like others have mentioned I'm not sure what happens now to the gravity waves we've detected.

<comment><USER20> I'm not convinced we have in fact detected gravity waves. From our point of view merging black holes would not move due to time dilation, but the waves detected are modeled after black holes without time dilation.

Although it's possible we detected a wave from a different source, not a black hole.

<comment><USER21> While we can never see them merging completely, we can see them asymptotically approach a merger, which does in fact take about 1/5th of a second to get most of the way there.

</comment></comment></comment><comment><USER40> How about Dark Meat? I like Dark Meat.</comment>


Astronomers find an ancient black hole the size of 12B suns - <AUTHOR> http://www.washingtonpost.com/news/speaking-of-science/wp/2015/02/25/astronomers-find-a-shockingly-ancient-black-hole-the-size-of-12-billion-suns/ <comment><USER2> To put this result in context, an important open question in astronomy is how supermassive black holes are formed. There are currently two viable formation mechanisms:

1\. The bottom-up model: After the first generation of star formation, the most massive stars formed black holes with masses somewhere between 10-100 solar masses. These then began accreting material and merging with each other and gradually grew into the supermassive black holes we see today.

2\. The direct collapse model: As galaxies were forming, there was generally a concentration of gas at the bottom of each galaxy's potential well. If this cloud were dense enough, under the right conditions it could collapse directly into a ~10^4-10^6 solar mass black hole without fragmenting into individual stars.

The bottom-up model has historically been considered more plausible because the physics involved is better understood. However, discoveries of very massive black holes very early in the lifetime of the universe are starting to pose very serious challenges for this model. The reason is that black holes cannot grow arbitrarily rapidly. The rate at which a black hole can accrete matter is limited by the "Eddington accretion rate" or the "Eddington limit." Above the Eddington limit the gas gets so hot as it accretes onto the black hole that radiation from the infalling gas blows away the rest of the gas. (There are many details in this process which I have glossed over, but suffice to say it's generally difficult to get an accretion rate that is much more than this limit.)

If you start out with a black hole with a mass of ~100 solar masses and you feed it constantly at the Eddington limit, you can just barely grow black holes large enough to power the quasars we see in the early universe. But as more distant and more massive black holes are discovered, it gets harder and harder to grow a stellar mass black hole into a supermassive black hole in the age that the universe has existed at that time, and you have to invoke mechanisms like super-Eddington accretion and black hole mergers to grow a large enough black hole. This may be possible for individual black holes, but the more fine-tuned the model becomes, the less likely it is to be the primary channel by which supermassive black holes form. These sorts of discoveries are therefore providing evidence that the simple bottom-up picture may not be correct and either super-Eddington accretion, mergers, or direct collapse is necessary to form these black holes.

<comment><USER3> > black hole mergers

Black holes can not merge - time dilation means it would take an infinite amount of time for them to do so.

<comment><USER4> It would only be infinite for someone in or near the black hole. Not for an observer at a distance.

</comment></comment></comment><comment><USER5> Things like this make me very skeptical that the accepted model is correct.

<comment><USER6> > Things like this make me very skeptical that the accepted model is correct.

To which "accepted model" are you referring – the cosmological model for the Universe, the determination of black hole masses, the formation and growth of supermassive black holes, or something else? As @nilkn notes, this discovery is in conflict with existing models of the formation and growth of (some) supermassive black holes, which is a reason this paper is in Nature.

<comment><USER7> I'll say it. We're running in a virtual machine. There.

<comment><USER8> [http://en.wikipedia.org/wiki/Holographic_principle](http://en.wikipedia.org/wiki/Holographic_principle)

<comment><USER9> The usefulness of the HP is principally in the application of the aDS/cft duality to otherwise intractable calculations. It doesn't have anything to do with the universe being virtual or computable. Perhaps you are thinking of [https://en.wikipedia.org/wiki/Digital_physics](https://en.wikipedia.org/wiki/Digital_physics).

</comment></comment></comment></comment></comment><comment><USER10> We already knew about several black holes more massive than that though (the news seems to be about how ancient it is too, not just its mass):

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

</comment><comment><USER11> _Mass_ , not size. Come on, this is basic astrophysics!

<comment><USER12> Technically, the radius of a black hole is uniquely determined by its mass, so one can construct a unit system where mass and radius use the same unit of measure...

<comment><USER13> That unit system might allow comparing black holes to other black holes. But our sun does not have the same density as a black hole, or? The nature article [1] does not compare it to the size of our sun, but to its mass.

[1] [http://www.nature.com/nature/journal/v518/n7540/full/nature1...](http://www.nature.com/nature/journal/v518/n7540/full/nature14241.html)

<comment><USER12> Actually, you can use this unit system (called Geometrized units [1]) for anything, but it is especially convenient for describing black holes and general relativity in general. As a rule of thumb, in the geometrized units, 1 solar mass = ~1.5 km = ~5 microseconds. They have the same units so you can use them interchangeably (Our sun weights 5 microseconds).

I'm just being pedantic here obviously..

[1] [http://en.wikipedia.org/wiki/Geometrized_unit_system](http://en.wikipedia.org/wiki/Geometrized_unit_system)

</comment></comment></comment></comment><comment><USER14> Probably stupid question, but do we have solid evidence that the laws of physics/constants were the same/behaved the same back then? I know that to be true for the last couple of billion years. But so early in the development of the universe?

<comment><USER15> You can get evidence by observing the early universe with telescopes and the like. I don't think anyone has observed the laws/constants being noticeably different although you can't really prove a negative.

<comment><USER6> You can put limits on how much they could have changed, though. And people do this, e.g., [0], which found the proton-to-electron mass ratio has not varied by more than a relative factor of 4e-7, over the past 7.5 billion years.

[0] [http://arxiv.org/abs/1412.7757](http://arxiv.org/abs/1412.7757)

</comment></comment></comment><comment><USER16> Arxiv paper, with more relevant (albeit highly specialized) information than Nature's abstract:

[http://arxiv.org/pdf/1410.2689.pdf](http://arxiv.org/pdf/1410.2689.pdf)

<comment><USER6> That is not the same paper. The preprint you linked was published in the Astrophysical Journal Letters, and discusses a different quasar (SDSS J013127.34-032100.1, at a redshift of z=2.5). The Nature paper is about SDSS J010013.02+280225.8, at redshift z = 6.30. The author list is similar, so it is likely the same team. But the arxiv link is a different discovery.

<comment><USER6> I made a typo: the linked paper in the parent comment to mine is about an object at redshift z=5.18, not z=2.5.

</comment></comment></comment><comment><USER17> Did the big bang and immediate expansion necessarily distribute matter uniformly? If not, couldn't this just be the dumb luck of this black hole that it started its life itself with many solar masses, so it didn't need to accrete as much in the next 900 million years?

<comment><USER4> The idea is that the incredibly fast inflation immediately following the big bang smeared out the mass and energy of the universe very thinly, so that any unevenness got flattened out.

</comment></comment><comment><USER18> I love the timing of this with the release of a new/old theory that the universe has always existed :

[http://zeenews.india.com/news/space/no-big-bang-new- theory-s...](http://zeenews.india.com/news/space/no-big-bang-new-theory- suggests-universe-always-existed_1544948.html)

This would make the age of the this black hole less of a mystery.

I always new that there was a relationship between black holes and quasars (In/Out) but was unaware that there was an established relationship between specific events. Does anyone have links to this ?

<comment><USER19> Cosmology from quantum potential ( Ahmed Farag Ali, Saurya Das )

      It was shown recently that replacing classical geodesics
      with quantal (Bohmian) trajectories gives rise to a
      quantum corrected Raychaudhuri equation (QRE). In this
      article we derive the second order Friedmann equations
      from the QRE, and show that this also contains a couple
      of quantum correction terms, the first of which can be
      interpreted as cosmological constant (and gives a correct
      estimate of its observed value), while the second as a
      radiation term in the early universe, which gets rid of
      the big-bang singularity and predicts an infinite age of
      our universe. [1]

[1] [http://arxiv.org/pdf/1404.3093v3.pdf](http://arxiv.org/pdf/1404.3093v3.pdf)

<comment> saiya-jin If universe is older than big bang, why don't we see anything older than that? I mean, there isnt such a drop in visibility of galaxy/bright object that is 5 billion vs 10 bilion years old. So, where are all 30 or more billion year old objects? Maybe there wasn't ultimate singularity in the beginning, but universe is definitely not the same no matter how far you look in the past.

<comment><USER20> I think the answer is here [1].

[1] [http://en.wikipedia.org/wiki/Observable_universe#Misconcepti...](http://en.wikipedia.org/wiki/Observable_universe#Misconceptions_on_its_size)

</comment></comment></comment></comment><comment><USER21> What if it was two supermassive blackholes rotating around center of mass? Could we tell the difference?

Wouldn't time around them be slowed so much that it would look like they don't move at all?

<comment><USER22> The term to search for would be "supermassive black hole binaries". Apparently, these systems have a characteristic fingerprint.

[http://arstechnica.com/science/2015/01/supermassive-black- ho...](http://arstechnica.com/science/2015/01/supermassive-black-hole-binary- discovered/)

</comment></comment><comment><USER23> How Douglas-Adams funny would it be if the mega black hole had somehow been created by someone spilling their coffee on a keyboard at the CERN LHC

<comment><USER24> 11.

</comment></comment><comment><USER25> >420 trillion times more luminous than our sun

So that would have a Habitable zone? How far away and how large?

<comment><USER26> Ignoring all other considerations, one could produce a distance using the inverse square law.

<comment><USER27> Would that just mean taking the square root of the luminosity and interpreting it as distance in AUs?

<comment><USER25> So... [https://www.google.com/search?q=sqrt%28420*10^12%29au+in+lig...](https://www.google.com/search?q=sqrt%28420*10^12%29au+in+light+years)

324 lightyears.

Assuming Sol habitable is 0.7 to 1.2au the translated would be 227 to 389. A shell of thickness approximately 160 light years where everything is in the habitable zone (as long as it is not too close to another heat source)

</comment></comment></comment></comment><comment><USER28> Can we see it with less than a million bucks (or a trip to Wyoming)?

<comment><USER29> >It was even detectable with a relatively small telescope, though researchers in China did have to ask for help from astronomers in Chile and the United States to get a higher-resolution look.

<comment><USER30> I have a feeling that "relatively small" telescopes which find new black holes to publish in Nature are still quite expensive by normal person standards.</comment></comment></comment>


Red dust over Sydney - <AUTHOR> http://blog.flickr.net/en/2009/09/22/red-dust-over-sydney/

<comment><USER2> It was also like that here in Brisbane today. It was strange seeing everyone with masks over their mouths. Looked like the apocalypse.

Here's some more info about it, for anyone interested:

<http://www.news.com.au/story/0,27574,26114000-421,00.html>

</comment><comment><USER3> I snapped some photos from my bedroom this morning:

[http://enneff.posterous.com/clovelly-gordons-bay-in-the- dust...](http://enneff.posterous.com/clovelly-gordons-bay-in-the-dust-storm- very-w)

</comment><comment><USER4> Damn, I was in Sydney 2 days ago so I just missed it. They're pretty spooked about climate change and water shortages down there. This isn't going to help matters any. It still would have been cool to witness. They say this is the worst dust storm in 70 years.

<comment><USER5> Craziness, me too. I was back home for six weeks and then this happens the day after I leave. . .

<comment><USER4> Its always surprising how small a world HN seems to be, but how much globe we all cover. Wouldn't surprise me if we were on the same plane. Didn't go thru LAX did you?

I'm just glad I didn't get an extended stay courtesy of mother nature.

</comment></comment></comment><comment><USER6> Bushfire-season around Sydney is also an interesting time. Ash falls all through the city and down at Bondi you can see it drifting like rain onto the now-grey beach.

During the Hailstorm[1], the Sydney sky had green glow, of all things.

Now if Sydney has a plague of Locusts/Earthquake it may be time to postpone Mardi-Gras and Sleaze Ball... just to be safe ;)

\----

[1] <http://en.wikipedia.org/wiki/1999_Sydney_hailstorm>

<comment><USER7> Yeah the weather can be a bit wild here at times - but its not really that bad. Not hurricane (or cyclone) bad (living up north for a while is worse).

</comment></comment><comment><USER8> I managed to get some shots this morning on my way to work. All taken on my 3GS.

It caused air pollution levels to be 1500 times more than normal ([http://www.smh.com.au/environment/sydney-dust-blanket- causes...](http://www.smh.com.au/environment/sydney-dust-blanket-causes- highest-air-pollution-on-record-20090923-g2eu.html)) and it sure felt like it, sucking down all that dust. Can't have been good for me.

Most surprising sight for me was witnessing people smoking cigarettes still.

<http://emberapp.com/baz/images/dust-storm-pyrmont-1/> <http://emberapp.com/baz/images/dust-storm-pyrmont-2/> <http://emberapp.com/baz/images/dust-storm-pyrmont-3/> <http://emberapp.com/baz/images/dust-storm-pyrmont/>

<comment><USER9> Looks like someone works at Google :-) (for others, google office is to the left of those photos).

What a weird morning.

</comment></comment><comment><USER10> The sky was purplish red this morning and by 8AM it was yellow. I went out to buy bread and came back tasting powder in my lungs.

</comment><comment><USER11> You beat me, I just posted a dupe! <http://news.ycombinator.com/item?id=838978>

</comment><comment><USER12> Reminds me of the ending of Mad Max 3 - it must suck for the locals, but it's still pretty cool.

<comment><USER3> Nope, it's just fun for the locals. Apart from the asthmatics and firefighters responding to malfunctioning alarms.

<comment><USER13> The first I knew something was wrong was hearing the local mall's fire evacuation alarm going off at 6am this morning. Then I opened my eyes to see blood-red light coming in around the edges of the window and the smell of soil.

My next thought was: it must be a bad time to have one of those "eco" datacentres that vent directly to the atmosphere :-)</comment></comment></comment>


Unexpected diversity in electric eels, strongest living bioelectricity generator - <AUTHOR> https://www.nature.com/articles/s41467-019-11690-z <comment><USER2> Biology is at a severe disadvantage when it comes to using electricity.

For an electric circuit, you need both conductors and insulators. The best conductors are metals and superconductors. Metals are very hard for biological processes to deposit, and superconductors require super cold temperatures incompatible with biology.

Insulators are also very hard for biology, because most biological processes involve water, and water is a pretty bad insulator since it dissolves ions so readily.

Considering all that, it's amazing how much use of electricity biology manages!

</comment><comment><USER3> Wow, the idea than electric eel should be treated as a complex of several species is really interesting. A slightly different language should have evolved among the species. A blind animal needs a measurable variation in electric signals to know if other possible partners are friend of foe</comment>