The Price of Anarchy - <AUTHOR> https://en.wikipedia.org/wiki/Price_of_anarchy <comment><USER2> I just want to mention that many commenters here are reading much more into the name politically than do the game theorists/computer scientists who actually do research on it. The research is focused on the game theory and not meant to make any sort of political points or value judgement. The main question asked is how to design systems so that even in a game-theoretic equilibrium, the total "welfare" is close to the best possible.

<comment><USER3> Ding ding ding. The Price of Anarchy originally described the surprising result that internet routing seems to work despite the lack of a central planner. [1] The "central planner" is a theoretical maximum for the routing problem - it represents an oracle that automatically knows and applies an optimal routing solution. It's not some kind of government.

It's kind of hilarious seeing all of these people commenting about how this is "utopian" thinking, ancap-blah-blah, and "who says the central planner would be just?" People read what they want to read, I suppose.

If you do want to read something interesting about the price of anarchy, check out this other paper [2], written by one of the original authors, which shows that the PoA = 1 (that is, there is no cost) when there are private "owners" of the edges in a routing network who are allowed to charge a "toll" for traversing that edge. Makes you wonder if a globally-standard-but-locally- owned electronic tolling system could replace gas taxes to fund our roads in a fairer way. This could remove the undue toll burden shouldered by certain unlucky people who have to commute across a heavily tolled bridge. (Seattlites should know what I'm talking about).

[1] [http://www.cs.yale.edu/homes/jf/poa.pdf](http://www.cs.yale.edu/homes/jf/poa.pdf) [2] [https://people.eecs.berkeley.edu/~christos/papers/selfishrou...](https://people.eecs.berkeley.edu/~christos/papers/selfishrouters.pdf) [3] [http://theory.stanford.edu/~tim/papers/routing.pdf](http://theory.stanford.edu/~tim/papers/routing.pdf)

<comment><USER4> _> It's kind of hilarious seeing all of these people commenting about how this is "utopian" thinking..._

I suppose you're referring to me, since I'm the only one who has used that word.

To clarify, I was _replying to a comment_ , not making any comment directly relevant to the paper or PoA.

That said, if someone applied this paper's results directly to a defense of anarchy, I would call that application Utopian because I don't think game theory provides a particularly compelling model for all of society. FWIW such an application certainly wasn't the author's intent, and also is not what was going on in that thread.

 _> Makes you wonder if a globally-standard-but-locally-owned electronic tolling system could replace gas taxes to fund our roads in a fairer way. This could remove the undue toll burden shouldered by certain unlucky people who have to commute across a heavily tolled bridge. (Seattlites should know what I'm talking about)._

This is an interesting idea (which I think is the role that mathematical models applied to social systems _should_ play -- as a stimulant for interesting ideas and possibly a way of bounding the possible. A basis from which you rapidly diverge, which is OK. TBF I think this is what is also going on in the other thread...)

By "standard", do you mean "every mile is taxed equally"? Or "according to construction/upkeep cost"?

The latter seems hard to calculate and easy to fabricate. I think in a realistic system you'd just always end up with really high bridge tolls. In that sense, I think this application of this paper is Utopian in the sense that, when applied to the toll problem, it makes unwarranted assumptions about accurate pricing.

If by standard you just mean "equal", why not just use gas taxes and set them so that tolls aren't necessary? They approximate distance traveled pretty well, so should be pretty identical to tolling each mile equally. With the added benefit of also indirectly taxing pollution.

<comment><USER3> Nothing personal about your comment particularly - I agree with how you're characterizing it. I was reacting to the instant jump to political thought people were making when the PoA has plenty of interesting implications in the merely technological realm :)

> By "standard", do you mean "every mile is taxed equally"? Or "according to > construction/upkeep cost"?

Perhaps confusing wording on my part - by standard I meant that the system that actually detects the car and charges the dollars and cents is standardized. In other words, a frictionless lingua franca for tolling that exerted negligible inconvenience on the driver as they were driving. Think "everybody has a Visa", not "every item costs $1".

The tolls themselves would be priced neither uniformly nor "at cost" to offset construction expenses. Rather, they would simply be set to maximize profit for the local municipality that owned the tolling machines. Pricing the edges to maximize profit minimizes congestion, and theoretically does exactly as well as a super-deity oracle with perfect information that could plan everybody's route from start to finish. (This perhaps counterintuitive result is described in ref 2 from the grandparent). Whatever money is made in aggregate is used for all repairs and maintenance, so the idea is that small back roads would help to subsidize the cost of bridges, which are disproportionately expensive to repair compared to their importance in the road network. More importantly, the price to drive on any road is directly reflective of the externality you impose while driving on it. Right now, the expense and complication of exacting the toll is high enough that we only extract tolls at critical points like bridges, which means we only use tolls to discourage congestion in these few places. We set the tolls too high there to offset the fact that there should be tolls on feeder streets and other areas that are getting backed up and contributing to the overall gridlock.

In practice, you'd have to get around some issues surrounding the advertisement of road prices to the driver. The system would have to strike a balance between being fair and fatiguing drivers with too much shopping choice. In this respect, perhaps you could be right that there is some idealized thinking going on. But it is just an idea, after all.

<comment><USER5> This reminds me of the sunpass/turnpike system in South Florida. A toll is charged to your account by driving through toll booths located at entrance and exit ramps (done through an RFID chip or something similar appended to the windshield). The tolls generated are used towards maintaining that highway. It tends to be much less congested with more considerate drivers, compared to 95.

</comment></comment></comment></comment></comment><comment><USER6> I think that this is a really interesting concept, but dislike the name. All social anarchists (anarchist-communists, anarchist-syndicalists, even mutualists etc) would see anarchy as a social process rather than a purely individualised "every man for himself" system. It disregards the possibility for non-coercive collective forms of decision making.

but, saying this, a concept that discovers the loss in a system where each actor is purely self-interested is useful and interesting.

<comment><USER7> I talk with a lot of anarchists and perhaps the only ones of them who are truly in the spirit of "every man for himself" are an-caps and Stirnerists.

<comment><USER8> Most anarcho-capitalists that I know and from who I learn are absolutely not about "every man for himself" at all. Charity and voluntary cooperation are major parts of the society as they would like it to become. See [https://wiki.mises.org/wiki/Friendly_society](https://wiki.mises.org/wiki/Friendly_society) and [https://en.wikipedia.org/wiki/Dispute_resolution_organizatio...](https://en.wikipedia.org/wiki/Dispute_resolution_organization)

<comment><USER4> _> ...as they would like it to become... Friendly society... DRO..._

I think this has always been my primary gripe with ancap -- it's Utopian. And all Utopian thinking has the same problem -- it's either irrational, or very rational but starting from very strong axioms. Ancap writers, to their credit, tend to care a lot about crafting strong, rational arguments.

When I think about ancap (or any political theory that sets off my Utopia alarms), I reason through the entirety of society. I raise a lot of objections to myself, and make a note each time I come to the conclusion that I need some assumption about how people will behave.

Then I take those assumptions, and apply them to various state-based systems. Usually I end up with an equally Utopian world, or only require a small delta in the axioms to end up at a Utopian world. To me, that suggests that it's the axioms that are doing all the heavy lifting. If you can make enough assumptions, the state is much more than unnecessary -- it's also _irrelevant_! You get a Utopia either way! The enemy isn't the state, it's human behavior.

FWIW the same exercise can be used to derive ancap out of a thorough analysis of communist literature. And it also applies to more centrist policy proposals that posit Utopian-level returns.

At least, that's my experience with struggling through ancap literature. YMMV.

<comment><USER9> I don't think its all that Utopian. An-Caps take a lot of care to make there institution prove against human weakness. There is also a lot of study into historical examples that explain part of how a An-Cap society would work.

I don't one can expect more from any group. An-Capism is as un-utipian as you can get while still having some vauge definition of an ideal system.

Most AnCaps happily admit that the assumed society would not be near perfect. In fact, I would actually say that it would probably not be that much better then what we have now.

I don't think the axioms are that special, its basic rational choice political science/economics that is applied in most AnCap arguments.

<comment><USER4> _> An-Capism is as un-utipian as you can get while still having some vauge definition of an ideal system... Most AnCaps happily admit that the assumed society would not be near perfect._

Perhaps. That doesn't make it any less Utopian in my book.

 _> I don't think the axioms are that special, its basic rational choice political science/economics that is applied in most AnCap arguments._

Depends on the writer. There certainly are writers for whom this is true. IMO it's _not_ true of Molyneux, to name one.

Of course, rational choice is not special, but it is an enormous assumption that we're pretty sure is not a realistic description of how people actually behave...

<comment><USER9> Then I don't understand your definition of Utopian or how it is useful.

Molyneux is no longer an AnCap, he has gone of and is basically something on its own now.

There are actual economics/poetical science PhD working on this stuff, see for example Peter Leeson, Bryan Caplan.

> Of course, rational choice is not special, but it is an enormous assumption > that we're pretty sure is not a realistic description of how people actually > behave...

Rational choice in this context means not Homo Economicus (as in mathematical maximisation of expected outcome) but rather rational choice limited by information and so on. This assumtion is much weaker and applies to enough people as to make it useful.

Its basically what much micro economics and political science already does. I don't know what better scientific disciplines we have to make better evaluation of theoretical system of humans.

</comment></comment></comment></comment></comment></comment></comment><comment><USER10> Wow, people are really running away with the political analogy used here.

Calm down folks, they're not ragging on decentralized systems. If you read and comprehend the definitions in the article, you'll see that it's a fully general solution that allows for emergent organization through market systems or cooperation. You can bake those things into the strategies and utility functions of the actors.

It's just a fun and descriptive name for the difference between an idealized central controller (which can force everyone into a configuration that maximizes an arbitrary global utility function) and the lack of such a controller. The outcomes could be the same, they could be different. If you factor in the negative utility of having the central authority in the first place, you can game-theoretically justify your particular favored level of anti-authoritarianism.

</comment><comment><USER11> Already in the first line it claims that anarchy is a system wherein

>a system degrades due to selfish behavior of its agents

To my point of view, most game theory is just capitalistic ideology disguised in mathematical models.

<comment><USER12> If anything, this sounds anti-capitalistic - capitalism is based on an assumption that selfish behaviour of individuals produces greater good for the society.

<comment><USER13> "It is not from the benevolence of the butcher, the brewer, or the baker that we expect our dinner, but from their regard to their own interest" \- Wealth of Nations, Adam Smith

I tend to think of self-interest being equivalent to selfishness. Your point makes me wonder if self-interest is not equivalent to selfishness, at least to Economists.

<comment><USER12> Well, what you quote is true, but I think a lot of discussion stems from focusing on the wrong question, namely "does selfishness lead to better outcomes" as opposed to _when_ it does, and when it does not.

Too many people seem to approach economy as an ideology rather than a complex system in which a given approach produces good results here and bad results there, and everything should be subject to optimization and careful design.

<comment><USER14> > _Too many people seem to approach economy as an ideology rather than a > complex system_

Few of these people have any decision-making authority. This mass ignorance of economics _does_ occasionally bubble up on the policy side. But it is generally, at least in the United States, contained by more knowledgeable (and influential) parties.

<comment><USER15> ...like Alan Greenspan?

</comment></comment></comment></comment></comment></comment><comment><USER16> That has the most math notation of anything I've seen written about anarchy in some time!

<comment><USER17> Math is important. It tells us the shape of the possible. Game theory tells us when we're creating an unstable set of incentives. Our intuition for fairness is only a crude approximation of game theory.

Societies and their moral systems (there's little difference) don't come out of nowhere.

Sentiments like "game theory is just capitalistic ideology" make me sad. Math, like all sciences, is true whether you accept it or not.

<comment><USER6> it may be 'true' within the set of axioms on which it rests, but 'wrong' in that those axioms (rational self-seeking behaviour, etc) don't hold in reality. More, those axioms themselves could be reflections of capitalist ideology.

</comment></comment></comment><comment><USER18> Think of it as structured vs unstructured if you can't avoid gettng hung up on the name.

Basically this is talking about the net difference between what is locally optimal and globally optimal in a multi agent system.

<comment><USER19> an ("without") + arkhos ("ruler"). Seems like a fine name to me.

</comment></comment><comment><USER20> Isn't libertarian thinking (put very heavily on the edge) the exact opposite?

That a system will become more efficient if actors are let to do things for their own sake, and that actors are smart enough to calculate the negative impact of short term selfish action (that is, actors can help out now, with an exception of a positive roi)

<comment><USER21> This assumes a theoretical optimal central planner, a superintelligent BDFL of sorts.

Libertarian thinking is that in practice humans are so bad at management that every time we tried central planning it came up even worse than non-optimal Nash Equilibria (which are the failure mode of non-centrally-managed agent systems.) Libertarians would say that no dictator or government in history turned out to know better than The Market. That The Cost of Regulation is higher than The Cost of Anarchy.

Of course, both costs are high for some problems and low for others, and the solution to practical problems usually lies at neither this extreme nor that one.

</comment></comment><comment><USER22> This submission seems to be a kind of follow-up to the one about Braess's paradox ([https://news.ycombinator.com/item?id=13352513](https://news.ycombinator.com/item?id=13352513)).

<comment><USER23> I have seen clusters of posts and have not had the time to study: Are they a dialog between unrelated people who share an interest in a topic, or is one person pursuing a theme?

</comment></comment><comment><USER24> Incomplete models are incomplete. It completely ignores the ways on which the mentioned transport should take place. It ignores that you usually don't have one place from which everybody starts but multiple places to other multiple places.

And if you think about it, individual car mobility is this in practice. The ways are build by someone else but you can decide how and where to drive. And it kinda failed in many areas.

<comment><USER25> It's not clear what you are referring to. The section on Selfish Routing begins with Braess's Paradox but swiftly moves on to a Generalized Routing Problem which appears to address your concerns.

</comment></comment><comment><USER26> "In the 'centralized' solution, a central authority can tell each agent which path to take in order to minimize the average travel time"

That's a wishful thinking. Central authority can and usually is selfish and corrupted but the impact of it is much bigger.

So we can call this piece of math a science but voting for centralized systems based on that is super naive.

<comment><USER26> I see my comment is not well received.

Who will explain me why we assume that a single unit is selfish, but a big one contained of many selfish units is altruistic?

<comment><USER27> You assume the central planner to be the same as a single unit (as in, of the same kind, the same species).

Who is to say that the central planner must be the ontological equal of a single unit? Why not a more complex system?

You could have for example a quorum of single-unit who will need to reach a consensus concerning their diverging self-beneficial impetus. You can also imagine, if you represent the interest of each single unit as a vector in some kind of space, that the quorum must navigate a product of those vectors.

You can imagine an AI then, a machine exploring that vector space that could learn to balance the wants and needs of its single units.

Et cætera. I don't know exactly why you comment was not well received, I am not able myself to downvote comments here and I did not do that, but my own opinion about yours was that it was basing itself on some assumptions that were biased by some real-world considerations that were irrelevant for the concept presented.

<comment><USER26> Thank you for your reply.

"Who is to say that the central planner must be the ontological equal of a single unit"

My impression is that's what most people here are discussing.

I can see a definition of an anarchy in your quorum example, can't you? But you say we could have AI which will find a balance. Interesting concept. Does it imply obeying AI <=> obeying the law?

<comment><USER27> Well, the quorum could be organized in any matter of way. Expected a consensus for a decision would be akin to anarchy indeed, however there could always be some kind of recursive hierarchy, with another sub-committee of higher authority that would make other units diverge. (Parties within an assembly, with deputies having to follow their party lines). This quorum could also be tied to following the interest of the masses outside or lose substantial advantages, thus tying their own selfishness to the common good.

It could be anarchy. It could be anything else.

The AI could simply do whatever its specialization is. It could be trying to direct the single-units or to disorganize them and try to keep some level of entropy. Maybe its own benefit would be a generalized state of chaos. Whatever.

The system itself could be considered the legal framework. The relationship between any supervisor and its units could be the metaphor for any subservient relationship in the real world, going from managed teams to parenting to politics to social dynamics between friends. It does not mean anything as long as the specifics of the system itself are not defined to permit the dynamics to be correctly mapped on some real-world dynamics.

Obeying the law? Are you obeying the law of gravity? Is it from your own will that you agree to stay on the ground?

<comment><USER26> Well yes, I am obeying the law of gravity :D Is your point, that AI could replace human will?

<comment><USER27> No, sorry it was somewhat tongue in cheek. It's just that within the simulation, the way a single unit obeys a central planner (not at all, partially, entirely) is defined by the rules of the simulation, so the rules of the world.

So asking if that rule, that authority of the AI over the units is similar to human law, is I think a bit beside the point. It's more akin to the law of physics. It's simply the fabric of that reality.

Of course, you could then create a simulation that would try to recreate the same kind of domination as within a human society, but that would be only one kind of simulation, one kind of system, with specific parameters. It would not give much about the very essence of the system itself, only of it within constraints.</comment></comment></comment></comment></comment></comment></comment>


Ask HN: What good books have you read in 2016? - <AUTHOR> <comment><USER2> "Deep Work" by Cal Newport. He emphasizes the need for deep intellectual work to prosper in the knowledge economy and suggests ways to practice getting to that level of work.

It is part rumination and part self help. I highly recommend it.

<comment><USER3> interesting summary here: [https://www.youtube.com/watch?v=KX_2a_jsGYw](https://www.youtube.com/watch?v=KX_2a_jsGYw)

</comment></comment><comment><USER4> I'm finally starting to read "Don Quixote". A good way to celebrate the 400 anniversary of the death of Miguel de Cervantes (and Shakespeare). Disclaimer: I'm Spanish, so it's about time :)

Available in English for free through Project Gutenberg

[https://www.gutenberg.org/ebooks/996](https://www.gutenberg.org/ebooks/996)

And for Spanish readers like me, here it is in several electronic formats:

[http://manybooks.net/titles/cervantesetext992donq10.html](http://manybooks.net/titles/cervantesetext992donq10.html)

<comment><USER5> This book should be required reading. One of the best experiences I've ever had with fiction was reading this in high school. It's a massive read, I think I got through it in like 8 days over Christmas holiday.

</comment></comment><comment><USER6> Avogadro Corp: The Singularity is Closer than it Appears by William Hertling, as well as the other three books in the series.

[https://www.amazon.com/Avogadro-Corp-Singularity-Closer- Appe...](https://www.amazon.com/Avogadro-Corp-Singularity-Closer-Appears- ebook/dp/B006ACIMQQ)

<comment><USER7> I really enjoyed this series.

</comment></comment><comment><USER8> I'm still reading it but: Small Wars, Far Away Places. [0]

It's about how after WW2 lots of the empires started crumbling and how that affected the smaller countries of the world. It is very well researched, and incredibly interesting.

[0] [http://www.amazon.com/Small-Wars-Far-Away- Places/dp/02307523...](http://www.amazon.com/Small-Wars-Far-Away- Places/dp/0230752322/ref=sr_1_sc_1?s=books&ie=UTF8&qid=1463289805&sr=1-1-spell&keywords=small+wares+far+away+places)

</comment><comment><USER9> The more I read, the more I realize that fiction has a way of teaching the same lessons as nonfiction, only in a better, humane way that is not like someone lecturing at you from a podium, but more like a friend sitting down for a heart-to-heart conversation with you.

In this vein, I've started catching up on all the classics I haven't read yet, and there are a lot of them. At first, I was hesitant to dive into classics, because I thought they were hard to read and highbrow. This has mostly not been the case (with the exception of Wuthering Heights, which I found impossible to get through).

To wit, the best books I've read this year include:

A Tale of Two Cities - Impossible to get through the first several chapters, but after that, you're off to the races between France and England in the 18th century. Dickens used historical books as reference, but recreated the mood entirely from imagination. A better primer than anything in the news about Anglo-French relations, learning trust, and sacrifice.

No Country for Old Men - Want to understand the current fear of the Mexican border that has so bolstered Trump's popularity, as well as the ramifications of having a country full of veterans who don't have any medical support or care? Read this book.

Farenheit 451, A Clockwork Orange, Handmaid's Tale - Much better and scarier than any news clipping today about the possible future path for government interference in thought and action. Takes things to their logical conclusions.

And one non-fiction book that I did enjoy, Bringing Up Bebe, which is about the contrasts between child-rearing in France and America, but on a much larger scale, about the different things that seem culturally obvious to us, but are completely different to other cultures. This book made me really re- examine American food culture in a way Michael Pollan's diatribes have not.

</comment><comment><USER10> Still mostly reading childrens books.

This is not my hat: [https://www.amazon.co.uk/This-Not-Hat-Jon- Klassen/dp/1406353...](https://www.amazon.co.uk/This-Not-Hat-Jon- Klassen/dp/1406353434)

Black dog: [https://www.amazon.co.uk/Black-Dog-Levi- Pinfold/dp/184877052...](https://www.amazon.co.uk/Black-Dog-Levi- Pinfold/dp/1848770529)

FArTHER: [https://www.amazon.co.uk/FArTHER-Grahame-Baker- Smith/dp/1848...](https://www.amazon.co.uk/FArTHER-Grahame-Baker- Smith/dp/1848771339) (Sadly this book uses a stupid font. Other than that it's lovely.)

Pirate Diary: [https://www.amazon.co.uk/Pirate-Diary-Journal-Jake- Carpenter...](https://www.amazon.co.uk/Pirate-Diary-Journal-Jake- Carpenter/dp/0744594308)

I get these from the CILIP Kate Greenaway award. Once you know the name of the writer, or illustrator, or even publisher, you can usually find more good books. [http://www.carnegiegreenaway.org.uk/greenaway.php](http://www.carnegiegreenaway.org.uk/greenaway.php)

CILIP is a UK librarian organisation. The US equivalent award is probably something like the Caldecott Medal: [http://www.ala.org/alsc/awardsgrants/bookmedia/caldecottmeda...](http://www.ala.org/alsc/awardsgrants/bookmedia/caldecottmedal/caldecottmedal)

</comment><comment><USER11> How to Get Filthy Rich in Rising Asia: A Novel - Mohsin Hamid. This is my book of choice for the year: I read it cover-to-cover in a single day. Refreshingly written in second-person perspective, totally engaging.

Finally read the Zones of Thought series by Vernor Vinge. Love his slight twist on physics that allows for for both post-singularity tech and low-tech to exist in the same universe.

The Dark Forest by Cixin Liu (second book in the Remembrance of Earth's Past translated from Mandarin) had a bit of a slow start, but really built up to a good finale.

Elon Musk: Tesla, SpaceX, and the Quest for a Fantastic Future - Ashlee Vance. Good read and made me really appreciate what Elon has done through financially to get Tesla and SpaceX up.

</comment><comment><USER12> Picketty's "Capital in the Twenty-First Century".

If you have an interest in inequality of wealth and income, particularly how it has evolved over the last hundred years or so in some developed countries, it is certainly worth a read.

</comment><comment><USER13> Currently reading: "The Information - A History, A Theory, a Flood"

I like it so far.

</comment><comment><USER14> "This changes everything" by Naomi Klein. It's a very well-written, liberal book on climate policy failures written by an investigative journalist.

I think it was written in 2014, so it doesn't cover the latest trends in fracking or solar. I didn't know anything about the climate industry coming from a silicon valley background, so this was an ingestible yet detailed primer.

<comment><USER12> You might also be interested in reading "Windfall: The Booming Business of Global Warming" by McKenzie Funk.

</comment></comment><comment><USER15> Currently reading "Utopia for Realists" [https://www.amazon.com/Utopia- Realists-Universal-Borders-Wor...](https://www.amazon.com/Utopia-Realists- Universal-Borders-Workweek-ebook/)

An interesting big picture look at the world. It questions what we understand and do about work and life.

</comment><comment><USER16> I really enjoyed Brian Krebs' Spam Nation and I think it would appeal to the HN crowd. [http://www.amazon.com/Spam-Nation-Organized- Cybercrimefrom-E...](http://www.amazon.com/Spam-Nation-Organized- Cybercrimefrom-Epidemic/dp/1501210432)

</comment><comment><USER17> "Listen, Liberal!" by Thomas Frank. A must-read if you care about politics in America

</comment><comment><USER18> Reading _The Meaning of Science_ by Tim Lewens right now. It's an introductory "Philosophy of Science" book, and I'm enjoying it so far. Up to where I'm at now, the author has covered Karl Popper and his falsification oriented framework, and Thomas Kuhn and the "scientific revolution / paradigm shift" model.

A couple of other ones from this year that stand out to me:

 _Disrupted_ by Dan "Fake Steve Jobs" Lyons

 _It 's Not The Big That Eat The Small, It's The Fast That Eat The Slow_ by Jason Jennings

In terms of fiction, this years haul includes:

 _The Bazaar of Bad Dreams_ by Stephen King

 _The Last Mile_ by David Baldacci

</comment><comment><USER19> _Understanding Computers and Cognition: A New Foundation for Design_ by Terry Winograd and Fernando Flores. Highly recommended if you're interested in how people interact with computers (and how computers interact with people, and how both interact with the world in general). [http://www.amazon.com/Understanding-Computers-Cognition- Foun...](http://www.amazon.com/Understanding-Computers-Cognition-Foundation- Design/dp/0201112973)

</comment><comment><USER20> I know it is not "productivity" but I had a real good time reading was "Dungeon Hacks: How NetHack, Angband, and Other Roguelikes Changed the Course of Video Games" [1]

It talks about the creation of rogue games (rogue, nethack, adom) and its authors and co-authors.

Well written made me play nethack again. So your productivity will decrease :)

[1] - [http://amzn.to/1spSott](http://amzn.to/1spSott)

</comment><comment><AUTHOR> I will add a couple books I've read so far in 2016, both of which are not from 2016:

Sapiens by Yuval Noah Harari. This book was an unexpectedly amazing overview of the history, current status and possible future of human beings.

The Emperor of All Maladies by Siddhartha Mukherjee. I put this off because I'm not very interested in medicine. It was a mistake, this is one of the most well written non fiction books I've ever read.

</comment><comment><USER21> Gettysburg The Final Fury by Bruce Catton.

[https://www.amazon.com/Gettysburg-Final-Vintage-Civil- Librar...](https://www.amazon.com/Gettysburg-Final-Vintage-Civil-Library- ebook/dp/B00AUSCOWO?ie=UTF8&ref_=dp_kinw_strp_1)

I'm not much of a reader. I like short, concise, non-fiction, and this was perfect! Highly recommended.

If anyone can recommend similar books for me, please do.

</comment><comment><USER22> Its an old book. But has a lot of interesting aspects.

Business @ The Speed Of Thought By Bill Gates and Collins Hemingway

[https://en.wikipedia.org/wiki/Business_@_the_Speed_of_Though...](https://en.wikipedia.org/wiki/Business_@_the_Speed_of_Thought)

</comment><comment><USER23> Reread _Blood Meridian_. The newness of good books twenty years later is one of the benefits of getting older.

<comment><USER24> That is an excellent, though fucking brutal book.

</comment></comment><comment><USER25> Thinking, Fast and Slow by Daniel Kahneman: [http://www.amazon.com/Thinking- Fast-Slow-Daniel-Kahneman/dp/...](http://www.amazon.com/Thinking-Fast-Slow- Daniel-Kahneman/dp/0374533555)

Great book about the way humans think.

</comment><comment><USER26> Letters from a Stoic Getting Real Cambodia Noir Vagabonding

All great reads!

</comment><comment><USER27> Superintelligence by Nick Bostrom, one of the leading minds analysing and developing AI as it relates to human civilisation.

</comment><comment><USER28> Linchpin by Seth Godin. cool take on why we need to all be artists instead of cogs in a machine.

</comment><comment><USER29> I started the Wheel of Time series and am currently through book 3 and I am loving it.</comment>


Startup Quote: Jonah Peretti, co-founder, BuzzFeed - <AUTHOR> http://startupquote.com/post/1511264800

<comment><AUTHOR> You can drastically increase your chances for success if you try lots of things and bring the best forward.

\- Jonah Peretti (@peretti)

<http://startupquote.com/post/1511264800></comment>


Infographics to the Aid of the 99 Percent - <AUTHOR> http://www.good.is/post/occupy-design-visual-tools-for-the-99-percent?utm_campaign=daily_good&utm_medium=email_daily_good&utm_source=headline_link&utm_content=Occupy%20Design%3A%20Visual%20Tools%20for%20the%2099%20Percent

<comment><USER2> That's not a great chart, especially for a sign or something people will only see for a second.</comment>


A Visionary Project Aims for Alpha Centauri, a Star 4.37 Light-Years Away - <AUTHOR> http://www.nytimes.com/2016/04/13/science/alpha-centauri-breakthrough-starshot-yuri-milner-stephen-hawking.html?mabReward=A6&moduleDetail=recommendations-2&action=click&contentCollection=Americas&region=Footer&module=WhatsNext&version=WhatsNext&contentID=WhatsNext&src=recg&pgtype=article <comment><USER2> So the whole thing should weigh in the order of several grams, yet it should be able to deflect 100GW of incoming radiation near perfectly (otherwise it will instantly vaporize) while maintaining structural integrity under the acceleration of 60,000g for two minutes?

And whatever laser sources we're using must track this smartphone-sized object during these two minutes across several million kilometers. Perfectly. (It also means that whatever course deviation the object experiences must be anticipated _seconds before it happens_ , because at the end of the two minutes the object will be ~10 light-seconds away.)

If they could pull this off it will be the next Apollo, but I'm skeptical.

Edit: Just realized we have even more problems, about the reflective coatings. If the laser is green, by the time it's flying away at 0.2c, the laser won't be green any more thanks to the Doppler effect! I'm too lazy to calculate, but it will definitely shift toward the red. So whatever reflective coating we use must be able to work near-perfectly over a wide range of spectrum.

<comment><USER3> You're right to be skeptical, because this is going to be very difficult and has many challenges that need to be overcome.

But that doesn't mean we should sit here and say "nope, can't be done".

People were skeptical when planes first flew, when it was attempted to put people on the moon, and so on.

Jeez, people were skeptical when SpaceX said they could land a first stage on a barge at sea, and posted endlessly about how it couldn't be done.

Don't be one of those people.

Even if they "fail" to make all of this work and get something to Alpha Centauri, they're still going to vastly expand mankind's knowledge of a lot of difficult space-related technologies, which is a huge win.

This is hacker news, where people are trying to do difficult things to change the world. That's the whole point.

<comment><USER4> People were also skeptical of all the people before the Wright brothers who jumped off cliffs and killed themselves. Skepticism is the natural worldview of an engineer, because the universe is incredibly hostile to our ideas.

<comment><USER5> >Skepticism is the natural worldview of an engineer

This is in a nutshell why me and my (MBA)boss get into arguments.

</comment></comment></comment></comment><comment> david-given This is a variation of the old Starwisp idea from 1985:

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

tl;dr: a lightweight (about 1kg) vehicle made out of carbon wire mesh. It acts as a microwave mirror. You both use this for propulsion, by blasting it with microwaves from a Sol-system maser cannon, and for data recovery; its sensors cause the reflected microwave signal to be perturbed based on what its sensors see.

So, you accelerate them (in bulk) at about 2G up to .1c. You ignore it until it's about 80% of the way there, and then for fire the maser at it again; the beam reaches the starwisp as it passes through the target system and powers the sensors. A few years later you read back the return signal.

There were a whole bunch of technical problems with it, not least how to build a microwave lens 560km across, but it's still vastly more plausible than trying to push steel cans across the interstellar gulf. I'd be really interested to see if this version works.

</comment><comment><USER6> This is a pretty cool initiative — I looked into beamed propulsion a bit while teaching a course this past fall, and it seems to me that if we (or human technologies) are going to reach a star in our lifetimes, this is by far the most likely way. Still _very_ challenging though.

For a quite detailed recent treatment of optical/IR propulsion see this paper by Philip Lubim:([http://www.deepspace.ucsb.edu/wp- content/uploads/2015/04/A-R...](http://www.deepspace.ucsb.edu/wp- content/uploads/2015/04/A-Roadmap-to-Interstellar-Flight-15-h.pdf))

For a thorough, if somewhat outdated, treatment of the "starwisp" idea using microwaves rather than optical/IR lasers, see this paper: [http://path-2.narod.ru/design/base_e/starwisp.pdf](http://path-2.narod.ru/design/base_e/starwisp.pdf) by Robert Forward.

To poll the success of this overall endeavor, as well as start to make predictions about which components will/won't work, Metaculus is launching a series of questions —check it out if you have expertise or opinion: [http://www.metaculus.com/questions/#/?order_by=-publish_time](http://www.metaculus.com/questions/#/?order_by=-publish_time)

<comment><USER7> I'm disappointed that more people don't mention Robert Forward when this idea is being covered in the media. (Probably because his Usenet posts, papers, and books predate the World Wide Web.)

<comment><USER6> agreed! The starwisp paper is really very nice.

</comment></comment></comment><comment><USER8> Sending a swarm of unguided relativistic projectiles across the universe seems profoundly rude.

<comment><USER9> It would be nice if they could use solar wind to decelerate as they approached. I know there's not enough energy there to insert them into an orbit, but they might get time for a few more pictures?

<comment> david-given You can --- you use a thing called a magsail.

The short version is: remember the old Bussard ramscoop idea? You use a magnetic field to collect interstellar hydrogen which you then fuse for thrust? Turns out that in our part of the galaxy, you get more drag from the sail than you do from the fusion thrust, so the idea was scrapped.

An embarrassingly long time later people finally realised that they'd invented a fuelless brake, and the idea was resurrected (but without the fusion drive). The maths are quite plausible and the sail itself trivially simple --- just a wire loop.

[http://www.centauri-dreams.org/?p=22138](http://www.centauri- dreams.org/?p=22138)

However, I don't think they'd be compatible with this idea --- I suspect you wouldn't get one big enough to be useful in a one gram package. But estimating the numbers is beyond me. Here's the paper if you want it. [http://www.niac.usra.edu/files/studies/final_report/320Zubri...](http://www.niac.usra.edu/files/studies/final_report/320Zubrin.pdf)

<comment><USER10> Very fascinating! I had no idea we had such a viable option for braking.

Two questions for you if you're up for it.

Could we use this concept for braking during earth re entry to depend less on complex heat shields?

Why is the idea of a bussard ramscoop not viable?

</comment></comment></comment></comment><comment><USER11> So, how is a tiny smartphone-sized probe supposed to transmit data back to Earth from 4.37ly away?

<comment><USER12> That is a good question. The Voyager spacecraft send out detectable signals with a ~20 Watt signal. This is larger than the ~3 W signal that a smartphone sends, but by less than an order of magnitude.

Voyager is at ~130 AU. Alpha Centauri is at ~275,000 AU. With the 1/r^2 decrease in signal, that means the signal from earth will be smaller by a factor of ~3 x 10^6. Now, supposing we have ~1000 of these smartphone probes, this means that their combined signal will be weaker than the Voyager signal by a factor of ~3000. We might imagine that they are somewhat more optimized to send a stronger signal than an ordinary smartphone. Let's say they have a 30 W radio instead of 3 W. This means that they will have a weaker signal by a factor of ~300. This is a lot, but if they manage to build a detector that has a larger effective diameter than the Deep Space Network by a factor of ~15. Given the budget of the project, and the fact that they have 20 years of time to prepare after the launch, this could be feasible.

Looking at the project's website, though, it looks like they are taking the approach of using a laser onboard the probe instead of using a traditional radio transmitter [1]. This would increase the efficiency of the transmission by several orders of magnitude. It might even be possible to detect the signal from a single probe with this approach.

[1]: [http://breakthroughinitiatives.org/index.php?controller=Foru...](http://breakthroughinitiatives.org/index.php?controller=Forum&action=viewforum&id=14&page=1)

<comment><USER13> it seems ridiculous to use anything other than a laser IMO.

<comment><USER12> Almost certainly. But using a laser requires much better aim than a radio transmitter.

</comment></comment></comment></comment><comment><USER14> What about the energy dissipated by collision with the interstellar medium? Won't that slow the probe considerably?

Apologies for significant errors and appreciation for corrections in the following hasty and unchecked calcs.

Wikipedia [1] says the ISM density ranges from as little as 1e-4/cm^3 for hot, ionized regions to 1e6/cm^3 for cool, dense regions.

Let's say it's all neutral hydrogen, which conveniently masses 1g/mole. A mole is 6.02e23 particles. A single H atom masses about 1.66e-27kg. And let's say the ISM has a hydrogen atom density kind of midway between the extremes: 10/cm^3 (=1e7/m^3).

Let's say the spacecraft presents 2.54cm x 2.54cm (1 square inch) = 6.45e-4 m^2 to the ISM as it moves. I think this is small compared with what the project is proposing, but we can scale as needed.

At 20% of C, the spacecraft sweeps out a volume of [(3e8 _.2)m /sec]_(6.45e-4m^2) = about 3.9e4m^3 every second, which contains about 3.9e11 hydrogen atoms, or a mass of about 6e-16kg/sec.

If all those atoms hit and stick to the spacecraft, they all get accelerated to the spacecraft's velocity. At 20%C, relativistic mass increase should be small, so let's ignore it. The energy needed to accelerate one hydrogen atom to 20%C is about 3e12J/atom.

If the spacecraft is hitting 3.9e11 atoms/sec and spending 3e-12J/atom accelerating impacting atoms to 20%C, that's slightly over 1 Watt that's decelerating the spacecraft.

Over a 20-year trip (6.31e8 seconds and assuming no deceleration), that's 6.31e8 W-sec, or 631 megaJoules of energy needed to sustain 20%C because of collisions with the interstellar medium.

A Watt isn't much, but over a 20 year trip, it integrates to a pretty big energy requirement, or a significant deceleration of an unpowered, very low mass spacecraft.

It looks to me like small, light probes won't maintain their high initial velocity very long into the cruise phase without ongoing propulsion.

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

<comment><USER15> Good point. On their website, they list the specific challenges that they need to address, including a page for "4 Photon Thrusters". Would those be able to counteract the deceleration?

[http://breakthroughinitiatives.org/Challenges/3](http://breakthroughinitiatives.org/Challenges/3)

<comment><USER14> Perhaps they might. Looking forward to reading the entire project description when I get home this evening.

</comment></comment></comment><comment><USER16> Oddly the most practical use for this is as an interstellar weapon. You don't need to solve the problem of communicating back to Earth, you just need a little terminal guidance.

If an iPhone weighs 100 g and we use a non-relativistic formula for energy at 1/4c, that is 2.8 x 10^14 joules, a ton of TNT equivalent is about 4.1 x 10^9 joules, so that is a cool 70kT -- The impact velocity would be high enough to break the Columb barrier as well, so you might get a nuclear boost to the yield as well.

<comment><USER17> > Oddly the most practical use for this is as an interstellar weapon.

I completely don't advocate this, but the 9-year-old-boy part of my brain thinks it'd be pretty awesome to announce our presence to the universe by attacking a star system.

<comment><USER16> One of the explanations of why we are not seeing evidence of ETs is that everybody is hiding and afraid they might get bombed by their neighbors; that's because bombing your neighbors is orders of magnitude easier to do than visiting them -- you don't need to solve the problem of decelerating on the other end for one thing.

</comment></comment></comment><comment><USER18> How close does a tiny cell-phone camera objective lens have to get to an interstellar object before it can resolve detail better than the High-Def Space Telescope will?

<comment><USER12> A cell phone camera probably has a resolution of ~1 arcminute (about the resolution of the human eye). The Hubble has a resolution of ~0.05 arcseconds. The HDST would have a resolution of ~0.002 arcseconds. So to get comparable resolution to Hubble the probe would have to be at a distance of (.05 / 60) * 270,000 AU ~ 225 AU and a distance of (.002 / 60) * 270,000 AU ~ 9 AU to beat HDST. A camera on such a telescope would probably be of somewhat higher resolution, however. In fact, it would probably be at the diffraction limit, which for a ~1 cm aperture in visible light would be closer to ~10". This would increase the distances above by a factor of 6 or so.

Resolution isn't the only thing, though. The contrast is extremely important. A little probe in the Alpha Centauri system would be able to take clean images of any planets in the system. A telescope in our solar system trying to directly image these planets has to contend with contamination of light from the stars.

</comment></comment><comment><USER19> It seems to me that the accuracy required to aim an unguided projectile anywhere near the target stars will be impossible. They'll fly by pretty far. At what distance to Alpha Centauri does an iPhone quality camera outmatch the Hubble's photos?

<comment><USER20> "The light beamer must focus a spot smaller than the sail onto the sail, as it orbits 60,000km above the Earth's surface. This alignment must be produced when the target star system (Alpha Centauri) has the correct configuration with respect to all planetary and stellar bodies in the intervening space, such that the flyby occurs within 2 AU of the target planet. Using on-board photon or others thrusters, the nanocraft will have the ability to make some modest mid-course corrections, on the order of 1-2 AU.

"The task of pointing the array is dominated by the problem of keeping the sail on the beam. This problem is defined by the width of the sail and the distance to it. As an example, for meter-scale sail size the launch distance is on the order of a few million km. The pointing accuracy required for beam stability at this distance is on the order of a milliarcsecond. There are several mitigation approaches that could be used to counter these effects. A model of the atmosphere, calibrated with radar, laser beam, and optical measurements in real time, would enable the required beam precision to be achieved. Targets such as Alpha Centauri are bright star systems that will inform pointing requirements.

"Monitoring the laser beam output provides the information needed to form the beam. The Starshot system would be very different than a conventional telescope, and specialized to its purpose. For example, most ground-based telescopes, such as the Keck telescope, point to within a few arcseconds and can track in a closed loop mode to better than 100 milliarcseconds. For the purposes of Starshot, a significant improvement on this precision is required. However, the beam synthesis inherent in the phased array system provides considerable fine-pointing capability, supplemented by closed loop tracking of the beacon on the spacecraft."

[http://breakthroughinitiatives.org/index.php?controller=Foru...](http://breakthroughinitiatives.org/index.php?controller=Forum&action=viewforum&id=2&page=1)

<comment><USER21> > on-board photon or others thrusters

So the flash can also be used for course corrections? Cool!

</comment></comment></comment><comment><USER22> How is such thing able to communicate back with earth? Doesn't it require a lot of energy to create signal that we will be able to receive on earth (or satelite)?

<comment> rm_-rf_slash Not a scientist but I first read this on The Economist and they summed it up pretty well:

"At its destination it would beam back pictures of the star's planets with its on-board laser. No current observatory could possibly pick up such a signal—but the kilometre-wide launch array should be able to. The optical systems used to meld the output of the lasers could be used in reverse as a vast and sensitive telescope."

[http://www.economist.com/news/science-and- technology/2169687...](http://www.economist.com/news/science-and- technology/21696876-interstellar-travel-means-thinking-both-very-big-and-very- small-new-plan)

<comment><USER23> This might be a stupid question, but if we have the technology to see a blinking light the size of a postage stamp trillions of miles away, why would we need to send a probe with a camera all the way out there in the first place?

<comment><USER24> Because while all we can see is the blinking light, the probe can see the things close to it far more clearly. As the above quote says the probe will "beam back pictures of the star's planets." We can receive these pictures through the data received from that blinking light, but we can't see the planets in question. Now we can.

<comment><USER23> But why would we be unable to see the star's planets if we are able to see a probe that small?

<comment><USER25> You've gotten pretty poor answers so far. I suspect they'd try to communicate in a wavelength where there is little interference. It's one thing to notice "there is a tiny amount of wavelength X light from the vicinity of alpha centauri" and a whole lot harder to notice the difference between two light sources close together at the same wavelength. The latter requires sensitivity to magnitude AND incredible angular precision. It's like seeing a flashlight from a long way off even though you couldn't make out an object that size in daylight. You know the flashlight is on, but you can't resolve it spatially.

<comment><USER26> Would it be an accurate analogy to say this is why stars in the night sky appear the same size (point-like), but vary in brightness?

</comment></comment></comment></comment></comment></comment></comment><comment><USER27> Messrs Milner and Zuckerberg are surely aware that their business is perceived as an occasionally creepy timesink that made them enormously rich while adding little value to society. I'm sure they're not happy about this and would want to change this perception. One way to accomplish this is to pay a team of celebrity scientists for the privilege of associating your names with theirs.

</comment><comment><USER28> This is quite an interesting proposal, although there are some major technological challenges to address:

 _To achieve that energy would require an array about a mile across combining thousands of lasers firing in perfect unison._

</comment><comment><USER29> > Estimating that the project could cost $5 billion to $10 billion, Mr. Milner > is initially investing $100 million for research and development. He said he > was hoping to lure other investors, especially from international sources.

It would be cool if there was one or more endowments for this sort of thing, to perpetuate the mission(s), similar to how schools have endowments.

</comment><comment><USER30> I know we don't currently have the technology for this, but it makes complete sense. Get small things moving really fast instead of big things moving slow.

</comment><comment><USER31> Zuck to fund interstellar travel w/in decades? 2040 Breaking News: Alpha Centauri Rejects Facebook's 'Free' Internet

</comment><comment><USER32> A step towards such a project is to send such probes to every object in the solar system.

</comment><comment><USER33> Say you could accelerate a ~1g camera to 0.2c.

I don't know how to do general (hard) AI, but if I did, I can't think of a fundamental reason I couldn't shrink the AIs down to ~1g and make them able to survive 60,000G. So you could send a bunch of AIs on a 20 year trip to Alpha Centauri.

I would imagine Stephen Hawking has already put two and two together in this way; he often warns that humans should leave Earth to avoid extinction.

Even if we can't colonize other stars with people within this century, AIs could be thriving there within that timeframe. At least our "descendants" (the AIs) would be protected from extinction (by redundancy across stars).

</comment><comment><USER34> A quite similar proposal was discussed on Hacker News two months ago: [https://news.ycombinator.com/item?id=11151497](https://news.ycombinator.com/item?id=11151497)

</comment><comment><USER35> I wonder what plans they have for communicating with a probe light-years away. Consider New Horizons. It has a power budget and antenna gain way beyond something that can be crammed into a few grams. Yet, the bit rate is so low it's still sending back data it gathered in 2015 from an encounter mere light- hours away.

Even if the laser propulsion aspect of this works out, I think communicating with something that far away is fantastically beyond state-of-the-art in wireless communications.

<comment><USER20> "Images of the target planet could be transmitted by a 1Watt laser onboard the nanocraft, in a 'burst mode' which uses the energy storage unit to rapidly draw power for the power-intensive laser communications mode. Upon approach to the target, the sail would be used to focus the laser communication signal.

"For a 4m sail, for example, the diffraction limit spot size on Earth would be on order of 1000m. A kilometer-scale receiving array would intercept 10-14 of the transmitted signal. The main challenge is to use the sail as diffraction limited optics for the laser communication system. This would be achieved by shaping the sail into a 'Fresnel lens' upon approach to the target. The sail structure could be different at the launch and communication phases. In order to maintain a high transmission through the Earth's atmosphere, the communication would need to operate at a wavelength shorter than that used by the launch laser system, due to the Doppler shift of the nanocraft relative to the Earth."

[http://breakthroughinitiatives.org/index.php?controller=Foru...](http://breakthroughinitiatives.org/index.php?controller=Forum&action=viewforum&id=13&page=1)

<comment><USER36>
        "For a 4m sail, for example, the diffraction limit spot size
        on Earth would be on order of 1000m."

That must be a misprint; the diffraction-limited spot size would be on the order of 10 million kilometers. It's correct when it says a 1 km^2 collector would intercept ~10^{-14} of the transmitted signal.

[https://www.google.com/search?q=4+light+years+*+1+micron+%2F...](https://www.google.com/search?q=4+light+years+*+1+micron+%2F+4+meters)

[https://en.wikipedia.org/wiki/Airy_disk#Size](https://en.wikipedia.org/wiki/Airy_disk#Size)

</comment></comment></comment><comment><USER37> I am a self-proclaimed 'newbie' when it comes to understanding energy, astronomy, and physics in general, but I have a few questions and any answers or opinions would be appreciated:

1.) Why in the world does the 'Light / Laser Beamer' need to be physically located on earth? Why not in space?

2.) Is building 'check-points' for both data and power atop the planets not a possibility? (Solar, chemical, etc).

<comment><USER38> As for #1 it's just a matter of logistics. It would actually be a little easier to do from space because you don't have to worry about the effects of the atmosphere, but it would be a pretty massive piece of infrastructure and it's likely that within this time frame it would be vastly simpler and cheaper to build it on earth.

<comment><USER39> For a laser of the proposed magnitude surely a little bit of air isn't going to make a significant difference. From what I can gather the thing would be classified as a WMD and capable of carving a smiley face on Pluto.

<comment> david-given Heat air up enough and it turns into plasma. Plasma's opaque. That's going to do terrible things to your beam focus.

I remember hearing that this is a problem with high-energy laser weaponry, which is why it tends to be pulsed, to give the hot air time to dissipate. But I can't find a reference now.

</comment></comment></comment></comment><comment><USER40> I wonder how they intend for the probe to actually _communicate_ back to earth. Flying by Jupiter... The data downlink feed from New Horizons was about 38 kilobits per second. After the Pluto flyby... it was down to 2 kilobits per second and has been decreasing the further away it gets.

Perhaps it could be done with laser? Having said that, I'd think the beams focus would be quite wide by the time it reaches earth. It would have to be both perfectly formed and aimed with absolute accuracy. (I don't work with lasers and may be off on this, so take this paragraph on principle rather than factual).

Maybe with some form of quantum entanglement? Current forms of usable quantum communication still require mediums like fiber optics as far as I understand. Ex: [http://www.nature.com/news/quantum-communications-leap- out-o...](http://www.nature.com/news/quantum-communications-leap-out-of-the- lab-1.15093)

And how to keep this iphone sized device powered?

<comment><USER41> > Maybe with some form of quantum entanglement?

[https://en.m.wikipedia.org/wiki/No- communication_theorem](https://en.m.wikipedia.org/wiki/No- communication_theorem)

Your other questions are all addressed in an article in The Atlantic: [http://www.theatlantic.com/science/archive/2016/04/yuri- miln...](http://www.theatlantic.com/science/archive/2016/04/yuri-milner- zuckerberg-starshot-interstellar-centauri/477669/?single_page=true)

</comment></comment><comment><USER42> Is it going to just do a fly by or will it somehow enter orbit once it reaches Alpha Centauri? How is it going to transmit data back to earth in a manner that would overcome the signal to noise ratio? Will power be solar or nuclear? How would it know when it is there to begin operating, especially if it uses solar power?

<comment><USER43> Answers to your questions are mostly in the article. Did you read it?

Fly by.

Laser.

Nuclear.

</comment></comment><comment><USER44> Related article at [https://news.ycombinator.com/item?id=11481351](https://news.ycombinator.com/item?id=11481351) (but comments moved here).

</comment><comment><USER42> If this works, it would probably be more useful for probing objects in our solar system. You could send a probe to Jupiter and hear back in ~4 hours. Waiting ~25 years for results from Alpha Centauri would be rather painful in comparison. Getting anything interesting back would be a long shot as the instruments would be rather limited and solar systems tend to be rather large.

I imagine/hope that they would probably do tests in the solar system before trying to send them to Allha Centauri.

</comment><comment><USER45> to me the most intimidating problem is to make sure that the the beam is symmetric and sail is perfectly symmetrical reflecting the beam, otherwise it will go in very different direction than intended. Given the high acceleration during the short time period, i don't see how it can be sufficiently corrected for the beam and sail asymmetries. It is like kicking a soccer ball - you'd like to hit a perfect "9" ("upper 90" in US), yet ...

</comment><comment><USER9> _Moreover, to keep the beam tightly focused on one probe at a time would require an adaptive optics system that compensated for atmospheric turbulence — something astronomers know how to do over a span of 10 meters, the size of a big telescope mirror now, but not over a mile._

Would it be easier just to put the lasers on the moon?

<comment><USER46> It might be easier to fire the lasers from the moon, but getting the lasers to the moon would be a huge pain.

<comment><USER47> Not to mention supplying these hypothetical moon lasers with enough power to blast these mini-probes into another star system.

<comment><USER39> [https://en.wikipedia.org/wiki/Helium-3](https://en.wikipedia.org/wiki/Helium-3) ought to do the trick.

<comment><USER39> I'm a bit surprised at the downvotes. I'm no scientist, but I meant this suggestion in earnest. As far as my layman's knowledge goes, I've always understood the Moon's He-3 reserves to be a "vast, as-yet-untapped power resource".

<comment><USER48> People have to learn how to harvest power from fusion before.

<comment><USER43> You know how they have chemically pumped lasers?

So it would be awesome to directly pump the laser from H3 fusion.

H3 fusion is actually very easy - I think we could do it today. We just don't have a readily available source of H3 for fuel.

<comment><USER49> 3He fusion is easy—you can do it in a garage with some hacked-together equipment.

However, 3He fusion with _net power output_ is _exceptionally_ hard, even with complete disregard to cost. Much harder than deuterium-tritium fusion. We don't know how to do it yet.

<comment><USER43> Thanks for the correction. Seems the rosy predictions I remembered are not accurate.

</comment></comment></comment></comment></comment></comment></comment></comment></comment><comment><USER50> Did this remind anyone of the Polis' spreading and searching the stars in Diaspora (by Greg Egan)

</comment><comment><AUTHOR> How significant are the relativistic effects at 0.2c (the probe speed they are aiming for)?

<comment><USER51> To the probes, wouldn't the 20-year flight 'feel' like 16?

<comment><USER52> Not that much. Time dilation due to speed is sqrt(1 - v^2/c^2). At 0.2c, that's 98%, so 20 years would "feel like" 19.6 years.

<comment><USER53> (I Agree.)

As a rule of thumb, you can approximate sqrt(1 - v^2/c^2) = 1 - 1/2 (v/c)^2. So if v/c = 2, then the correction is approximately 1 - 1/2 .2^2 = 98% as you said. This formula is easier for back of the envelope calculations and the important point is that it's quadratic. (I always forget the 1/2 :(. )

The GP comment used the wrong correction of 1 - v/c, that is not quadratic so the correction is much bigger.

<comment><USER52> Cool trick. It starts to fall apart at higher speeds (at c, the approximation produces 1/2, when it should be 0), but it looks like up to 0.5 or 0.5 it's decent.

<comment><USER53> Yes, this is the first two terms of the Taylor series near 0, so it works only at "low" speed.

For speeds that are close to c, you have to use another "Taylor" series to get a good approximation. If v is close to c, then the approximation of the correction is sqrt(2(c-v)/c). So at 99%c you get 4.5%.

</comment></comment></comment></comment></comment></comment><comment><USER54> Here's my big question: How do you slow down? 4.37 light years does not take into account all the time required to slow the hell down. Am I missing something? Isn't this the biggest fundamental issue with long range space travel?

<comment><USER55> You don't. You get a few hours (tops) to look around at anything interesting in Alpha Centauri before zooming out of the target system and off into really deep space.

Kind of like the New Horizons mission, which never stopped at Pluto. It just flew right on by, but still got a ton of useful scientific data.

</comment></comment><comment><USER56> I'll join the skeptics line with this observation: _even if_ we are able to put this little device near Alpha Centauri, how the heck will we get a signal back from it? Will it have the juice to beam a picture back to Earth?

</comment><comment><USER57> We should send even smaller nano-probes that would be even easier to accelerate and would have the capability to collect dust and build it into larger probes that would talk back to us when they come online!

</comment><comment><USER58> Why do we need thousands of theses things, not just a couple of big ones? There seems to be some concern over the size constraints, but don't really see the advantage of having many of them?

</comment><comment><USER59> Why not go to Proxima Centauri? It's closer!

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

</comment><comment><USER60> The project estimates are completely off. Building a 1gigawatt power plant costs 10billion. Let alone building 100 of them. Also making the laser array. Also you can't have reflection without absorption. Also we don't have solar sails that fit the bill.

This project is barely physically and economically plausible. Its not a question of scaling, or engineering. The physics just don't work.

We have a way to get a space craft to 20% of C. Its called Project Orion. [https://en.wikipedia.org/wiki/Project_Orion_%28nuclear_propu...](https://en.wikipedia.org/wiki/Project_Orion_%28nuclear_propulsion%29)

<comment> gene-h You are putting out 100 gigawatts for 2 minutes. One does not need 100 one gigawatt powerplants, just some way to store and release a lot of energy really fast.

Second, we have mirrors that can reflect up to 99.999% of a single wavelength of light(such as that emitted by a laser)[0]. There is a detailed analysis of the concept in [0] and the Breakthrough Foundation has a detailed list of challenges associated with this project at [1].

Getting the laser out of the atmosphere is probably one of the biggest challenges with this.

[0] [http://www.deepspace.ucsb.edu/wp- content/uploads/2015/04/A-R...](http://www.deepspace.ucsb.edu/wp- content/uploads/2015/04/A-Roadmap-to-Interstellar-Flight-15-u.pdf) [1] [http://breakthroughinitiatives.org/Challenges/3](http://breakthroughinitiatives.org/Challenges/3)

</comment></comment><comment><USER61> Ahem.. why does the object have to be behind the solar sail? Cant it be, one object hanging between two solar sails? Or Three?

Is there something i dont get here?

<comment><USER62> The spot size of the laser will presumably be considerable after 10 light- seconds and we wouldn't want to irradiate the nano satellite.

</comment></comment><comment> rm_-rf_slash Why don't we focus and reflect the sun's rays instead? Or even combine this and the traditional rocket method by putting the emitters in space to catch the sun and push these tiny craft after they've been shot from the Earth by the zillions in a single satellite. That way we deal with two big problems at once: generating laser energy sufficient for escape velocity, and focusing lasers through an atmosphere layer. Better yet, we can use SpaceX's reusable rockets and save even more on launch costs.

<comment> david-given Apparently you can't collimate sunlight because it's not a point source.

But I've been unable to find an explanation as to exactly why which I can understand, because this aspect of optics is deeply unintuitive, but the magic phrase to search for is 'conservation of éntendue'. If you find one, let me know.

<comment><USER63> Have you seen the XKCD What If on this topic? [1] It doesn't get into the details of éntendue, and even makes a joke about the topic's complexity, so it probably won't satisfy your technical demands. But I've found the arguments about reversibility (light paths through lenses are reversible, so how could one point map back to multiple points?) and area increase (lenses do not intensify image values but can change the overall image size) intuitive enough to help quell myself and my friend's arguments about the matter.

[1] - [https://what-if.xkcd.com/145/](https://what-if.xkcd.com/145/)

</comment></comment></comment><comment><USER64> Would they slow down when they reach another star? What kind of observations can you do if you move at that speed?

<comment><USER65> From my poor understanding of GR, there will be no limit on the measurements. You just have to take relative motion into consideration when interpreting them.

<comment><USER64> You move the earth-sun distance in 8 minutes. I am not sure how well you can track with a camera at that speed to get any decent pictures.

<comment><USER65> Doesn't it depend on how far the object is from you and at what speed you're moving relative to it? And they plan on moving at 0.2c, not 1c.

</comment></comment></comment></comment><comment><USER66> So basically project something that we are never going to know or measure whether or not it has succeeded?

<comment><USER67> They describe a plan for sending a signal back.

</comment></comment><comment><USER68> Why not accelerate slower with smaller lasers? What harm in taking 2 days? 2 months? to get to speed.

<comment><USER69> The longer you take the further away it will be and the range of the lasers is only so far. The average speed during acceleration is 0.1c so if you take 2 days it would be 51 billion km away which is out of range.

<comment><USER68> Ok. 10 minutes then.

</comment></comment></comment><comment><USER70> Bah... I think that it's better to make a magnetic luncher on the Moon.

</comment><comment><USER71> Let's build a mass driver around the circumference of the Moon. Like a cannon in a particle accelerator shape.

</comment><comment><USER72> Does that mean that the US will be the winning civilization?

<comment><USER73> "civilization"? You mean like when Ghandi was (allegedly) asked what he thought of Western Civilization, and replied, "I think it would be a good idea!"

<comment><USER74> I think they meant the video game. Space race victory

<comment><USER75> Unlikely. I think these spacecraft won't fare so well against the mind-worms.

</comment></comment></comment></comment><comment><USER76> Mr. Ha

</comment><comment><USER77> I thought very strange things start to happen at even 10% the speed of light (mass increase, etc.) so 20% sounds impossibly ambitious?

Also the fastest physical object we've ever observed is only 1000 miles per second. A far cry from even 10% of c

Then there is that pesky problem of deceleration.

<comment><USER78> At 20% the speed of light, time would dilate by around 2%, but that's about the extent of the effects, afaik.

Also: why bother decelerating at all? Take a picture as you fly by.

<comment><USER79> Have you ever tried to take a picture from a moving car? They never turn out.

<comment><USER80> The sun is 8 light minutes away from earth. These babies would span that distance in 40 minutes. If the plan is to take planetary images I would call that basically crawling speed in terms of angular velocity (unless they are on actual collision course).</comment></comment></comment></comment>


Company threatens to sue volunteers who 3D-printed valves for coronavirus aid - <AUTHOR> https://www.theverge.com/2020/3/17/21184308/coronavirus-italy-medical-company-threatens-sue-3d-print-valves-treatments <comment><USER2> Story is not true. [https://www.theverge.com/2020/3/17/21184308/coronavirus- ital...](https://www.theverge.com/2020/3/17/21184308/coronavirus-italy- medical-3d-print-valves-treatments)

</comment><comment><USER3> $11,000 for a plastic valve. Unreal. No wonder hospitals are always stretched to the limit when they're being gouged like this.

Think of it this way, a hospital could buy 10 valves or hire a physician for a year. Are these valves typically re-used? Are they going through them faster because they don't want to risk infecting other people?

<comment><USER4> It's not $11,000 for a plastic valve. It's $11,000 for a plastic valve and the many thousands of hours of R&D, testing, validation, certification and risk.

<comment><USER3> Let's say the regulatory costs add up to $100,000,000 and the valve has a marginal cost of $1.00 to make and distribute. They would have to sell just 10,000 units to more than offset their investment. I think I'd wager the world needs more than 10,000 air valves.

How can one justify this kind of vicious exploitation of publicly funded healthcare?

<comment><USER4> All three of your numbers are purely hypothetical and are likely out by one or two orders of magnitude.

My point is that people saying that it is overpriced don't understand the input costs of medical devices.

<comment><USER5> "Let's say the regulatory costs add up to $100,000,000 and the valve has a marginal cost of $1.00 to make and distribute."

That's two numbers relating to the cost of production. The second is the cost that a 3D printer doing one off prints actually costs (it's in the article, as a rough estimate.) The first number is a deliberately chosen "insane" example figure to show the absurdity of an $11,000 part. A medical test n license for a single part of a device does not cost anything like $100M.

Now as to the market for these things - the third number. Nearly 8,000 people have died so far. I can't be arsed to extrapolate further but I recall reading that these are single use devices.

</comment></comment></comment></comment></comment><comment><USER6> > A medical device manufacturer has threatened to sue a group of volunteers in > Italy that 3D printed a valve used for life-saving coronavirus treatments. > The valve typically costs about $11,000 from the medical device > manufacturer, but the volunteers were able to print replicas for about $1 > (via Techdirt).

What's the name of the manufacturer?

<comment><USER7> Right. I'm wondering the same. Enough bad pr and this will change quickly.

<comment><USER8> No it won't. What are we gonna do, stop buying from them? We are not their customers to begin with, hospitals' procurement departments are.

<comment><USER6> > No it won't. What are we gonna do, stop buying from them? We are not their > customers to begin with, hospitals' procurement departments are.

You're wrong. We're not living in some capitalist cartoon. Even the greediest CEO doesn't want to be a villain in a lifesaving story like this.

</comment></comment></comment></comment><comment><USER9> Where did this company "threaten" to sue? All I can find is the following source

"Now, despite the country battling an unprecedented health crisis, there is potential for a legal battle with local media reporting that the manufacturers of the valves are refusing to share their blue print for further production and could potentially sue for copyright breaches."

So they may have the _option_ to sue?

<comment><USER10> > However, when the pair asked the manufacturer of the valves for blueprints > they could use to print replicas, the company declined and threatened to sue > for patent infringement, according to Business Insider Italia. Fracassi and > Ramaioli moved ahead anyway by measuring the valves and 3D printing three > different versions of them.

Which links to [https://it.businessinsider.com/coronavirus-manca-la- valvola-...](https://it.businessinsider.com/coronavirus-manca-la-valvola-per- uno-strumento-di-rianimazione-e-noi-la-stampiamo-in-3d-accade-nellospedale-di- chiari-brescia/), in Italian, and I don't understand Italian.

<comment><USER9> Translate to the rescue!

"having received a negative remarry - indeed they also received threats of complaint for patent infringement"

Coming from Massimo Temporelli, so checks out

<comment><USER11> "received a negative remarry"

Wat?

<comment><USER12> I don't speak Italian, but I think the issue is this:

> risposata negativa

"Risposata" _is_ "remarry." Presumably they wanted "risposta," which is "response." Probably just a typo.

<comment><USER13> I speak Italian, can confirm

</comment></comment></comment></comment></comment></comment><comment><USER14> Right on the heels of SoftBank-owned Labrador Diagnostics LLC suing over COVID tests: [https://news.ycombinator.com/item?id=22598988](https://news.ycombinator.com/item?id=22598988)

Which company is suing over the 3D-printed valves? We need to name and shame. If we're unwilling to call out monopolists putting profits over even human life, then we, too, are complicit.

On another note, I'm of the increasingly-strong belief that patent suits should be deemed automatically dismissed if the "infringement" is a response to either an inability or unwillingness of the patent holder to actually use that patent productively (i.e. produce something using that patent). In this case, if the original manufacturer is out of stock, 3D printing replacements should be fair game. Likewise, if we don't have enough testing kits, making and distributing more should be fair game.

</comment><comment><USER15> > we are not going to spread the drawing.

This part seems less than optimally ethical. If it's a choice between helping other hospitals to save lives and to avoid additional legal liability, this seems like a good hill to go bankrupt on.

But...if someone slipped the file to me I wouldn't publish it either. So I can't fault them for being as faulty as me.

<comment><USER13> They said they would print them for free for any hospital that needed them, I assume they would also send the drawings if asked by a hospital

</comment></comment><comment><USER16> At least in the US, I believe so long as you do not sell or transfer items, you can make them for your own use without licensing the patent. To win a law suit, the company would have to "show harm". They can't. They lost exactly zero sales.

<comment><USER17> This is the opposite of true in that US patent law forbids even personal use but most European jurisdictions permit it.

<comment><USER18> Force majeure.

<comment><USER19> ???

<comment><USER13> [https://en.wikipedia.org/wiki/Force_majeure](https://en.wikipedia.org/wiki/Force_majeure)

I think "Necessity" is more applicable [https://en.wikipedia.org/wiki/Necessity_(criminal_law)](https://en.wikipedia.org/wiki/Necessity_\(criminal_law\))

In italian: "Stato di necessità" [https://it.wikipedia.org/wiki/Stato_di_necessit%C3%A0](https://it.wikipedia.org/wiki/Stato_di_necessit%C3%A0)

Rough translation: Cannot punish someone for something if he did it to save himself or others from a grave damage, due to a danger he did not cause voluntarily, and not avoidable in other ways, if the thing done is proportional to the danger

(IANAL)

<comment><USER20> Plus lets be honest (not sure if civil law still has jury trials), NO jury, not even if they imported a single person from several random countries would convict them. Not a single one.

<comment><USER13> Jury trials in Italy are only for the gravest crimes (like some murders)

</comment></comment></comment></comment></comment></comment></comment><comment><USER21> They should hire them instead. Maybe together they can cut production costs so this life saving equipment doesn't have to be sold for $11,000.

<comment><USER10> I'm sure the cost of these valves are not in the production but in the research of coming up with the design to produce and other things before production. So they price in order to recoup already spent money and get some profit on it too. For sure it doesn't cost them 11k to make.

<comment><USER22> Valves are mature technology. The expense to develop it is negligible. The expense to push it through regulatory apparatus might not be.

Most likely it is a trivial variation on an already approved design, varied solely for the purposes of obtaining a new patent, and of getting an exclusive requirement for it to be used on the machine.

There is no defensible reason to presume good faith on the part of a medical equipment manufacturer, even though a few do have it.

<comment><USER10> > There is no defensible reason to presume good faith on the part of a medical > equipment manufacturer, even though a few do have it.

I agree and I also think it's incredibly shitty of a medical company to threaten to sue in these trying times. Really exposes what they are all about. I was just trying to see the coin from the other side, trying to understand.

</comment></comment></comment></comment><comment><USER23> This story has been updated since. [https://www.theverge.com/2020/3/17/21184308/coronavirus- ital...](https://www.theverge.com/2020/3/17/21184308/coronavirus-italy- medical-3d-print-valves-treatments) Basically the company does not plan to sue, and was not selling the part at $10,000.

</comment><comment><USER24> This article feels like low quality clickbait to me. The company isn't even named, and there's no source given for the claim that a lawsuit was threatened.

<comment><USER25> This. There is insufficient details for the level of outrage people are displaying.

</comment></comment><comment><USER26> I call bullshit.

Their is no way this valve cost $11,000. A quick google search for PEEP valves for respirators sow that they sell for a few dollars, 20 at most.

It seems unlikely that any company would sue in such circumstances, it would be a PR nightmare.

If the story was true prices would most likely be listed in euros.

When this 3d printed valves story appeared a few days ago those exact figures were cited on Reddit as a joke.

How they ended up presented as "Facts" on TheVerge is anyone's guess.

</comment><comment><USER27> Having seen the prices charged for drugs and how they then calculate future prices (after the R&D costs have been recovered), I have a very sceptical view of any comments that say we need to consider R&D and regulatory cost recovery before complaining about the prices being charged for anything in the medical technology field. Having also discussed what was seen by someone I know who left the corrupt world of advertising to go to the medical technology world, I also consider anybody saying the same about recovery of R&D and regulatory costs to either being a liar or deluded. The gentleman in question went back to the advertising world because they were innocent children compared to the corruption and price gouging that went on inside the medical technology industries.

There is a captive market here and the seller can sell at any price they want and make any markup they want because they can. There are some very honourable people and companies who do not price gouge in the field. But it seems that these are a very small minority.

Now mind you, this kind of price gouging occurs anywhere there is a captive market. But some industries are more susceptible to it than others.

</comment><comment><USER28> I'm all for letting companies have a limited monopoly on innovations, but this just seems short-sighted. It's the kind of behavior that gets nations to pass something like "medical necessity" legislation allowing them to infringe patents under certain circumstances, or impose profiteering and price gouging statutes, or re-thing all of their health care systems' compensation levels for equipment & procedures. It's the sort of thing that can raise public ire against the entire medical device industry.

</comment><comment><USER29> People are quibbling about money while millions of lives are at stake. We need tens of thousands of these medical devices and we need them fast. Like in the coming weeks.

If companies who suddenly find themselves in a strategic position don't get what they need to do, then the Government needs to take control using emergency powers, and use any available production capacity in the country to ramp up production, fast.

We'll also need to do many other things. We should adopt a wartime mentality, focus on solving the problems at hand, and stop wasting time. At least in Italy they get this now.

</comment><comment><USER30> I'd like to see them try. To sell this kind of critical equipment to Italian hospitals you have to guarantee there will be no shortages even (especially) in critical conditions. They failed to uphold their part of the bargain with the country and at this moment both the government and the people are very short on patience. Probably, if they even try to sue the volunteers they are going to lose all their contracts with Italian hospitals in a matter of days.

</comment><comment><USER31> This linked article actually names "the manufacturer" and the lawyers. Name and shame! [https://www.techdirt.com/articles/20200316/14584244111/softb...](https://www.techdirt.com/articles/20200316/14584244111/softbank- owned-patent-troll-using-monkey-selfie-law-firm-sues-to-block- covid-19-testing-using-theranos-patents.shtml)

<comment><USER32> That appears to be about the troll suing about vaccines, not this situation of an manufacturer suing to stop 3d printing.

</comment></comment><comment><USER33> Printcrime[1,2] by Doctorov becoming reality in one of the most nasty ways imaginable.

[1] [https://craphound.com/overclocked/Cory_Doctorow_- _Overclocke...](https://craphound.com/overclocked/Cory_Doctorow_- _Overclocke..).

[2] E-book download: [https://www.gutenberg.org/ebooks/19000](https://www.gutenberg.org/ebooks/19000)

</comment><comment><USER34> This is adding nothing new over the previous BusinessInsider piece. It's just reporting (again) that this company asserted patent rights after the hospital and the 3D-printing firm requested the design in .STL format due to being unable to secure supplies in an unprecedented emergency. Which is what we knew already.

</comment><comment><USER35> The world needs IP rules like the FCC (USA) has for Amateur Radio.

The rules are basically if lives are in danger, anything goes.

<comment><USER36> Same for the FAA, right?

<comment><USER37> Damn straight. They also already exist by the way. You don't need any license for an ultralight or gyro as I recall.

</comment></comment></comment><comment><USER38> Let them threaten. This is newsworthy when they actually sue. It would also require them to go on the record, with their names and the names of their executives and lawyers on full display. My money would be on that not happening.

</comment><comment><USER19> Circumstances such as this call for mandatory licensing or pooling of patents.

The system itself is broken and should be abolished, as has been long and well argued.

</comment><comment><USER39> At first glance, this reads like the sort of horrible thing only a fictional megalomaniac villain would do, say, in a Bond movie.

</comment><comment><USER40> This crisis is really showing many ridiculous and completely unnecessary conditions in our systems and these will break down.

</comment><comment><USER41> For what it worth the company might loose rights for their patent if it can be proven that it does not perform due diligence (chasing violators being one example).

<comment><USER42> I think you are confused with trademark law.

<comment><USER41> I am not.

"A patent owner (patentee) may be precluded from enforcing its patent against an alleged infringer after a period of time from the first notice identifying the patent and possible infringement (e.g., 4 ½ years) if the following conditions are met:

Misleading Conduct/Silence: The patent owner, through misleading conduct (or silence), leads the alleged infringer to reasonably infer that the patentee does not intend to enforce its patent against the alleged infringer (e.g., by sending a cease-and-desist letter followed by years of silence); Reliance: The alleged infringer relies on that conduct; and Prejudice: The alleged infringer will be materially prejudiced if the patent owner is allowed to proceed with its claim (e.g., alleged infringer has continued selling and expanding product lines). This legal doctrine known as patent equitable estoppel applies on a case-by-case basis to each patent asserted by the patent owner. Therefore, a patent owner may have other patents to enforce which may not be barred by equitable estoppel." \- [http://www.patenttrademarkblog.com/consequences-of- patent-ow...](http://www.patenttrademarkblog.com/consequences-of-patent- owners-delay-or-inactivity-against-infringer/)

Again I am getting downvotes for reporting facts. I guess mob opinion rules.

<comment><USER43> It's still a horrible inhuman thing to do. If the responsible CEO of the company were not a sociopath, he would have

1\. provided the STL files for the plastic valve when the hobbyist 3D printer asked for them

2\. granted a no-cost patent licence.

That way the requirement by law to defend the patent does not arise in the first place.

<comment><USER41> Did I ever say I like the situation? We are literally surrounded bu stupid and sometime outright criminal (in a normal human sense) laws. Civil forfeiture alone - whoever came up with this brilliant idea deserves a jail time. Go call them a-holes. Feels better?</comment></comment></comment></comment></comment>


The people pushing for a decentralized web - <AUTHOR> https://thenewstack.io/the-people-pushing-for-a-decentralized-web/ <comment><USER2> Ward Cunningham is into this kind of thing, and its partly why he semi-retired the original wiki (c2.com) in pursuit of a decentralized wiki. But I don't get his "federated" version.

It's hard enough coordinating centralized content. Forking giant balls of content and creating bunches of parallel versions just makes a messy problem messier. Decentralization won't solve the down-sides of his original wiki. I have various suggestions for dealing with the downsides of that wiki that would take a while to explain, but they include, among other things, easy clone-ability (mass export), and custom "favorites" and "dis-favorites" lists. One could comment on and rank pages/topics/sections on their own server, but otherwise leave the original content centralized. If you like a specific commentator/ranker, you "subscribe" to their particular filter.</comment>