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You've arrived at the main page of Digressions, my personal blog. To leave a comment to a post (and please do!) click on the post title and you'll find a Comments box at the bottom of the post, or click on the Comments link at the bottom of posts on the main page. If you want to read about watches, clocks, and other mechanical diversions, I'm the US editor for Revolution Magazine, whose homepage is at www.revo-online.com.

Tuesday, September 2, 2014

The World's Funniest Joke.

You can stop looking.

Many years ago an intrepid group of anthropologists set out to examine the cold weather survival practices of the Inuit people, believing that their traditional ice and snow shelters must surely be inefficient. To determine whether this was true they took the temperature of Inuit who had passed a harsh night either in an igloo, in the body cavity of a traditionally hunted and killed member of the cetacean family known as Phocenidae or Porpoises, or in a stretched-fabric modern temporary shelter held rigid by poles of aluminum.
Two of the scientists met to compare results.
"Observe," the first said. "The Inuit who sheltered in the ice shelters actually showed a lower drop in mean body temperature than those who used the body cavity and residual warmth of recently killed mammalian cetaceans, as well as those in the stretched fabric shelters we provided."
"Sheer bosh!" exclaimed the other. "Do you mean to tell me it is always true that any shelter is worse, in the midst of a harsh Arctic night, than one made of ice and snow?"
The other retorted, "My dear colleague, I do not know if it is true for all, under all circumstances, for our study did not evaluate all options. We can, and indeed should conclude, however, that it IS true . . . for all in tents and porpoises."

What Lies Beneath: Loricifera

So in the course of procrastinating last night (if only I could get paid to do it, although probably some people would think that's exactly what I get paid to do) I ran across something interesting. 

You can basically divide all life on Earth into two groups: the eukaryotes, and everything else (which includes, mostly, bacteria and the archaea.) Eukaryotes include anything --single or multi-celled --with a membrane-bound central nucleus ("eukaryote" is from a Greek root, meaning, roughly, "good kernel.")

Virtually all eukaryotes --humans, animals, plants, fungi, many protozoans, and so on --also contain in their cells, tiny organelles called mitochondria; mitochondria are, essentially, cells-within-a-cell that allow the use of oxygen for the production of energy. (ADP+P-->oxidative phosphorylation-->ATP anybody?) Mitochondria actually existed as free-living organisms at one time; around 2 billion years ago, a bigger cell tried to eat one. The proto-mitochondrion, however, resisted digestion, and became an endosymbiont --its energy producing capabilities traded off to the host cell in exchange for a supply of glucose and, one presumes, some measure of protection from harm.

The other major endosymbiont in eukaryotic organisms is of course the chloroplast, which is found in plants, algae, and even in some unicellular eukaryotes. The chloroplast uses sunlight, water, and carbon dioxide to generate energy and make food (glucose.) An interesting thing about chloroplasts is that there has been an example of the beginnings of an endosymbiotic relationship between chloroplasts and a host cell fairly recently, in evolutionary terms --Paulinella, a photosynthetic amoeba, appears to have, at some point, ingested another photosynthetic microorganism and, apparently knowing a good thing when it saw it, decide to hang on to the chloroplasts.

For the longest time (since high school biology, basically) I was under the impression that was it: the only endosymbionts used in energy production were chloroplasts and mitochondria. As it turns out, however, there is another: the hydrogenosome. Hydrogenosomes, like mitochondria and chloroplasts, appear to be the result of endosymbiosis, and they require no oxygen. Until recently, they were thought to exist only in protozoa (they're the main energy producing organelle in Trichomona vaginalis and Plasmodium falciparum, the latter being the parasite responsible for most deaths due to malaria.)

However, in 2010, scientists investigating the depths of Mediterranean found the first known multicellular organism using hydrogenosomes --which is also the first multicellular animal known that spends its entire life in an oxygen-free environment. The critter in question is Loricifera --there are three species currently known to exist, and they're rather appealing looking, with fronds extending from a protective shell (albeit they're tiny, the biggest run to about a millimeter: giants among their kind.) The ones discovered live in a huge pool of ultra-salty water deep below the surface, at around 3000 meters, in the L'Atalante basin --the boundary between salt and fresh water, or halocline, prohibits mixing of salt and fresh water, so below the halocline the water is totally oxygen free.

Apparently they eluded detection for so long thanks to their rarity, and the extremely firm grip they keep on the bottom gravel.

Delayed Choice Quantum Eraser: Spooky Action At A Distance In Time And Space?

The physicist Richard Feynman once said, approximately, that all of quantum physics could be understood if you understood the double-slit experiment and thought through its consequences carefully.  (This is obviously in spirit, if not in reality, something of a follow-up to the LHC visit article Part III which has yet to be written.)  The double slit experiment is important because it is the experimental evidence of something often talked about but poorly understood: so-called wave-particle duality.

It was thought by Newton that light was "corpuscular" in nature; he thought it must be made up of particles.  Later it was found that if you take a beam of light, and shine it through two tall, narrow, adjacent slits, you get an interference pattern --this can only happen if light is a wave of some sort.  Even later, the photoelectric effect seemed to show the contrary: that light was indeed corpuscular in nature.

The funny thing is this: take a beam of light or some other suitably quantum-sized particle, like an electron.  Fire it through one slit: you will see a simple blurred outline, roughly in the shape of the slit: a diffraction pattern, due to the scattering of the light waves.  Fire it through two slits, and you will see an interference pattern: alternating light and dark bands, which can be interpreted as reinforcing and cancelling wave-fronts.  It would seem the case is closed: light is wave-like in nature --but the case is more complicated.

As it happens, if you are using a beam of light and you have good equipment, you can turn the intensity of the beam down until only one photon is being emitted at a time.  You will see, on your detector, only one "hit" at a time, at a specific location.  Yet, if you let the "hits" build up over time, they will eventually form an interference pattern --as if, somehow, the particle had passed through both slits at once and was somehow interfering with itself.  And this is a very funny thing.  (Here we clearly intend, "funny" to mean "intensely intuitively frustrating; Einstein, and Schrödinger and quite a lot of other physicists, philosophers, and simple well-intentioned layman have found it anything but funny.  It led to one of the best quotes in the history science, which was Schrödinger's remark about the famous equation that bears his name, and describes the wave-function of a quantum system:  "I don't like it, and I'm sorry I ever had anything to do with it.")

Now all this is already trying enough: we are unable to understand intuitively what this means, because at the physical scales our five senses can operate within we are not familiar with any such behavior.  The problem, naturally, has gotten even worse as quantum mechanics has evolved.  Einstein postulated that if you put a detector at each of the two slits, this would reveal which of the slits through which the particle had passed.  If this is the case, then the particle should, so to speak, no longer be able to pass through both slits at once --in technical terms you may say the superposition of states (slot A and slot B) has collapsed into a single discrete value.  It was not technically possible to do such experiments until the 1970s but it indeed proved true.

Now, suppose you were to somehow mark the particle so you could tell after it had passed through the slit, which one it had passed through.

As it turns out, when you do this, what you expect would happen, does.  If you know through which slit the particle passes, then the interference pattern disappears.  But suppose you could somehow erase the mark, so to speak, after the particle passed through the slit?  If we follow through the logic of the experiment, then "erasing" this quantum information should cause the interference pattern to re-appear.

The manner in which the notion has been put to the test experimentally is extremely interesting.

Take a photon source: a laser will do nicely.  Let the photons pass through two slits.  Then let the photons pass through a special prism that splits each photon into two photons.  As each pair came from a single parent they are said to be entangled --as with most common-sensible sounding terms in quantum mechanics this has a precise mathematical formulation which need not concern us here.  It broad terms, it means that the two "child" photons cannot be thought of as completely separate quantum systems: they must be described as parts of a larger quantum system.  In practical terms this means that if you measure some aspect of one "child" you will know the complementary aspect of the other without having to take a measurement of it directly.

Having started with one stream of photons, you passed them through the two slits, yielding two sets of photons.  Having passed each stream subsequently through a producer of entangled pairs, you now have four "children."  One of each set of twins is referred to technically as the "signal" photon, and the other is referred to as the "idler."

Now if you know through which slit the signal photons have passed, you should not see any interference pattern with the signal photons.  If you do not, they should create an interference pattern.  Here is the important part.  You arrange the pathways of the "idler" photons so that they arrive at one of four detectors.

At two of these detectors, you can tell through which slit the parent of the idler photon passed.  If you compare the idler photons from these detectors with the signal photons, then an interference pattern emerges.

Oddly enough, however, if you compare the signal photons with the other two detectors --at which you cannot tell through which slit the parent of the idler photon passed --then the interference pattern disappears.  You have "erased" that information.

The truly peculiar thing about this, is that you can set up your idler photon pathway so that it takes longer for the idler photons to get to the detectors than it does for the signal photons --the usual interval is 8 nanoseconds but in principle it could be as long as you like --billions of years, even.  The results would still be the same --which seems to imply that the idler photons are sending information backwards in time.  This worried a lot of people.

As it turns out, however, there is a catch: you can only observe an interference pattern for the subset of photons which you compare to the idler particles that have arrived at the detectors that erase their origin.  If you look at the whole set of signal photon detections, they do not form an interference pattern taken alone.  This does something very happy: it saves causality.

The information contained in this statement is true to the best of my knowledge and belief.

Sunday, December 15, 2013

How The Grinch Was Misdiagnosed: A Christmas Tale (aka Not Part III Of a Visit to the LHC)

In the spirit of the holidays, I have been considering the problem of the Grinch, who, as all know, once made an attempt to "steal Christmas."  Attempts to analyze the Grinch Problem often consider the matter from a psychiatric standpoint, asserting that the Grinch may have suffered from a combination of chronic depression and narcissistic personality disorder, with aspects of grandiosity.

However, as a medical man myself (as the Eldest Offspring never tires of reminding me, I "have a degree in baloney," though I consider this a base slur against the ancient art of Chinese medicine) I think the matter is best considered from a purely pathophysiological perspective.

For an explanation for the malevolent tendencies of the personality of the Grinch, we need look no further, in my opinion, than the fact clearly noted in the classic case history presented by Dr. Seuss, MD, DDS, MRCS, etc. etc. in which it is quite clearly stated that the heart of the Grinch is, and I quote, "two sizes too small."

This reference to a pathological condition of the cardiac organ has often been thought, given the author's other well-respected analyses of psychopathology (especially concerning the origins of visual and aural hallucinations in the trauma of abandonment; see "Horton Hatches The Egg," i.e.) to be an uncharacteristic flight of metaphorical fancy on the part of this otherwise notoriously pragmatic clinician.  I propose, however, that Dr. Seuss was no more than noting the bare facts of the case, and that it is in this chronic cardiac insufficiency that the secret to the mysteriously unpleasant personality of the Grinch may be found --and furthermore I assert that the utmost importance of this very fact eluded the notice of Dr. Seuss, the Grinch's most famous chronicler.

Consider the inescapable consequences of this lamentable affliction.  With a heart "two sizes too small," numerous sequelae of the most unpleasant nature must inevitably follow.  Such chronically moribund cardiac output will result in hypotension and poor delivery of oxygen, glucose, and other vital substances to the cerebral cortex, producing a profoundly, and perpetually, dysphoric mood state --identical, indeed in many respects indistinguishable, from that produced by hypofunction of the thyroid gland.

Exertional fatigue, cyanosis (one need only note the characteristic complexion, as shown by Dr. Seuss clearly in his coloured plates --which may, as well, indicate obstruction by stones of the common bile duct) as well as persistent, painful cramping of the muscles (in particular in the lower extremities) must also ensue.  The long term stress induced by this condition will also lead to excessive secretion of stress hormones, in particular cortisol, and again we need only observe the distended abdomen of the Grinch to see that in addition to his other woes, he suffers from advanced Cushing syndrome.

The obviously cruelly cold climate he inhabits would predispose him, thanks to poor perfusion by blood of the extremities, to the painful cold-induced condition known as Raynaud's syndrome.

In short, his desire to "steal Christmas" is the result not of some deep rooted defect of character, but of the almost unbearable physical pain and stress occasioned by what is obviously a tragically undiagnosed congenital cardiomyopathy --compounded by an entirely natural hostility towards the time of year when, thanks to the turn of the seasons, his condition would be most exacerbated.

 Though some may feel that my review of the case is an uncollegial slur against Dr. Seuss' reputation -the envy of a lesser man for one long regarded as eminent in our field --it is rather, I feel, to the Grinch that the medical profession owes an apology, for a decades-long act of character assassination that could easily have been avoided through a judicious course of a cardio-tonic --extract of digitalis would have answered nicely.

Happy Holidays!

Saturday, August 24, 2013

Interlude, Or, Not Part 3 Of A Visit To The LHC, Or, Thoughts On Tête de Veau

It's not the promised update --which, mea culpa, mea maxima culpa, is coming --but rather a little meditation on something else.

Today's New York Times magazine has a short piece on the history of, and various forms taken by, the picnic ("an early mention can be traced to a 1649 satirical French poem, which features the Frères Pique-nicques, known for visiting friends 'armed with bottles and dishes.'") There is a mention also of a dish recommended for picnicking by Mrs. Beeton in her classic Book of Household Management from 1861 for something called a "collared calf's head." Morbidly fascinated, I searched for the recipe and found this, at celtnet.org:

"INGREDIENTS.—A calf's head, 4 tablespoonfuls of minced parsley, 4 blades of pounded mace, 1/2 teaspoonful of grated nutmeg, white pepper to taste, a few thick slices of ham, the yolks of 6 eggs boiled hard. Mode.—Scald the head for a few minutes; take it out of the water, and with a blunt knife scrape off all the hair. Clean it nicely, divide the head and remove the brains. Boil it tender enough to take out the bones, which will be in about 2 hours. When the head is boned, flatten it on the table, sprinkle over it a thick layer of parsley, then a layer of ham, and then the yolks of the eggs cut into thin rings and put a seasoning of pounded mace, nutmeg, and white pepper between each layer; roll the head up in a cloth, and tie it up as tightly as possible. Boil it for 4 hours, and when it is taken out of the pot, place a heavy weight on the top, the same as for other collars. Let it remain till cold; then remove the cloth and binding, and it will be ready to serve. Time.—Altogether 6 hours. Average cost, 5s. to 7s. each. Seasonable from March to October."

I notice this is in broad strokes essentially the same as the notorious (or maybe infamous) French dish known as tête de veau. I have never seen tête de veau on the menu of any American restaurant (and I don't expect to --Americans pay a lot of lip service to nose-to-tail dining but when push comes to shove I've noticed most of us still recoil from innards.) The collared calf's head flavorings bear a family resemblance to the famous sauce gribiche, which is the traditional accompaniment to a tête de veau, and which is based on egg, vinegar, capers, and parsley --really, a gussied-up sauce vinaigrette, which also gives it a passing relationship to chimichurri sauce, I suppose, but that's another post. In any case, one of the best discussions of tête de veau (in English, anyway) is of course in M. F. K. Fisher, who said in How To Cook A Wolf (1941) that " . . . I have lived about three-fourths of my life in the United States and I have never been served anything even faintly suggestive of the undisguisable anatomy of a boiled calf's head, in this my homeland."

In fact, she writes so well on the subject of tête de veau that I think I will quote her further.

"I must admit that my own first introduction to tête de veau was a difficult one for a naive American girl. The main trouble, perhaps, was that it was not a veal's head at all, but half a veal's head. There was the half-tongue, lolling stiffly from the neat half-mouth. There was the one eye, closed in a savory wink. There was the one ear, lopped loose and faintly pink over the odd wrinkles of the demi-forehead. And there, by the single pallid nostril, were three stiff white hairs." (I notice now, which I have never before, despite having read this passage more or less regularly since I first found the book in my mother's kitchen at the age of ten, the incantatory use of "stiff.")

My own introduction to, and so far only encounter, with tête de veau was at a restaurant in Paris on my 50th birthday, which I supposed was as good a time to eat someone's head as any, and it was preceded by an excellent dish of sea urchins and a great deal of wine, so by the time the tête de veau arrived I was in a beamingly uncaring and open-minded mood. As it happened my tête de veau was served off the bone, and was deliciously gelatinous --the brains, however, perhaps in a nod to the "undisguisable anatomy" of what I can only assume is the more classical presentation, were served separately in all their convoluted glory.  I believe, although wine and time have somewhat blurred the memory, that the brains were served with a fish fork and knife, and that most mysterious of culinary implements, the cuillère à sauce individuelle, or sauce spoon, the correct use of which I've never been able to divine. 

The thing about eating the head of an animal is that it's impossible to deny the identity between you and the creature you are consuming --there is a whiff of timor mortis there that's not present in a chop or a steak.  The head of an animal is a tombstone that says, As I Am Now, So Shall You Be, and eating it is both an act of self-sustenance, and an act of resignation.

Probably the most coy recipe in the world for tête de veau (or at least, the coyest I have ever read) is one that cannot be recommended for its hewing to tradition as it omits the sauce gribiche. It does, however, more than make up for it by being the only one I have ever read (and I assume the only one in the world) that recommends swearing an oath over Milton's Defensio pro Populo Anglicano before devouring the dish.


Coda:  My host for the evening I first ate tête de veau reminds me that it was at Le Violon d'Ingres which I believe at one point had a Michelin star, not that it really matters.  I note in perusing the menu that their tête de veau is indeed as I recall --something of a deconstructed affair, with the tongue and brains served separately.  Also I note that rather than a sauce gribiche, the restaurant prefers a sauce ravigote which is essentially identical to a sauce gribiche but omits the egg, which means that it will break more easily as the albumins in the egg white are not present to emulsify the oil and vinegar.  I'm reluctant to say this as I've run across at least once recipe for a sauce ravigote which does use eggs and seems indistinguishable from a sauce gribiche.  Anyhow, I would certainly happily recommend Le Violon d'Ingres to anyone looking for a wonderful tête de veau in the 7th Arrondissement or for that matter anywhere in Paris.  Owned by the famous Christian Constant and at least as of November the Twenty First Two Thousand and Twelve Anno Domini, a rather nice place to consume the partitioned head of a young veal with sauce wossname.

Sunday, July 28, 2013

One Ring To Rule Them All: A Visit To The Large Hadron Collider (Part 2)

If you want to you can read Part 1 first.  I thought this was going to be shorter but the tale grows in the telling.  The best part is that it's all true.

To get to the LHC, we had to go to France --well, strictly speaking, the Collider was already practically under our feet even in Meyrin.  You can see a part of it --one of the factory-sized surface points --from the Geneva airport, as a matter of fact; if you're landing or taking off, and you happen to be in a window seat looking north, you can see a cluster of buildings with what look like miniature nuclear power plant cooling towers on the roof, just past a parking area for small planes.  Our visit was to one of the main research facilities located on the LHC ring --the CMS Detector, which is in Cessy, France, just across the border.  (Crossing from Switzerland to France is, for an American used to hours-long waits and exhausted, suspicious immigration agents to get back into the US at JFK, almost comically low-key --no passports asked for or shown, and I don't particularly remember even stopping.  We may have slowed down a bit.)

The 27 kilometers-in-circumference main accelerator ring of the LHC straddles the border between Switzerland and France, just to the north of the city of Geneva itself.  The giant ring is buried under the earth at depths which vary depending on the surface geography; the collider tunnel is anywhere from 50 to 175 meters underground (greatest depths are under the Jura mountains, shallowest are near Lac Leman/Lake Geneva.)  There are several reasons for its subterranean location; cost of surface real estate is one, and shielding from cosmic radiation is another.  The tunnel containing the main ring once housed another particle accelerator: LEP, or the Large Electron Positron Collider, which was decommissioned in the year 2000 to make way for the LHC.

Getting packets of protons up to as close to the speed of light as possible isn't easy and while the largest ring is the most attention-getting part of the entire complex, it's actually the final stage in a four-step process involving a complex of equipment, some parts of which are more than half a century old.  The ladies and gentlemen at CERN get their protons by stripping off the electrons from hydrogen atoms --the excellent animated film showing the process on CERN's website depicts a rather banal bottle of hydrogen gas.  (Hydrogen, the simplest chemical element, consists of exactly one proton with one lonely electron orbiting it.)  This happens in the injection chamber of LINAC 2, the linear accelerator that's the first stage in getting fast-moving particles into the LHC itself.  With the electrons gone, all that's left are single protons --these have a positive charge, and so, can be accelerated by electrical fields and contained by electromagnets.

Protons leave LINAC 2 are already moving fast --about 1/3 the speed of light (c.)  From LINAC 2 the protons go into the PSB (Proton Synchrotron Booster) where they're divided into four packets and pumped up to even higher speeds --91.6% c.  Powerful electromagnets keep the protons on a circular path while they gain speed.  The third stage is the even larger Proton Synchrotron.

The circular Proton Synchrotron is old --it was first used in November of 1959, and was briefly the world's most powerful particle accelerator.  Today its main purpose is to help feed high speed particles into the main ring of the LHC --and it's been upgraded over the decades so that its beam is now a thousand times more powerful than its original design.  At 628 meters, it's a massive piece of equipment.  The protons injected into the PS only stay there for about 1.2 seconds, but during that time, they go to 99.9% c.  

This close to the speed of light, Einstein's theory of relativity starts to make itself felt in a big way.  One of the main insights from relativity theory is that things look different depending on your frame of reference, or where you're looking at things from (hence the name --it's all relative.)  To us, stationary observers with respect to the protons, the increase in speed means an increase in energy --as the protons go faster, they gain mass.  (This is a weird effect to someone who has never heard of relativistic effects before, but I don't make the news, I just report it.)  The speed limit for the universe is the speed of light itself --nothing can go faster; particles with mass can get close but never reach this velocity. At c, a particle would have infinite mass, which is Not Allowed.  (Photons, which have no mass, do travel at the speed of light --well, they are light, so they would, wouldn't they.)

As they leave PS, the protons have about 25 times their rest mass, and this close to the speed of light, any further addition of energy results in a lot of increase in mass and very little in velocity.

There's one more stage before the protons can enter the main ring, though.  From the Proton Synchrotron, they go into the Super Proton Synchrotron (CERN is running out of superlatives, obviously.  May I suggest as the next obvious bit of nomenclature the I Can't Believe It's A Synchrotron synchrotron.)  SPS is stage four, the last before the LHC proper.  SPS has been flinging particles around since 1976 (in 1983, it was used for the Nobel Prize-winning discovery of the W and Z bosons, which are the gauge bosons for the weak force --one of the four fundamental forces.)  Yet more energy is added to the protons here --and while there is not much gain in velocity, there is a lot of mass added (remember, mass-energy equivalence: E=MC^2.)  The unit used for mass-energy is the electron volt, and while protons leaving LINAC 2 --stage one --have an energy of 50 MeV (fifty million electron volts) by the time the protons are fired from SPS into the main ring, they've reached a mass of 450 GeV (giga --billion --electron volts.)

Finally, the protons are ready for prime time: the Large Hadron Collider itself.  When the Collider is in operation, it takes about a half hour for SPS to fill it with 2,808 individual "packets" of protons.  The packets are pumped with yet more energy in the LHC.  The LHC actually consists of two tunnels, --in one, protons go around clockwise, and in the other, counterclockwise.  The beams cross at four points spaced around the ring --these are the giant detector caverns, and when particles collide at high energy and produce a burst of energy and fundamental particles, it's these detectors that gather information about the event --evidence that the scientists at CERN, and around the world, sift through in hopes of finding, among other things, traces of the Higgs boson.

The protons in the LHC main ring are brought up to 99.9999991% c --they're moving so quickly that they're only traveling about three meters per second slower than light.  At these speeds they go around the ring 11,000 times in one second and the energy necessary to accelerate and contain them is greater than that used by the entire neighboring state of Geneva.  To generate the immense magnetic fields necessary to contain the proton beams, massive superconducting magnets are used --some as heavy as 27 tons.

If you like electromagnets (and hey, who doesn't) you'll love these.  Electromagnets work by generating a magnetic field when current flows through them, and it takes a lot of current to make magnetic fields strong enough to contain the proton beams, which are powerful enough melt a half a ton of copper.  The proton beam wouldn't make a bad weapon, if you could aim it --it's so powerful a special "beam dump" chamber had to be constructed to give the proton beam someplace safe to go.  The beam, in case of a superconductor failure, has to be dissipated in about 90 milliseconds, which is equal to about 4 TW (terawatts, or trillions of watts.)  The beam dump cavern contains a target of graphite composite eight meters long and a meter in diameter, and it's surrounded by a thousand tons of concrete radiation shielding.

So much current is used that it would melt the magnets if they weren't cooled to near absolute zero by liquid helium, which makes them superconductors --in a superconductor, current flows without resistance, but most known superconductors only become superconductors at very low temperatures.  The LHC's superconducting magnets are kept at a temperature colder than interstellar space --1.9 K, or about -271.25 degrees Celsius (absolute zero, the coldest possible temperature, is 273.15 degrees Celsius.)  It takes 96 tons of liquid helium to maintain the magnets at the right temperature --which means the LHC is both the largest particle accelerator in the world and the world's biggest refrigerator.

It may now be occurring to the reader that this much energy comes with some inherent dangers, and indeed, something going wrong with the LHC would be bad.  In September of 2008, something did go wrong. The LHC was being powered up for the first time, but an electrical short occurred between two superconducting magnets.  The result was one of the worst things that can happen to a superconductor: a so-called "quench," or accidental loss of superconductivity.  Temperatures almost instantly skyrocketed as the sudden electrical resistance produced a tremendous heat spike, this caused vaporization of liquid helium along a considerable stretch of the ring tunnel.  Automated emergency shutdown occurred but the damage was horrendous, even at far lower than maximum power --the liquid helium had vented with enough force to rupture the proton tunnels, contaminating them with soot, and rip multi-ton magnets off their concrete bases.  The amount of liquid helium released was so large --several tons --that it was two weeks before repair teams could enter the affected section of the ring to evaluate the damage (it was, one scientist commented drily, "not a pretty sight.")

The LHC had its share of teething problems, some of them almost comical --in one instance, in November of 2009, another quench incident almost occurred when power was lost due to a short in an electrical substation on the surface.  The reason was about as French as causes of superconductor failure come --a passing bird bearing a chunk of baguette in its beak had apparently dropped a piece of the world's most famous bread into a transformer.  This somewhat risible incident fortunately didn't cause any damage --a controlled shutdown prevented another quench incident --but the number of setbacks led to some interesting speculation about the nature of the Higgs boson.

 In particular, several scientists speculated that there is a form of cosmic censorship preventing the Higgs boson from being observed.  Bech Nielsen and Masao Ninomiya, of the Niels Bohr Institute in Copenhagen and the Yukawa Institute for Theoretical Physics in Kyoto, suggested that "reverse chronological causation" was behind the accidents at the LHC --in essence, the Large Hadron Collider was traveling backwards in time from the future to prevent itself from working.  Said Nielsen, in an email to the New York Times, "It is our prediction that all Higgs-creating machines will have bad luck."

If correct, the hypothesis would have gone a long way towards explaining why the US cut funding for its own home-grown mega-atom-smasher, the Superconducting Supercollider, which would have been 87 kilometers in circumference and had three times the power of the LHC (naturally, it would have been located in Texas.)  The SSC was canceled in 1993.  The apparent success of the LHC in finding evidence for the existence of the Higgs boson has pretty much put this somewhat bizarre theory to rest, but as the Times pointed out in its coverage, subatomic physics is not exactly a field where intuitively sensible behavior of physical systems is expected --Niels Bohr once famously said, to a colleague, "We are all agreed that your theory is crazy.  What divides us is whether your theory is crazy enough to be correct."

Speaking of crazy, there were some somewhat fringe worries that the LHC would do something at least as spectacular as commit temporal suicide --some people were worried that it would cause the end of the world.  The two favorite apocalyptic scenarios involved the accidental creation of a miniature black hole or the accidental creation of a type of exotic matter particle known as a strangelet.  Without going too much into technical details (OK, if you must, it's a mixture of up, down, and strange quarks) the problem with strange matter is that it may be more stable than normal matter --the concern is that strange matter may thus be contagious; any ordinary matter it comes into contact with would be turned into strange matter, like ice turning into ice-nine in Kurt Vonnegut's Cat's Cradle.  This has obviously not happened.

Black holes are what you get when an especially massive star burns out its fuel and can no longer prevent itself from collapsing under its own weight.  It collapses so powerfully that it becomes a singularity --a point object of infinite density, with a gravitational field so enormous that nothing can escape (well, nothing that gets closer than the black hole's event horizon.)  The possibility that such a thing could form in one of the collision caverns at LHC, and devour the Earth by sucking you and all you know and love into the maw of a singularity, naturally drew a lot of attention (the Daily Mail produced a representative headline of the tabloid press coverage: "Are We All Going To Die Next Wednesday?")

As it turns out this is not a problem either, for various reasons --one of them is that black holes do lose mass and eventually evaporate through a rather complicated process known as Hawking radiation, and any microscopic black hole would simply evaporate before it has a chance to do any damage.  A working group set up examine the problem pointed out that cosmic ray collisions in the Earth's upper atmosphere are more energetic than anything the LHC could produce and that if such events could cause the apocalypse it would have happened by now.  Probably the most trenchant rebuttal to those who insisted that firing up the LHC would lead to the end of the world came from physicist Brian Greene, who said to The New York Times, "If a black hole is produced under Geneva, might it swallow Switzerland and continue on a ravenous rampage until the Earth is devoured?  It's a reasonable question with a definite answer: no."

All this was running through my head earlier this month on the car ride to the CMS detector --our car left the industrial environs of Meyrin and the Geneva airport behind, crossed into France, and then we found ourselves winding through the French countryside.  Then, we turned up an unprepossessing driveway and found ourselves outside a tall hurricane fence topped with barbed wire.  An affable security guard waved us through, and we saw an enormous complex of buildings --surface evidence that deep below, humanity was going through Nature's pockets for loose bosons.

Saturday, July 27, 2013

One Ring To Rule Them All: A Visit To The Large Hadron Collider (Part 1.)

I noticed in telling people about visiting the Large Hadron Collider that a surprising number of folks have never heard of it.  In brief, it's the world's largest and most powerful "atom smasher" --a giant ring 27 kilometers in circumference, buried under hundreds of feet of rock, straddling the Swiss-French border.  It was built to probe the fine structure of matter and space-time, by accelerating tiny bits of matter up to very close to the speed of light and then smashing them together (some people say it's rather like throwing a watch against a wall and watching the bits fly out to see how it works, which is not an exact analogy but it gives you the basic idea.)

 If you know that all the matter you see around you is made of atoms, which are in turn made of smaller particles --protons, neutrons, and electrons --and that these particles interact with each other and with fields like the electromagnetic field, you know enough to go on with.

"You don't have anything on your calendar for the first day you're in Geneva," the PR rmanager's email said. "Anything you'd like to do?" "Well," I wrote back, "I've always wanted to visit the Large Hadron Collider."  I meant it as a joke but apparently, she took me seriously.  The visit to the LHC and CERN took place not on my first day there, which was just as well --I had for some reason (and I don't know why, JFK--GVA is a flight I've made more times than I can count, in the line of duty) absolutely crippling jet lag and my first day I couldn't do much more than lie on the bed in my room at La Reserve, feeling bone-crushingly tired and wishing I could sleep, which I couldn't.  It was no fault of the hotel's --La Reserve is located in the Swiss countryside on the shore of Lac Leman, just outside Geneva; it's one of the most relaxing hotels in Europe but I couldn't nod off for the life of me.  Two glasses of wine with dinner didn't do anything but wake me up, and though I'd brought some melatonin with me I decided --rather foolishly --to white-knuckle it through the night.  Melatonin works as far as sedation goes but it also has been increasingly giving me very, very unpleasant dreams and I've been trying to avoid it, though in retrospect I probably should have just knocked myself out.

The next day started early --my hosts on this trip to Geneva were from a small-batch watch company called Roger Dubuis, which makes a few thousand watches per year for the luxury market in a state-of-the-art facility in Meyrin, which is a suburb of Geneva.  Geneva is both a city and a Canton; Meyrin is located in the Canton of Geneva, which makes the watches made by the company eligible for the prestigious Geneva Hallmark.  This is a quality standard granted by the Canton for watches made to a certain level of quality specified by the Geneva Seal criteria.  It's expensive to adhere to the requirements --the cost over making a standard movement is around thirty to forty per cent --but it's one of the company's main selling points; they remain the only company whose production is one hundred per cent Geneva Seal approved.  

I'd long since forgotten that I'd mentioned the LHC to the company's PR manager in New York as I didn't honestly think that touring the LHC was possible, and I hadn't noticed that on my schedule for the day there were 2 hours set aside for "transport to a surprise destination," which I assumed was an off-site facility of some sort --an engraver, an enamelist's studio, a dial factory.  As it turned out, the surprise destination was indeed the Large Hadron Collider.

The LHC is located at the headquarters of the Conseil Européen pour la Recherche Nucléaire,or CERN, which was established in 1957 with 12 member states and now has 20. CERN's purpose was and is to conduct high energy particle physics experiments, and the Large Hadron Collider is the latest and most powerful particle accelerator --an atom smasher, in popular parlance --in CERN's arsenal.  Basically, particle accelerators like the LHC accelerate subatomic particles up to very high speeds --the LHC takes packets of protons up to very close to the speed of light --and smashes them together in order to explore how matter and the structure of space-time as we observe them today, came into existence.

If you observe the Universe today, you can see that it's expanding (this was an unpleasant surprise for Einstein, who favored a static model) and if you run the clock backwards, the Universe gets progressively smaller and denser and hotter.  At time=zero, theory predicts that the very early universe experienced a phenomenon known as the Big Bang, which began as a moment in time when all the matter and energy in the Universe was concentrated in an extremely tiny area --a dimensionless point of infinite energy and density, or singularity.  

The earliest period of the history of the Universe is known as the Planck epoch, after the physicist Max Planck, and lasted for a very short period of time, known as the Planck Time --this is the amount of time it takes for light to travel the Planck Length, which is an extremely short distance; about 1.616 x 10 to the minus 35th power meters. It's impossible to have an intuitive sense for how tiny such a distance is (the Scale of the Universe animation is pretty good though) but it helps to note that it is about 10 to the minus 20th power smaller than the diameter of a proton.  Evidence for the Big Bang is robust --the left-over radiation from the Big Bang has been detected and mapped by deep space microwave radiation telescopes on satellites like the WMAP probe --and though the Big Bang theory is widely accepted, it raises, to put it mildly, a lot of questions.

Most people would like to know where all the matter and energy (we should just say mass-energy, as by Einstein's equation, E=MC^2, we know they are equivalent) came from, which is a highly speculative subject in cosmology.  Part of the problem is that we do not, at present, have the theoretical tools necessary to make mathematically reliable predictions about the earliest stage of the Big Bang, much less answer questions about where all the stuff that became all the stuff we see now came from.  We can reliably date the age of the Universe to a little over thirteen billion years, but the problem with understanding the very early universe is that during the Planck Epoch, the energy density of the universe was so high that the fundamental forces --the electromagnetic force, weak force, strong force, and gravity --are thought to have been unified into a single force.  

Gravity is the odd man out; we have an excellent theory for gravitation --general relativity --and an excellent theory for subatomic particle behavior --quantum mechanics.  However, when you try to make relativity and quantum mechanics play nice together, terrible things happen --the equations begin to generate ridiculous infinities, which scientists take as evidence that neither relativity nor quantum mechanics are complete theories.  What we want is sometimes given the rather Promethean name of a Theory of Everything --a TOE --which would allow us to make sensible predictions about how gravity works at the quantum scale, but so far a good theory of quantum gravity has proven very elusive.  String theory, which postulates that fundamental particles are not point objects, but instead minute strings of mass-energy whose frequency modes correspond to different fundamental particles, is an attempt to cope with the disconnect between relativity and quantum mechanics; quantum loop-gravity theory is another.

The Large Hadron Collider was constructed to help answer questions about conditions in the early universe.  In particular, one of the major unanswered questions it was designed to look into is the mechanism by which particles acquire mass.  The Standard Model of particle physics, which describes the fundamental particles and their interactions (via quantum mechanics) has successfully described all known subatomic particles, as well as the forces through which they interact, and although it is not complete, it's proven pretty solid ever since it got its name in the 1970s.  The Standard Model also predicted the existence of particles which, at the time it was first being formulated, had not yet been observed.  

One reason certain particles --like the so-called "top quark" --had not yet been observed in existing particle accelerators was that such particles are very massive, and thanks to E=MC^2 we know it takes a lot of energy --a very high energy density --to create such particles in the lab.  Such particles also tend to rapidly decay, as they shed energy, into other, more stable particles.  The top quark was finally detected, after a long search, with a machine called the Tevatron --an enormous particle accelerator located at the Fermi National Accelerator Laboratory (Fermilab) in Illinois, USA.  The Tevatron was a colossus --the main accelerator ring was 6.86 kilometers in circumference, and it collided protons and antiprotons together at TeV --trillion electron volt --energies.  Decommissioned in 2011, it was during its operating lifetime the only machine powerful enough to create and observe the top quark.

Despite its success, the Standard Model has some gaps, one of which is a mechanism for describing why particles that have mass, have mass (why a particle should need to "have" something as basic as mass is another question, but suffice to say there are reasons, which is why things like protons and neutrons have mass, and things like photons don't.)  The Higgs boson is the particle --first hypothesized in 1964 --thought to be responsible for giving mass to certain fundamental particles.  

Bosons are one of two classes of elementary particles (the other is the group known as fermions) and for certain reasons they are often force-carrying particles  in the Standard Model --for instance, photons are the force-carriers for the electromagnetic force.  When particles interact electromagnetically, they exchange photons.  The bosons that mediate such interactions are called gauge bosons, and the Standard Model predicted a field --known as the Higgs field --with which elementary particles would interact in order to gain mass (a massless particle like the photon, by contrast, would not interact with the Higgs field.)  The Higgs boson is the gauge particle of the Higgs field, just as the photon is the gauge particle of the electromagnetic field.  The Higgs field, if it exists, would have a non-zero minimum energy in empty space.

Finding the Higgs boson became, after the discover of the top quark, one of the most important remaining goals in confirming the predictive ability of the Standard Model.

The problem, though, is energy.  Nobody really knew exactly how much energy would be necessary to observe the Higgs boson, and theory predicted that the Higgs field emerged about 10 to the minus tenth power seconds after the big bang --many orders of magnitude after the Planck Epoch (whose duration is the Planck Time, remember --about 10 to the minus 44th power seconds) but still so close to time=zero that the energy density of the universe was extremely high.  It was thought possible that Higgs bosons might have been created in very small numbers in accelerators like the Tevatron, but to make them in large enough numbers to be observed with a high enough confidence to confirm the Higgs field's existence --bear in mind that Higgs bosons exist for too short a time to be observed; what scientists would look for are decay products specific to the decay of the Higgs boson --a bigger machine was needed.  And that's where the Large Hadron Collider came in.

Go to part 2