Top 10 discoveries about waves    

Gravitational radiation reminds science of its debts to the physics of waves

surfer on a wave

CATCH A WAVE Physicists are the surfers of science, with a long history of fascination with waves.

Physics fans are a lot like surfers. Both think waves are really fun.

For surfers, it’s all about having a good time. For physicists, it’s about understanding some of nature’s most important physical phenomena. Yet another detection of gravitational waves, announced June 1, further reinvigorates the world’s science fans’ excitement over waves.

Waves have naturally always been a topic of scientific and mathematical interest. They play a part in an enormous range of physical processes, from heat and light to radio and TV, sonograms and music, earthquakes and holograms. (Waves used to even be a common sight in baseball stadiums, but fans got tired of standing up and down and it was really annoying anyway.)

Many of science’s greatest achievements have been discoveries of new kinds of waves or new insights into wave motion. Identifying just the Top 10 such discoveries (or ideas) is therefore difficult and bound to elicit critical comments from cult members of particular secret wave societies. So remember, if your favorite wave isn’t on this list, it would have been No. 11.

10.  Thomas Young: Light is a wave.

In the opening years of the 19th century, the English physician Young tackled a long-running controversy about the nature of light. A century earlier, Isaac Newton had argued forcibly for the view that light consisted of (very small) particles. Newton’s contemporary Christiaan Huygens strongly disagreed, insisting that light traveled through space as a wave.

Through a series of clever experiments, Young demonstrated strong evidence for waves. Poking two tiny holes in a thick sheet of paper, Young saw that light passing through created alternating bands of light and darkness on a surface placed on the other side of the paper. That was just as expected if light passing through the two holes interfered just as water waves do, canceling out when crest met trough or enhancing when crests met “in phase.” Young did not work out his wave theory with mathematical rigor and so Newton’s defenders resisted, attempting to explain away Young’s results.

But soon Augustin Jean Fresnel in France worked out the math of light waves in detail. And in 1850, when Jean-Bernard-Léon Foucault showed that light travels faster in air than water, the staunchest Newton fans had to capitulate. Newton himself would have acknowledged that light must therefore consist of waves. (Much later, though, Einstein found a way that light could in fact consist of particles, which came to be called photons.)

9. Michelson and Morley: Light waves don’t vibrate anything.

Waves are vibrations, implying the need for something to vibrate. Sound vibrated molecules in the air, for instance, and ocean waves vibrated molecules of water. Light, supposedly, vibrated an invisible substance called the ether.

In 1887, Albert A. Michelson and his collaborator Edward Morley devised an experiment to detect that ether. Earth’s motion through the ether should have meant that light’s velocity would depend on its direction. (Traveling with the Earth’s motion, light’s speed wouldn’t be the same as traveling at right angles to the direction of motion.) Michelson and Morley figured they could detect that difference by exploiting the interference phenomena discovered by Young. But their apparatus failed to find any ether effect. They thought their experiment was flawed. But later Einstein figured out there actually wasn’t any ether.

8. James Clerk Maxwell: Light is an electromagnetic wave.

Maxwell died in 1879, the year Einstein was born, and so did not know there wasn’t an ether. He did figure out, though, that both electricity and magnetism could be explained by stresses in some such medium.

Electric and magnetic charges in the ether ought to generate disturbances in the form of waves, Maxwell realized. Based on the strengths of those forces he calculated that the waves would travel at the fantastic speed of 310 million meters per second, suspiciously close to the best recent measurements of the speed of light (those measurements ranged from 298 million to 315 million meters per second). So Maxwell, without the benefit of ever having watched NCIS on TV, then invoked Gibbs’ Rule 39 (there’s no such thing as a coincidence) and concluded that light was an example of an electromagnetic wave.

“It seems we have strong reason to conclude that light itself (including radiant heat, and other radiations if any) is an electromagnetic disturbance in the form of waves propagated through the electromagnetic field,” he wrote in 1864. His “other radiations, if any” turned out to be an entire spectrum of all sorts of cool waves, from gamma radiation to radio signals.

7. Heinrich Hertz: Radio waves.

Not very many people took Maxwell seriously at first. A few, though, known as the Maxwellians, promoted his ideas. One physicist who had faith in Maxwell, or at least in his equations, was Hertz, who performed experiments in his lab in Karlsruhe, Germany, that successfully produced and detected radio waves, eventually to be exploited by propagandists to spread a lot of illogical nonsense on talk radio.

His success inspired much more respect for the equations in Maxwell’s theory, which Hertz found almost magical: “It is impossible to study this wonderful theory without feeling as if the mathematical equations had an independent life and an intelligence of their own, as if they were wiser than ourselves,” Hertz said. His prime experimental success came in 1887, the same year that Michelson and Morley failed to detect the ether. Hertz died in 1894, long before his discovery was put to widespread use.

6. John Michell: Seismic waves.

Michell, an English geologist and astronomer, was motivated by the great Lisbon earthquake of 1755 to investigate the cause of earthquakes. In 1760 he concluded that “subterraneous fires” should be blamed, noting that volcanoes — “burning mountains” — commonly occur in the same neighborhood as frequent earthquakes.

Michell noted that “the motion of the earth in earthquakes is … partly propagated by waves, which succeed one another sometimes at larger and sometimes at smaller distances.” He cited witness accounts of quakes in which the ground rose “like the sea in a wave.” Much later seismologists developed a more precise understanding of the seismic waves that shake the Earth, using them as probes to infer the planet’s inner structure.

5. Wilhelm Röntgen: X-rays.

Roentgen's first x-ray of his wife's handWhen Hertz discovered radio waves, he knew he was looking for the long-wavelength radiation foreshadowed in Maxwell’s equations. But a few years later, in 1895, Röntgen found the radio wave counterpart of the opposite end of the electromagnetic spectrum — by accident.

Mysterious short-wavelength rays of an unknown type (therefore designated X) emerged when Röntgen shot cathode rays (beams of electrons) through a glass tube. Röntgen suspected that his creation might be a new kind of wave among the many Maxwell had anticipated: “There seems to exist some kind of relationship between the new rays and light rays; at least this is indicated by the formation of shadows,” Röntgen wrote. Those shadows, of course, became the basis for a revolutionary medical technology.

Besides providing a major new tool for observing shattered bones and other structures inside the body, X-rays eventually became essential tools for scientific investigation in astronomy, biology and other fields. And they shattered the late 19th century complacency of physicists who thought they’d basically figured everything out about nature. Weirdly, though, X-rays later turned out to be particles sometimes, validating Einstein’s ideas that light had an alter ego particle identity. (By the way, it turned out that X-rays aren’t the electromagnetic waves with the shortest wavelengths — gamma rays can be even shorter. Maybe they would be No. 11.)

4. Epicurus: The swerve.

Not exactly a wave in the ordinary sense, the swerve was a deviation from straight line motion postulated by the Greek philosopher Epicurus around 300 B.C. Unlike Aristotle, Epicurus believed in atoms, and argued that reality was built entirely from the random collisions of an infinite number of those tiny particles. Supposedly, he thought, atoms would all just fall straight down to the center of the universe unless some unpredictable “swerve” occasionally caused them to deviate from their paths so they would bounce off each other and congregate into complex structures.

It has not escaped the attention of modern philosophers that the Epicurean unpredictable swerve is a bit like the uncertainty in particle motions introduced by quantum mechanics. Which has its own waves. 

3. Louis de Broglie: Matter waves.

In the early 1920s, de Broglie noticed a peculiar connection between relativity and quantum physics. Max Planck’s famous quantum formula related energy to frequency of a wave motion. Einstein’s special relativity related energy to the mass of a particle. De Broglie thought it would make a fine doctoral dissertation to work out the implications of two seemingly separate things both related to energy. If energy equals mass (times the speed of light squared) and energy equals frequency (time Planck’s constant), then voilà, mass equals frequency (times some combination of the constants). Therefore, de Broglie reasoned, particles (of mass) ought to also exist as waves (with a frequency).

That might have seemed wacky, but Einstein read de Broglie’s thesis and thought it made sense. Soon Walter Elsasser in Germany reported experiments that supported de Broglie, and in America Clinton Davisson and coworkers demonstrated conclusively that electrons did in fact exhibit wave properties.

De Broglie won the physics Nobel Prize in 1929; Davisson shared the 1937 Nobel with George Thomson, who had conducted similar experiments showing electrons are waves. Which was ironic, because George’s father, J.J. Thomson, won the 1906 Nobel for the work that revealed the existence of the electron as a particle. Eight decades later Ernst Ruska won a Nobel for his design of a powerful microscope that exploited the electron’s wave behavior.

2. Max Born: Probability waves.

De Broglie’s idea ignited a flurry of activity among physicists trying to figure out how waves fit into quantum theory. Niels Bohr, for instance, spent considerable effort attempting to reconcile the dual wave-particle nature of both electrons and light. Erwin Schrödinger, meanwhile, developed a full-fledged “wave mechanics” to describe the behavior of electrons in atoms solely from the wave perspective. Schrödinger’s math incorporated a “wave function” that was great for calculating the expected results of experiments, even though some experiments clearly showed electrons to be particles.

Born, a German physicist and good friend of Einstein’s, deduced the key to clarifying the wave function: It was an indicator of the probability of finding the particle in a given location. Combined with Werner Heisenberg’s brand-new uncertainty principle, Born’s realization led to the modern view that an electron is wavelike in the sense that it does not possess a definite location until it is observed. That approach works fine for all practical purposes, but physicists and philosophers still engage in vigorous debates today about the true physical status of the wave function.

1. LIGO: Gravitational waves.

graph of gravitational wave detectionSoon after he completed his general theory of relativity, Einstein realized that it implied the possibility of gravitational radiation — vibrations of spacetime itself.  He had no idea, though, that by spending a billion dollars, physicists a century later could actually detect those spacetime ripples. But thanks to lasers (which maybe would have been No. 11), the Laser Interferometer Gravitational-Wave Observatory — two huge labs in Louisiana and Washington state — captured the spacetime shudders emitted from a pair of colliding black holes in September 2015.

That detection is certainly one of the most phenomenal experimental achievements in the history of science. It signaled a new era in astronomy, providing astronomers a tool for probing the depths of the universe that are obscured from view with Maxwell’s “other radiations, if any.” For astronomy, gravitational radiation is the wave of the future. 

Follow me on Twitter: @tom_siegfried

           Exfo WA-7100 Sale price: $10,988.00    

Exfo WA-7100

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Exfo-Burleigh WA7100 Wavemeter WA-7600 and WA-7100 Optical Channel Analyzers employ proven scanning Michelson interferometer-based Wavemeter technology to determine the absolute wavelength of an optical signal under test by comparing its interfere...(Continue to site)

          Astronomers Build the Most Advanced Observatory in the World from LEGO®   

It took some of the brightest minds in science and technology to build ESO’s Paranal Observatory in Chile, one of the largest and most sophisticated telescope facilities in the world. Now Dutch astronomer Frans Snik and a team of dedicated helpers have created a unique LEGO® model of the entire Paranal platform, complete with replicas of the four 8.2-metre VLT Unit Telescopes (UT), the four 1.8-metre Auxiliary Telescopes and other astonishingly minute details [1].

This mind-boggling one-of-a-kind model has been handed over to ESO and is on display at the ESO Headquarters in Garching, Germany. When the ESO Supernova Planetarium & Visitor Centre opens at the ESO Headquarters in spring 2018, the model will be displayed there.

The model of the Paranal platform, at a scale of approximately 1:150, comprises the VLT telescopes and their dome structures, and all of the instruments used on the real VLT are also present. It also has accurate models of the VST, VISTA and the Control Building. Each 8.2-metre UT on the VLT platform comprises exactly 3104 parts, and the whole Paranal platform model required over 25 000 individual parts — plus a substantial amount of time and patience! The telescopes rotate and all the dome shutters and vents open and close. The four Auxiliary Telescopes can be moved into position along their tracks, just like the real things, and the VLTI tunnels house a working miniature interferometer that can produce real fringes.

Building a model telescope is an excellent way to understand how complex modern astronomical instruments work and anyone ambitious enough (and with around 5000 euros to spare) can build their own version of these huge telescopes. Frans Snik will be pleased to provide the necessary instructions.

As if that wasn’t enough, ESO’s Extremely Large Telescope, currently being built close to Paranal, can also be built — to the same scale as the Paranal model — out of LEGO®.


[1] The LEGO® Paranal began its small-scale existence in 2014, when Snik designed and built his first LEGO® model of ESO’s Extremely Large Telescope (ELT). Later on a  LEGO® model of the 8.2-metre VLT Unit Telescopes (UT) was conceived.

          Auf dem Weg zu empfindlicheren Sensoren   
image description
Verschränkte Lichtzustände ermöglichen die Erhöhung der Sensitivität in der optischen Interferometrie, einer Messmethode in der Physik. Hierfür benötigt man sogenannte pfadverschränkte Photonenzustände in zeitlich wohl definierten Pulsen. Bisher war die Erzeugung solcher Zustände jedoch nur begrenzt...
          ‘Bulges’ in volcanoes could be used to predict eruptions   

A team of researchers from the University of Cambridge have developed a new way of measuring the pressure inside volcanoes, and found that it can be a reliable indicator of future eruptions. Using a technique called ‘seismic noise interferometry’ combined with geophysical measurements, the researchers measured the energy moving through a volcano. They found that […]

The post ‘Bulges’ in volcanoes could be used to predict eruptions appeared first on Geology Page.

           The study of point stress effect using double exposure holograph interferometry techniques    
Bidin, Noriah and Kua, Hock Chuan (2003) The study of point stress effect using double exposure holograph interferometry techniques. In: IPTA 2003, 2003, Kuala Lumpur.
           Three-dimension feature reconstruction from differential syntetic aperture radar interferometry (DINSAR)    
Marghany, Maged and Hashim, Mazlan (2009) Three-dimension feature reconstruction from differential syntetic aperture radar interferometry (DINSAR). In: Proceeding of 2009 IEEE International Conference on Antennas, Propagation and Systems (INAS 2009), 2009.
           Elasticity measurement using holographic interferometry double exposure technique    
Chuan, Kua Hock and Bidin, Noriah (2004) Elasticity measurement using holographic interferometry double exposure technique. Jurnal Teknologi, 41 . pp. 55-64.
           Differential synthetic aperture radar interferometry (DINSAR) for 3D coastal geomorphology reconstruction    
Marghany, Maged and Hashim, Mazlan (2009) Differential synthetic aperture radar interferometry (DINSAR) for 3D coastal geomorphology reconstruction. International Journal of Computer Science and Network Security, 9 (5). pp. 59-63. ISSN 1738-7906
          S-au descoperit două găuri negre implicate într-o interacțiune stranie: ele orbitează una în jurul celeilalte. E prima dată când se confirmă existența unui asemenea fenomen!   
Într-o serie de observații recente, în măsură să revoluționeze concepțiile existente cu privire la caracteristicile formațiunilor de acest tip, astronomii au folosit undele radio pentru a cerceta două găuri negre supermasive care se rotesc una în jurul celeilalte, într-un dans gigantic, al titanilor Cosmosului. Această descoperire, combinată cu observațiile referitoare la undele gravitaționale provenite de la LIGO (Observatorul interferometru laser de unde gravitaționale), deschid un drum complet nou în studiul găurilor negre. În prima parte a anului trecut, cei de la LIGO anunțau că au detectat undele gravitaționale. Astronomii au studiat, cu atenție, galaxia 0402+379, localizată la o distantă de nu mai puțin de 750 milioane de ani-lumină de Pământ. Este o galaxie eliptică, descoperită în urmă cu 22 de ani. Această galaxie a reprezentat un important candidat pentru această investigație. Se bănuia că deține două găuri negre supermasive care au intrat în interacțiune ca urmare a fuziunii a două galaxii diferite. Aceste două formațiuni au fost examinate încă din anul 2003, dar acum se poate confirma, pentru prima dată, că ele se rotesc una în jurul celeilalte. Descoperirea este raportată de către Astrophysical Journal. Profesorul Greg Taylor, de la Universitatea din New Mexico, declară că astronomii scrutează de multă vreme cerul pentru [...]
          Ciencias Ocultas. Parte IV. Interferometría.   
Ver más: –Ciencias Ocultas. Parte I. BOMBA ATÓMICA Y EL DILEMA DEL HIDRÓGENO. –Ciencias Ocultas. Parte II. Fuerzas Fundamentales de la Física. –Ciencias Ocultas. Parte III. ELECTRODINÁMICA RELATIVISTA. Interferencia Es el fenómeno que se produce cuando dos o más ondas se superponen en una región del espacio: en cada punto las amplitudes de los campos se suman, de … Sigue leyendo Ciencias Ocultas. Parte IV. Interferometría.
          Ciencias Ocultas. Parte III. ELECTRODINAMICA RELATIVISTA   
Ver más: –Ciencias Ocultas. Parte I. BOMBA ATÓMICA Y EL DILEMA DEL HIDRÓGENO. –Ciencias Ocultas. Parte II. Fuerzas Fundamentales de la Física. –Ciencias Ocultas. Parte IV. Interferometría. “Las Propiedades de los cuerpos en movimiento”. Fuerza de Lorentz: La fuerza total F que actúa sobre la carga será igual a la suma vectorial de FE y de FB: Forma Clásica: E = … Sigue leyendo Ciencias Ocultas. Parte III. ELECTRODINAMICA RELATIVISTA
          Ciencias Ocultas. Parte I. BOMBA ATOMICA Y EL DILEMA DEL HIDROGENO   
Ver más: –Ciencias Ocultas. Parte II. Fuerzas Fundamentales de la Física. –Ciencias Ocultas. Parte III. ELECTRODINÁMICA RELATIVISTA. –Ciencias Ocultas. Parte IV. Interferometría. Explosión de la Fiebre del Oro: Durante la Fiebre del oro de E.E.U.U., se emplearon una gran variedad de explosivos para construir ferrocarriles, extraer oro y otros metales de las montañas, etc…, se probaron … Sigue leyendo Ciencias Ocultas. Parte I. BOMBA ATOMICA Y EL DILEMA DEL HIDROGENO
          (USA-WA-Redmond) Optical Scientist   
**Summary:** Oculus is a world leader in the design of virtual reality systems. We are currently seeking innovative researchers with a passion for technology to develop next generation consumer electronics, including near to eye display and imaging systems, at our research location in Redmond WA. Primary responsibility is developing optical systems, including sensors and visual optics, and related technologies building blocks to enable next generation architectures. **Required Skills:** 1. Drive development of system requirements to create new virtual experiences, and advance technologies necessary to create product architectures that can deliver these requirements. 2. Support modeling and experimentation for next-generation optics and displays 3. Engage cross-functionally with other researchers and engineers to develop concepts that advance the entire product pipeline (hardware, software, integration, infrastructure and applications) **Minimum Qualifications:** 4. PhD and/or postdoctoral assignment in the field of Optical Sciences, Physics, Electrical Engineering or related degree (or Masters Degree with industry experience also accepted) 5. Knowledge of optics including systems design and integration, imaging, illumination, radiometry and photometry, physical and geometric optics, statistics, and polarization 6. Understanding of sources (lasers and LED’s), spatial light modulators, diffractive optics, optical materials, and thin films optics 7. Experience in one or more system optimization and analysis tools, such as Matlab, C++, or Java 8. Experience in one or more optical design tools such as Code V, Zemax, or FRED 9. Knowledge and experience with color science, colorimetry, and visual optics 10. Familiarity with optical metrology tools such as interferometry, image quality testing, etc. **Preferred Qualifications:** 11. 5+ years of industry experience in Optical Research or Design 12. Expertise in optical and sensor system design maturation, including requirement development from physical based modeling, and knowledge of fabrication / vendor processes 13. Background in development of test automation using Labview, Matlab, Mathamatica or another program which enables custom analysis and automation of metrology **Industry:** Internet **Equal Opportunity:** As part of our dedication to the diversity of our workforce, Facebook is committed to Equal Employment Opportunity without regard for race, color, national origin, ethnicity, gender, protected veteran status, disability, sexual orientation, gender identity, or religion. We are also committed to providing reasonable accommodations for qualified individuals with disabilities and disabled veterans in our job application procedures. If you need assistance or an accommodation due to a disability, you may contact us at or you may call us at 1+650-308-7837.
          ESA and NASA to collaborate on mission to detect gravitational waves   

The European Space Agency (ESA) is partnering with NASA on a new space mission that will study gravitational waves from space. Known as the Laser Interferometer Space Antenna, or LISA, the project was approved by ESA's Cosmic Vision science program on June 20. Both space agencies will now work together to design the mission and outline a budget for it prior to construction.

The post ESA and NASA to collaborate on mission to detect gravitational waves appeared first on SpaceFlight Insider.

          New Method That Detects Bulges In Volcanoes Can Be Used To Predict Eruptions   
The seismic noise interferometry technique can be used to predict volcanic eruptions in the future.
          Big Bang fans rejoice: LSU professor sharing stage with Stephen Hawking   

LSU professor Gabriela González can add another distinction to her resume: sharing the stage with Stephen Hawking. The former spokeswoman for the Laser Interferometer Gravitational-Wave Observatory Scientific Collaboration, which detected gravitational waves 100 years after Albert Einstein predicted them, will join the renowned British physicist for his 75th birthday public symposium on Sunday. The Stephen...

The post Big Bang fans rejoice: LSU professor sharing stage with Stephen Hawking appeared first on Baton Rouge Business Report.

          Perspective, Perhaps   
Last week, according to some real news, Earth got a wave hello from far away, from some-3-billion-year-old vibrations that were set off when two black holes smashed into each other. (Really? There’s not room for both of you up there?) According to the New York Times, the collision—reported by the Laser Interferometer Gravitational-Wave Observatory, which felt the signal—resulted in […]
           In-plane disc brake vibration measurement using holographic interferometry    
Steel, William P., Fieldhouse, John D., Talbot, Chris J. and Crampton, Andrew (2004) In-plane disc brake vibration measurement using holographic interferometry. In: Total Vehicle Technology: Finding the Radical, Implementing the Practical (3rd International Conference). Wiley, pp. 261-274. ISBN 9781860584602
           The use of interferometry and image analysis techniques for metrology of MST devices    
Blunt, Liam, Jiang, Xiang, Xiao, Shaojun and Scott, Paul J. (2004) The use of interferometry and image analysis techniques for metrology of MST devices. In: 8th International Symposium on Measurement and Quality Control in Production, 12th-15th October, 2004, Erlangen, Germany. (Unpublished)
           High stability multiplexed fibre interferometer and its application on absolute displacement measurement and on-line surface metrology    
Lin, Dejiao, Jiang, Xiang, Xie, Fang, Zhang, Wei, Zhang, Lin and Bennion, Ian (2004) High stability multiplexed fibre interferometer and its application on absolute displacement measurement and on-line surface metrology. Optics Express, 12 (23). pp. 5729-5734. ISSN 1094-4087
          All of the VLT telescopes are now modelled in LEGO®   

Frans Snik’s LEGO® model of ESO’s Paranal platform reproduces each of the 8-metre Unit Telescopes in remarkable detail. It also includes the smaller Auxiliary Telescopes that can combine with the Unit Telescopes to form the VLT Interferometer. A laser underneath the model platform even mimics the optical system of the interferometer.

          A LEGO® interferometer!   

Frans Snik’s LEGO® model of ESO’s entire Paranal platform even includes a laser that represents in miniature the complex optical system that allows the VLT Interferometer to obtain phenomenally detailed images of the most exotic objects in the Universe.

          Transfer of atomic mass with a photon solves the momentum paradox of light   
The propagation of light in a transparent medium is associated with the transfer of atomic mass density.

In a recent publication, Aalto University researchers show that in a transparent medium each photon is accompanied by an atomic mass density wave. The optical force of the photon sets the medium atoms in motion and makes them carry 92% of the total momentum of light, in the case of silicon.

The novel discovery solves the centennial momentum paradox of light. In the literature, there has existed two different values for the momentum of light in the transparent medium. Typically, these values differ by a factor of ten and this discrepancy is known as the momentum paradox of light. The difference between the momentum values is caused by neglecting the momentum of atoms moving with the light pulse.

To solve the momentum paradox the authors prove that the special theory of relativity requires an extra atomic density to travel with the photon. In related classical computer simulations, they use optical force field and Newton´s second law to show that a wave of increased atomic mass density is propagating through the medium with the light pulse.

The mass transfer leads to splitting of the total momentum of light into two components. The fields’ share of momentum is equal to the Abraham momentum while the total momentum, which includes also the momentum of atoms driven forward by the optical force, is equal to the Minkowski momentum.

”Since our work is theoretical and computational it must be still verified experimentally, before it can become a standard model of light in a transparent medium. Measuring the total momentum of a light pulse is not enough but one also has to measure the transferred atomic mass. This should be feasible using present interferometric and microscopic techniques and common photonic materials”, researcher Mikko Partanen says.

See the video: Photon mass drag and the momentum of light in a medium

Potential interstellar applications of the discovery

The researchers are working on potential optomechanical applications enabled by the optical shock wave of atoms predicted by the new theory. However, the theory applies not only to transparent liquids and solids but also to dilute interstellar gas. Using a simple kinematic consideration it can be shown that the energy loss caused by the mass transfer effect becomes for dilute interstellar gas proportional to the photon energy and distance travelled by light.

“This prompts for further simulations with realistic parameters for interstellar gas density, plasma properties and temperature. Presently the Hubble’s law is explained by Doppler shift being larger from distant stars. This effectively supports the hypothesis of expanding universe. In the mass polariton theory of light this hypothesis is not needed since redshift becomes automatically proportional to the distance from the star to the observer”, explains Professor Jukka Tulkki.

Research article: Mikko Partanen, Teppo Häyrynen, Jani Oksanen, and Jukka Tulkki. Photon mass drag and the momentum of light in a medium. Physical Review A 95. DOI: 10.1103/PhysRevA.95.063850

More information:

Mikko Partanen
Doctoral Candidate
Aalto University

Jukka Tulkki
Aalto University
tel. +358 50 520 4360

          Spatio-temporal mapping of plate boundary faults in California using geodetic imaging   

The Pacific–North American plate boundary in California is composed of a 400-km-wide network of faults and zones of distributed deformation. Earthquakes, even large ones, can occur along individual or combinations of faults within the larger plate boundary system. While research often focuses on the primary and secondary faults, holistic study of the plate boundary is required to answer several fundamental questions. How do plate boundary motions partition across California faults? How do faults within the plate boundary interact during earthquakes? What fraction of strain accumulation is relieved aseismically and does this provide limits on fault rupture propagation? Geodetic imaging, broadly defined as measurement of crustal deformation and topography of the Earth’s surface, enables assessment of topographic characteristics and the spatio-temporal behavior of the Earth’s crust. We focus here on crustal deformation observed with continuous Global Positioning System (GPS) data and Interferometric Synthetic Aperture Radar (InSAR) from NASA’s airborne UAVSAR platform, and on high-resolution topography acquired from lidar and Structure from Motion (SfM) methods. Combined, these measurements are used to identify active structures, past ruptures, transient motions, and distribution of deformation. The observations inform estimates of the mechanical and geometric properties of faults. We discuss five areas in California as examples of different fault behavior, fault maturity and times within the earthquake cycle: the M6.0 2014 South Napa earthquake rupture, the San Jacinto fault, the creeping and locked Carrizo sections of the San Andreas fault, the Landers rupture in the Eastern California Shear Zone, and the convergence of the Eastern California Shear Zone and San Andreas fault in southern California. These examples indicate that distribution of crustal deformation can be measured using interferometric synthetic aperture radar (InSAR), Global Navigation Satellite System (GNSS), and high-resolution topography and can improve our understanding of tectonic deformation and rupture characteristics within the broad plate boundary zone.

          'Bulges' in volcanoes could be used to predict eruptions   

A team of researchers from the University of Cambridge have developed a new way of measuring the pressure inside volcanoes, and found that it can be a reliable indicator of future eruptions. Using a technique called 'seismic noise interferometry' combined with geophysical measurements, the researchers measured the energy moving through a volcano.

Der Durchmesser feiner Drähte lässt sich interferometrisch beispielsweise wie ...
          Conference gives undergraduate women skills, inspiration to pursue physics careers   

Meg Urry was the first tenured woman professor in the Physics Department at Yale University and was often the only woman in her physics classes, including her graduate class at MIT, but she still heard a fellow student complain that women were unfairly given advantages over their male colleagues. “That’s when I realized there was something fishy going on,” she said.

Urry spoke at the 2017 APS Conference for Undergraduate Women in Physics (CUWiP) Mid-Atlantic Regional Conference at Princeton University. She told students that she is still often the only woman in the room even though her department now has six out of 32 female faculty members – the highest number of the top 50 physics departments in the U.S. “That’s crazy, right?” Urry said. “If we were offered the same opportunities and had the same treatment, women would be half the faculty in every subject.”

Urry, a professor of astrophysics at Yale whose research focuses on active galaxies that host supermassive black holes in their centers was one of the plenary speakers at the conference, which focused on giving young women the tools to stay in physics and other STEM fields. More than 200 women attended Jan. 13 to Jan. 15 at Princeton University.

Addressing unconscious bias

Urry noted that the percentage of women in the U.S. graduating from college with physics degrees has remained flat at 20 percent for the past decade. Women in physics and other fields are affected by unconscious bias, Urry said. She cited one study that found participants who were given the resumes of equally qualified men and women were more likely to pick resumes with men’s names on them.

The Princeton CUWiP Conference was one of nine conferences nationwide and one in Canada that took place simultaneously. Other host institutions included Harvard University, Virginia Polytechnic Institute, and the University of California, Los Angeles. The conference was offered free aside from a $45 registration fee and travel expenses. It was funded by the DOE’s Office of Science and the National Science Foundation through grants to the American Physical Society.

Shannon Swilley Greco, a Science Education program leader at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL), organized the conference with Lyman Page, chair of the University’s Physics Department, and graduate student Laura Chang. Greco told the young physicists that she hopes the conference will inspire them to stay in a physics or STEM field. “I don’t ever want anyone to leave the field they loved because they felt ill-prepared,” she told the young physicists, “or because they just had so much doubt that they were afraid they weren’t where they were supposed to be, or that they were made to feel unwelcome or uncomfortable.” 

The conference kicked off on Friday, Jan. 13, with a tour of University research laboratories, including the Andlinger Center, Geosciences, and PPPL. More than 60 people attended the PPPL tour, which visited PPPL’s National Spherical Torus Experiment-Upgrade test cell and control room. “I love it!” said Bernadette Haig, a student at Fordham University. “This is new stuff for me, so it’s really cool!”

“Don’t get discouraged”

Women on a career panel made up of women at Google, Solvay, and Princeton and Rowan universities, advised the young women to be persistent. “The golden rule is don’t get discouraged,” said Katerina Visnjic, a senior lecturer in the Princeton Physics Department, who is redesigning the introductory physics curriculum. “When you see scientific results presented, that is the last 1 percent of the work that went into that. It doesn’t reflect the 99 percent that didn’t work.”

The conference offered a variety of workshops on topics from “Mental health,” and “Out in STEM,” to “Negotiation and other professional skills.” In the workshop on “Combatting imposter syndrome & bias and developing a growth mindset,” David Yaeger, an assistant professor of psychology at the University of Texas, Austin, said intelligence is just one factor that predicts an individual’s success. “Intelligence itself is malleable especially in your developing stage,” Yaeger added. “Every time you do a hard mathematical proof, your brain actually changes.”

The “How to be an ally” workshop focused on how to be an ally to under-represented groups. “If you have privilege, use that privilege,” said Geraldine Cochran, dean of the Douglass Project for Rutgers Women in STEM. “If you are only looking at job candidates who have graduate degrees from Harvard and Princeton, why not look at people who did really well but have not gone to undergraduate institutions like that?”

Developing a work-life plan

Students attending a workshop on work-life balance were encouraged to think about developing a work-life plan that builds in time for outside activities and simply having fun. “How are you going to find ways to motivate yourself that help you feel fulfilled? And what is a full life apart from what you imagined a successful life is?” asked Amada Sandoval, director of the Princeton University Women’s Center.

Nergis Mavalvala, a physics professor known for her role in the confirmation of gravitational waves at the Laser Interferometer Gravitational-Wave Observatory, broadcast her keynote speech from Harvard, with all 10 conferences broadcasting video greetings from their audiences. (The Princeton group did a wave).

Among numerous “Hot Topics in Physics” speakers was Fatima Ebrahimi, a PPPL physicist, who discussed her research studying a phenomenon in magnetic reconnection that could be used to start fusion devices called tokamaks and might also yield insights into magnetic reconnection, the process that triggers solar flames, the Northern Lights, and other astrophysical phenomena. “If you know plasma physics, there’s no boundary,” Ebrahimi told students. “You can do detailed analysis in the lab but then you can move on and answer fundamental questions in astrophysics.”

Several students presented their research in a poster session at the end of the day on Jan. 14. On Jan. 15, the final day of the conference, Katja Nowack, an experimental condensed matter physicist at Cornell University, discussed her research. The conference concluded with a Career and Research Expo at the Frick Chemistry Laboratory Building.

CUWiP Plus at PPPL

A group of about 20 students attended a CUWiP Plus session at PPPL, where they spent Sunday afternoon and Monday morning learning about plasma physics led by physicist Arturo Dominguez, Science Education senior program leader. A second group entitled, "Physics on All Scales," learned about astrophysics through a giant radio antenna and a trip on Sunday to the Princeton University Imaging and Analysis Center.  

Participants in the conference said they enjoyed meeting other female physicists. “I wanted to come to the conference because there are only eight women in my year in physics,” said Katherine Guido, a student at the Stevens Institute of Technology in Hoboken, New Jersey. “I thought it would be really cool to talk to other women physicists.”  

“I think it’s amazing.” said Jessica Irving, an associate professor in the University’s Geosciences Department. “I’ve never been to a meeting like this before – a meeting full of women who are excited about science.”

PPPL, on Princeton University's Forrestal Campus in Plainsboro, N.J., is devoted to creating new knowledge about the physics of plasmas — ultra-hot, charged gases — and to developing practical solutions for the creation of fusion energy. The Laboratory is managed by the University for the U.S. Department of Energy’s Office of Science, which is the largest single supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit

Conference gives undergraduate women skills, inspiration to pursue physics careers

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          Nuit Blanche in Review (June 2017)   

Since the last Nuit Blanche in Review (May 2017) we've had three implementations related to Deep Neural Networks, a few in-depth post ranging from training nets to compressive sensing,  a dataset, two Paris Machine Learning meetups, one meeting announcement, several videos of talks and four job announcements. Enjoy !


In depth


Paris Machine Learning meetup




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