Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Fingerprints in the sky explained

09.11.2004


Today, a group of physicists published the most compact and elegant explanation of one of nature’s simplest phenomena: the way light behaves in the sky above us. This research appears today (Tuesday, 9th November) in the New Journal of Physics, published jointly by the Institute of Physics and Deutsche Physikalische Gesellschaft (German Physical Society).



Michael Berry and Mark Dennis from the University of Bristol, in collaboration with Raymond Lee of the US Naval Academy, have successfully predicted the patterns of polarisation of skylight, explained in broad outline by Lord Rayleigh in 1871, using elliptic integrals – a type of mathematics with deep geometrical roots, often described as “beautiful”.

The blue sky seen through polaroid sunglasses gets darker and brighter as the glasses are rotated. This reveals something almost invisible to our unaided eyes: daylight is polarized light. This means that the light waves vibrate differently in different directions. The effect is strongest at right angles to the sun, and weaker elsewhere. It creates patterns in the sky that look similar to the ridges in human fingerprints and are used by many species of birds and flying insects as an aid to navigation.


A striking feature of the pattern is a pair of points near the sun where the light is not polarized at all (this point is a singularity and the pattern breaks down here). Although they have been studied for nearly two centuries, no one attempted to construct a model using the most obvious feature - the singularities - until now.

Sir Michael Berry said: “We wondered: what if you start with the singularities and write the simplest description of polarisation that puts the singularities in the right places? We found that this gives a remarkably good fit to the observational data, and predicts the pattern across the whole sky.” “This is beautiful mathematics in the sky. Using elliptic integrals, we’ve been able to replace pages and pages of formulae with one very simple solution that predicts the pattern extremely well” “After almost 200 years there’s now a way of understanding this natural phenomenon which is very different from previous models, but utterly natural. It’s a modern theme of physics to study things by looking at their singularities – to think about them geometrically.”

In order to test their theory, co-author Raymond Lee took four different polarized photographs of each of two clear-sky cases at the United States Naval Academy in Annapolis, Maryland, using a Nikon digital camera with a specially converted fisheye lens. When they compared these detailed observations to the pattern predicted by their model, they found that the fit was very good, indicating that the arrangement of the singularities could be vital in shaping the overall “fingerprint in the sky”.

Many scientists and mathematicians believe that simple, concise explanations of natural phenomena are better or closer to some underlying truth than more complex ones. Professor Marcus du Sautoy, from the Mathematical Institute at the University of Oxford, said: “Having a sense of beauty and aesthetics is an important part of being a scientist. Nature seems to be a believer in Occam’s Razor: given a choice between something messy or a beautiful solution, Nature invariably goes for beauty.

"This is why those scientists with an eye for aesthetics are often better equipped for discovering the way Nature works. We might find a complicated ugly solution but that is probably a sign that we haven’t yet found the best explanation. The fact that there is so much beauty at the heart of Nature is what gives scientists a constant sense of wonder and excitement about their subject.”

David Reid | alfa
Further information:
http://www.iop.org
http://www.njp.org

More articles from Physics and Astronomy:

nachricht Astronomers find unexpected, dust-obscured star formation in distant galaxy
24.03.2017 | University of Massachusetts at Amherst

nachricht Gravitational wave kicks monster black hole out of galactic core
24.03.2017 | NASA/Goddard Space Flight Center

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>