Rice Science in the News

So the other point of Catalyst blog is to detail interesting things going on with science and engineering and several interesting things happened this month within the hedges. I never meant to wait this long, but finals and holidays derailed any hope of nonessential work. So much belatedly, two cool things I’ve been meaning to write about.

First, one of Rice’s own just got major recognition. Dr. James Tour was ranked one of the ten most prolific chemists of the last decade by Times Higher Education.  The ranking was based on how many papers Dr. Tour has published and how often papers he was an author on are cited by other researchers.   With an average 62.76 citations per paper, Dr. Tour’s research is highly regarded.  Much of Dr. Tour’s research focuses on nanotechnology and crosses several disciplines; Tour is mainly a chemistry professor, but is also a professor of computer science and a professor of mechanical engineering and materials science (in fact, many professors who do research in nanotechnology have an additional appointment in materials science if they are from another department).   Nanotechnology seems to be a recurring theme in the Times list.  Counting Dr. Tour, four of the top ten chemists do research in nanotechnology, and another two do work in materials chemistry/science.  Once again, congratulations Dr. Tour. 

From the physics department, we have a surprising but predicted result from the physics department.  Dr. Randy Hulet’s atom cooling group has come up with experimental support for an interesting bit of quantum theory.  In the 1970s, Russian physicist Vitaly Efimov (a professor at the University of Washington) predicted that there could be quantumer trimers: systems where three particles are bound together in a quantum state.  Like the commonly referenced example of Borromean rings, the particles can only be bound if all three are present.   Hulet’s research page says that this happens because the interactions between two particles are so strong that the third particle actually causes the system to achieve a new equilibrium point.  Until this blogger takes quantum mechanics, that’s all I can really say about the nature of the system.  Efimov’s theory has two other interesting consequences.  One is that the trimer can form over a large range of sizes, with the particles ranging from quarks to atoms, and being able to scale all of those orders of magnitudes is pretty impressive in the world of quantum mechanics.  The other cool thing is that the effect repeats itself.  Efimov predicted that if you find a stable trimer, you would find another one by scaling the energy up or down a factor of 22.7… and you could do this forever.  There is no other word to describe this but awesome.

Unfortunately for the theory, experimentalists have had a hard time proving it.  Early work by nuclear physicists failed to find the trimers because the systems had too much kinetic energy from heat.  Using laser cooling, physicists have been able to remove so much energy from the atoms that quantum effects would start to show.   Dr. Hulet’s group used another quantum effect, called Feshbach resonance, to manipulate how cooled lithium atoms would interact with each.  They found the predicted scaling of the trimers and also found a predicted tetramer state of four particles close to each trimer.  In a fitting end to this story, Hulet announced the results at a meeting in Rome that Efimov was also attending.  Efimov, excited for proof of his theory after so long, gave Dr. Hulet a high five after the meeting ended.

Is the Earth Hydroelectric?

Prepare to have your textbooks rewritten Earth science majors.  Or at least that might happen if new research into Earth’s magnetic field holds true.  Gregory Ryskin from Northwestern has developed a new theory of what produces the field.  Current theories, called dynamo theories, say that the field is a result of convection currents and rotation in the outer core.  Since the outer core is a layer of molten, electrically conductive iron this creates a magnetic field, though the actual details are a bit more complicated than that.  And of course, the operative term describing the current view is “theories”.  Geophysicists haven’t worked out the final details, and the article mentions that computer models tend to produce different results.

Ryskin takes a radically different approach.  He was looking to explain the constant changes in magnetic field strength in different regions.  Currently, these are blamed on turbulence in the core.  Ryskin based his theory on something else that is constantly changing:  ocean currents.  Saltwater is electrically conductive, so it could work similar to the molten iron of the core.  One piece of evidence in support of the new theory is that changes in the strength of ocean currents have been linked to changes in magnetic fields.  The theory also has some interesting consequences. Changes in ocean currents might be linked to geomagnetic field reversals.  The movement of tectonic plates and landmasses alters the routes currents follow, and therefore would affect the Earth’s magnetic field.  Climate changes that affect ocean currents would also have an effect on the magnetic field.

Ryskin himself is an interesting researcher as you can see on his faculty page.  He’s a chemical and biological engineering professor at Northwestern.  But a good deal of his work is on physics, and now, geology (all the recent articles listed on his page went to a physics journal, with the exception of one geology paper).  Score one for multidisciplinarity?  I think so.  The traditional geologists don’t seem terribly excited by the new research.  I wonder if it’s some slight bias against an outsider coming in and trying to rework a central tenet of their field.  More likely, though, this is just another case of slow acceptance of new theories in science. The dynamo theory does a lot, so there’s no need to drop it at the first sign of something else.  More evidence is needed.

Also, I seem to have lots of questions about how we could get this evidence.  I feel that it would be relatively easy to test Ryskin’s theory directly.  Couldn’t we just get a lab to make a model of Earth and the oceans, rotate it, and measure the magnetic fields?  Or just pore over several years of data on magnetic fields and ocean currents from NASA and analyze it for correlations?  I still like the dynamo theory after having read lots of books on the planets, but Ryskin’s theory makes me wonder about the very watery nature of Earth.  The oceans are electrically conductive and the currents move relative to Earth’s rotation.  Perhaps they could affect the strength of magnetic field, even if they aren’t the cause?