Breaking the Ice Shelf - Why Hide the Crack?

The ice shelf breaks away. Click to enlarge.

In December 2006 it was widely reported that the 25.5-square-mile Ayles ice-shelf broke free from Ellesmere island, some 500 miles south of the North Pole. (See the National Geographic report for more details.)

This event actually occurred in 2005 when it had been observed by satellite images (click here for animations of the event), but, according to Luke Copeland of the University of Ottawa Global Laboratory for Cryospheric Research, the information was not released until the reasons for the split could be determined.

Not surprisingly, Copeland and colleagues found that the event, which was sizeable enough to register on earthquake monitors 155 miles away, is consistent with global warming.

I understand that scientists should be as deliberate as possible in doing their research, and circumspect (or silent) about their work until all of the essential methodology of good scientific research prior to publishing are carried out.

But I find it incredibly surprising that the news of the ice-shelf breaking off was held back from publication for almost one-and-a-half years! After all, the ice-shelf cracking is incontrovertible data that is not in question. More important, it is essential data for all inhabitants of this planet.

Why was the news withheld?

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Locally Localized Gravity, or If I Only Had a Brane

The Institute of Contemporary Art (ICA), at the University of Pennsylvania will be running a very interesting show titled Locally Localized Gravity from January 20 - March 25, 2007.  From the ICA website description:

Locally Localized Gravity responds to an alternative mode of art making wherein artists produce events, run collectives and galleries, publish zines and small artist's books—generally acting as catalysts in their communities. In other words, they rarely focus only on traditional object-based practices. The exhibition, which will include over 100 artists, musicians, designers, lecturers, performers, and creators from Philadelphia and other cities, will be one non-stop event and on view in ICA's first floor galleries and terrace.

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The title is borrowed from string theory, a complex scientific term describing four-dimensional gravity (three dimensions of space and one of time). It was suggested to the curators by artist Matthew Ritchie, whose own work explores ideas of string theory, among many things. The term locally localized gravity can be applied to art scenes where artists, by generating a huge amount of energy, can create centers of gravity.

This description of the meaning of LLG is maximally condensed for public consumption.  It is not the point of the exhibit, nor the role of ICA to give a detailed explanation.  However, because I have participated in an ICA in the past, I was asked to send them a more detailed blurb on locally localized gravity. While my piece might not make the ICA material, I am posting my submission here because LLG touches on the most extreme questions one can ask of any physical model, namely what is the ultimate nature of the universe?

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In Praise of Friction The Media Slips Again

I recently posted a complaint about physics misconceptions promulgated by the media. To be fair, I need to report a good job describing the physics of a situation when it appears.

In an article posted on Dec. 27, 2006 by the op/ed staff of the North County Times (near San Diego), and titled A Physics Lesson, the authors do a very nice job of describing the role of friction in driving:

Your tires rely on friction to speed up, turn or stop. On a dry day, there's usually plenty of friction when the rubber hits the road. When it rains, the weight of your car must push water out of the way for the tires to reach the road.

The faster you drive, the greater amount of water your tires must push aside. If that water gets trapped between the asphalt and the tires, you'll lose control of your car -- you'll be hydroplaning. The lesson here is that when the roads are wet, you can't drive as fast as you would on a normal day. Even if the rain is light, slow down at least five to 10 mph.

When I teach a first-semester course in Physics, I typically begin the first day trying to get students to identify forces acting on them as they do basic things. My favorite example is on walking. I ask the following question: if you go from standing still to walking at a steady pace, you accelerated. According to Newton there must be an unbalanced force acting on you in the direction of your acceleration. What is this force?

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A Jolting Message: Hemingway's Snow and Climate Change

Kilimanjaro, then and now. Click to enlarge.I have remarked before on the ever-increasing media coverage given to global warming. As more and more scientific evidence comes in about the effects of global warming (see my recent post On the Increase in Greenland Ice Loss), the facts, interpretations, scientific theories, and political reactions to climate change are incredibly varied in the face of almost overwhelming evidence. Making sense of what is really happening, and how we should react, calls for insightful commentary from expert sources.

One such source is an article by Doug Macdougall of the Scripps Institution of Oceanography titled Jolting Messages on Climate Change. (The Chronicle, April 2006). In addition to his clear enunciation of global climate change facts and a strong call for "jolting messages" that will move "politicians and the public into effective action," Macdougall reviews five books about climate change published in 2005 and 2006:

• Climate Crash: Abrupt Climate Change and What it Means for our Future, by John D. Cox
• Field Notes From a Catastrophe: Man, Nature, and Climate Change, by Elizabeth Kolbert
• Kicking the Carbon Habit: Global Warming and the Case for Renewable and Nuclear Energy by William Sweet
• The Weather Makers: The History and Future Impact of Climate Change, by Tim Flannery
• The Winds of Change: Climate, Weather, and the Destruction of Civilizations, by Eugene Linden

According to Macdougall, each of these books have strong points. I encourage you to read Macdougall's reviews, which are very even-handed. Some of the authors are more pessimistic than the others in terms of what can be done (via science, engineering, politics), but all agree on the scope of the problem. Most of the books do take on the sudden climate changes that were first observed in studies of the Greenland ice sheet.

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Frisbees in Space: Gettin' Funky With Gravity

This is a cautionary tale of frisbees in space, and those in the media who report about them...

Probably the main issue in all of physics education is how to help students learn in the face of their often serious misconceptions about the nature of forces in the world. Most carry with them an Aristotelian view of physics, in which forces are needed for motion. This view is in direct contrast with Newton's Laws (specifically the First Law). According to Newton, forces are needed to change motion, i.e. accelerate an object.

The Aristotelian view leads to totally incorrect views of everyday situations, views that are repeated continually because they have become so ingrained in our thinking and reactions. For example,when a driver moves to the left when making a sharp-right-hand turn, the common statement is that there is a "centrifugal force" pushing leftward. There is no such force: the driver is moving straight while the car moves to the right. The driver then feels the door on the left - the inclination is then to assume that a force "pushed" the driver into the door. There are many other situations where we instinctively believe that a force is acting when in fact it isn't. (See Aristotelian Physics and Why We Hate It by R.G. Brown of Duke U.)

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It's No Fluke: When Mandates Meet Models

In today's news, NJ & NY fishermen are understandably upset because the allowed number of fluke permitted to be caught in the upcoming season has been reduced by 28%.  Just as the number of deer is regulated, with certain numbers of permits issued during deer season, several fish species, and spawning and feeding areas are tightly controlled.  Both of these "game" species are subject to three often irreconcilable forces: scientific predictions in the form of regulatory commissions, local needs of those relying on the game for a livelihood, and the contingencies of politics.

The amount of any species permitted to be caught ("harvested" in the parlance of population minders and modelers) is chosen with one of two possible goals:

1. to keep the overall population in a steady state, i.e. the harvesting rate is basically the net birth rate  (absolute birth rate - death rate)
2. to increase the overall population - i.e. the harvesting rate is greater than the net birth rate 

Presumably the 3rd option - harvesting faster than the series can regenerate, is not a consideration in game or food species, or there soon would be no species left.

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Predicting Nothing and Next - to - Nothing: A Nobel Thought

Temperature fluctuations in CMB. Click to enlarge.John Mather and George Smoot were named winners of the 2006 Nobel Prize in Physics this past month.  Their work on the NASA Cosmic Background Explorer (COBE) is primarily experimental.  The accuracy of their instruments and subsequent precision of their results are remarkable achievements.

What the measurements imply is even more remarkable, and is a great example of the deep interplay between understanding and prediction that happens when things break the right way, when theory and experiment mutually reinforce each other illuminating a deep secret about the universe.  ( Hence the Nobel prize...)

Mather and Smoot were checking on the two major predictions of inflationary Big Bang theory:

• The cosmic microwave background (CMB) - a measure of the intensity of radiation present in the universe as a function of wavelength.  Theory predicted that the measured radiation should follow an almost-perfect blackbody spectrum. (i.e. should follow the mathematical form first determined by Planck in 1900 - the beginning of Quantum Mechanics).  The major parameter used to fit CMB to a blackbody spectrum is temperature, hence finding an experimental blackbody curve can be a very accurate thermometer
• The temperature  of the CMB should vary very slightly for different portions of the sky, i.e. the universe.  It is only with these fluctuations that inflationary theory predicts the eventual clumping of interstellar matter to form stars, proto-galaxies and ultimately the solar system and planets.

Measured vs. Theoretical CMB. Click to enlarge.Click on the graph to the left to see a fit that's "almost perfect"  It is a graph of the experimentally measured spectrum superimposed on a black body function. The size of the data squares represent the uncertainties in measurement. The fit is astonishingly good - as perfect a fit as has ever been seen in an experiment as complex as the COBE. So the first piece of the puzzle came in as desired.  What about the temperature fluctuations?

The figure at the top of this post shows the temperature variation of the CMB over a certain region of the sky. Mather and Smoot measured incredibly tiny temperature variations - approx. 30 microkelvin, again, in line with theory.

So the Nobel goes to experimenters who measured "nothing" - i.e. no measurable deviation from a perfect black-body spectrum, and next-to-nothing - temperature variations so miniscule that a few clusters of atoms moving with slightly different velocities would throw off the results.

What to make of these results?  By themselves, the results are merely facts - interesting facts, to be sure, but simply facts.  It is only in coordination with theoretical predictions that these facts come alive - stating for all that there is something to the theory in the first place.  And, because of that very positive reinforcement, the data+theory yields an understanding about the universe that is much deeper, and stronger, than at any other stage in the history of the cosmological beliefs of Earth's inhabitants. 

The Evolution of the 40 - 40 Club

This just in from the Nov. 28, 2006 Onion -  Kansas Outlaws Practice Of Evolution:

TOPEKA, KS - Any living being that undergoes genetic modification favoring survival could face jail time under the new law.

A really clever piece on our favorite state, I enjoyed reading it today probably a whole lot more than if I had seen it yesterday - a day of unfortunate and fortunate events.

I was at Penn State attending a meeting of the Scientific Benchmark subcommittee of the PA Governor's Commission on College and Career Success.  The subcommittee's charge includes proposing revisions to the current PA state teaching standards.  This was my first meeting, and I was amazed to meet such an energetic and dedicated group of secondary and higher-ed faculty working on this important project.  Everyone in the room has one overarching goal - to ensure that ALL students learn essential mathematics and science concepts  and skills - necessary for success in today's, and especially tomorrow's world.

This was the fortunate event.

The unfortunate events were my reading two disturbing articles earlier in the day.  In one, I read a report of the August survey done by Jon Miller of Michigan State University. The results of the poll suggest that only 40% of the U.S. believe in evolution (BTW, the only country with a smaller percentage is Turkey, while countries such as Sweden and Denmark have an 80% belief rate)  Miller's study attributes this disturbing dichotomy as a perfect-storm effect of religion, politics, and LACK of GENERAL SCIENTIFIC KNOWLEDGE of core biological ideas.  (Check out the National Geographic report on the poll.) 

The other article was even more depressing:  The Chronicle of Higher Ed reported that in a survey by the American Council on Education, 46% of those polled said that colleges and universities should not require students to take more courses in math and science, while 46 percent said students should be required to do so. This deep division is evidence that all of the messages and news about American students falling farther and farther behind in terms of essential skills for the 21st Century are not being heard.  (Click here to read the original study - "Math and Science Education and United States Competitiveness: Does the Public Care?")

Where is the Math/Science PR?  With the constant stream of news stories about American students falling further and further behind the rest of the world's students, it seems to be everywhere, but no one (or at least 40% aren't listening.

Luckily for me, but really luckily for our students and our country, the fortunate event outweighed the unfortunate events.  The effort to make science standards the best they can be as a preparation for our students' future success will also produce a perfect PR machine, as students who are successful realize that it was the mathematics and science that formed the foundation of their success.   And the students who follow them will generate the demand that will lead to more math and science at all education levels.

Then we won't be in the 40-40 club anymore, which will be quite an evolution!

Where There's Smoke There's Hot Air: Prediction Without Understanding

Montgolfier Balloon over Paris, 1783. Click to enlarge.Sometimes prediction is easy without any understanding.  Take driving a car, for example.  Stepping on the gas causes the car to accelerate if it is in gear.  How many drivers actually understand why this happens, short of the basic guess that "more gas" somehow got to the engine?  Clearly one doesn't have to understand anything about internal combustion engines to predict what will happen when the engine gets more gas, or gets the wrong octane gas, and so forth.

So Prediction without Understanding is a common occurrence. 

A related happenstance is when accurate prediction occurs even with a totally incorrect understanding.

Consider the first human flight, which occurred on Nov. 21, 1783 when two Frenchmen ascended above Paris in a hot air balloon.  The balloon was designed by the Montgolfier brothers, who believed that thick smoke caused the balloon to stay in the air.  Of course, the thick smoke was a byproduct of whatever they burned in the fire at the throat of the balloon , but it was the hot air (less dense air)  caused by the fire that actually led to the balloon floating.

OK, so the Montgolfiers weren't that far off - you don't have to dig too far to find the connection between thick smoke and hot air, after all.  But this example does raise a more interesting question:  when is it the case that understanding is totally lacking, yet predictions are right on? 

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On the Mathematical Nature of the World

I had one of those very rewarding teaching moments yesterday in my General Physics lab.  Some students and I got into a discussion of just what is physics, what is the connection between mathematics and physics, and whether the world is itself mathematical.

The nature of the world as mathematical is a common theme in the Chaos and Fractals course.  I have developed a seminar module  that has one main reading, and I keep finding supplemental readings every time I teach the course. I list a few of these here in order to collect them in one place - for future renditions of the course, and as a post that will hopefully generate some debate from interested readers.

The main reading is John Barrow's The Mathematical Universe in which he poses the question "The orderliness of nature can be expressed mathematically. Why?"  This article is an excellent summary of the main schools of mathematical philosophy - realism, inventionism, formalism, and constructivism.

Anyone interested in deeper views of  mathematical realism must read The Unreasonable Effectiveness of Mathematics in the Natural Sciences.  This 1960 article by Eugene Wigner is definitely the  "mother-of-all mathematics and the world"  arguments for realism.  In it he describes the uncanny connection between mathematics developed as part of pure, formal, abstract systems and physical observation, which naturally leads to ontological questions on the  mathematical nature of the world:

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