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By Tushna Commissariat
In case you have ever wondered why so many theoretical physicists study climate change, physicist Tim Palmer from the University of Oxford in the UK has a simple answer: “because climate change is a problem in theoretical physics”. Indeed, Palmer, who won the Institute of Physics’ 2014 Dirac medal, studies the predictability and dynamics of weather and climate, in the hopes of developing accurate predictions of long-term climate change. The answer, according to Palmer, lies at the intersection between chaos theory and inexact computing – which requires us to stop thinking of computers as deterministic calculating machines and to instead “embrace inexactness” in computing. Palmer talked about all this and more in the latest public lecture from the Perimeter Institute in Canada – you can watch his full talk above.
When someone says the word “physicist”, what image or persona comes to mind? That is the question the Institute of Physics (which publishes Physics World) was hoping to answer with its recent member survey based on diversity, titled “What Does a Physicist Look Like?” The Institute’s main aim with this diversity survey, which about 13% of its members responded to, was “to understand the profile of our members and gain some insights into who they are – diverse people with different ages, ethnicities, beliefs and much more”. You can read its entire results here.
And if you are in the mood for some more data and reports, take a look at this rather telling report from the White House on “Big Data: a Report on Algorithmic Systems, Opportunity,and Civil Rights“. According to the White House blog, the report was based on case studies of “credit lending, employment, higher education and criminal justice” and illustrates how big data techniques can be used to detect and prevent bias and discrimination, while also highlighting the specific risks involved when “technologies can deliberately or inadvertently perpetuate, exacerbate or mask discrimination”.
For those of you wondering exactly what the inside of a black hole looks like and how such a volatile environment would affect objects from everyday lives, take a look at this post on the JPhys+ blog by physicist Simone Taioli at the Charles University in Prague. Based on a recent paper in the Journal of Physics: Condensed Matter (published by IOP Publishing), he talks about how they use both crystallographic group theory and computer simulations to answer those questions without throwing themselves into the pits of a black hole.
For some light weekend reading, take a look at this MIT Technology Review blog post about how spider silk has been used to make the first ever biological superlens.
Kudos for Tim Palmer’s excellent talk on chaos and climate change. Note that at the heart of the Lorenz equations and the Navier-Stokes equations you will find fractal geometry playing a dominant role.
Note also that Prof. Palmer’s fascinating new theory of how to unify fundamental physics, including the realms of quantum gravity, QM and cosmology, has at its heart dynamical systems evolving on zero-measure fractal invariant subsets of the available state space.
Well, it’s a fractal world, after all.
RLO ———-Fractal Cosmology
Dr. Oldershaw, the reprentation of the treatment of the non-linear Navier-Stokes equations for the climate dynamics through a line of encapsulable Russian dolls is indeed fractal in nature represented through a power law, but the difficulty is that all of these equations are coupled and have to be treated simultaneously and depending on the capacity of the best available computer, one cannot go beyond a certain minimum size of the doll which is still quite big and which represents an important uncertainty of the calculation to represent the weather at certain moment in time.
Sure, but do you understand that, as nonlinear dynamical systems, their evolution in state space obeys the limiting fractal attractors?
Early in the talk, Prof. Palmer explicitly explains that the differential Lorenz equations obey underlying fractal(chaotic) attractors. That’s the take-home message of deterministic chaos/nonlinear dynamical systems theory.
Dr. Palmers new theory that he has developed recently (papers available at the arXiv repository) posits that the entire cosmos is a nonlinear dynamical system evolving within the constraints of a zero-measure invariant fractal subset of the total state space.
Any way you cut it, the proposed theme is that fractal geometry plays a dominant and exceedingly fundamental role in theoretical physica and the actual physical cosmos.
The Einstein’s GTG’s non-linear equations govern the dynamics of the universe; here the different parts of the universe mutually interact due to this non-linearity like the Navier-Stokes non-linear equations, when applied to the dynamics of the atmosphere, and the power-law or the fractal nature shows up. If this non-linearity were not present, there should be no power-law or the “fractality” in the dynamics of the universe.
Agreed, for the most part.
However, bear in mind that we also need to include the quantum and sub-quantum realms in our modeling of the cosmos, and so far attempts to unify General Relativity and quantum physics have not borne much fruit.
A new and radical attempt to achieve such a unification is the goal of Palmer’s latest research and papers. It looks to me to be a highly unique and promising effort based on nonlinear dynamical systems, deterministic chaos, and the the well-known role that fractal geometry plays in such models.
Palmer’s papers can be found and downloaded for free at the arXiv repository. They are highly mathematical and full of interesting and promising ideas.
RLO
Discrete Scale Relativity