Cable News

Fourth Undersea Cable Failure in Middle East from Schneier's blog. What's going on?

A fun article by Neal Stephenson in Wired 1996 Mother Earth Mother Board about the ocean spanning fiber optic cable network.

The Balloon Blowup Analogy

Jim Kelnhofer, underwater videographer extraordinaire, asked the following nontrivial question (about cosmology, when it comes to underwater video, the questions flow in the other direction:)

ok, so I've been thinking about space and time a bit and the fact that there is no real center to the universe, or so everyone says. The analogy that I kind of get is that points in three dimensional space are kind of like points on the surface of a balloon. And, as you blow up the balloon all the points recede from one another as the universe, represented by the balloon, grows. I can sort of conceptually get this, though I don't completely comprehend all the math involved in the 3D/2D transformations. My question would be, is the expansion of the balloon representative of time, and does that translate to the center of the universe being time t=0? Is that how the math works out or what the math means?

jim...

Here's my less than satisfying response.

One way to understand a weird space is to formulate it as a subspace of a simpler space. For example, we can understand a balloon, the surface of a sphere, which is a slightly tricky space, by thinking of its embedding in good old flat three dimensional space.

General Relativity, on the other hand, is formulated in terms of Differential Geometry. In Differential Geometry, the spaces are called Manifolds. By definition an n-dimensional manifold can be completely covered (nicely) by n-dimensional Euclidean slabs (called charts in the literature).

By the way, if you think about it, the surface of a sphere cannot be modeled so nicely by just one chart (you end up leaving out at least one or two points, like the North and South poles). It takes at least two charts.

So there are these two ways to bootstrap our knowledge and intuition about Euclidean space to handle more general spaces: embeddings and coverings.

Can a given n-dimensional manifold (defined by coverings) always be embedded in a "nice" way in some higher-dimensional Euclidean space? That's an interesting question. John Nash, the dude depicted in the movie and book "A Beautiful Mind" found some impressive stuff along those lines.

General Relativity doesn't start off by worrying much about embeddings, it's fundamentally about the local properties of the space - that was the way Einstein went about it. Local properties can usually be addressed nicely by a covering formulation, you don't even need an embedding as it turns out.

There are more complications, in addition to Differential Geometry, once Time and Causality are involved.

There are however various ways to try to visualize a global picture of different space/time models. One popular way is the Penrose diagram.

Unfortunately it's not very easy to get from the local situation to a more global picture. It fact it is damn hard.

For example, Einstein came up with the local formulation, but he never got very far himself with global solutions (the ones he found are pretty trivial really).
One of Stephen Hawking's claims to fame is a book called "The Large Scale Structure of Space/Time" which is full of very hairy math addressing these global questions.

So the way mathematical physics often works is, people try to get the local formulation right, then they do some very hairy stuff to see what sorts of global implications follow.

What's been going on in the mathematics community, getting back to the time of Gauss in the 1800's, is that they've been able to come up with all kinds of bizarre "geometries" that are quite different than the Euclidean geometry that seems to be intuitive for most of us human types. However, the mathematical work tends to have a purely spatial flavor about it. Einstein happened to have a mathematician buddy who showed him one of these formalisms called Riemannian Geometry and Einstein basically kludged Time in. The nature of the kludge is that, locally, everything looks like Special Relativity, and the space-time geometry of that had already been worked out, by Einstein and other dudes at that time. The mathematical consequences of this have been slow to unfold, even though it's now been over 90 years.

Mathematicians have been very creative, they have given us powerful tools for formulating things with lots of dimensions and weird shapes. Sometimes there's even originally a physical motivation for some of that, but often they're just spinning out lots of crazy new junk for their own amusement. Every once and a while, someone with a more practical bent grovels through the math literature and finds something inadvertently useful, to the horror of Pure Mathematicians everywhere.

The interesting thing now is, we have these observations (red shifts, the cosmic microwave background, etc.) that seem to give some hints about what the global picture might be like. After the astronomers observe something new and cool, the physicists have to see if they can reproduce those results in their models. Lately they've been having a hard time of it, hence all the buzz about Dark Matter and Dark Energy.

So after all that did I even manage to address Jim's question about the Balloon Analogy? Not really! I think that model might have been specifically designed to show the universe could be finite, but still not have a center, at least at t>0. Even so there is apparently a singularity at t=0 when, if you extrapolate backward, the balloon seems to just materialize out of nowhere: a Big Bang.

Old Jewish Joke

A mother buys her son two ties, he visits her wearing one of them. She frowns and says, "What, you didn't like the other one?"

Dark Energy Crisis

Dark Energy and Dark Gravity

Observations provide increasingly strong evidence that the universe is accelerating. This revolutionary advance in cosmological observations confronts theoretical cosmology with a tremendous challenge, which it has so far failed to meet. Explanations of cosmic acceleration within the framework of general relativity are plagued by difficulties. General relativistic models are nearly all based on a dark energy field with fine-tuned, unnatural properties. There is a great variety of models, but all share one feature in common -- an inability to account for the gravitational properties of the vacuum energy. Speculative ideas from string theory may hold some promise, but it is fair to say that no convincing model has yet been proposed. An alternative to dark energy is that gravity itself may behave differently from general relativity on the largest scales, in such a way as to produce acceleration. The alternative approach of modified gravity (or dark gravity) provides a new angle on the problem, but also faces serious difficulties, including in all known cases severe fine-tuning and the problem of explaining why the vacuum energy does not gravitate. The lack of an adequate theoretical framework for the late-time acceleration of the universe represents a deep crisis for theory -- but also an exciting challenge for theorists. It seems likely that an entirely new paradigm is required to resolve this crisis.

Globular Clusters and Gravity

Using globular clusters to test gravity in the weak acceleration regime

We report on the results from an ongoing program aimed at testing Newton's law of gravity in the low acceleration regime using globular clusters. It is shown that all clusters studied so far do behave like galaxies, that is, their velocity dispersion profile flattens out at large radii where the acceleration of gravity goes below 1e-8 cm/s/s, instead of following the expected Keplerian fall off. In galaxies this behavior is ascribed to the existence of a dark matter halo. Globular clusters, however, do not contain dark matter, hence this result might indicate that our present understanding of gravity in the weak regime of accelerations is incomplete and somehow incorrect.

Dark Matter in Galaxies

Dark Matter in Galaxies: Conference Summary

Abstract. The competition between CDM and MOND to account for
the ‘missing mass’ phenomena is asymmetric. MOND has clearly demonstrated that a characteristic acceleration a0 underlies the data and understanding what gives rise to a0 is an important task. The reason for MOND’s success may lie in either the details of galaxy formation, or an advance in fundamental physics that reduces to MOND in a suitable limit. CDM has enjoyed great success on large scales. The theory cannot be definitively tested on small scales until galaxy formation has been understood because baryons either are, or possibly have been, dominant in all small-scale objects. MOND’s predictive power is seriously undermined by its isolation from the rest of physics. In view of this isolation, the way forward is probably to treat CDM as an established theory to be used alongside relativity and electromagnetism in efforts to understand the formation and evolution of galaxies.

Reionization Review

The Frontier of Reionization: Theory and Forthcoming Observations

The cosmic microwave background provides an image of the Universe 0.4 million years after the big bang, when atomic hydrogen formed out of free electrons and protons. One of the primary goals of observational cosmology is to obtain follow-up images of the Universe during the epoch of reionization, hundreds of millions of years later, when cosmic hydrogen was ionized once again by the UV photons emitted from the first galaxies

Under the assumption that general relativity describes the evolution of the Universe, the measured CMB anisotropies indicate conclusively that most of the matter in the Universe must be very weakly coupled to electromagnetism and hence cannot be the matter that we are made of (baryons). This follows from the fact that prior to hydrogen recombination, the cosmic plasma was coupled to the radiation through Thomson scattering. Small-scale fluctuations were then damped in the radiation-baryon fluid by photon diffusion. The damping is apparent in the observed suppression of the CMB anisotropies on angular scales well below a degree on the sky, corresponding to spatial scales much smaller than 200 comoving Mpc. To put this scale in context, the matter that makes up galaxies was assembled from scales of < 2Mpc. In order to preserve the primordial inhomogeneities that seeded the formation of galaxies, it is necessary to have a dominant matter component that does not couple to the radiation fluid

Empathy, Gender, Fantasy and Fiction

High Empathy (Mostly Women), Low Empathy (Mostly Men) and the Movies in the New York Times.

To test empathy levels and the subjects’ reactions to various melodramas, the researchers turned to several classic short stories, like “The Last Leaf” by O. Henry, that include struggles against adversity and melancholy plot twists.

People with low empathy (mostly men) who believed the stories to be fantasies liked them much better than those who were told the stories were factual. The reverse held true for people with high empathy, who were mostly women.

Another surprising observation from the study: not one of the 492 students tested reported having read or heard any of the stories, even though some are quite prominent. “I was appalled,” Professor Argo said.

The Intergalactic Medium

The Physics of the Intergalactic Medium

Intergalactic space is filled with a pervasive medium of ionized gas, the Intergalactic Medium (IGM).

The reionization of the IGM is one of the principal unsolved problems of cosmological structure formation.

The Flyby Anomaly

Is the physics within the Solar system really understood? discusses the flyby anomaly as well as the Pioneer anomaly and others. Simulation of the flyby anomaly by means of an empirical asymmetric gravitational potential with definite spatial orientation explores this anomaly and explains:

During several Earth flybys carried out since 1990, some spacecrafts have experienced an unexpected and until now unexplained anomalous velocity increase. This phenomenon is called the flyby anomaly and looks like the effect of an instantaneous acceleration of the spacecraft at the time of closest approach to Earth.

Ultra High Energy Cosmic Rays

Ultra High Energy Cosmic Rays: origin and propagation

We discuss the basic difficulties in understanding the origin of the highest energy particles in the Universe - the ultrahigh energy cosmic rays (UHECR). It is difficult to imagine the sources they are accelerated in. Because of the strong attenuation of UHECR on their propagation from the sources to us these sources should be at cosmologically short distance from us but are currently not identified. We also give information of the most recent experimental results including the ones reported at this conference and compare them to models of the UHECR origin.

The highest energy cosmic ray ever detected had the energy of a 290km/h tennis ball! From a single particle. Gasp.

Faint Irregular Galaxies

Gas rich galaxies from the FIGGS survey

The FIGGS (Faint Irregular Galaxy GMRT Survey) is aimed at creating a multi-wavelength observational data base for a volume limited sample of the faintest gas rich galaxies.

Some of these objects have very extreme dynamical mass to light ratios. Over 100 in some cases.

These very large dynamical mass to blue luminosity ratios naturally lead one to ask whether extremely gas rich dwarf galaxies have abnormally small baryon fractions, i.e. have they just been inefficient at forming stars, or did they end up with less than the typical baryon fraction?

Neutrinos are So Weird

Neutrino Properties, Cosmology

We now know that neutrinos have masses and that the flavor eigenstates (νelectron, νmuon, νtau ) are not the mass eigenstates (ν1, ν2, ν3).

This means that an electron muon is a quantum mechanical mixture of different masses and a neutrino that has a definite mass is a quantum mechanical mixture of the different flavors (electron, muon, tau).

Gack.

Car Key Fobs

A post from Scheier on Security

my wife used to live along the flight path of a smallish airport, and often all the garage doors in the neighbourhood would start opening and closing on their own when a plane flew over.

Gertrude Bell

The Queen of the Quagmire By Rory Stewart in the New York Review of Books.

[In talking to an Arab nationalist leader] I said complete independence was what we ultimately wished to give. "My lady" he answered—we were speaking Arabic —"complete independence is never given; it is always taken."

Problem/Solution

Problem: while a woman was working construction her male co-workers would help themselves to her tools.
Solution: she painted her tools hot pink.

A Single Molecule Radio

Nanotube Radio

We have constructed a fully functional, fully integrated radio receiver from a single carbon nanotube. The nanotube serves simultaneously as all essential components of a radio: antenna, tunable band-pass filter, amplifier, and demodulator. A direct current voltage source, as supplied by a battery, powers the radio. Using carrier waves in the commercially relevant 40-400 MHz range and both frequency and amplitude modulation techniques, we demonstrate successful music and voice reception.

An Enigmatic Object near the Center of the Galaxy

The enigma of GCIRS 3 - Constraining the properties of the mid-infrared reference star of the central parsec of the Milky Way with optical long baseline interferometry

On the second page of this preprint there's a fascinating image of the center of our galaxy in mid infrared, highlighting GCIRS3, the hottest and most compact of the sources of thermal dust irradiation in that vicinity. It appears that this object is a cool dust-forming carbon star.

University has some mice that will kick your butt.

Case Western develops superstrong mice

Researchers at the university have bred a strain of "mighty mice," known as PEPCK-Cmus mice because of specific genetic enhancements, that can run for six hours at a speed of 20 meters per minute, or a total of 5 or 6 kilometers.

The Art of Reviewing Books

"I never read a book I must review," said Oscar Wilde, "it prejudices you so."

The Status of Fundamental Physics Today

Fundamental Physics: Where We Stand Today by John Baez.

By fundamental physics, I mean the search for a small set of laws which in principle determine everything we can calculate about the universe. The reductionist dream – not always practical, but very seductive. Where do we stand in the search for these laws? What do we know, and what are the mysteries? Why do many physicists feel stuck?

Magnetic Monopoles!

Magnetic Monopoles in Spin Ice

Electrically charged particles, such as the electron, are ubiquitous. By contrast, no elementary particles with a net magnetic charge have ever been observed, despite intensive and prolonged searches. We pursue an alternative strategy, namely that of realising them not as elementary but rather as emergent particles, i.e., as manifestations of the correlations present in a strongly interacting many-body system. The most prominent examples of emergent quasiparticles are the ones with fractional electric charge e/3 in quantum Hall physics. Here we show that magnetic monopoles do emerge in a class of exotic magnets known collectively as spin ice: the dipole moment of the underlying electronic degrees of freedom fractionalises into monopoles. This enables us to account for a mysterious phase transition observed experimentally in spin ice in a magnetic field, which is a liquid-gas transition of the magnetic monopoles. These monopoles can also be detected by other means, e.g., in an experiment modelled after the celebrated Stanford magnetic monopole search.

Before the Big Bang?

A talk by Roger Penrose: Before the Big Bang? A new perspective on the Weyl curvature hypothesis

The Brightest Supernova So Far

SN 2006gy: Discovery of the most luminous supernova ever recorded, powered by the death of an extremely massive star like Eta Carinae

We report our discovery and observations of the peculiar Type IIn supernova SN2006gy in NGC1260, revealing that it reached a peak magnitude of -22, making it the most luminous supernova ever recorded. It is not yet clear what powers the total radiated energy of 1e51 erg, but we argue that any mechanism -- thermal emission, circumstellar interaction, or 56Ni decay -- requires a very massive progenitor star. The circumstellar interaction hypothesis would require truly exceptional conditions around the star probably experienced an LBV eruption like the 19th century eruption of eta Carinae. Alternatively, radioactive decay of 56Ni may be a less objectionable hypothesis. That power source would imply a large Ni mass of 22 Msun, requiring that SN2006gy was a pair-instability supernova where the star's core was obliterated. SN2006gy is the first supernova for which we have good reason to suspect a pair-instability explosion. Based on a number of lines of evidence, we rule out the hypothesis that SN 2006gy was a ``Type IIa'' event. Instead, we propose that the progenitor may have been a very massive evolved object like eta Carinae that, contrary to expectations, failed to completely shed its massive hydrogen envelope before it died. Our interpretation of SN2006gy implies that the most massive stars can explode earlier than expected, during the LBV phase, preventing them from ever becoming Wolf-Rayet stars. SN2006gy also suggests that the most massive stars can create brilliant supernovae instead of dying ignominious deaths through direct collapse to a black hole.

The Quantum Measurement Problem

This preprint Can the Quantum Measurement Problem be resolved within the framework of Schroedinger Dynamics and Quantum Probability? addresses a fundamental problem in the foundations of physics. Traditionally a quantum measurement consists of two physical subsystems: a quantum subsystem (like an atom) and a classical subsystem (like a measuring instrument). The quantum subsystem is modelled using the often counterintuitive framework of quantum theory and the classical subsystem is modelled using the less startling laws of classical physics. Each subsystem in isolation evolves in a reasonably straightforward deterministic fashion, but when the two subsystems are coupled together something rather mysterious happens: a quantum measurement, which is fundamentally probabilistic in nature.

Ultimately, it's expected that the "classical" subsystem should be modelled by quantum theory as well and so too the composite of the two subsystems. After all, the classic subsystem is in term made up of constituents (like atoms) which obey the laws of quantum theory. However, it's been difficult to work out a completely quantum description of the measurement process. So much so that there has even been speculation that consciousness might be irreducibly involved.

The Family Tree of the Placental Mammals

In PNAS Genomics, biogeography, and the diversification of placental mammals

Among the placental mammals, phylogenetic branching events have been inferred by using either nucleotide sequence data (4–11) or rare insertion/deletion patterns (12–15). Many of the results recognize four primary eutherian groups: Afrotheria, Xenarthra, Laurasiatheria, and Euarchontoglires. Afrotherians (e.g., elephants, hyraxes, manatees, aardvarks, tenrecs, and allies) are a clade of mammals that originated in Africa, and whose extant members still mostly remain on that continent with the exception of Asian elephants and sirenians such as the Florida manatee. The Xenarthra includes the sloths, armadillos, and anteaters that today are restricted to South and Central America (although some Xenarthra, such as the nine-banded armadillo, have recently dispersed to North America). The Laurasiatheria (e.g., bats, eulipotyphlans, pangolins, carnivores, perrisodactyls, and cetartiodactyls) is a diverse clade including extant lineages that originated in the ancient northern continent of Laurasia. The Euarchontoglires includes the species from five living mammalian orders (e.g., primates, treeshrews, flying lemurs, rabbits, and rodents). This last group remains the most controversial, and a number of recent studies have suggested it is not valid (4, 6, 7).

The Human Visual System is Tuned for Animals

From this PNAS article: Category-specific attention for animals reflects ancestral priorities, not expertise

Visual attention mechanisms are known to select information to process based on current goals, personal relevance, and lower-level features. Here we present evidence that human visual attention also includes a high-level category-specialized system that monitors animals in an ongoing manner. Exposed to alternations between complex natural scenes and duplicates with a single change (a change-detection paradigm), subjects are substantially faster and more accurate at detecting changes in animals relative to changes in all tested categories of inanimate objects, even vehicles, which they have been trained for years to monitor for sudden life-or-death changes in trajectory. This animate monitoring bias could not be accounted for by differences in lower-level visual characteristics, how interesting the target objects were, experience, or expertise, implicating mechanisms that evolved to direct attention differentially to objects by virtue of their membership in ancestrally important categories, regardless of their current utility.

Where do Supernovas Come From?

In the preprint Constraining the Type Ia Supernova Progenitor: The Search for Hydrogen in Nebular Spectra the investigator looks for hydrogen emissions that are expected by theories of supernova formation. This signal has not been detected to date.

The "Mean King's" Problem

Quantum theory makes many very peculiar predictions and worse, they have always been confirmed by experiment. First of all, quantum theory often gives only a probability for an outcome. Einstein disliked this, hence his comment "God does not play dice with the Universe".
A further odd situation is a mutually complementary set of measurements. In a two state quantum system (also known as spin 1/2), there are exactly two possible outcomes for any measurement. Depending on the state of the system and the measurement chosen, quantum theory assigns a probability to each outcome. If a measurement is performed on a system and the actual outcome is noted, the new state of the system is determined - there's no addition influence from the original state. Two measurements X and Y are complementary when the probabilities of the two possible outcomes of Y performed immediately after X, are equally likely. In this case, performing X first completely randomizes Y's outcomes. The definition of a mutually complementary set of measurements is: each pair of measurements is complementary. As it turns out, in quantum theory for a two state system, we may have a set of three mutually complementary measurements, but no more.

The preprint The "mean king's problem" with continuous variables explains the "mean king's" problem:

In its original version [1] (and as
retold in the whimsical setting of Refs. [2, 3]), a physicist,
Alice, is challenged by a mean king to precisely ascer-
tain the outcome of an ideal measurement that the king
performs of a spin-1/2 observable randomly chosen from
the mutually complementary set {ˆσx, ˆσy, ˆσz}.

So first Alice gets access to the system (she can perform measurements and observe the outcome), then without Alice being present the King gets to choose and perform one of the three complementary measurements and notes the outcome. Alice returns and may perform additional measurements on the system. Finally the King reveals which measurement he performed and Alice must predict the outcome.

How can Alice possibily do such a thing? As it turns out, it's crucial that Alice uses an auxillary quantum system. She performs her measurements not just on the King's system, but on a composite system which includes her auxillary. She seperates the original system and her auxillary while the King is doing his thing but recomposes them when she gets her second shot.

Cosmic Microwave Background Anomalies

Probing the Origin of the Large-angle CMB Anomalies

There has been mounting evidence that the large-angle cosmic microwave background (CMB) anisotropy has anomalies roughly at 3 sigma level.

Overhang

Overhang

How far over the edge of the table can we reach by stacking n identical, homogeneous, frictionless blocks of length 1? A classical solution achieves an overhang asymptotic to 1/2 ln n. This solution is widely believed to be optimal. We show, however, that it is exponentially far from optimality by constructing simple n-block stacks that achieve an overhang of cn^1/3, for some constant c>0.

With the restriction that only one block can be on top of another, the classical solution is optimal. However with multiple blocks on top of each the solution can be improved significantly.

Reason and the Passions

"Reason is, and ought only to be the slave of the passions, and can never pretend to any other office than to serve and obey them"
David Hume

Childhood Origins of Adult Resistance to Science

Childhood Origins of Adult Resistance to Science in Science Magazine.

Resistance to certain scientific ideas derives in large part from assumptions and biases that can be demonstrated experimentally in young children and that may persist into adulthood. In particular, both adults and children resist acquiring scientific information that clashes with common-sense intuitions about the physical and psychological domains. Additionally, when learning information from other people, both adults and children are sensitive to the trustworthiness of the source of that information. Resistance to science, then, is particularly exaggerated in societies where nonscientific ideologies have the advantages of being both grounded in common sense and transmitted by trustworthy sources.

Accelerated Expansion

Astrophysics preprint Chasing Lambda

Recent astronomical observations of SNIa, CMB, as well as BAO in the Sloan Digital Sky Survey suggest that the current Universe has entered a stage of an accelerated expansion with the redshift transition at about z=0.5. While the simplest candidates for explanation of this fact is cosmological constant/vacuum energy there exist a serious problem of coincidence. In the theoretical cosmology we can find many possible approaches alleviating this problem by applying new physics or other conception of dark energy. We consider state of art candidates for the description of accelerating Universe in the framework of the Bayesian model selection. We point out advantages as well as troubles of this approach. We find that the combination of four data bases gives a stringent posterior probability of the LambdaCDM model which is 74%. This fact is a quantitative exemplification of a turmoil in modern cosmology over the Lambda problem.

Ultra Compact Dwarf Galaxies

In the astrophysics preprint UCDs - more massive than allowed?, Ultra Compact Dwarf Galaxies (UCD) found in Galaxy Clusters are observed to have a very high mass to light ratio. One possible explanation is an extraordinarily dense concentration of Dark Matter.

Chimpanzees are insensitive to fairness

Chimpanzees Are Rational Maximizers in an Ultimatum Game in Science Magazine.

Traditional models of economic decision-making assume that people are self-interested rational maximizers. Empirical research has demonstrated, however, that people will take into account the interests of others and are sensitive to norms of cooperation and fairness. In one of the most robust tests of this finding, the ultimatum game, individuals will reject a proposed division of a monetary windfall, at a cost to themselves, if they perceive it as unfair. Here we show that in an ultimatum game, humans' closest living relatives, chimpanzees (Pan troglodytes), are rational maximizers and are not sensitive to fairness. These results support the hypothesis that other-regarding preferences and aversion to inequitable outcomes, which play key roles in human social organization, distinguish us from our closest living relatives.

Gould's Belt

Many of the bright stars in the spectacular constellations Orion and Scorpio are a part of Gould's Belt a nearby ring of stars - the cause of which is still unknown.

Cosmic Reionization

In the Big Bang model of cosmology, early in the history of the universe it was too hot for neutral hydrogen gas, all the electrons were stripped from the nucleus (usually a proton), and the hydrogen gas filling the universe was ionized. As the universe expanded, the temperature cooled enough for neutral hydrogen, and the electrons became bound to protons. At some point stars began to form and the ultraviolet radiation the stars radiated was sufficient to ionize hydrogen gas once again - cosmic reionization. In this preprint Testing Reionization with Gamma Ray Burst Absorption Spectra the era of reionization is studied by looking for very ancient gamma ray bursts, the most energetic events known in the universe.

Communication with Gravitational Waves?

Generation and detection of gravitational waves at microwave frequencies by means of a superconducting two-body system

In engineering, it could open up the possibility of intercontinental communications by means of microwave-frequency gravitational waves directly through the interior of the Earth, which is transparent to such waves. This would eliminate the need of communications satellites, and would allow an economical means of communication with people deep underground or underwater in submarines in the oceans. Such a new direction of gravitational-wave engineering could aptly be called “gravity radio”

Chilling Account of the "Storm Worm"

Gathering 'Storm' Superworm Poses Grave Threat to PC Nets by Bruce Schneier. See also his blog: Schneier on Security for interesting information on security and privacy.

How to Grow a Silicon Crystal

It's not easy!
Czochralski Crystal Growth Method from the BBC.

Czochralski Crystal Growth Process tells more about why it is difficult.

Britney's Guide to Semiconductor Physics

Britney's Guide to Semiconductor Physics
It is a little known fact, that Ms Spears is an expert in semiconductor physics. Not content with just singing and acting, in the following pages, she will guide you in the fundamentals of the vital laser components that have made it possible to hear her super music in a digital format.

Vanadium Dioxide is Fast

Timing nature’s fastest optical shutter

It's nature's fastest quick-change artist: In less than the time it takes a beam of light to travel a tenth of a millimeter, vanadium dioxide can switch from a transparent to a reflective, mirror-like state.
How this material (VO2) can turn from a transparent insulator into a reflective metal so rapidly has physicists scratching their heads, but a collaboration among researchers at Vanderbilt, Oak Ridge National Laboratory and Lawrence Berkeley National Laboratory has clocked the transfiguration at one-tenth of a trillionth of a second.

More on the Pioneer Anomaly

Here's the abstract from a new preprint: Physics Engineering in the Study of the Pioneer Anomaly

The Pioneer 10/11 spacecraft yielded the most precise navigation in deep space to date. However, their radio-metric tracking data received from the distances between 20--70 astronomical units from the Sun has consistently indicated the presence of a small, anomalous, Doppler frequency drift. The drift is a blue frequency shift that can be interpreted as a sunward acceleration of a_P = (8.74 +/- 1.33) x 10^{-10} m/s^2 for each particular spacecraft. This signal has become known as the Pioneer anomaly; the nature of this anomaly remains unexplained.
Recently new Pioneer 10 and 11 radio-metric Doppler and flight telemetry data became available. The newly available Doppler data set is significantly enlarged when compared to the data used in previous investigations and is expected to be the primary source for the investigation of the anomaly. In addition, the flight telemetry files, original project documentation, and newly developed software tools are now used to reconstruct the engineering history of both spacecraft. With the help of this information, a thermal model of the Pioneer vehicles is being developed to study possible contribution of thermal recoil force acting on the two spacecraft. The ultimate goal of these physics engineering efforts is to evaluate the effect of on-board systems on the spacecrafts' trajectories.

Here's a previous post on the Pioneer Anomaly.

30 Rock

I haven't actually watched this show, but it's having a season premier this week. As I understand it, Alec Baldwin does a good job playing Jack, a crazy network executive in the show. There's a review in the New York Times Sophomore Jitters and Seinfeld Vision :

Jack has decided to increase advertising revenues by digitally inserting Mr. Seinfeld into NBC shows like “Law & Order” and “Deal or No Deal.” Jack calls his computer-generated fakery “SeinfeldVision.” The counterfeited comedian shows up at Rockefeller Center to complain, and that’s when the show goes a little wobbly: Mr. Seinfeld is strangely ill at ease playing himself, making his self-impersonation unpersuasive.

Tina Fey is the creator of the show and also appears in it. In real life she has a family and a very busy schedule - here's a quote from a recent interview:

"At home,” she added, “I cry” — about, among other things, not being home enough.

A census of nearby galaxies

In Mining the Local Volume 550 galaxies have been found within 10 million parsecs. A surprising observation was that there seems to be an absence of dark matter outside of the galaxy groups - if I understood the paper correctly. The preprint had some nice graphics too!

The Ant Nebula

The gorgeous Ant Nebula image from the .Hubble Space Telescope

Surprisingly Evolved Galaxies in the Early Universe

This astrophysics preprint describes A Population of Massive and Evolved Galaxies at z>=5, when the universe was less than a billion years old, which "... seems surpising at first sight". z is the redshift which according to the standard Big Bang models of cosmology is related to the age of the galaxy.

The galaxies found in this study are remarkable in that they contain a large stellar mass, have small physical sizes and that their main epoch of star formation occured at z >= 10. Galaxies with similar properties have, however, also been found by others.

Here's another preprint Morphologies of Two Massive Old Galaxies at z ~ 2.5 which says

Considerable observational evidence has built up over
the past few years that a substantial fraction of the mas-
sive galaxies around us today were already massive at
very early epochs.

the Jailing of Black America

Chilling statistics from the New York Times article: Jena, O. J. and the Jailing of Black America by ORLANDO PATTERSON of Harvard University.

America has more than two million citizens behind bars, the highest absolute and per capita rate of incarceration in the world. Black Americans, a mere 13 percent of the population, constitute half of this country’s prisoners. A tenth of all black men between ages 20 and 35 are in jail or prison; blacks are incarcerated at over eight times the white rate.

The effect on black communities is catastrophic: one in three male African-Americans in their 30s now has a prison record, as do nearly two-thirds of all black male high school dropouts.
...
The rate at which blacks commit homicides is seven times that of whites.

Something is very wrong - obviously. See Prof. Patterson's article for his perhaps surprising views.

I don't think that word means what you think it means

“Today, a megayacht is indispensable,” said Olivier Milliex, head of yacht finance at the Dutch bank ING. “It’s not like 15 years ago, when a yacht was a luxury item.”
[emphasis added]

from The New York Times: For the Yachting Class, the Latest Amenity Can Take Flight

Boston Molasses Disaster

The Boston Molasses Disaster of 1919 has to be one of the most bizzare calamities ever.

"A large molasses tank burst and a wave of molasses rushed through the streets at an estimated 35 mph (56 km/h), killing 21 and injuring 150. The event has entered local folklore, and residents claim that on hot summer days the area still smells of molasses."

Though I used to live less than a mile away and still live fairly nearby, I don't ever remember hearing of this event.

Great Storm of 1953

Speaking of winter weather, The Great Storm of 1953 in the North Sea was one of the great weather catastrophes in recent history. While 1,835 lost their lives in Holland, a much great calamity was narrowly avoided - from Wikipedia:

The Schielandse Hoge Zeedijk dyke along the river Hollandse IJssel was all that protected three million people in the provinces of South and Noord Holland from flooding. A section of this dyke, known as the Groenendijk, was not reinforced with stone revetments. The waterlevel was just below the crest and the seaside slope was weak. Volunteers worked to reinforce this stretch. Neverthelesss, the Groenendijk collapsed under the pressure around 5:30 am on 1 February. The seawater moved into the deep polder. In desperation, the mayor of Nieuwerkerk commandeered the river ship de Twee Gebroeders (The Two Brothers) and ordered the owner to plug the hole in the dike by navigating the ship into it. Fearing that the ship might break through and dive into the polder, captain Arie Evegroen took a row boat with him. The mayor's plan turned out to be successful, as the ship lodged itself firmly into the dike, saving many lives.

The North Atlantic Oscillation

For the past five years I've spent several weeks each winter with the Humpback Whales of the Silver Bank in the Dominican Republic. I'm planning to go again this year. Naturalist Tom Conlin of Aquatic Adventures leads expeditions that give us the opportunity to observe these magnificent animals and their fascinating behaviour.

Being moored 80 miles offshore on the Silver Bank, I've taken a keen interest in the weather. In the winter of 2005 (February/March) in particular, I noticed a seemingly relentless series of "cold fronts" which brought high winds, rain and cooler weather from the north. Typically the wind on the Silver Bank (which is north of the Dominican Republic and south of the Turks and Caicos) blows from the east at 10-15 knots and brings pleasant warm temperatures in the 80's farenheight. The cold fronts would bring higher winds (20-30 knots), cooler temperatures and rain, often in a series of very localized squalls.

The North Atlantic Oscillation seems to be a major factor in the winter weather for a vast region including the Silver Bank: see the maps on this NAO page at Columbia University. It appears that when the NAO index is negative, the easternly winds reaching the Silver Bank will be weaker. The page also says the the Eastern U.S. experiences more cold air outbreaks. The Silver Bank cold fronts seemed to originate from cold systems in the U.S. which then moved south (my interpretation from looking at the satellite weather maps available on the boats).

So the question is: was the NAO index actually particularly negative in the winter of 2005? And of course, what are is prospect for the upcoming winter of 2008?

And the answer is ...

Apparently the NAO index was dropping rapidly in the winter of 2005, it was in transition from a fairly high index to a fairly low one. Here's a graphic I found at NOAA.

NOAA graphic

The next step would be to find actual weather data for the region as opposed to relying on my subjective recollections.

How to Steal Cars?

RESEARCHERS SAY THEY'VE HACKED CAR DOOR LOCKS

"KeeLoq is badly broken," the paper says, adding, tongue-in-cheek, "Soon, cryptographers will all drive expensive cars."

Unknown Symmetry in Mesons?

Towards understanding broad degeneracy in non-strange mesons
Authors: S.S. Afonin
Abstract: The spectroscopic regularities of modern empirical data on the non-strange mesons up to 2.4 GeV can be summarized as a systematic clustering of states near certain values of energy. It is getting evident that some unknown X-symmetry triggers the phenomenon. We review the experimental status of this symmetry and recent theoretical attempts put forward for explanation of broad degeneracy.

preprint

By the way, a meson is a strongly interacting particle composed of a quark-antiquark pair.

A bright millisecond radio burst of extragalactic origin

D. R. Lorimer, M. Bailes, M. A. McLaughlin, D. J. Narkevic, F. Crawford
(Submitted on 27 Sep 2007)
Abstract: Pulsar surveys offer one of the few opportunities to monitor even a small fraction (~0.00001) of the radio sky for impulsive burst-like events with millisecond durations. In analysis of archival survey data, we have discovered a 30-Jy dispersed burst of duration <5 ms located three degrees from the Small Magellanic Cloud. The burst properties argue against a physical association with our Galaxy or the Small Magellanic Cloud. Current models for the free electron content in the Universe imply a distance to the burst of <1 Gpc No further bursts are seen in 90-hr of additional observations, implying that it was a singular event such as a supernova or coalescence of relativistic objects. Hundreds of similar events could occur every day and act as insightful cosmological probes.

A bright millisecond radio burst of extragalactic origin

A pulsar is thought to be a rotating neutron star.

The Small Magellanic Cloud is a satellite galaxy of our Milky Way, it's visible in the Southern Hemisphere.

The Sun is Peculiarly Deficient in Lithium

According to the preprint below, the sun has a strangely low amount of Lithium.

"For example, the depletion in the
observed solar Li abundance by about a factor of 200
relative to that found in meteorites is not explained by
standard stellar evolution models. Since more physically
realistic models, calculated from basic principles, cannot
be computed yet, non-standard stellar evolution models
have to introduce free parameters to reproduce the ob-
served Li depletion"

"The Sun appears to be lithium-poor by a factor of 10 com-
pared to similar solar type disk stars"

HIP 56948: A Solar Twin With a Low Lithium Abundance

Sun's 'twin' an ideal hunting ground for alien life in New Scientist.

The Proton Spin Problem

The proton (and neutron) are supposed to be composed of quarks and gluons. The spin of the proton is known. It would be nice to be able to calculate the spin based on the physics of its components - presumably the Standard Model of particle physics. This has proved difficult. Here's a recent preprint discussing the problem:

Resolution of the Proton Spin Problem
Authors: F. Myhrer, A.W. Thomas
(Submitted on 26 Sep 2007)
Abstract: A number of lines of investigation into the structure of the nucleon have converged to the point where we believe that one has a consistent explanation of the well known proton spin crisis.

preprint

Search for a Solution of the Pioneer Anomaly

Search for a Solution of the Pioneer Anomaly
Authors: Michael Martin Nieto, John D. Anderson
(Submitted on 25 Sep 2007)
Abstract: In 1972 and 1973 the Pioneer 10 and 11 missions were launched. They were the first to explore the outer solar system and achieved stunning breakthroughs in deep-space exploration. But beginning in about 1980 an unmodeled force of 8 X 10^-8 cm/s^2, directed approximately towards the Sun, appeared in the tracking data. It later was unambiguously verified as being in the data and not an artifact. The cause remains unknown (although radiant heat remains a likely origin). With time more and more effort has gone into understanding this anomaly (and also possibly related effects). We review the situation and describe ongoing programs to resolve the issue.

preprint

a previous pioneer anomaly post

William Henry Fox Talbot - Pioneering Photographer

"(In) October, 1833, I was amusing myself on the lovely shores of the Lake of Como in Italy, taking sketches with a Camera Lucida, or rather, I should say, attempting to make them; but with the smallest possible amount of success...
After various fruitless attempts I laid aside the instrument and came to the conclusion that its use required a previous knowledge of drawing which unfortunately I did not possess.
I then thought of trying again a method which I had tried many years before. This method was to take a Camera Obscura and to throw the image of the objects on a piece of paper in its focus - fairy pictures, creations of a moment, and destined as rapidly to fade away...
It was during these thoughts that the idea occurred to me... how charming it would be if it were possible to cause these natural images to imprint themselves durably and remain fixed on the paper!"

William Henry Fox Talbot on Wikipedia

Franklin, the Lightning Rod Known Round the World

Book review in the New York Times by By WILLIAM GRIMES Published: August 16, 2005.

Pennsylvania Academy of the Fine Arts

STEALING GOD'S THUNDER
Benjamin Franklin's Lightning Rod and the Invention of America
By Philip Dray

Unlike many of his European counterparts, Franklin showed a distinctly American obsession with practicality and efficiency. As a child he suggested to his father that if all the meat being salted for the winter meals were blessed at once, it would not be necessary to say grace at each meal, resulting in "a vast saving of time."

I like Ben!

General Relativity Resolves Galactic Rotation Without Exotic Dark Matter

by F. I. Cooperstock, S. Tieu, Preprint in the physics archive.

The stars in galaxies are observed to have "flat rotation curves", the velocity of the stars is the same, independent of their distance from the center of their galaxy. However, when we look at the distribution of luminous matter in the galaxies, Newtonian gravity predicts that the velocity of stars should fall off. Hence all the buzz about "Dark Matter", that there must be non-luminous matter in galaxies which is causing the stars to rotate uniformly.
However, Newtonian gravity is not the final word. Einstein's 1915 theory of gravity, General Relativity, makes more accurate predications. It was thought though, that because gravity is very weak in galaxies (apart from black holes and the small supermassive region at the very center of the galaxies) that the differences between Newton's theory and Einstein's theory would be insignificant.
To the contrary, the authors point out that the differences are very significant. They claim to reproduce the observed rotation curves with a quite reasonable distribution of matter, consistent with the observed distribution of luminous matter using General Relativity instead of Newtonian gravity.
There's been a veritable industry of Dark Matter research with all kinds of exotic proposals for new, hereto unobserved forms of matter. This now appears superfluous.

The Arrow of Time and the Initial Conditions of the Universe

by Robert M. Wald. preprint at the physics archive.

Wald is critical of "inflation" the standard explanation for some of the key features of the Big Bang.

In This Corner, in the Flouncy Skirt and Bowler Hat...

By JUAN FORERO
Published: July 21, 2005 article in the New York Times


Noah Friedman-Rudovsky for The New York Times

Wrestlers warming up in El Alto, Bolivia, near La Paz. Indigenous women, dressed in their traditional garb, are the stars of the increasingly popular bouts, Bolivia’s version of the World Wrestling Federation

Thickness of ventromedial prefrontal cortex in humans is correlated with extinction memory

Article published online in PNAS.

The ventromedial prefrontal cortex is a part of the brain which has been show to be involved in fear extinction. In this study, the subjects were conditioned to associate a light with an electric shock. Then they were shown the light without the shock - the extinction phase. The next day they were again shown the light with no shock, to test "extinction retention". Skin conductivity was used to measure fear. There was a correlation between the thickness of the medial orbitofrontal cortex and lower skin conductivity.


Jack in "24" could be pretty thick.

Flying Snakes

Check out the flyingsnake.org web site for images and movies of the flying snakes of Asia. They jump from trees and then glide of course, they don't truly fly.

Brain Under Surveillance: The Microglia Patrol

Perspective in Science Magazine.


Microglia patrol the brain and shield it from injury. Microglia continually extend (green) and retract (yellow) processes, surveying their immediate environment within the brain. The processes move rapidly toward a site of injury, such as a damaged blood vessel in the brain, in response to the localized release of a chemoattractant (gradient of orange) from the injured sited. Once at the target site, the processes form a barrier to protect healthy tissue.
CREDIT: PRESTON HUEY/SCIENCE

Researchers have used two-photon microscopy on living mouse brains to image microglia (common brain immune cells) in motion. They genetically engineered the mice so that their microglia were fluorescently labeled.

A previous microglia post

The Pioneer Anomaly

from NASA

The Pioneer and Voyager spacecraft are furthest from the Sun of any spacecraft launched so far. They are experiencing a small but apparently significant unexplained sunward acceleration. There's a proposal to launch a new mission to understand this phenomenon: A Mission to Explore the Pioneer Anomaly

Saturn's Rings

Waves and Small Particles in Ring A

See the full explanation and an even larger version of this gorgeous image at JPL/NASA

Stephan’s Quintet

Stephan's Quintet as imaged by the Gemini Observatory using the Multi-Object Spectrograph on Gemini North. The interacting members of the cluster are almost 300 million light years away. The galaxy NGC 7320 (top–center) is thought by most astronomers to be in the foreground (about 8 times closer) and is distinguished in this image by multiple red blobs indicating hydrogen clouds where stars are forming. Orientation: North–bottom, East–right.
Galactic Contortionists Captured by Gemini

From the image gallery at the National Optical Astronomy Observatory.

New Pillow from Japan

TOKYO - A new product on the Japanese market has been designed for the single girl in need of some manly comfort while she sleeps.

The “Boyfriend Arm’s Pillow” is shaped like a giant arm which will hold you all night without the need for the real thing.

The almost life-size boyfriend pillow is the product of the Japanese bed linen maker, Kameo Corp., located in the Japanese city of Fukuoka. The company already sold more than 1,000 pillows since its launch last year. It costs $80 dollars (8,500 yen) and is currently only sold in Japan on the Internet.
Kameo is now planning to upgrade the pillow by producing different models, including a muscular one. And the company is also working on the prototype for a fake female lap shaped pillow targeting male users.

The company says the shape of the pillow does not just provide the illusion of having someone sleeping next to you. Tomoki Kakehashi of Kameo says the unique structure keeps the human body balanced by supporting the sleeper from both sides.

“My grandmother used to say that there is nothing more comfortable pillow than human,” says Kakehashi. “I always thought someone’s lap is the best pillow for me. So, I thought that maybe women want to sleep on the arm shaped pillow. As a fact, my kids always like to sleep on my arm. Human pillow seems to be warm and healing. This is why I made this arm shaped pillow.”

Saddam Hussein the Literary Lion Roars Again

Article in the New York Times on Saddam Hussein's latest literary effort. Doubt I'll read it (it's only available in Arabic at the moment) but the cover is cool.

Fire Ants Start a Sexual Revolution

Selfish genes. Fire ant queens and males fight the battle to propagate their genes by reproducing clonally.
CREDIT: Hawaii State Department of Agriculture


Do females fire ants belong to a different species than the males?

News report inScience.

Nature news:

Males pit their genes against females by chucking DNA out of eggs.
The sperm of the male ant appears to be able to destroy the female DNA within a fertilized egg, giving birth to a male that is a clone of its father. Meanwhile the female queens make clones of themselves to carry on the royal female line

From Evolutionary biology: Males from Mars in Nature

In an ant species — or is it two species? — females are produced only by females and males only by males. Explanations of this revelation have to invoke some decidedly offbeat patterns of natural selection.

Apparently in this species of fire ant (which is a quite common pest), queens pass on their genes to daughter queens without mixing in male genes - this is not the case in most ant species. Males somehow managed to take revenge, sons contain only the genes of their fathers. However workers, which are sterile, are still reproduced sexually! Bizarre.

Why does the Moon appear larger when it's on the horizon?

We just had a spectacular June moon conincident with the summer solstice - see this article on the BBC for example.

Why does the moon (or the sun) look bigger when it's on the horizon? First of all, the image of the moon isn't actually smaller when it's high in the sky. Compare it to a coin held at arm's length when it's high and when it's low and you'll see it's the same. (Though the moon can be bigger on particular days, such as we had recently).

The explanation is that we judge the moon to be futher away when it is on the horizon, because we have objects on the horizon for comparison. See this page at IBM for more details.

Brain Scans of Female Orgasms

The BBC and numerous other sites reported Dutch research of brain scanning couples having orgasms. The couples took turns manually stimulating each other while one partner had their head in a brain scan machine. First, there was little to report about male orgasms, they were too brief to register on current scanning devices. Also cold feet were a problem - literally. Only 50% of the couples were able to achieve orgasm with bare feet, while 80% could come wearing socks. Definitely something to keep in mind.
As it turns out, no particular part of the brain was activated during female orgasm - but there were definitely large parts of the brain deactivated. Specifically the parts of the brain associated with higher mental functions shut down, but also parts of the brain which are associated with the emotion of fear.
The women were also asked to fake an orgasm. The researchers reported they were quite convincing to the observer, but the difference was obvious on the brain scans.


Genuine orgasm: less brain actvity


Tell tale brain activity in a fake orgasm

a 'Jennifer Aniston' cell?

In Nature this week, there's a report and a News and Views article supporting the previously dismissed idea of a "grandmother cell".

How do neurons in the brain represent movie stars, famous buildings and other familiar objects? Rare recordings from single neurons in the human brain provide a fresh perspective on the question.

'Grandmother cell' is a term coined by J. Y. Lettvin to parody the simplistic notion that the brain has a separate neuron to detect and represent every object (including one's grandmother). The phrase has become a shorthand for invoking all of the overwhelming practical arguments against a one-to-one object coding scheme. No one wants to be accused of believing in grandmother cells. But on page 1102 of this issue, Quiroga et al.3 describe a neuron in the human brain that looks for all the world like a 'Jennifer Aniston' cell. Ms Aniston could well become a grandmother herself someday. Are vision scientists now forced to drop their dismissive tone when discussing the neural representation of matriarchs?

A specific neuron responded to pictures of Ms. Aniston


But not however, when she was depicted with Brad Pitt
(watch that hand, Jennifer!)

Astronomical pacing of late Palaeocene to early Eocene global warming events

Letter in Nature.

The Palaeocene−Eocene thermal maximum was a strong global warming event about 55 million years ago. The authors discovered another, somewhat smaller warming episode which occurred about 2 million years later. They related these events to periodic changes in Earth's orbital parameters. See also my previous blog entry on the Paleo/Eocene event.

Handbag Studio by Thomas Keneally

Thomas Keneally on how Schindler's list found him in Beverly Hills in Granta. Nice story.

The Story of O2

Banded Iron Formation

There's a really nice article in this week's Science about the history of gaseous oxygen in the earth's atmosphere. Everyone agreed that the earth started out without any gaseous diatomic oxygen. There was some debate about when free oxygen first appeared. Minerals older than 2.4 billion years or so showed no signs of oxidized iron (rust). But some researchers believed there was evidence of atmospheric oxygen even earlier. But now a detailed analysis of atmospheric sulfur chemistry supports the later date for oxygen. So there seems to have been a "Great Oxidation Event" around 2.4 billion years ago in which banded iron formations were laid down around the world. Photosynthetic algae appear at around 2.7 billion years ago and perhaps at that point they were producing enough oxygen to create the iron formations.

In the same issue of Science, there's also an article with evidence that the earth held on to its gaseous hydrogen for longer than previously thought, which would help explain some of the history of early life on the planet.

Neutrinos have Mass!

1987A supernova remnant near the center

Neutrinos are produced in several different ways: natural radioactivity here on earth; nuclear reactors; in copious quantities in the Sun and other stars; in supernovas (Wikipedia SN1987A article); and in the Big Bang (though these have yet to be detected, there's indirect evidence here Neutrino ripples spotted in space). In all cases they are ghostly particles, very hard to detect.

The Super-Kamiokande detector, half-filled with pure water. (Courtesy of the Institute for Cosmic Ray Research, the University of Tokyo.)

They were postulated theoretically by Wolfgang Pauli, but it took many years to actually find them.
For a long time one of the great mysteries of physics was the "Solar Neutrino Problem" - the actual number of neutrinos we could detect from the Sun was about a third of the expected flux. This was finally resolved by oscillations among the three types of neutrinos (hence the 1/3). This seems to imply, theoretically, that neutrinos have mass - which has yet to be measured, though it must be very, very small. Until the oscillations were discovered, it was usually assumed that neutrinos were massless, for both theoretical and experimental reasons.
Here are two "popular" articles by John N. Bahcall of Princeton:
Solar Neutrinos: A Popular Account and Solving the Mystery of the Missing Neutrinos

The three years 2001 to 2003 were the golden years of solar neutrino research. In this period, scientists solved a mystery with which they had been struggling for four decades. The solution turned out to be important for both physics and for astronomy. In this article, I tell the story of those fabulous three years.

Here's a recent, more technical review of Neutrino Physics in general by Boris Kayser.

There are many interesting questions about neutrinos which still need to be answered by new experiments (from Kayser).

1. How many neutrino species are there? Are there sterile neutrinos?
There's already an experiment (LSND) which suggests that there might be more than three types of neutrinos. If there are more than three types then there are combinations which do not even couple to the weak nuclear force - they would only interact via gravity. These are the so-called sterile neutrinos.

2. Are neutrinos their own antiparticles?
Charged particles cannot be their own antiparticle, an antiparticle must have the opposite electric charge. But neutrinos are, naturally, electrically neutral, so it's possible. It could be, however, that there's another conserved quantity the "lepton number". It's not clear whether there is such a quantity, but if there is, there thould be distinct antineutrinos.

3. Do neutrino interactions violate CP (charge/parity conservation)?
Why does the universe seem to be made almost entirely of matter, rather than equal amounts of matter and antimatter? CP violation occurs in quarks, but that doesn't appear to be sufficient to explain the observed matter/antimatter imbalance. Since we are made of matter not antimatter, perhaps neutrino interactions are the reason we exist!

Let us not forget neutrino poetry, by John Updike no less.

Recasting Mermin's multi-player game into the framework of pseudo-telepathy

Preprint by Gilles Brassard, Anne Broadbent, Alain Tapp

Entanglement is perhaps the most non-classical manifestation of quantum mechanics. Among its many interesting applications to information processing, it can be harnessed to reduce the amount of communication required to process a variety of distributed computational tasks. Can it be used to eliminate communication altogether? Even though it cannot serve to signal information between remote parties, there are distributed tasks that can be performed without any need for communication, provided the parties share prior entanglement: this is the realm of pseudo-telepathy.
One of the earliest uses of multi-party entanglement was presented by Mermin in 1990. Here we recast his idea in terms of pseudo-telepathy: we provide a new computer-scientist-friendly analysis of this game. We prove an upper bound on the best possible classical strategy for attempting to play this game, as well as a novel, matching lower bound. This leads us to considerations on how well imperfect quantum-mechanical apparatus must perform in order to exhibit a behaviour that would be classically impossible to explain. Our results include improved bounds that could help vanquish the infamous detection loophole.

In Mermin's game, n players are given a simple task which definitely requires communication in a classical setting. By using quantum techniques (involving the notorious concept of entanglement), the task can be performed without any communication at all - hence the "pseudo-telepathy".

The problem, by the way is very simple. It requires three or more players. Each is given an input bit (0 or 1). They are promised that the total number of input 1's is even. They each then produce an output bit. If the sum of the input bits is divisible by four, there should be an odd number of output 1's. If the sum of the input bits is not divisible by four, the sum of output bits should be divisible by two (an even number of output 1's).

Chi-hwa-seon a film by Im Kwon Taek

The Korean film festival continues with this period piece about the life of the 19th century Korean painter Ohwon. Beautiful photography but a somewhat chaotic story of a chaotic life and times.

By the way, in the shot on the cover of the DVD, I believe the characters are depicted in sexual intercourse. It's very hard to tell what's going on beneath those elaborate Korean costumes!



Chunhyang is another even more beautiful film by the same director.

The Isle, a film by Ki-duk Kim

A beautiful, cruel and disturbing Korean film. Pretty little fishing huts atop small barges are moored on an idyllic lake. The mute female proprietor provides fishing tackle, coffee and sex to visiting fishermen. Serial fish hook abuse ensues.

Redback Spiders

Andrade's web page is fascinating, not to mention that she must be most attractive spider copulation researcher imaginable!

Maydianne C.B. Andrade

Much of my current research involves studies of the sexually cannibalistic Australian redback spider (Latrodectus hasselti), and its close relatives, the black widows (genus Latrodectus). Redback spiders are intriguing because males actively 'encourage' females to cannibalize them while they mate. Unlike most other sexually cannibalistic species (e.g., praying mantids) where males attempt to escape from the female's jaws, redback males actually 'somersault' onto the female's mouthparts during copulation = male sexual sacrifice.

The copulatory somersault

(A) Copulation begins with the male standing on the female's abdomen. Both spiders are facing in the same direction and are 'belly to belly'. The male has two copulatory organs (the palps) that are attached at the anterior-most part of his 'head' (cephalothorax). Copulation begins when one of the palps is inserted into the female's genital opening. In most other black widow spiders, the pair copulates while in this posture.

(B) In redbacks, however, a few seconds after palp insertion, the male, using the palp as a pivot, moves into a 'headstand' posture.

(C) The male then quickly turns through 180 degrees, landing with his 'back' (the dorsal surface of the abdomen), directly above the female's fangs. In most matings, the female begins to extrude digestive enzymes almost immediately. She also pierces the male's abdomen with her fangs and begins to consume him while he is transferring sperm.

There's a video of this on her web site.
A previous spider mating post

Appearance DOES Matter

Which person is more babyfaced?
FROM TODOROV et al.
Perspective in Science.

Take a look at these two snapshots. Which man is more babyfaced? Most viewers would say it's the person on the right. And that's the person who lost a 2004 U.S. congressional election to his more mature-faced and competent-looking opponent. In fact, about 70% of recent U.S. Senate races were accurately predicted based on which candidates looked more competent from a quick glance at their faces. This remarkable effect, reported by Todorov et al. on page 1623 of this issue, likely reflects differences in "babyfacedness". A more babyfaced individual is perceived as less competent than a more mature-faced, but equally attractive, peer of the same age and sex. Although we like to believe that we "don't judge a book by its cover," superficial appearance qualities such as babyfacedness profoundly affect human behavior in the blink of an eye.

Rapid Acidification of the Ocean During the Paleocene-Eocene Thermal Maximum

According to the wikipedia entry "The end of the Paleocene (55.5/54.8 Ma) was marked by one of the most significant periods of global change during the Cenozoic, a sudden global change, the Paleocene-Eocene Thermal Maximum, which upset oceanic and atmospheric circulation and led to the extinction of numerous deep-sea benthic foraminifera and on land, a major turnover in mammals."

report in Science. Summary:

A rapid and large global warming event, the Paleocene-Eocene Thermal Maximum (PETM), raised interior ocean temperatures by 4º to 5ºC around 55 million years ago, a rise not equaled in any single event since then. This warming, whose origin is still debated, was accompanied by a dramatic negative carbon isotopic excursion. One hypothesis is that the release of 2000 gigatons of carbon from the destabilization of methane clathrates on the sea floor account for both the carbon isotopic signal and the temperature increase. Zachos et al. (p. 1611) now show that the carbonate compensation depth (roughly the depth at which calcium carbonate is no longer found in the sediment, because of dissolution during sinking) of the ocean rose by more than 2 kilometers during the PETM, which could have happened only if the amount of CO2 added to the ocean was much more than that which has been estimated in the clathrate scenario. They find that 4000 gigatons of carbon would have been needed, so the release of clathrates alone could not have been the cause of the warming.

Art of Science Competition at Princeton

Driven
Anton Darhuber, Benjamin Fischer and Sandra Troian
Microfluidic Research and Engineering Laboratory, Department of Chemical Engineering
SECOND PRIZE WINNER
This image illustrates evolving dynamical patterns formed during the spreading of a surface-active substance (surfactant) over a thin liquid film on a silicon wafer. After spin-coating of glycerol, small droplets of oleic acid were deposited. The usually slow spreading process was highly accelerated by the surface tension imbalance that triggered a cascade of hydrodynamic instabilities. Such surface-tension driven flow phenomena are believed to be important for the self-cleaning mechanism of the lung as well as pulmonary drug delivery.

gallery page at Princeton.

DNA of Deadbeat Voles May Hint at Why Some Fathers Turn Out to Be Rats

Larry J. Young/Yerkes National Primate Research Center
Prairie voles on gels of their DNA, a possible clue to their home life.

Excellent article in today's New York Times.

Some male prairie voles are devoted fathers and faithful partners, while others are less satisfactory on both counts. The spectrum of behavior is shaped by a genetic mechanism that allows for quick evolutionary changes, two researchers from Emory University report in today's issue of Science.
...
People have the same variability in their DNA, with a control section that comes in at least 17 lengths detected so far, Dr. Young said.
...
The Emory researchers recently noticed that in their prairie vole colony, some fathers spent more time with their pups and some less. They traced the source of this variability to its molecular roots, a variation in the length of the DNA region that controls a certain gene.

This is the gene for the vasopressin receptor, the device used by neurons to respond to vasopressin. Voles with long and short DNA segments had different patterns of vasopressin receptors in their brains, which presumably changed their response to the hormone.

In Voles, a Little Extra DNA Makes for Faithful Mates news article in Science.

Prairie voles are renowned for being faithful mates, but some individuals are more faithful than others. The difference may lie in their so-called junk DNA.

... Elizabeth Hammock and Lawrence Young of Emory University in Atlanta, Georgia, report that fidelity and other social behaviors in male prairie voles seem to depend on the length of a particular genetic sequence in a stretch of DNA between their genes. The longer this repetitive sequence, or microsatellite, the more attentive males were to their female partner and their offspring. Those with shorter microsatellites neglected their mates and pups, at least to some degree.

Although there's no evidence that human infidelity or poor parenting stems from similar variations, Hammock and Young, as well as other researchers, have begun to explore whether microsatellites can account for behavioral differences between people and primates such as chimps and bonobos.

Microsatellite Instability Generates Diversity in Brain and Sociobehavioral Traits: the research article on vole genetics and behaviour in today's Science Magazine.

Here is Young's web page at Emory University

QCD and Natural Philosophy

by Frank Wilczek. This is getting embarrassing! The embarrassment of Wilczek riches continues with this 2002 preprint at the physics archive.

His take on the "Reductionist Program"

The reductionist program, roughly speaking, is to build up the description of Nature from a few laws that govern the behavior of elementary entities, and that can't be derived from anything simpler. This definition is loose at both ends.
On the output side, because in the course of our investigations we find that there are important facts about Nature that we have to give up on predicting. These are what we - after the fact! - come to call contingencies. Three historically important examples of different sorts are the number of planets in the Solar System, the precise moment that a radioactive nucleus will decay, or what the weather will be in Boston a year from today. In each of these cases, the scientific community at first believed that prediction would be possible. And in each case, it was a major advance to realize that there are good fundamental reasons why it is not possible.
On the input side, because it is difficult - perhaps impossible - ever to prove the non-existence of simpler principles. I'll revisit this aspect at the end of the lecture.
Nevertheless, and despite its horrible name, the reductionist program has been and continues to be both inspiring and astoundingly successful. Instead of trying to refine an arbitrary a priori definition of this program, it is more edifying to discuss its best fruits. For beyond question they do succeed to an astonishing extent in "reducing" matter to a few powerful abstract principles and a small number of parameters.

Cosmology

Although it is usually passed over in silence, I think it is very important philosophically, and deserves to be emphasized, that our standard cosmology is radically modest in its predictive ambitions. It consigns almost everything about the world as we find it to contingency. That includes not only the aforementioned question of the number of planets in the Solar System, but more generally every specific fact about every specific object or group of objects in the Universe, apart from a few large-scale statistical regularities. Indeed, specific structures are supposed to evolve from the primordial perturbations, and these are only characterized statistically. In inflationary models these perturbations arise as quantum fluctuations, and their essentially statistical character is a consequence of the laws of quantum mechanics.
This unavoidably suggests the question whether we might find ourselves forced to become even more radically modest. Let us suppose for the sake of argument the best possible case, that we had in hand the fundamental equations of physics. Some of my colleagues think they do, or soon will. Even then we have to face the question of what principle determines the solution of these equations that describes the observed Universe. Let me again suppose for the sake of argument the best possible case, that there is some principle that singles out a unique acceptable solution. Even then there is a question we have to face: If the solution is inhomogeneous, what determines our location within it?

Another rationalization for considering the Anthropic Principle

As we have just discussed, the laws of reductionist physics do not suffice to tell us about the specific properties of the Sun, or of Earth. Indeed, there are many roughly similar but significantly different stars and planets elsewhere in the same Universe. On the other hand, we can aspire to a rational, and even to some extent quantitative, “derivation” of the parameters of the Sun and Earth based on fundamental laws, if we define them not by pointing to them as specific objects – that obviates any derivation – but rather by characterizing broad aspects of their behavior.
In principle any behavior will do, but possibly the most important and certainly the most discussed is their role in supporting the existence of intelligent observers, the so-called anthropic principle. There are many peculiarities of the Sun and Earth that can be explained this way. A crude example is that the mass of the Sun could not be much bigger or much smaller than it actually is because it would burn out too fast or not radiate sufficient energy, respectively.
Now if the Universe as we now know it constitutes, like the Solar System, an inhomogeneity within some larger structure, what might be a sign of it? If the parameters of fundamental physics crucial to life – just the ones we’ve been discussing! – vary from place to place, and most places are uninhabitable, there would be a signature to expect. We should expect to find that some of these parameters appear very peculiar – highly nongeneric – from the point of view of fundamental theory, and that relatively small changes in their values would preclude the existence of intelligent observers. Weinberg has made a case that the value of the cosmological term Lambda fits this description;and I’m inclined to think that ... and several other combinations of the small number of ingredients in our reduced description of matter and astrophysics do too. A fascinating set of questions is suggested here, that deserves careful attention.

The Unreasonable Ineffectiveness of QCD

There some aspects of QCD I find deeply troubling – though I’m not sure if I should!
I find it disturbing that it takes vast computer resources, and careful limiting procedures, to simulate the mass and properties of a proton with decent accuracy. And for real-time dynamics, like scattering, the situation appears pretty hopeless. Nature, of course, gets such results fast and effortlessly. But how, if not through some kind of computation, or a process we can mimic by computation?
Does this suggest that there are much more powerful forms of computation that we might aspire to tap into? Does it connect to the emerging theory of quantum computers? These musings suggest some concrete challenges: Could a quantum computer calculate QCD processes efficiently? Could it defeat the sign problem, that plagues all existing algorithms with dynamical fermions? Could it do real-time dynamics, which is beyond the reach of existing, essentially Euclidean, methods?
Or, failing all that, does it suggest some limitation to the universality of computation?
Deeply related to this is another thing I find disturbing. If you go to a serious mathematics book and study the rigorous construction of the real number system, you will find it is quite hard work and cumbersome. QCD, and for that matter the great bulk of physics starting with classical Newtonian mechanics, has been built on this foundation. In practice, it functions quite smoothly. It would be satisfying, though, to have a “more reduced” description, based on more primitive, essentially discrete structures. Fredkin and recently Wolfram have speculated at length along these lines. I don’t think they’ve got very far, and the difficulties facing such a program are immense. But it’s an interesting issue.

Inventory and Outlook of High Energy Physics

by Frank Wilczek. The list of well-written articles by Wilczek continues with this 2002 preprint at the physics archive.

"No Conclusion"

But all this progress should not mark an end. Rather it allows us to ask – that’s easy enough! – and (more impressive) to take meaningful, concrete stabs at answering some truly awesome questions. Do all the fundamental interactions derive from a single underlying principle? What is the quantum symmetry of space-time? To what extent are the laws of physics uniquely determined? Why is there any (baryonic) matter at all? What makes the dark matter? Why is there so little dark energy, compared to what it “should” be? Why is there so much, compared to everything else in the Universe? These are not merely popularizations or vulgarizations but genuine, if schematic, descriptions of a few of our ongoing explorations.

The Universe is a Strange Place

by Frank Wilczek. Continuing the Wilczek orgy - preprint in the physics archive. This time the subject is cosmology, instead of particle physics. The abstract:

TThis is a broad and in places unconventional overview of the strengths and shortcomings of our standard models of fundamental physics and of cosmology. The emphasis is on ideas that have accessible experimental consequences. It becomes clear that the frontiers of these subjects share much ground in common.

"Cosmology"

..., one set of exogenous parameters in the standard model of cosmology specifies a few average properties of matter, taken over large spatial volumes. These are the densities of ordinary matter (i.e., of baryons), of dark matter, and of dark energy.
We know quite a lot about ordinary matter, of course, and we can detect it at great distances by several methods. It contributes about 3% of the total density.
Concerning dark (actually, transparent) matter we know much less. It has been “seen” only indirectly, through the influence of its gravity on the motion of visible matter. We observe that dark matter exerts very little pressure, and that it contributes about 30% of the total density.
Finally dark (actually, transparent) energy contributes about 67% of the total density. It has a large negative pressure. From the point of view of fundamental physics this dark energy is quite mysterious and disturbing, as I’ll elaborate shortly below.

Cosmic Rays

Perhaps not quite so sharply posed, but still very promising, is the problem of the origin of the highest energy cosmic rays. It remains controversial whether there so many events observed at energies above those where protons or photons could travel cosmological distances that explaining their existence requires us to invoke new fundamental physics. However this plays out, we clearly have a lot to learn about the compositions of these events, their sources, and the acceleration mechanisms.

Is the Universe a Strange Place?

The observed values of the ratios ...[formulas for the cosmological density ratios] are extremely peculiar from the point of view of fundamental physics, as currently understood. Leading ideas from fundamental theory about the origin of dark matter and the origin of baryon number ascribe them to causes that are at best very remotely connected, and existing physical ideas about the dark energy, which are sketchy at best, don’t connect it to either of the others. Yet the ratios are observed to be close to unity. And the fact that these ratios are close to unity is crucial to cosmic ecology; the world would be a very different place if their values were grossly
different from what they are.
Several physicists, among whom S. Weinberg was one of the earliest and remains among the most serious and persistent, have been led to wonder whether it might be useful, or even necessary, to take a different approach, invoking anthropic reasoning. Many physicists view such reasoning as a compromise or even a betrayal of the goal of understanding the world in rational, scientific terms. Certainly, some adherents of the “Anthropic Principle” have overdone it. No such “Principle” can substitute for deep principles like symmetry and locality, which support a vast wealth of practical and theoretical applications, or the algorithmic
description of Nature in general. But I believe there are specific, limited circumstances in which anthropic reasoning is manifestly appropriate and unavoidable.

The highlighted opinion concurs with my own - for whatever that's worth. The Anthropic Principle seems like one of those things which get invoked when you run out of better ideas. That Weinberg and Wilczek, who have had many very good ideas indeed, are driven to this resort seems like a bad sign to me.

A Constructive Critique of the Three Standard Systems

by F. Wilczek. Preprint in the physics archive.
Abstract:

It has become conventional to say that our knowledge of fundamental physical law is summarized in a Standard Model. But this convention lumps together two quite different conceptual structures, and leaves out another. I think it is more accurate and informative to say that our current, working description of fundamental physics is based on three standard conceptual systems. These systems are very different; so different, that it is not inappropriate to call them the Good, the Bad, and the Ugly. They concern, respectively, the coupling of vector gauge particles, gravitons, and Higgs particles. It is quite a remarkable fact, in itself, that every nonlinear interaction we need to summarize our present knowledge of the basic (i.e., irreducible) laws of physics involves one or another of these particles.

More critical remarks on the Standard Model:

Looking critically at the structure of a single standard model family, as displayed in Figure 3, one has no trouble picking out flaws.
The gauge symmetry contains three separate pieces, and the fermion representation contains five separate pieces. While this is an amazingly tight structure, considering the wealth of phenomena described, it clearly fails to achieve the ultimate in simplicity and irreducibility. Let me remind you, in this context, that electroweak “unification” is something of a misnomer. There are still two separate symmetries, and two separate coupling constants, in the electroweak sector of the standard model. It is much more accurate to speak of electroweak “mixing”.
Worst of all, the abelian U(1) symmetry is powerless to quantize its corresponding charges. The hypercharge assignments – indicated in Figure 3 by the numerical subscripts – must be chosen on purely phenomenological grounds. On the face of it, they appear in a rather peculiar pattern. If we are counting continuous parameters, the freedom to choose their values takes us from three to seven (and more, if we restore the families). The electrical neutrality of atoms is a striking and fundamental fact, which has been checked to extraordinary precision, and which is central to our understanding of Nature. In the standard model this fact appears, at a classical level, to require finely tuned hand-adjustment.

Gravity

What makes this very tight, predictive, and elegant theory of quantum gravity “bad” is not that there is any experiment that contradicts it. There isn’t. Nor, I think, is the main problem that this theory cannot supply predictions for totally academic thought experiments about ultrahigh energy behavior. It can’t, but there are more pressing issues, that might have more promise of leading to contact between theory and empirical reality.
A great lesson of the standard model is that what we have been evolved to perceive as empty space is in fact a richly structured medium. It contains symmetry-breaking condensates associated with electroweak superconductivity and spontaneous chiral symmetry breaking in QCD, an effervescence of virtual particles, and probably much more. Since gravity is sensitive to all forms of energy it really ought to see this stuff, even if we don’t. A straightforward estimation suggests that empty space should weigh several orders of magnitude of orders of magnitude (no misprint here!) more than it does. It “should” be much denser than a neutron star, for example. The expected energy of empty space acts like dark energy, with negative pressure, but there’s much too much of it.
To me this discrepancy is the most mysterious fact in all of physical science, the fact with the greatest potential to rock the foundations. We’re obviously missing some major insight here. Given this situation, it’s hard to know what to make of the ridiculously small amount of dark energy that presently dominates the Universe!

The Flavor/Higgs Sector

We know of no deep principle, comparable to gauge symmetry or general covariance, which constrains the values of these couplings tightly. For that reason, it is in this sector where continuous parameters proliferate, into the dozens. Basically, we introduce each observed mass and weak mixing angle as an independent input, which must be determined empirically. The phenomenology is not entirely out of control: the general framework (local relativistic quantum field theory, gauge symmetry, and renormalizability) has significant consequences, and even this part of the standard model makes many non-trivial predictions and is highly over-constrained. ...
Neutrino masses and mixings can be accommodated along similar lines, if we expand the framework slightly. ... The flavor/Higgs sector of fundamental physics is its least satisfactory part. Whether measured by the large number of independent parameters or by the small number of powerful ideas it contains, our theoretical description of this sector does not attain the same level as we’ve reached in the other sectors. This part really does deserve to be called a “model” rather than a “theory”.

Another cute sarcastic remark (somewhat unfairly out of context):

Finally let me mention one redeeming virtue of the Higgs sector. (“Virtue” might be too strong; actually, what I’m about to do is more in the nature of advertising a bug as a feature.)