Sunday, October 19, 2014

Progress in Fusion Energy

Lockheed engineers recently claimed to have a breakthrough idea for a fusion reactor. Cheap, plentiful fusion power is only 20 years away!

Cynical observers familiar with the long history of fusion power research contained their enthusiasm. 50 years or so ago, when peaceful fusion power had already frustrated the expectations of its devotees for a while, a prescient wit observed that fusion power was fifty years away - and always would be. If that's been updated to twenty years away - with the same qualification - that might be considered progress of a sort.

The possibility of extracting energy from nuclear fusion was first understood in the 1920, and the great astrophysicist Eddington quickly appreciated that such fusion must power the stars. The Wikipedia article cited above notes that the first fusion reactor patent dates to 1948.

Getting hydrogen atoms to fuse to form helium is a multi-step process, but the basic idea is simple: get two protons close together and they can fuse to form deuterium (plus a positron, a neutrino, and a photon). A couple of more steps gets one to helium. The hard part is getting those protons really close together - about 10^-13 cm apart. It's hard because protons carry electrical charge and consequently repel each other.

It's a pretty easy lab experiment though - just accelerate protons to a few tens of thousands of electron volts (or so) and slam them into a proton rich target, and some tiny fraction will fuse in one of the stages of helium formation. Stars manage the feat by getting their internal temperatures up to about 15 million K. At that temperature, an incredibly tiny fraction of their protons will react. Because stars are really big - about 24,000 Earth masses, minimum - it takes a while for the energy released in fusion to leak out, and enough remains behind long enough to keep the temperature up and the reaction going.

Aside from stars, we really only know one way to keep the fusion energy from leaking out too fast to sustain thermonuclear fusion - take a big mass of hydrogen isotopes and drastically compress it to super high temperature with the blast of X-rays from a nuclear bomb. At the super high temperatures and densities achieved, a whole lot of fusion takes place before it has time to blow itself to smithereens.

Neither the gravitational confinement of the star nor the inertial confinement of the thermonuclear bombs can be domesticated on human scale, so other means of confinement must be sought. Such efforts have been failing now for about 2/3 of a century.

Friday, October 17, 2014

Training an Army to Fight ISIS

It will take years, they say.

Let me provide a clue: The US has demonstrated again and again that it is absolutely incompetent to train one side of a civil war. Vietnam, Iraq, Afghanistan. Like all our other proxy armies, they will show up to get they paychecks until they are faced with actual combat, at which point they will flee like mice before a cat.

My guess is that the root problem is that we are selling something that they aren't buying, but it probably doesn't matter.

Monday, October 13, 2014

Lumo Confuses Himself About Probability - Again

Unfortunately I must report that the Blogfather has once again gotten himself dizzy while chasing his tail in yet another futile attempt to make his version of Statistical Mechanics make sense. This time he decides that suitable mutilation of the concept of probability will do the trick:

But what's important to notice is that the meaning of the probability always refers to the situation

a property is unknown/blurred at t=1−ϵ it is well-known/sharp at t=1+ϵ

The two signs simply cannot be interchanged. The very meaning i.e. the right interpretation of the wave function or the phase space probability distribution is in terms of probabilities so the time-reversal-breaking quote above is inevitably understood in every and any discussion about probability distributions and wave functions.

He is trying to tell us that probability only applies to prediction of the future - though the stuff about wave functions and quantum mechanics is thrown in mostly for obfuscation. Oddly enough, he forgets one of the more familiar roles of probability in particle physics - his subdiscipline - is in retrodiction. Suppose one is measuring the cross section for a particular type of event as a function of energy and one notices more events at one energy than the rest. The question one then wants to answer is what is the probability that the current state resulted from the various possible or imaginable states in the past - is the bump in your curve a fluctuation or does it indicate resonance producing a real change in cross section.

Probability is a more versatile concept than is imagined in the Lumonator's world. We use it in a for more time symmetric fashion than he imagines. Of course all these ideas, including the unitary evolution of the quantum state, have been discussed by more subtle minds than mine or Lumos. He really ought to read some of them.

Zombies and Vampires

Zombies and Vampires are a major infestation in television and even movies. How should we explain the popularity of this sort of ancient pagan mythology in a supposedly scientific age? Aside from being cheap to film, these tribal dramas must tap into our primal psychology somehow.

The zombie and the vampire are typically contagious and evil. A suggestion that caught my eye is that the zombies metaphorically represent the poor and the vampires the rich. Each threaten, prey upon, and lust after the human - representing perhaps the middle class. In an age when middle class membership is increasingly fragile, with status heavily dependent upon circumstances seemingly beyond individual control, with poverty an illness or layoff (zombie bite) away, many may crave the vampire bite (lottery ticket?) that offers a way out.

Thursday, October 09, 2014

Entering and Leaving - Hong Kong Style

Tyler Cowen looks at elevator and subway leaving protocol in Hong Kong and makes just the kind of (IMHO) spectacularly dumb Libertarian/Coasean analysis I would expect:

I’ve noticed in Hong Kong that exiters are not accorded absolute priority. That is, those entering the elevator can push their way through before the leavers have left, without being considered impolite, unlike in the United States. In part, Hong Kongers are in a hurry, but that does not itself explain the difference in customs. After all, exiters are in a hurry too, so why take away their priority rights? Perhaps we should look again to Coase. If some people who wish to enter are in a truly big hurry, they can barge forward. Furthermore, an exiter who is not in a hurry at all can hold back, knowing that someone will rush to fill the void, rather than ending up in the equilibrium of excessive politeness where each defers to the other and all movements are delayed. That is not an equilibrium you see often in downtown Hong Kong.

There is another positive effect from the Hong Kong method. If you will be exiting the elevator, you have to step forward early on and be ready to leave promptly, to avoid being swamped by the new entrants. That means the process of exit takes place more quickly. And so the entrants who are in a hurry actually do get on their way earlier than would otherwise have been the case.

#smallstepstowardamuchbetterworld

- See more at: http://marginalrevolution.com/marginalrevolution/2014/10/should-everyone-leave-the-elevator-subway-car-before-others-try-to-enter.html#sthash.QqnJUbJE.dpuf

Nonsense, I say. The trouble with competitive exiting is turbulence - everybody is slowed down when the fluid particles, er people, try to push past each other. The point of competitive exiting has nothing to do with efficiency and everything to do with helpless pawns in the economy expressing their frustrations by pushing other people around. I think of it as degeneracy pressure, human style.

Wednesday, October 08, 2014

Tribal Shibolleths

Astrophysics is encrusted with odd conventions that serve as a monument to history, tradition, and the history of measurement technologies. The magnitude system, for example, is, as one of my Astronomy professors put it, "so irrational that it serves just to keep the physicists out." Of course there is the matter of a couple thousand years of history plus more modern questions of measurement that keep it in place. A related notion is measurement of distances in parsecs (and kiloparsecs and megaparsecs) rather than the much more rational (and covariant minded) light years or even meters. Add to that a vast amount of idiosyncratic notation and convention as well as plenty of necessary purely descriptive knowledge and the physicist wonders if he is dealing with physics or stamp collection, in Rutherford's metaphor. The answer, of course, is both.

Astronomy has been and remains more of an observational than experimental science.

One of the more peculiar traditions of astronomy is referring to all elements but hydrogen and helium as "metals". I have no idea where that came from. Any ideas?

Monday, October 06, 2014

Presidential Liars

All presidents, I suspect, need to do a little lying. It's part of the politicians job description. Richard Nixon and Bill Clinton famously came acropper on some of their more outrageous lies. Of course telling a lot of lies doesn't necessarily make one a good liar. Nixon had a way of looking like he was lying even when he accidentally told the truth. Clinton's lawyerly evasions were a give away.

In the lying department, no President in my memory could touch Ronald Reagan. His twin strengths were the degree to which he was unconstrained by logic or consistency and his apparent ability to believe utterly in his own mythology.

As his daughter (Patti Davis) wrote:

...this “the most aggravating aspect of discussing anything with my father. He has this ability to make statements that are so far outside the parameters of logic that they leave you speechless.”

Perlstein, Rick (2014-08-05). The Invisible Bridge: The Fall of Nixon and the Rise of Reagan (Kindle Locations 10954-10956). Simon & Schuster. Kindle Edition.

Secret Police

The revelations of the 70's about the lawlessness and incompetence of our somewhat ironically named "intelligence" agencies never seemed to lead to any fixing of the blame - deniability, plausible and implausible being one of the few things they consistently managed.

And so, for those few scattered Americans seriously following the intelligence investigations, a fundamental and fundamentally disturbing question lingered: Were our presidents lawless and wicked? Or just bumbling nobodies, Gerald Fords, every last one of them— dumb, ignorant pawns of secret police agencies? To ask the question was to stare into an abyss. So Senator Church papered over the abyss.

Perlstein, Rick (2014-08-05). The Invisible Bridge: The Fall of Nixon and the Rise of Reagan (Kindle Locations 10810-10813). Simon & Schuster. Kindle Edition.

Philosophy and Physics

Sean Carroll scored some kind of a gig at a conference on the philosophy of cosmology in the Canary Islands, and writes about it here. Cosmology and cosmogony are among the oldest questions addressed by philosophy but that doesn't mean that philosophy has anything useful to say to the recently created science of cosmology. Sean comes up with ten questions for this new discipline, but I'm not too impressed. I doubt that the guy whose desk Sean got would be either.

Some of the questions probably have answers that physics may be able to answer, e.g.,

1. In what sense, if any, is the universe fine-tuned? ...

2. How is the arrow of time related to the special state of the early universe?

Others strike me as meaningless or content free - and perhaps thereby suitable subjects for academic philosophy.

The Lumonator takes a swing at question 2., thereby revealing yet again his peculiar incomprehension of statistical mechanics.

After Watergate

...Americans tired of scandal and muckraking. Perhaps even more importantly, so did the establishment press. The Washington Post and The New York Times adopted policies of studied indifference or overt hostility towards the Congressional committees that revealed layer after layer of CIA and NSA lawbreaking and incompetence.

Glamorous, globe-trotting Henry Kissinger had weathered his own Watergate storm— for bugging reporters and his own staffers— and remained the punditocracy’s beau ideal. He was fresh from his latest triumph in “shuttle diplomacy,” securing a preliminary peace framework between Israel and Egypt, when the indefatigable Otis Pike had the temerity to demand from him a memo by a State Department staffer named Thomas Boyatt that had apparently criticized the CIA’s poor intelligence regarding the crisis in Cyprus, where the U.S. ambassador, Rodger Paul Davies, had been machine-gunned to death the previous August. The Pike Committee’s chief counsel soon received a thundering phone call from the Times’ James Reston: “What the hell are you guys doing down there? Are you reviving McCarthyism?”

This, it turned out, was the administration’s public relations line— Pike was running a “McCarthyite inquisition,” as State Department official Lawrence Eagleburger said in his testimony before the committee. An editorial called “Pike’s Pique” noted that by calling “junior staff officers to testify under oath about what recommendations they made to the policy officials,” the congressman was reintroducing the practices that “almost wrecked the U.S. Foreign Service during the McCarthy period.” Then, since Kissinger forbade such junior staffers to testify, the Church Committee voted to subpoena Kissinger himself— and the Times’ editorialists called that “neo-McCarthyism,” too. Kissinger decided to testify before the Pike Committee the day after General Allen of the NSA, on October 30, though on his own terms: he summarized what he said was the thrust of Boyatt memo, still withholding the actual document from evidence— just the sort of Stennis-style compromise that, when Richard Nixon had proposed it during the crisis of October 1973, had sent tout Washington up in arms.

Perlstein, Rick (2014-08-05). The Invisible Bridge: The Fall of Nixon and the Rise of Reagan (Kindle Locations 10529-10543). Simon & Schuster. Kindle Edition.

Sunday, October 05, 2014

Spying On Americans

Many have been disturbed - rightly, I think - by the revelation of the immense amount of spying on Americans by the NSA and other agencies. I don't care for it either, but we should not lose track of the fact that this is nothing new. The hearings of the 1970's on the CIA conducted by Frank Church's Senate committee and Bella Abzug's House Committee had revealed that the NSA had already been monitoring the phone and telegraphic traffic of Americans for forty years.

It had also, Abzug revealed, been monitoring both the phone calls and the telegrams of American citizens for decades. President Ford had persuaded Church not to hold hearings on the matter. Abzug proceeded on her own. At first, when she subpoenaed the private-sector executives responsible for going along with the programs, the White House tried to prevent their testimony by claiming that each participating private company was “an agent of the United States.” When they did appear, they admitted their companies had voluntarily been turning over records and cables to the government at the end of every single day for more than forty years. The NSA said the programs had been discontinued. Abzug claimed they still survived, but under different names.

Perlstein, Rick (2014-08-05). The Invisible Bridge: The Fall of Nixon and the Rise of Reagan (Kindle Locations 10481-10486). Simon & Schuster. Kindle Edition.

Little has changed but the technology. Go ahead, be indignant, and protest to Congress - but don't imagine that this was the creation of Obama, or Bush. Neither was born when this started.

Saturday, October 04, 2014

(Slightly) Tall, Smart, and Charming

Thanks to Swedish military conscription tests that measure every eighteen year-old male's height, cognitive ability, and non-cognitive ability, Sweden has a great resource for tracking the correlation of these test scores with later life outcomes. Steve Hsu looks at a study which which does the math for corporate CEO's. It turns out that they are just a bit above average in each category (0.5, 1.0, and 1.5 SD respectively).

Evidently, if you want to be a CEO, it might help to be a couple of inches taller than average, have an IQ of about 115, and a NCQ of around 122.5.

About that Non Cognitive Ability (Steve's quote):

[Non-cognitive ability:] Psychologists use test results and family characteristics in combination with one-on-one semi-structured interviews to assess conscripts’ psychological fitness for the military. Psychologists evaluate each conscript’s social maturity, intensity, psychological energy, and emotional stability and assign a final aptitude score following the stanine scale. Conscripts obtain a higher score in the interview when they demonstrate that they have the willingness to assume responsibility, are independent, have an outgoing character, demonstrate persistence and emotional stability, and display initiative. Importantly, a strong desire for doing military service is not considered a positive attribute for military aptitude (and may even lead to a negative assessment), which means that the aptitude score can be considered a more general measure of non-cognitive ability.

HTH you more than it did me.