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Yonatan Zunger
Distinguished Engineer on Privacy at Google
Distinguished Engineer on Privacy at Google

Yonatan's posts

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The art of Kremlinology, North Korean edition: this article is a fascinating in-depth dive into how much information experienced analysts can pull out of a single propaganda picture. This shot of Kim Jong-Un announcing an improved North Korean nuclear weapon leaks important information about bomb power, missile range, the way the program is being run, and Kim's political strategy for the near future. Key clues include the diameter of the bomb, the coat Kim is wearing, the clothes the people around him are wearing, and the positioning of the white markings on the missile hull.

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I've been noting for a while that "scaling up deportations" requires giving people in the field more unreviewable authority to declare someone un-American -- without that troublesome burden of "courts."

And indeed, here's a dive into how this is being implemented, with officers deep in the bowels of DHS given authority to order "expedited removals" of a much wider class of people. With the anticipated change in the rules for asylum screenings, and the fact that once you have been removed, it's far more difficult to retroactively challenge the order, this turns into an effective mechanism for threatening anyone who "looks foreign" with summary deportation.

NB that the accompanying plan to deport everyone to Mexico, regardless of their country of origin, is another logistical optimization: if you had to figure out someone's country of origin, you'd start needing process, and might have to call into question whether they should be deported at all.

(My earlier article on the subject:

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Let's say you need to build a defense system against small drones, which might be armed with anything from cameras to bombs. You need something which can identify targets, tell friend from foe, disable them in-flight, and do so without endangering people on the ground -- crucial if (for example) a drone attack were made on a crowded urban area. The perfect system would be able to fly up to the drone, grab it, and safely land it.

A nearly perfect system for this already exists, and has for millions of years: Aquila chrysaetos, the golden eagle. And now the French Air Force is training them to hunt and kill drones.

h/t +A.V. Flox

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Something which may be of interest to various security- and open-source minded folks: we just open-sourced a distributed, secure file-sharing system. Full technical details at .

(I know most of its authors, and they're very, very, good at what they do)

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This essay is full of so many interesting thoughts and important points that it's hard to summarize. Just read it; it's worth your while. 
The best article that has, or even could be written on the fall of Milo, & the psychology of his Lost Boys of the alt-right. A truly delicious piece of writing:
Whatever anyone claims, it’s hard to shake off being run out of town by 3,000 people screaming that you’re a Nazi. It’s the sort of thing that gives everyone but the coldest sociopath at least a little pause, and most of this crew don’t have the gumption or street smarts to function outside of a Reddit forum. They’re not the flint-eyed skinheads that many anti-fascists are used to fighting. I’m not a brawler, but I’d wager that these kids could be knocked down with a well-aimed stack of explanatory pamphlets, thus resolving decades of debate about whether it’s better to punch or to reason with racists.
+Yonatan Zunger

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Good news: California is almost entirely out of a drought that was the worst in centuries!

Bad news: ... Because all of the rain that didn't fall for the past however many years has been falling. At once.

Welcome to the American West, where we have two kinds of precipitation: droughts and floods.

h/t +blanche nonken

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Something amazing: we have not only the first detection of Earth-sized planets outside our Solar System, but a detection of seven planets around a single star only 40 light-years away - right next door by astronomical standards. These planets orbit a dim dwarf star named Trappist-1 (after the telescope which discovered it, the Transiting Planets and Planetesimals Small Telescope in Chile), and by happy chance, are angled in a good way for us to study them. Even better, at least one of them is in the star's "Goldilocks Zone" - at the right sort of temperature to support things like liquid water and an atmosphere.

The paper itself won't be out until Wednesday, but you can get preliminary data about the system here: . (This includes coordinates, but you'll need a strong telescope to see it; this dim star in Aquarius has an apparent magnitude of 18.80, about as bright in the sky as the dwarf planet Eris)

The system is unusual in that three of the planets may support life: Trappist-1d, e, and f. Even more interestingly, the three are similar enough that someone from one planet could potentially survive on the others. All three have roughly terrestrial gravity -- maybe 0.7g's on d and e, and 0.6g's on f. They are of similar sizes, having surface areas 60, 80, and 110% of Earth's, respectively.

Trappist-1d is the most Earthlike: the average temperature is 288K (15C, 59F), the same as on Earth. If you looked up in the sky there with human eyes, you would see a salmon-colored star, about five and a half times the apparent diameter of our own Sun, but somewhat dimmer; at noon, it would be about 15% brighter than it is on Earth. Of course, eyes which evolved on Trappist-1d wouldn't be tuned to the yellow light of our own Sun; they would be much more likely to see light much further into the infrared and less into the blues, and the light would look a "neutral white" to local eyes, just like our own Sun does to us.

If anything has evolved to photosynthesize in the Trappist-1 system, its analogue of chlorophyll would be principally absorbing in the far infra-red, and the local plants would look dark and reddish to our eyes; the oranges and yellows that make up so much of our own vision would be as exotic to Trappists as the ultraviolet which bees see is to us.

But daily life there would be somewhat more different, because in such tight orbits (close in around a small star, with a "year" of four days on Trappist-1d), the planets would be tidally locked to the Sun, with one side always facing it, much like the Moon always faces one side to the Earth. This means that this Earthlike temperature would be the daily temperature nearly every day on the sunny side, at the equator, and it would get steadily colder as you went out to the dark side -- but how much colder depends tremendously on how thick an atmosphere the planet has. It could be anything from hundreds of degrees below zero, the temperature of exposed space, if the planet has no atmosphere, all the way up to inhabitable but chilly temperatures if the atmosphere is thick. (Further investigation will tell us more about this, since as the planet passes in front of its star, we can see which colors of light are absorbed and how much by its atmosphere)

Weather patterns on tidally locked planets are unusual; if you want a sense of it, you can consider this paper ( about what tidal locking would do to it. This may well cause the climate to be so unstable that the planet could never evolve life; we'll have to do more science to figure that out.

The two further-out planets are a bit less hospitable; Trappist-1e averages 251K (21C, -8F), roughly the weather of winter in Fairbanks, and 1f averages a chilly 219K (-54C, -65F), the sort of weather you associate with central Antarctica.

This means that 1dians, if they developed short-range space travel, would be able to travel to these places, but absent some really good reason, they would be more likely to be the home of isolated outposts than major settlements. (Given the small size of this system - planets closely packed around a tiny star -- this is far easier to reach than Mars is for us; at closest approach, 1d and 1e are less than three times as far apart as the Earth is from the Moon. During this peak, 1e would be huge in 1d's sky, about 20% bigger than the full Moon is in our own. But you would never see this from the light side; at closest approach, 1e is "behind" 1d, with the full 1e visible only at the center of the dark side. The inhabitants of the light side of 1d would see it only through half-phase, before it sank below the horizon.)

There are far more calculations like this we could do (especially since we apparently have information about their relative orbital periods, which would let us chart the skies there in somewhat more detail) but I have actual work to do...

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And I can't quite believe this, but there's yet another positive story to share today. This is about a paper that came out recently on particle physics. Like an awful lot of papers in particle physics, it proposes an extension to the Standard Model (our best current understanding of the field, which has done remarkably well in predicting an awful lot of things) which can explain a lot of currently open questions about the universe.

However, this paper has some nice features which most papers of this sort don't. There's a sort-of tradition in particle physics (which I'm embarrassed to admit I've participated in) of publishing "pissing on trees" papers: you come up with some theory, show that it's not inconsistent with what we've observed so far about the universe (and it turns out there are an awful lot of things you can do which aren't inconsistent, even once you take the full scientific rigor of professional physicists into account), and publish it as "maybe." This is called "pissing on trees" because if it turns out later that this theory was right, then you've published one of the original papers on it, and a great deal of credit will follow; that is, you're staking out your claim ahead of time, but not really producing anything that valuable, because most of these "maybes" are pretty far-out.

This "SMASH" paper (short for "Standard Model + Axion + Seesaw + Higgs," a short description of the three kinds of extension to the SM it provides) does considerably better, though. With a fairly minimal extension to existing physics (proposing three new families of particle, each of which is considered not-outrageous) they manage to explain a bunch of difficult open problems in physics at once. And rather nicely, the SMASH hypothesis is straightforwardly testable – to the extent that several planned experiments already in the works should be able to say a definitive "yes" or "no" to it within the next decade.

I won't try to give a full explanation of the things it explains, since this gets really technical really fast. The short list is inflation (what force caused the universe to expand really rapidly in its early history, so that its current size is "really big" rather than "about the size of a grapefruit"), reheating (how inflation stops and that energy of expansion somehow gets converted into matter instead of a big, empty universe), dark matter (what is this mysterious substance which appears to form a quarter of the mass of the universe, yet be transparent to light?), baryogenesis (in particular, why is there so much more matter than antimatter in the universe? It's handy for the "not going boom all the time" business, but it's far from obvious why it should be true), and stability (why at daily-life energy scales, certain high-energy properties of physics don't cause Higgs bosons to suddenly become infinitely heavy and attractive or similar weird things which many theories fall victim to).

There are plenty of theories which explain these individually, but SMASH is nice in giving systematic answers to all of them – which makes me far more interested in it than in most papers of this sort.

Of course, it'll take a lot of experiment to see if this goes anywhere, but for once, we actually have an existing experimental roadmap which will answer that. :)

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Even more promising news for the day: Trump has somehow convinced LGEN McMaster to take on the role of National Security Advisor. As the article below goes into, McMaster has a reputation for being a competent, intelligent grown-up. He is also bald, white, tall, and muscular, which means that he looks enough like Trump's idea of a military / intelligence leader that Trump may actually listen to him.

Given that it's been made clear that the NSA will not have full authority over staffing at the NSC, and eg does not have the power to kick Bannon off his council, it's been expected that it would be very hard to hire anyone good for this role - the first candidate mooted, Harward (also known as as a grown-up) basically said Hell No. But apparently McMaster will take that risk. So best of luck to him, and hopefully he'll manage to achieve something useful!

(The NSA is the President's chief advisor on natsec issues, and chairs NSC meetings which the President doesn't attend. This has nothing to do with the other NSA, the National Security Agency, which is the agency that does signals intelligence and crypto and the like.) 

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And in yet more amusing news for the day, apparently there is still one line in polite society that you can get in trouble for crossing. Milo Minderbinder Yiannoupolos' defense of pedophilia (how "inter-generational relationships" are often crucial to the development of young people, especially among gay men, and it just goes on from there into a sort of NAMBLA manifesto) has gotten him disinvited from CPAC and his book deal cancelled.

Twitter is currently a mass of people saying "I was fine with him before, but this is too much!," of people replying on the lines of "wait, you were fine with the doxxing of trans students, and the abuse campaigns against game developers, and all the racist and violent speech, but this you're not OK with?," and a lot of other people (myself included) just shaking our heads and saying "OK, apparently this is what it takes for people to notice that he is not a nice guy."

But let's not dwell on that! Let's instead enjoy a seasonally appropriate recipe from +John Scalzi​. Mmm, Schadenfreude Pie...
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