Thursday, March 31, 2016

Lemuel

We hit Proverbs 31 yesterday, and I snagged for a few minutes on "Give strong drink to him who is perishing,
And wine to him whose life is bitter." Every working day I see people on the street whose life is bitter because of wine and who wrecked their world with strong drink. And other drugs. I should add to it?

Lemuel's land didn't have morphine drips, but it did have bone cancer. Obvious, of course. I miss things sometimes.

Wednesday, March 30, 2016

Low bid

UW got the maintenance contract for IceCube for the next 5 years. Rumor has it we were the only bid--that two other groups had asked about how we ran the facility and decided they couldn't make any money on the job--but the NSF won't tell us that. There'll be some belt-tightening, but things should still run OK.

I told her she should have asked to use the cherry-picker truck behind her. The back rows are hard to see.

Percussive maintenance?

Magnet therapy, orgone, monkey glands, theraputic touch, Thync: this time for sure!

Something about DIY brain-zapping seems just a trifle ill-advised. Given the differences in shape of faces and skulls, does the Einstein wanna-be have any notion in exactly which areas of the brain those currents are going to flow? A mm or two here or there for the maximum current density, what difference does... oh. Yes.

I gather that there can be real effects from brain zapping with low currents, so perhaps it isn't entirely fair to compare Thync to orgone. But do-it-yourself?

If it makes a difference, flee. If it doesn't, try a peppermint. It probably won't help, but it'll be more fun.

Monday, March 28, 2016

Escalation

I'm trying to figure out how this works:
It started when Wilkins, a black man, allegedly pushed and choked a 19-year-old white woman, with Wink, a white man, coming to help the woman.

"His assistance actually contributed to escalating matters, with his use of a contemptuous word to describe an African American," said police spokesman Howard Payne.

Officers moved in to break up the fight while Wink allegedly kept yelling "White power", besides other racial epithets.

I suppose technically intervening to stop the woman being choked was an escalation, but throwing around insults seems a relatively mild escalation compared to choking or punching.

I wonder how it actually happened. Reporters aren't always reliable sources, but then neither are police--especially when filtered through a reporter.

Saturday, March 26, 2016

The Fellowship by Philip and Carol Zaleski

We have a poster advertising a Bodleian exhibit of Tolkien's paintings for The Hobbit in our bedroom, a souvenir of my mother in law's trip to England about 30 years ago. It is possible to look at that daily and not think "Did he paint other things too?"

Of course. That's not the focus of The Fellowship, of course: The topic only comes up a few times. But that's one of the little details I'd not known. Like the little detail that Swann proposed an opera based on Perelandra. No, I can't imagine how that would work. Even setting aside the distracting costume problems, how on Earth do you make music for that?

The book ties together the lives of Tolkien, Lewis, Williams, and Barfield before, during, and after the Inkling flourishing (it kept on with different members for years). They were none of them perfect (poor Williams, trying to do magic...) -- very far from it -- but they were dedicated to literature and to writing to catch the imagination.

Barfield is the odd duck here. He had to drop out to spend 30 years in a law firm. As the others died off he came back into a role as a link to the rest and a writer and lecturer. In pre-Internet days I learned of his participation in the Inklings (and the claim that he was the brightest of them all) and figured that if I liked T/L/W so well, I needed to read Barfield. I trotted down the the university library and brought home a book of his and sat down to enjoy -- what in blazes is this?

Anthroposophism was his thing, and evolution of consciousness and challenges to the nature of knowledge and I gave it up as a very bad job after about a chapter and a half. I gather from The Fellowship that Lewis didn't take Anthroposophism seriously and that this wounded Barfield deeply. I fear that I would have been less tactful.

I didn't know how painful writing LOTR was, and it hadn't occurred to me how old they all were by the time the last book came out.

The authors consider some of their contemporary writers to have been better stylists, but ... The local NPR station plays "art songs" sometimes. I've never liked them. Plenty of skill, but something's missing.

You don't need this book to appreciate the Inkling's works. But if you want to know about them this is a good choice.

Aiming

If you haven't read this article about "the replication crisis in psychology", do. It's pretty clear and concise.

A visitor noticed that one ranch fence was riddled with bullet holes, each beautifully dead center in the target. He congratulated the owner on his marksmanship. The owner said "Truth to tell, I shoot first and draw the target second."

Friday, March 25, 2016

Privilege revisted

I don't know if I’m alone in judging the "white privilege" slogan to be incompetent when it isn't dishonest. I think I get what the honest folk are driving at, but as someone said a long time ago, you catch more flies with honey than with vinegar. No doubt it gives the lecturers satisfaction to prod their audiences into feeling guilty, but I believe they'd get more mileage from a different approach.

Suppose I were to address the folks I work with, and try to persuade them that they needed to support special support and outreach campaigns. That would hardly be a gigantic challenge—a large chunk of them are reflexively leftist, though probing suggests this is largely cultural rather than ideological. Some lean a bit libertarian, though.

I think I’d try something along these lines.


Colleagues: You are the 1%! Not in terms of money, of course. Few of us are dripping with extra cash. But in terms of intellect you are all easily in the top 1%. Philosophy, Physics, and Mathematics are the three fields at the University attracting the highest IQ—and in this sort of business, IQ matters. You are at a world-class project at a world-class university: the cream of the cream of the crop.

How did you get to where you are?

There are three factors that gave you your success and position: Heredity, Opportunity, and Virtue.

That last one probably startled you. I’ll explain it in a moment.

First is Heredity. You were born with gifts other people don’t have in anything like the same proportion. Those capacities for mathematics and analysis aren’t the only gifts worth having: I can’t compose music worth beans, for example. But as pretty much any parent of more than one child knows, babies are NOT the same. You and I didn’t earn those talents; we were born with them.

Second is Opportunity. If you were born in the USA or Germany or Sweden or Japan and a few others, you basically won the world’s lottery. You may have to spend a little time in the third world to realize how many opportunities our ancestors provided for us that we take completely for granted. Here you can find books, schools, teachers—many for free for anybody—for just about anything you might want to learn about in the world. There are even opportunities for people with physical or mental handicaps—some of you are too young to know how rare and new that is.

Third is Virtue. Don’t be afraid of the word. Self discipline is a virtue that you must have if you plan to develop any skill at all. You needed some fortitude to get here, and some wisdom in organizing your life to reach your goals. Turning raw talent into ability takes dedication and time, and hope. You had them. But recall this: you had to learn those virtues, and you have to keep practicing them. If you are anything like me, you have quite a way to go in developing them all.

Your position in the 1% comes from 3 factors, only one of which you have any control over.

You can easily find people who weren’t born with equal gifts, or who had the bad luck to grow up near terrible schools, or who have suffered some trauma that made it hard to use opportunities, or whose parents didn’t teach them virtues. Some of them come to college. Now they have the opportunity, though they may have some catching up to do. Nor you nor I nor any university can change their talents.

What ought you do to help them achieve what they are capable of?

There’s an old French phrase: noblesse oblige. You have been given a great deal: talent, opportunity, instruction—what responsibilities do you have to those less well off? I do not ask what claim they have on you—there is no agreed-on basis for any such claim. I ask what responsibilities do you have, to God or to society, to those not as blessed as you?

One answer, especially applicable to academics, is that we have a duty to help instruct others. I don’t mean just as a professor, I mean volunteering in schools and giving clear answers to people in everyday conversation. Many, maybe most, of us do things like that. (I get a lot of Is the multiverse real questions, do you?)

Another answer, that especially relates to college student who come with disadvantages, is that we can offer hope. I listed that among the virtues earlier. I didn’t mean the Christian theological virtue of hope, I mean natural hope, the companion of fortitude. Without hope, who would take advantage of the opportunities presented?

You don’t teach hope in seminars, or with youtube videos and pretty posters. You teach it one on one, just like you teach the rest of the virtues. You get to know someone, and encourage them. That easy, and that hard. Who has time? I have a family to take care of, and a commute, and the daily work. I don’t meet very many students outside our group. I do meet neighbors, and random strangers. So do you.

When I say teach hope, I don’t mean be unrealistic. I once had the unpleasant duty of explaining to an enthusiastic friend that his plan for a new career was not going to work at all, in large part because of personal failings. Look together with your friends for what they can do, and ways to do it.

Noblesse oblige, 1%. What is your duty?


Does that sound more appealing?

UPDATE:

Let me be explicit, and fold injuries into the talent category. Physical or psychological injury may prevent you from actually using your talent. If that's fixable, it probably needs a pro.

Liberian stories

Patrick Burrowes has a collection of Liberian stories, together with comments of his own on the scene. This is from the selection of "Dilemma Tales," tales where the storyteller asks his listeners to figure the ending. In his collection of stories the question at issue seems to involve precedence.
Two rich women who lived in the same town fell in live with a poor man who lived in the forest.
The first woman built him a fine house and garden, and put cattle and goats in the nearby fields, and sent a messenger to bring him in.

The second woman into the forest to find the poor man; she gave him rich food and wine, and brought him back to town.

Which of these two rich women deserved to have the man?

This story, The Deadly Oracle reminds me of Clumsy Hans.

Thursday, March 24, 2016

Aspergers and emotions

I read the NYT review of Switched On the other day, and didn't quite know what to make of it. John Robison underwent "transcranial magnetic stimulation" to see if that would have any effect on his Aspergers. Apparently it did, and the book is a description.

I'd like to know more, and am on the on-hold list at the library. A few questions come to mind after reading the review.

  • What exactly is this supposed to be doing?
  • What exactly became of the other patients and why is he different?
  • Did his newfound emotions map correctly onto what they were supposed to? He said that most people seemed sad to him now--not sure that's an accurate observation.

Anybody know more?

We need reminders

Joe Garagiola died yesterday. My wife (the baseball fan) remembers nothing but good about him as a player or as interviewer: professional and humble. His first book said something to the effect that "Not only was I not the best catcher in the Major Leagues, I wasn't even the best catcher on my street!" (A friend named Berra lived on the same street.)

With the news headlines full of criminals and politicians and pundits, I can forget that we have some decent human beings among us.

Another:

Decades later, the Orthodox theologian Father Thomas Hopko described the impact of that election this way: "One could have gone to Syosset and become a metropolitan, or go to Dallas and become a saint."

During a 1999 visit to Knoxville, Tenn., the lanky Texan folded down onto a kid-sized chair and faced a circle of pre-school and elementary children. With his long white hair and flowing white beard, he resembled an icon of St. Nicholas -- as in St. Nicholas, the monk and 4th century bishop of Myra.

As snacks were served, a child asked if Dmitri liked his donuts plain or with sprinkles. With a straight face, the scholarly archbishop explained that he had theological reasons -- based on centuries of church tradition -- for preferring donuts with icing and sprinkles.

A parent in the back of the room whispered: "Here we go." Some of the children giggled, amused at the sight of the bemused bishop holding up a colorful pastry as if he was performing a ritual.

"In Orthodoxy, there are seasons in which we fast from many of the foods we love," he said. "When we fast, we should fast. But when we feast, we should truly feast and be thankful." Thus, he reasoned, with a smile, that donuts with sprinkles and icing were "more Orthodox" than plain donuts.

We might do well to spend a little more time figuring out what makes people good.

Tuesday, March 22, 2016

Who remembers these?

I remember seeing these from time to time when I was growing up. Sometimes I got them, sometimes I didn't--I was young at the time.

AVI suggested somewhere that The Two Cultures would be useful to read (it's around here somewhere, I think--haven't gotten to it). Everybody knows the gist, though. And yet I wonder--many of the STEM folk I know are pretty widely read. My former supervisor studied Ukrainian on the side (and ran a small farmette and also owned and managed an apartment building in Aspen). We ran into the new manager of IceCube at the opera a couple of months ago. And I remember reading parts of the self-evaluation the University required of its various departments some years ago, and being more favorably impressed with the literary style of the Physics Department's than of the English Department's section.

People don't know what's solid and what's fashion outside their fields. I can't be bothered to read Derrida. Or to try to plow through Joyce's Ulysses--the ROI looks ridiculously low. (The original was fun, though.) Lewis' rule of thumb that old books survived because they were solid seems like a good one, but it leaves you out of touch with the modern fashions of one culture.

On the other side, though in the opposite direction, people who try to keep up with bleeding edge science as misreported in the media don't get a good feel for what's solid in science. (Multiverse anyone? I get questions about it all the time, and give the same answer: Nah, not real.) I wonder if that difference in direction is significant: classic vs current?

I shouldn't give the wrong impression, though: those STEM folks know more movies and anime than seems possible given only 24 hours in a day.

Monday, March 21, 2016

Lead in the ink?

Researchers think some of the charred scrolls from Herculaneum used lead in the ink. With a fine enough beam and good detectors, one might be able to reconstruct the writing on the different layers of the scroll without trying to unwrap it. It would take some doing: the letters are not uniform, they're on curved surfaces, and the scattering from all layers mixes together. But it looks interesting. I'd guess that if they get the go-ahead, it might take another 10 years. I assume they'd have to build a rig that would slowly move the scroll to and fro through the beam--too hard to pan the beam.

The abstract is here: you can't get the article without a subscription.

Technology that distances

If there were a human being on the other end of the phone, I might answer their canned questions, though generally I include plenty of caveats. If it were a human being standing in front of me, I might invite them in for a discussion.

But a robo-call that demands that I punch buttons to shoehorn my judgements for the convenience of their machinery? Forget it.

I've gotten 4 calls in the past 2 days, all wanting to know how I plan to vote. It probably doesn't help my attitude that I've been sick as a dog for the past 4, but I've a long-standing habit of hanging up on robo-calls.

Sunday, March 20, 2016

Cultural appropriation

From Powers of Mind by "Adam Smith":
Ram Dass had become an archetype, a metaphor himself. Kids followed him to India, around India. The Indians were a bit bewildered. "The young Americans," they said, "dance and sing kirtan all day." Kirtan are religious chants and songs. "But they're so young. Don't they know the stages? First you're a student, then you go into a profession or business, then you become a householder, then your household grows up and doesn't need you any more, and then you go do kirtan all day."

A little injection of "Come, follow me?"

Friday, March 18, 2016

This n that

There's been news about a "diphoton resonance" at 750 GeV/c^2 in LHC experiments. The latest news from the Moriond conference is that the signal is still there, though it still doesn't rise to discovery level. What is it? Nobody knows. There are hundreds of theory papers (many appearing within days of the initial announcement) explaining it as this or that, but for now we don't know which, if any, is correct.

One big problem is that we only have one decay mode to work with: into two photons. Pretty much everything proposed expects that the particle (if such it is) will decay much more frequently into other things--but the backgrounds are gigantic. Decay into two photons is rare, but much cleaner. The other "decay modes" will take quite a bit more analysis to tease out, though some modes should be understood by the end of the year.

It is unexpected. It may be nothing very out of the ordinary, but everybody hopes not.


Is dark matter found in ultra-heavy particles, with masses comparable to a human cell nucleus? Answer: they don't know, and we don't have any handy way of testing that.

They suggest some indirect methods based on the Cosmic Microwave Background and what the Universe was doing at a very early era that we don't understand very well.


It looks like the cosmic rays we get on Earth come from quite a wide variety of sources. Most are protons, but some are heavier nuclei. The spectrum of energies shows several kinks in slope, as though one source pooped out and a fainter one took over. Currently we think quite a few come from a nearby supernova--which, among other things, would imply that the energy spectrum was different 20 million years ago.

Thursday, March 17, 2016

Primes

"Lemke Oliver again found that primes seem to avoid being followed by another prime with the same final digit. The primes “really hate to repeat themselves,” Lemke Oliver said." It doesn't matter what base (> 2) you use. In base 3, primes can end in 1 or 2 (not 0--that would mean they were divisible by 3 and therefore not prime). On the average, a prime ending in 1 tends to be followed more often by a prime ending in 2, and vice versa. It isn't a huge effect, but it needed some explanation, and the team found one.

If you want details, this should more than satisfy your curiosity.

AVI discusses a First Things article about curiosity as a temptation. The researchers who found this feature of primes are certainly deeply curious about primes, but this is their life-work, and probably their calling. I would never be more than a dilettante in that field, and more likely merely a curious onlooker.(*)

So how much time can I spend on learning about such things before it becomes a failing?


(*)The last thing I investigated turned out to have been solved more than two centuries ago. I'm a bit behind the times. (I didn't solve it.)

Wednesday, March 16, 2016

Leagues

From The Collapse of the Third Republic by William Shirer:
Middle and upper-class youths, many from the universities or just out of them, formed the phalanx of the various leagues that in January had taken to the streets. The most active and effective of these was the royalist Action Francaise, whose storm troopers were organized as Camelots du Roi. Their spirits roused by the daily dose of inflammatory articles by Charles Maurras, the poet-philosopher of Action Francaise, by Leon Daudet, who possessed the most vituperative pen in Paris, and by Maurice Pujo, leader of the Camelots, in the daily newspaper L’Action Francaise, they staged their first big demonstration on January 9, the day Parliament reconvened after the holidays. They were repulsed by the police before they could get to the Chamber, though on the Place de la Concorde, just across the Seine from the Palais-Bourbon, they were able to haul the Minister of Marine, Albert Sarraut, out of his car and rough him up before he was rescued by the police.

So far our leagues have mostly been from the left (Move On, BLM, various campus groups etc). I’m not sure if there is a classic right wing here anymore—left/right may not be the right classification. AVI noted that the "right," at least so far, tend to hunker down and the left tend to take to the streets. When the "right" starts taking to the streets in the same aggressive way(*), I’ll know to stick a fork in it. But of course it only takes one side to make a fight.


(*)The TEA party demonstrations have, in all instances I’ve heard of, not just been peaceful, but cleaned up after themselves—in stark contract to Occupy.

Thursday, March 10, 2016

Flashback

I got on the bus the other day, and sat down in the back, stretched, and looked around me. Of the five people nearest me, all were reading books. Paper and ink books.

I don't think that's a sign of the apocalypse; maybe the antipocalpyse?

Wednesday, March 09, 2016

Adventures in self-discovery

I decided to try my hand at a generic Facebook political image: one size fits all. After scaling and sliding pictures and text this way and that, I have come to the conclusion that I do not have natural artistic composition skills. Which might explain the snores during PowerPoint talks.

Visiting head of state

The Dalai Lama seems to like Madison, or perhaps Deer Park in Oregon. He comes here fairly regularly, about ten times so far.

I had domestic stuff to deal with and drove in to work late. Parking was special event parking rates--he was at the Overture center (a block from our offices). On the way by, there were 4 huge bus/trucks parked by the center, and on State Street a small crowd of all ages in Tibetan clothes with a Tibetan flag, handing out literature to people who were not wearing dark glasses and a hat and walking briskly.

Above it all a plane circled pulling a banner that read "DALAI LAMA STOP LYING." The news report doesn't say who dunnit, but I'd guess there was Chinese money in the loop somewhere.

I wonder about the big buses with blanked windows. Were they for the Lama and security? If so, I wonder if it seems ironic to him...

Monday, March 07, 2016

Cognitive dissonance

Our betters explain to us that income inequality is a bad thing. Then they sell state lottery tickets.

Sunday, March 06, 2016

Enjoy it while you can

Since we live in an umpteenth generation warfare world, what do autonomous drone aircraft/submarines mean to us in everyday life?

I know of three classes of drone aircraft: slow consumer loitering-capable, slightly faster consumer non-loitering, and high performance military gear. There’s probably plenty in between I don’t know about, and if there isn’t now there will be if somebody sees a need.

I assume jamming will work fine against completely remote-controlled drones, so fixed sites (isolated military bases, etc) can protect themselves pretty well. Not so random civilians.

Obviously drones are handy for assassinations. Top figures (e.g. heads of state) probably get pretty good drone spotting and interdiction coverage, and if not they will soon. Threats to the rest of us could be serious, though. Consider a loitering drone, completely remote controlled, that waits for the police chief to take out the garbage. Or if he’s willing to assume that kind of risk, waiting for one of his kids to appear. Yours truly thinks it reasonable to automatically shoot down drones inside city limits, whether Amazon likes it or not. And yes, city defenses would have to get waivers from the Migratory Birds Treaty Act—you couldn’t help nailing a few.

Most of us aren’t, outside of a civil war, likely to be assassination targets—and during a civil war partisans would probably run out of drones pretty quick and rely on the two-legged varieties.


Consider a military airbase inside the USA or friendly country. When they are far from cities, the approaches are over easily controllable area that can be laced with whatever detection and interdiction hardware they please. Non-existent neighbors won’t care about spectrum jamming or the occasional rocket landing on the roof.

We already have technology for trying to spot and scare off birds. This can be beefed up and given some teeth. Slow drones are being attacked with net guns; I assume automatic shotguns would work too. Higher altitude drones are harder to get at. Using one’s own patrol of interceptor drones might be the solution. Note that this works against autonomous drones as well as remote-controlled. Even so, there would be some non-zero breakthrough rate, and one could always overwhelm the defense somewhere.


Civilian airports, or military/civilian, or military that suburbia has surrounded, are a different problem. They can’t arrange for defense in depth. What could happen to them?

One simple attack is to have drones with explosive payload home in on the biggest radio signals. This could knock out jamming, but could also take out the local radar. Semi-autonomous drones could also damage the radar system, and in those places that still use a traditional control tower, make hash of that also. That makes the facility harder to use.

Hitting an aircraft doesn’t sound terribly easy, but loitering drones could stack up (no, not right over each other) in the descent path and let an aircraft hit them. The closer in to the landing field, the shorter the window the pilot has to hit, and the more likely your two dozen drones are to intersect the aircraft.

You could knock drones down if a fast jet buzzed the flight path, but that’s kind of risky for the buzz-er and leaves the air pretty turbulent for the next plane trying to land—another big risk. Maybe a few helicopters with nets could try to wrangle the drones? The next generation of drone software could include “big slow thing evasion,” which wouldn’t get them out of the way of jets but would with helicopters.

In any event, you can see that landing passenger jets every 90 seconds starts to look hard.

So, how do you deal with this sort of problem? The safe solution is to abandon the fixed investment in the existing airports and move them to the boonies, with fast transport to and from. Airlines would scream bloody murder. (And, as best as I can tell, the military bureaucracies aren’t always very good at hard choices either.) The usual approach (clamping down on sales of whatever technology) isn’t likely to be of much use, but it will be tried.

So, air travel becomes slower and more expensive, and more risky.


OK, how about sea travel? Autonomous loitering drone submarines could be coordinated to attack enemy ships, provided communications weren’t jammed. Suppose communications are proactively jammed. Drones would have to be able to ID their targets, and would tend to act alone, though possibly launching sub-drones (aka torpedoes?) to attack from multiple directions.(*)

Suppose ID isn’t easy, or this is a chunk of the ocean where you don’t care who gets hit. Daesh et al don’t much care who they hit. Then what you create is like a mobile mine—search out anything big and attack it.

Last time I checked, that kind of risk made transport costs soar. Luckily, loitering drone submarines are, and are likely to remain, expensive. Mobile mines could be quite a bit cheaper, but moving through the water takes a lot of energy, and moving on the surface exposes it to detection.

Hmm.


How about trains? If you armored them a bit? A drone with explosive payload can always take out a track, and if it is timed right so the train can't stop you could derail it. (I assume the tracks are instrumented, or will be.) Countermeasure: armor the train and slow it down, and add some drone knock-down flanges on the side (oopsies going through tunnels...).


Yes, of course I am assuming that some of the enemy will have infiltrated, and will not distinguish military from civilian targets. Why would they do things the hard way?

(*)I figure that sea battles will be pretty complicated. Where are the enemy drones, where are yours, how do you coordinate search and destroy, how do you keep your own screen of defenders—all in seawater and bad weather. With both aircraft drones and submarine drones, all partly autonomous. Sort of like fleet battles, but with more moving pieces.

Saturday, March 05, 2016

Ancient Acoustic Architecture

Byzantine church acoustics: "look at the walls and realize that they were looking at things acoustically. It wasn’t just about the architecture. They had these big jugs that were put up there to sip certain frequencies out of the air ... They built diffusion, a way to break up the sound waves by putting striations in the walls. They were actively trying to tune the space.”

Go have a read. I'd never heard of those chambers being used in a church before. I knew amphitheaters had resonators, though.

Connections

David Warren again.
I nevertheless noticed a mistake. This was Blackwell’s assertion that the “technology” used in mass politics is “neutral.”

...

Our “ideas with consequences” — such as civic freedom and autonomy, voluntarism, subsidiarity, personal responsibility, “traditional values,” and ultimately the Love of God — cannot be readily communicated to a mass audience through mass media, because a mass is not a man.

As is often the case, he puts things better than I do. I remember seeing public service announcements a time or three when I was a teen, and thinking--"that's not going to do much good." People laud Facebook as a means of connecting people (and true enough, I hear from people I'd not otherwise hear from), but the connection is so tenuous that people write things they'd not dream of saying in person--there seems to be no governor on the engine.

One mark of a good friendships is that you are a better person because of your association with your friend. Can I be a better person through PostIt-Note friendships?

Friday, March 04, 2016

More black holes

Although IceCube didn't have a clear signal to report that was coincident with the LIGO event, the Fermi gamma ray telescope did, sort of. They weren't pointing at the area at the time, and their resolution isn't so good off-axis. Still, seeing something at that moment and in that direction is very interesting.

The thing is, the LIGO event is supposed to have come from 2 merging black holes. When those giant eggbeaters started swirling round each other, you'd expect them to have splattered the accretion disk all over the kitchen, so to speak. There should have been nothing left around them.

So what caused the flash of gamma rays?

I asked Markus about what happens when black holes merge if one is charged, and he pointed me to an article by someone whose general relativity fu is much better than mine, who had a paper out 4 days after the announcement.

Black holes have mass, spin, and charge--and nothing else. You could think of feeding a black hole a diet of nothing but electrons. The result would be a charged black hole. After you fed it enough electrons you wouldn't be able to stuff any more in--the electrostatic repulsion would be too huge, bigger than the black hole's gravity. That maximum charge is obviously pretty big--I won't bother with numbers.

Zhang's paper points out that if one of the black holes was charged, its rapid orbit would twist up magnetic flux lines, and the merger would cause a pulse of radio waves. If the field was intense enough, you'd get gamma rays. Alas, the charge required is gigantic: about 1/10,000 of the maximum charge.

It is pretty hard to see how anything would accumulate that much charge. Over time, if your star is positively charged it will attract electrons, and if negatively charged will attract protons--and things will even out. (Having two fast black holes might change things a little--if there were enough matter left to work with.)

Must be something else.