Climate change is rapidly warming lakes around the world, threatening freshwater supplies and ecosystems, according to a new NASA and National Science Foundation-funded study.
Studies of Recent and Ancient Nepal Quakes Yield Surprises
The Gorkha, Nepal earthquake in 2015 triggered far fewer landslides and much less damage to glacial lakes than expected; while medieval times earthquakes caused massive landscape changes.
Cassini Closes in on Enceladus, One Last Time
A thrilling chapter in solar system exploration will soon conclude, as NASA’s Saturn-orbiting Cassini spacecraft makes its final close flyby of the ocean-bearing moon Enceladus.
Significant-Loophole-Free Test of Bell’s Theorem with Entangled Photons
Author(s): Marissa Giustina, Marijn A. M. Versteegh, Sören Wengerowsky, Johannes Handsteiner, Armin Hochrainer, Kevin Phelan, Fabian Steinlechner, Johannes Kofler, Jan-Åke Larsson, Carlos Abellán, Waldimar Amaya, Valerio Pruneri, Morgan W. Mitchell, Jörn Beyer, Thomas Gerrits, Adriana E. Lita, Lynden K. Shalm, Sae Woo Nam, Thomas Scheidl, Rupert Ursin, Bernhard Wittmann, and Anton Zeilinger
By closing two loopholes at once, three experimental tests of Bell’s inequalities remove the last doubts that we should renounce local realism. They also open the door to new quantum information technologies.
[Phys. Rev. Lett. 115, 250401] Published Wed Dec 16, 2015
Generation of Fresh and Pure Random Numbers for Loophole-Free Bell Tests
Author(s): Carlos Abellán, Waldimar Amaya, Daniel Mitrani, Valerio Pruneri, and Morgan W. Mitchell
A fast random number generator based on laser dynamics helps test the foundations of quantum physics.
[Phys. Rev. Lett. 115, 250403] Published Wed Dec 16, 2015
Strong Loophole-Free Test of Local Realism
Author(s): Lynden K. Shalm et al.
By closing two loopholes at once, three experimental tests of Bell’s inequalities remove the last doubts that we should renounce local realism. They also open the door to new quantum information technologies.
[Phys. Rev. Lett. 115, 250402] Published Wed Dec 16, 2015
Cosmological Higgs-Axion Interplay for a Naturally Small Electroweak Scale
Author(s): J. R. Espinosa, C. Grojean, G. Panico, A. Pomarol, O. Pujolàs, and G. Servant
Weak coupling of the Higgs boson to two axionlike states could lead to a naturally small electroweak scale, which could be detected via their astrophysical and cosmological effects.
[Phys. Rev. Lett. 115, 251803] Published Wed Dec 16, 2015
Broadband Acoustic Hyperbolic Metamaterial
Author(s): Chen Shen, Yangbo Xie, Ni Sui, Wenqi Wang, Steven A. Cummer, and Yun JingAn array of rigid paper squares contained in aluminum frames is used to create a hyperbolic acoustic metamaterial.[Phys. Rev. Lett. 115, 254301] Published Wed Dec 16, 2015
Watch Galileo launch
See the launch of Galileo satellites 11 and 12 on Thursday 17 December. Streaming starts at 11:30 GMT (12:30 CET)
Gamma rays tell story of their travels
A flare of very high-energy gamma rays emitted from a galaxy halfway across the universe has put new bounds on the amount of background light in the universe and given astrophysicists clues to how and where such gamma rays are produced.
The three eggs experiment
The three eggs experiment concerns 37 pre-service science teachers’ predictions about the impact
shapes of three uncooked eggs dropped from different heights. This experiment looks at energy
transformation from potential to kinetic energy, where th…
Gravitational potential: real-life results
The equilibrium surface of a large body of water is a gravitational equipotential. However, that
does not imply that in a local region of increased gravitational field g the height h of the water
surface will be lower to keep the potential gh constan…
Is the negative equivalent stiffness of a system possible?
The negative stiffness concept is seldom encountered in high school courses as well as in college
courses. This paper reports a system with negative equivalent stiffness, which is the most important
component in constructing a quasi-zero stiffness is…
Thomson’s ring experiment with resonant LC circuit
Thomson’s jumping ring experiment is conducted using a low voltage (24 V) electronic circuit. A coil
( L ) is connected with a capacitor ( C ) in parallel and is driven at its resonant frequency to
obtain a high current in the coil. A circuit sen…
Seeing lens imaging as a superposition of multiple views
In the conventional approach to lens imaging, rays are used to map object points to image points.
However, many students want to think of the image as a whole. To answer this need, Kepler’s ray
drawing is reinterpreted in terms of shifted camera ob…
Basic ideas and concepts in hot wire anemometry: an experimental approach for introductory physics students
The purpose of hot wire anemometry is to measure the speed of an air stream. The classical method is
based on the measure of the value of a temperature dependant resistor inserted in a Wheatstone
bridge (Lomas 1986 Fundamentals of Hot Wire Anemometry…
How to build a low cost spectrometer with Tracker for teaching light spectra
Optics is probably one on the most exciting topics in physics. However, it also contains some of the
less understood phenomena by students—the light spectra obtained from the diffraction of light. The
experimental study of light spectra for studyin…
Seeing balancing toys graphically and gravitationally
Description unavailable
Hawking temperature: an elementary approach based on Newtonian mechanics and quantum theory
In 1974, the British physicist Stephen Hawking discovered that black holes have a characteristic
temperature and are therefore capable of emitting radiation. Given the scientific importance of this
discovery, there is a profuse literature on the subj…
Wavelength estimation by using the Airy disk from a diffraction pattern with didactic purposes
In this paper a simple and easy to implement method that uses the Airy disk generated from a
Fraunhofer diffraction pattern due to a circular aperture will be used to estimate the wavelength of
the illuminating laser source. This estimation is based …
Detecting interferences with iOS applications to measure speed of sound
Traditional experiments measuring the speed of sound consist of studying harmonics by changing the
length of a glass tube closed at one end. In these experiments, the sound source and observer are
outside of the tube. In this paper, we propose the mo…
A plane mirror experiment inspired by a comic strip
A comic strip about a plane mirror was used in a high school optics test, and it was perceived that
a large portion of the students believed that the mirror should be larger than the object so the
virtual image could be entirely visible. Inspired on …
The XXL hunt for galaxy clusters
A team of telescopes reveals a 3-D view of a giant sample of monstrous galaxy clusters.
Meanwhile, in a galaxy not so far, far away…
The fantasy creations of the “Star Wars” universe are strikingly similar to real planets in our own Milky Way galaxy.
NASA Examines Global Impacts of the 2015 El Nino
People the world over are feeling, or will soon feel, the effects of the strongest El Niño event since 1997-98, currently unfolding in the eastern equatorial Pacific Ocean.
ESA astronaut Tim Peake begins six-month stay on Space Station
ESA astronaut Tim Peake, NASA astronaut Tim Kopra and Russian cosmonaut commander Yuri Malenchenko arrived at the International Space Station today, six hours after their launch at 11:03 GMT.
Galileos in the zone for launch
Galileos 11 and 12 are on the launch pad, attached to the top of their Soyuz rocket in readiness for this week’s launch.
Up close
Human spaceflight and operations image of the week: Principia launch pictured from just 113 m away
Internet is the primary source of information in Switzerland
88 out of every 100 people in Switzerland use the internet. Usage time is increasing and accessing the internet from mobile devices is considerably more frequent than before. The internet is now the most important source of information, and lots of app…
Three New Low-Energy Resonances in the ^{22} Ne(p,γ) ^{23} Na Reaction
Author(s): F. Cavanna et al. (The LUNA Collaboration)
New resonances are observed in 22Ne(p,γ)23Na reactions at energies relevant to element production in stars and novae. The resulting reaction rates are five times higher than previous measurements indicating a higher abundance of sodium and neon in these systems.
[Phys. Rev. Lett. 115, 252501] Published Tue Dec 15, 2015
Experimental Evidence for Dark Excitons in Monolayer WSe_{2}
Author(s): Xiao-Xiao Zhang, Yumeng You, Shu Yang Frank Zhao, and Tony F. HeinzPhotoluminescence measurements of WSe2, a 2D semiconductor, reveal optically forbidden excitations in the material.[Phys. Rev. Lett. 115, 257403] Published Tue Dec 15, 2015
Season’s greetings
Send an out-of-this-world e-card to your friends
Deal sealed for new Sentinel-1 satellites
ESA has ensured the continuation of the Sentinel-1 Earth observation satellite series for Europe’s Copernicus environmental programme by ordering two more satellites.
The €400 million contract was signed today with Thales Alenia Space of Italy to build Sentinel-1C and -1D.
Vote for the Top Space Stories of 2015
In 2015, astronomers found signs of dark matter close to home, unraveled the mystery of a famous supernova, and took a trip to Pluto.
Principia launch
Replay: ESA astronaut Tim Peake, NASA astronaut Tim Kopra and commander Yuri Malenchenko heading to the International Space Station
Principia liftoff
ESA astronaut Tim Peake, NASA astronaut Tim Kopra and commander Yuri Malenchenko were launched into space at 11:03 GMT (12:03 CET)
Go for the burn: how to melt a satellite
Imagine being confronted with half a tonne or more of metal and composite structures, electronics boxes and solar panels – an unwanted satellite. And then being handed a blowtorch and told to melt it into vapour.
New spin on star-forming galaxies
Astronomers think low spin is the ultimate cause of clumpy gas that drives high rates of galactic star formation.
Hubble solves missing water mystery for Hot Jupiters
Astronomers used the space telescope to probe whether the exoplanets lacked water or were simply hiding it with clouds or hazes.
How NASA Sees El Nino Effects From Space
NASA data are helping scientists learn more about some of El Niño’s key impacts around the globe.
Some Mars Minerals with Watery Past May be Relatively Young
Alteration of minerals by water may have been common on Mars into the second half of the planet’s age, a new analysis of observations by NASA’s Mars Reconnaissance Orbiter suggests.
Missing Water Mystery Solved in Comprehensive Survey of Exoplanets
Missing Water Mystery Solved in Vast Exoplanet Survey
Experimental Observation of Large Chern Numbers in Photonic Crystals
Author(s): Scott A. Skirlo, Ling Lu, Yuichi Igarashi, Qinghui Yan, John Joannopoulos, and Marin Soljačić
A two-dimensional photonic crystal has multiple topologically protected channels, which can be used to transmit and reroute light without scattering losses.
[Phys. Rev. Lett. 115, 253901] Published Mon Dec 14, 2015
Window on the past
Space Science Image of the Week: Mighty black holes at the core of distant galaxies brighten up XMM-Newton’s view of the Lockman Hole
Vega graduates with perfect record
Europe’s Vega light launcher is entering its commercial life boasting a flawless record and an impressive set of capabilities for a wide range of missions.
Neutral Hydrogen Structures Trace Dust Polarization Angle: Implications for Cosmic Microwave Background Foregrounds
Author(s): S. E. Clark, J. Colin Hill, J. E. G. Peek, M. E. Putman, and B. L. Babler
The morphology of diffuse neutral hydrogen structures can provide information about the orientation of polarized dust emission, a significant source of foreground contamination to the B-mode polarization of the cosmic microwave background.
[Phys. Rev. Lett. 115, 241302] Published Fri Dec 11, 2015
Ride along with Rosetta through the eyes of OSIRIS
Rosetta’s OSIRIS camera team has launched a new website to showcase their recent images of Comet 67P/Churyumov–Gerasimenko.
Ice matters
The satellite age has revolutionised our understanding of Earth, giving us accurate information to help critical agreements on climate change such as at the current COP21 conference in Paris. Diminishing polar ice is one of the most visibl…
Week In Images
Our week through the lens: 7-11 December 2015
Spot comet Catalina this weekend
Comet Catalina has crossed into Northern Hemisphere skies and is now visible through binoculars.
A “ghost from the past” recalls the infancy of the Milky Way
This globular cluster is in the last stages of its existence.
Catch comet Catalina on its way out of the solar system
In the coming months, comet Catalina — once thought to be an asteroid — should be visible with the naked eye for skywatchers in the Northern Hemisphere.
A super-Earth in our solar system? Not so fast.
Astronomers quietly submitted a research paper claiming they may have found a large planet on the far fringes of our solar system.
Talking climate
Discover more about the importance of ice sheets as an Essential Climate Variable to understand our changing world
Principia live
Watch ESA astronaut Tim Peake’s voyage to the International Space Station, including launch, docking and hatch opening on 15 December
Space telescopes see Jupiter-like storm on small star
While planets have been known to have cloudy storms, this is the best evidence yet for a star that has one.
How to simply demonstrate diamagnetic levitation with pencil lead
A new simple arrangement how to demonstrate diamagnetic levitation is presented. It uses pencil lead
levitating in a track built from neodymium magnets. This arrangement can also be used as a classroom
experiment.
Graphical representation for thermal equilibrium when transition temperatures are present
We propose the use of graphics in order to get a quick insight of the thermal equilibrium of two
bodies, when a transition temperature is present in the interval between both initial temperatures.
We have found two convenient variables in order to re…
Newton’s laws and kinetic energy
Newton’s first and second laws have implications for the kinetic energy as well as the momentum of a
body. It is recommended that this should be made explicit at an appropriate point in a course.
Audio frequency analysis in mobile phones
A new experiment using mobile phones is proposed in which its audio frequency response is analyzed
using the audio port for inputting external signal and getting a measurable output. This experiment
shows how the limited audio bandwidth used in mobil…
Magnetogate: using an iPhone magnetometer for measuring kinematic variables
This paper presents a method to measure the movement of an object from specific locations on a
straight line using an iPhone’s magnetometer. In this method, called ‘magnetogate’, an iPhone is
placed on a moving object (in this case a toy car) a…
Where is the Sun at sunset?
The question in the title above is exploited to analyse the relationship between different
astronomical models and frames of reference. The paper highlights the fact that the geostatic model,
the favoured model in ordinary discourse, even that of sci…
NASA Mars Rover Curiosity Reaches Sand Dunes
The Curiosity rover is examining the first active sand dunes ever studied up close on any planet besides Earth.
NASA Telescopes Detect Jupiter-Like Storm on Small Star
A star the size of Jupiter has a raging, giant storm
Can’t stop me now: Tim set for Principia launch
ESA astronaut Tim Peake, NASA astronaut Tim Kopra and cosmonaut commander Yuri Malenchenko will leave our planet for the International Space Station 15 December at 11:03 GMT, marking the start of Tim Peake’s Principia mission.
Out-of-Contact Elastohydrodynamic Deformation due to Lubrication Forces
Author(s): Yumo Wang, Charles Dhong, and Joelle FrechetteA dimple forms at the surface of a soft material when it is lowered into contact with a hard surface. This dimple stops the two surfaces coming into direct contact with each other.[Phys. Rev. Let…
Talking climate
Discover more about the importance of ocean colour as an Essential Climate Variable to understand our changing world
Earth from Space
Join us Friday, 11 December, at 10:00 CET for the ‘Earth from Space’ video programme. This week features a Sentinel-2A image of Les Deux Alpes in France
Top Space Stories of 2015: Water abounds in the outer solar system
Saturn’s moon Enceladus and Jupiter’s moon Ganymede offer oceans of possibilities under their icy surfaces.
The Very Large Telescope revisits a curious cosmic collision
Among the debris of a 360-million-year-old cosmic collision is a rare and mysterious young dwarf galaxy.
Top space stories of 2015: The Red Planet under water
An ocean the size of the Atlantic may have once covered Mars’ northern hemisphere.
Top space stories of 2015: Scientists spot youngest cluster of galaxies
Scientists spotted four distant quasars — bright centers of active galaxies — in close proximity to each other, making them the earliest galaxy cluster yet.
Top space stories of 2015: A surprise glow at the galaxy’s center
NASA’s NuSTAR spacecraft spotted an X-ray glow at the Milky Way’s monstrous heart. Its origin remains a mystery.
Top Space Stories of 2015: Supernova hunters see quadruple
Astronomers used the Hubble Space Telescope to catch a faraway galaxy focusing the light of an even more distant supernova four times over.
Top Space Stories of 2015: Deciphering a famous supernova
Several discoveries published in 2015 reveal changes to the blast site and uncover secrets of the explosion first seen 28 years ago.
Top space stories of 2015: Ceres takes center stage
NASA’s Dawn spacecraft entered orbit around Ceres March 6, revealing a pockmarked and ice-rich surface, as well as weird bright spots scientists now say is salt.
Top space stories of 2015: Pluto and its moons revealed
2015 was the “Year of Pluto,” revealing the icy world and its moons in stunning detail and upending much of what we thought we knew about this system.
The salty truth about Ceres’ bright spots
Scientists say salt best explains the weird white spots that stand out against asphalt colored Ceres.
Top space stories of 2015: Europe’s visit to Comet 67P
The European Space Agency’s history making visit to Comet 67P/Churyumov-Gerasimenko revealed surprising science about this dirty snowball.
Top space stories of 2015: Dark matter hints next door
Dark matter annihilation may be the cause of the gamma-ray glow emanating from nearby dwarf galaxy Reticulum II.
Exploring the aerodynamic drag of a moving cyclist
Although the physics of cycling itself is a complex mixture of aerodynamics, physiology, mechanics,
and heuristics, using cycling as a context for teaching physics has a tradition of certainly more
than 30 years. Here, a possible feature is the discu…
Web-based description of the space radiation environment using the Bethe–Bloch model
Space weather is a rapidly growing area of research not only in scientific and engineering
applications but also in physics education and in the interest of the public. We focus especially on
space radiation and its impact on space exploration. The t…
Physics League Across Numerous Countries for Kick-ass Students (PLANCKS)
Physics League Across Numerous Countries for Kick-ass Students (PLANCKS) is an international
theoretical physics competition for bachelor and master students. The intention of PLANCKS is to
increase international collaboration and stimulate the perso…
Non-physics peer demonstrators in undergraduate laboratories: a study of students’ perceptions
Laboratory demonstrators play a crucial role in facilitating students’ learning in physics subjects.
Inspired by the success of peer-led activities, we introduced peer demonstrators to support student
learning in first-year physics subjects that en…
Hysteresis in the phase transition of chocolate
We designed an experiment to reproduce the hysteresis phenomenon of chocolate appearing in the
heating and cooling process, and then established a model to relate the solidification degree to the
order parameter. Based on the Landau–Devonshire theo…
Revisiting the quantum harmonic oscillator via unilateral Fourier transforms
The literature on the exponential Fourier approach to the one-dimensional quantum harmonic
oscillator problem is revised and criticized. It is shown that the solution of this problem has been
built on faulty premises. The problem is revisited via the…
Computational tool for phase-shift calculation in an interference pattern by fringe displacements based on a skeletonized image
In this manuscript an algorithm based on a graphic user interface (GUI) designed in MATLAB for an
automatic phase-shifting estimation between two digitalized interferograms is presented. The
proposed algorithm finds the midpoint locus of the dark and…
A simple model for the energy supply of a stand-alone house using a hybrid wind–solar power system
A research project for secondary school students involving both physical measurements and modelling
is presented. The problem to be solved is whether and how a typical house can be supplied with
energy off-grid, based entirely on renewable energy sou…
New Clues to Ceres’ Bright Spots and Origins
Ceres reveals some of its well-kept secrets in two new studies in the journal Nature, thanks to data from NASA’s Dawn spacecraft.
Venus climate orbiter Akatsuki inserted into Venus’ orbit
After missing on their first attempt in 2010, the Japan Aerospace Exploration Agency successfully inserted the Venus Climate Orbiter Akatsuki into orbit around Venus.
No alien laser signals seen from strange star
The star has puzzled astronomers because it shows irregular dimming unlike anything seen for another star.
Talking climate
Discover more about the importance of aerosols as an Essential Climate Variable to understand our changing world
CubeSat calling
Technology image of the week: radio testing of the world’s first CubeSat designed for atmospheric reentry
EDRS-A and its laser are ready to fly
After a year-long wait in storage for a Proton rocket to become available, the EDRS-A laser communications payload and its Eutelsat host satellite are finally at the Baikonur cosmodrome and being prepared for launch in late January.
Talking climate
Discover more about the importance of soil moisture as an Essential Climate Variable to understand our changing world
Programmable Extreme Pseudomagnetic Fields in Graphene by a Uniaxial Stretch
Author(s): Shuze Zhu, Joseph A. Stroscio, and Teng LiA specially shaped ribbon of single-layer carbon can produce a strong magnetic-like effect within the material when it is pulled on its ends.[Phys. Rev. Lett. 115, 245501] Published Tue Dec 08, 2015
Launch positions
Human spaceflight and operations image of the week: ESA astronaut Tim Peake tries out his pressure suit and seat for 15 December launch
How to watch the Geminid meteor shower
Enjoying a meteor shower requires only comfort and patience. In this brief video, Senior Editor Michael E. Bakich gives some tips on spending a night under “shooting stars.”
Geminid meteor shower peaks under dark skies
Conditions are prime for this year’s Geminid meteor shower. Here are some helpful tips to enjoy the show.
Hubble helps solve mystery of “born again” stars
The most popular explanation is that an aging star spills material onto a smaller companion star, and the small star bulks up on mass to become hotter and bluer, thus becoming a blue straggler.