Blogs / Cosmic Variance

The Institute for Complex Adaptive Matter has released a new online museum, The Emergent Universe. This is, I think a truly novel approach to communicating the central ideas of the new field of emergent phenomena and complexity, combining the underlying physical basis of a wide array of examples with art and music. The site itself presents an animated, non-directed interface to branching sets of topics and what I guess one would call exhibits (since it’s a museum after all). A lot of these are quite fun, and instructive. A visitor is left with the feeling that there is lots more to explore. The interface itself, I have to say, is very cool and a glimpse of what is to come on the internet. Today’s text- and photo-heavy web pages are bound to give way to sleek sophisticated designs like this one…

Have fun!

What do you call snail locomotion?

(Walking is obviously not right. Slithering is closer. Sliming?)

I enjoy teaching.

But I really hate blackboards.

I’m not sure what the results of Chad’s latest poll will be, but I’m betting that I’m in the minority of scientists. The scientific community contains many former social outcasts who grew up flaunting the social rules, and yet have completely bought into the idea that using blackboards makes you look like a Real Scientist.

Well screw that. Students in the back can’t see what you write. You get dust all over your clothes. The chalk dries out your finger tips. The dust gets all over the floor, making a mess for your overburdened cleaning staff. For a community that prides itself on moving forward, why are we stuck with a 200+ year old technology that doesn’t work all that well?

Now, white boards have their problems too. They’re easier to see, but the markers are always dried out (and expensive to replace as well). They also are somewhat dusty (though not nearly as bad as chalk). Progress, but not perfect.

The solution, however, currently lies in your toddler’s grasp.

The Magna Doodle.

The Magna Doodle works by having small chambers filled with a thick liquid and magnetic filings. You drag a magnetic pen across the surface, and the metal filings jump to the surface, making the small chamber dark. To erase, you pull a lever that drags a magnet along the back surface, pulling the metal filings away from the front, making the chamber appear white again. No mess, no fuss, no need to replace any parts

It also is substantially easier to write on than the Etch-a-sketch. At least for most of us.

The Laffer Curve is a simple idea: a government can’t raise taxes forever and expect to increase revenue along the way. Eventually you’re taking so much in taxes that people don’t have any reason to earn income. The argument is simple (and correct): if you have zero tax rate you get zero tax revenue. If you raise taxes just a bit, nobody will be discouraged from working, and you will collect some amount of revenue; therefore, the curve of revenue versus tax rate starts at zero and initially rises. But if the tax rate is 100%, nobody has any reason to work, and your total revenues will be back at zero. By the wonders of math, there must therefore be a maximum of the curve somewhere in between 0% and 100% tax rate.

An important question is, where are we on the curve? The notion of the Laffer curve has been used to justify all sorts of tax cuts, under the assumption/claim that we are to the right of the maximum, so that cutting taxes will actually increase revenues. Serious economists generally don’t believe this holds true in the U.S. right now, but the lure of the idea is undeniable: lose weight by eating more ice cream!

Via Marginal Revolution, here’s a study by Mathias Trabandt and Harald Uhlig that tries to get it right. Obviously they have models that make various assumptions, and I have no idea how realistic those assumptions are. They study the U.S. and several European countries, and find that Denmark and Sweden are just a bit on the wrong side of the curve for the specific case of capital income taxation. For the most part, however, tax rates lie to the left of the maximum. In the U.S., especially, we are significantly on the left. Here is the graph for labor taxes:

The vertical line is our average tax rate; the curves represent different model assumptions. They estimate the U.S. could increase revenues by about 36% by raising taxes. That obviously doesn’t necessarily imply that we should — but we could.

Okay, it’s time to come clean – I am a ham. That is, I am an FCC-licensed amateur radio operator, call sign KI6GDQ. I got into it a few years ago because my wife’s parents and sister and brother in law are hams, and we all go camping in northern California every summer. Obviously a little hand held ham transceiver is not a bad way to communicate when there’s no cell phone coverage, though the range is limited to a few miles in the mountains up there.

And, living here in California, which a friend of mine notes is a beautiful land with a decidedly savage side, it’s not bad to have a means of communication that doesn’t depend on the grid, be it the electric grid or the Internet/phone grid. My in-laws live in Pacifica, south of San Francisco, which is hemmed in on all sides: the ocean to the west, mountains to the north and south, and the San Andreas fault to the east. A big earthquake could easily isolate them from the rest of the peninsula. So my father in law (N6FG) helps run a 2-meter repeater on a nearby mountaintop; he and and my mother-in-law (K6IIP) participate in local emergency response groups.

A friend of mine joked that amateur radio is the original social networking tool. (Well, unless you count the postal service.) Early in the last century, when radio was young, the advent of high-power vacuum tubes made it possible for amateurs to build transmitters that allowed them to talk to other hams all over the country, and around the world, ionospheric conditions permitting. At night, when the lower layers generated by solar radiation dissipate, a vast electromagnetic mirror called the F layer forms several hundred miles up. Signals from the surface can bounce off this mirror essentially all the way around the planet. Hard-core DXers still go to great lengths with antennas and legal-limit (1500 watt) transmitters to make contacts with Morse code. (And then there are the truly crazy ones who go on expeditions to remote islands off Antarctica solely for the purpose of making nearly 100,000 ham radio contacts all over the world.)

(more…)

Flip through a random magazine, and you are likely to be confronted by one of the great mysteries of modern times: an ad for a mechanical watch. For the past 30 years it has been possible to acquire a watch with a quartz movement for a minimal investment. These watches are small and light, and do an extraordinary job of keeping time (i.e, drifting by roughly one minute a year). Nonetheless, there is a flourishing market for watches with mechanical movements. These watches are generally large and heavy, are significantly more expensive, and most importantly, are far inferior as time pieces: easily a factor of ten worse than their quartz counterparts. How could there still exist a market for these obviously inferior watches? The answer lies somewhere in the unfathomable realm of fashion and marketing.

Last week’s New Yorker has an article [pay per view] by Patricia Marx about Baselworld 2009, the annual watch fair. Although I find the article annoyingly cutesy, it has some interesting tidbits. I guess there’s little reason to buy these watches besides the ineffable associations with the brand. So watchmakers go to extraordinary lengths to craft and define their brands:

Among the countless blowouts at Baselword, Breitling’s is considered to be the most lavish. A few years back, guests were taken in buses to a quarry that had been transformed into a mythical Persian landscape, appointed with sandpits and palm trees. Camels and white stallions roamed the premises, as did chickens. Guests were given flowing robes and head scarves to wear, and sat on cushions, where they were entertained by belly dancers while being served a Middle Eastern banquet and forbidden hooch. Hookahs were passed around. “Just when you thought it was over,” Roberta Naas, a watch-industry writer, told me, “one of the walls disappeared, revealing Siberian tigers and tiger tamers in cages.” After the animal act, the cages vanished in a puff of smoke, and, lo, another wall lifted and the pseudo oasis turned into a pseudo disco. Another year, at what the Breitling people call their “terrorist party,” the buses were pulled over at an abandoned warehouse by men in full military garb with machine guns, who subjected the passengers to interrogations. Afterward, there was dinner and dancing.

This was all in the middle of Switzerland. For a Swiss watch company. To what end exactly? You obviously can’t sell your watches on the basis of their time-keeping ability, so you craft a completely arbitrary image. And, amazingly, it actually works. Fortunes are being made selling bulky, antiquated, unreliable time pieces. The last paragraph of the article pays homage to the fact that time belongs to physicists:

It turns out that memories may be a thing of the future, if as some physicists believe, time runs backward (backward wristwatch, houseofrave.com, $28.95). More bad news: time may be running out of time. Other physicists speculate that our universe could mutate from space-time to just plain space. Time itself would cease to exist. Even your platinum Sotirio Bulgari with a perpetual calendar will be no good then ($212,000).

I have no idea what she’s talking about. Maybe our local expert on the arrow of time will chime in?

Modern humans have a fascination with time: how quickly it passes, what happened yesterday, what will happen tomorrow. I like to believe that physics has a role to play in this. On the one hand, Einstein was so kind as to show that time is a fairly complicated, observer-dependent quantity. And thus the only time that is really meaningful is, in some sense, the time we measure on our own watches. So we had better keep track! On the other hand, we have now firmly established that the Universe has not been around forever. It is only 14 billion years old. There is a huge psychological difference between living in an eternal Universe and one that has a finite history. It’s now incumbent upon us to keep track of the Universe’s age. Unfortunately, we’re still a little unclear as to the Universe’s life expectancy. Current indications are that the dark energy will continue to accelerate the Universe’s expansion, and therefore the Universe will last forever (instead of ending in a Big Crunch). However, given how little we understand about dark energy, this is at best an educated guess—nobody would be all that surprised if it turned out to be a much more complicated scenario. And so, in this framework of a Universe with a finite age, and an uncertain future, it makes sense to keep careful track of the passage of time. It is now 3:10:12 PM Mountain Standard Time on Friday, June 5. I need to get back to work.

Back in 1996, after the initially very mysterious explosion and crash of Flight 800 from JFK to Rome, there were numerous eyewitness accounts of a “streak in the sky” just before the crash. This led to the “missile theory” of the crash, which was eventually attributed to the explosion of the center fuel tank by the NTSB. But, also at the time, it was suggested that a meteor of sufficient size could have struck the plane, bringing it down.

Could a meteor have brought down Air France 447? Today we are starting to see reports that there actually may have been a meteor:

However, both pilots of an Air Comet flight from Lima to Lisbon sent a written report on the bright flash they said they saw to Air France, Airbus and the Spanish civil aviation authority, the airline told CNN.

“Suddenly, we saw in the distance a strong and intense flash of white light, which followed a descending and vertical trajectory and which broke up in six seconds,” the captain wrote.

Obviously for any given flight the chances are very, very small that a meteor will bring down an airliner, but as Hailey and Helfand pointed out in a letter to the NYT in 1996, the correct question to ask is this: “What is the probability that, for all flights in history, one or more could have been downed by a meteor?” They concluded that there was a 1-in-10 chance that this could happen…let’s use their logic, brought up to date somewhat, for 2009, for Flight 447.

Helfand, an astronomer, is presumably the one who estimated that “approximately 3,000 meteors a day with the requisite mass strike Earth”. This is a difficult number to get. How much mass? How fast does it need to be moving? But let’s assume that this number is correct; it translates to 125 meteors per hour.

Next we need to know the total number of flight hours at altitude for all commercial planes. In 2000 there were about 18 million flights per year. Clearly in the past 20 years (which we’ll take as our reference, since it spans 1989-2009, with both flights 800 and 447) it was not always so…but let’s take a guess that the 18 million figure is roughly correct for that 20 year period. That would yield 360 million commercial airline flights from 1989-2000. Hailey and Helfand assumed that each flight was two hours in duration. Again, a tough number to find on line, so we’ll take it at face value, giving us 720 million flight hours in our reference period.

They also claim that if there were 3500 planes in the air at any time, this would correspond to covering two-billionths of Earth’s surface. Now the earth’s surface area is 5×10¹⁴ m². Using my trusty HP-15c, I get that this would imply an average target area for a commercial airliner of 291 m², which is reasonable. Each plane, that is, covers 5.7×10^-13 of Earth’s surface. If a meteor hits the earth it has that probability of hitting a given plane on average.

So, in our reference 20-year period we have 720 million hours of flight time, times 125 meteors per hour, times 5.7×10^-13 = 0.051, which we can take as the average number of airliners struck by meteors in the period 1989-2009. That’s a one-in-twenty chance of some plane going down for this reason in that 20 year period. Extrapolating to all flights ever would require a better estimate of total flight hours, but it’s not twenty times the number in the past 20 years, for sure – that is, it’s not yet close to one.

Obviously there are a lot of uncertainties in this estimate; perhaps a factor of two from the number of meteors of sufficient mass per day, the average flight duration and number of flights?

Anyway the meteor idea is not crazy, though not likely. The weather seems more likely to be at the root of the tragedy…but we may never know. One thing, though, is clear: if we keep flying big planes at high altitude, eventually one will get hit by a meteor.

Miscellaneous happenings, including a couple of talks I’ll be giving — one on another coast, one in another plane of existence.

• 3 Quarks Daily has announced a series of four annual prizes, for blog posts in Science, Arts & Literature, Politics, and Philosophy. Science is the first one up, and they’re asking for nominations — the deadline is soon (June 1) so head over there and make suggestions. The final winner will be chosen by a well-known person in the appropriate field; this year’s Science judge will be Stephen Pinker. You are of course welcome to suggest your favorite CV post, because we like the attention. But this would also be a great opportunity to give a boost to that lesser-known blog that you really like and think should get more attention. (There are a lot of good blogs out there.) And if you are someone with a blog, don’t feel shy about nominating a post of your own — most readers don’t keep a mental file of your best posts over the last year.
• The World Science Festival is happening in New York (the U.S.’s second most interesting city) from June 10 to 14. I’ll be there, speaking at two different events. On Friday June 12 there is the WSF Spotlight, which is an informal forum with short talks and a lot of discussion. Participants include Kristin Baldwin (cell biologist), Dominic Johnson (political scientist), Christopher McKay (solar system researcher), and Frank Wilczek (not sure what he does for a living). I believe alcoholic beverages will be available; it’s that kind of event. Then on Saturday June 13 I’ll be on a panel discussing Time Since Einstein, with David Albert, George Ellis, Michael Heller, John Hockenberry, Fotini Markopoulou-Kalamara, and Roger Penrose. (I predict already that insufficient time will be a popular complaint about the time panel.)
• In Second Life, I’m giving a talk tomorrow morning at 10 am Pacific, sponsored by the Meta Institute for Computational Astrophysics. It will be a colloquium-level talk about “Dark Forces,” concentrating on building models of interacting dark matter and dark energy. Second Lifers can beam right there thanks to this elegant and finely-crafted link: http://slurl.com/secondlife/StellaNova/76/200/32.
• Max Brockman (son of John, doyen of Edge) has edited a new collection of essays: What’s Next? Dispatches from the Future of Science. There’s an essay by me in there on “Our Place in an Unnatural Universe.” You should buy it, because it would be like reading a set of interesting blog posts, but on paper. And most of these folks don’t have blogs!

(found in a list compiled by one of my kids, cross referenced to the relevant page number in Roald Dahl’s “Matilda”)

• gormless
• toddle
• diddled
• rakish
• throttling
• asinine
• formidable
• obstinate
• piffle
• regale
• aimiably
• blancmange
• parabola
• clot
• brigand
• suppurating
• implacable
• replete
• comatose
• swot

Gawd I love Roald Dahl. How could you read that list and not want to know what the book was about?

(Sadly, this is exactly the sort of language that tends to be lost in the “abridged” books all to frequently passed off to children — if you have a few minutes to spare, there is a brilliant reflection on abridged children’s literature here.)

The astronauts have wrapped up repairs on Hubble, and released it back into orbit (as of 8:58 EDT this morning)! This mission was just astounding from beginning to end. I didn’t get a chance to blog about it (because hey, it was sunny for once in Seattle), but Sunday’s repair of STIS was another day of drama, with one of the astronauts literally having to rip a handle off the instrument to get access to the panel they needed to unscrew. (Oh, and get this — they then had to peel off a g*ddm sticker to get at some of the screws! Oy.) Monday featured installation of new “outer blanket layers”, which help insulate the telescope. Installation was smooth, except for an accidental head doink on an antenna by John Grunsfeld (which is the first sign that any of the people up there right now may in fact share genetic material with the likes of me). Phil has been doing a great job keeping up on the spacewalks on Twitter, if you want a more detailed blow-by-blow.

The next phase is “Servicing Mission Observatory Verification” (SMOV), during which all the new instruments are put through their paces. This process is expected to take about 3 months, with early release images coming out in early September, with science programs expected to start running not long after. I’m getting myself prepared to be blown away!

PS. Oh, one random bit from my trip to the launch. I got to meet Dennis Overbye. I felt a bit like an 11 year old girl meeting a Jonas Brother.