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Updated: 1 year 44 weeks ago
Model puts new spin on hurricane prediction
Physicists in the US have got to grips with a phenomenon that can cause hurricane winds to intensify rapidly. So-called "eyewall replacement" occurs when the cloud wall encircling the eye of a major hurricane breaks down, only to be replaced by a new wall farther out. The physicists claim that this latest insight will help to predict when and to what extent hurricanes will intensify (Science 315 1235).
When graphene meets negative refraction
Graphene and negative refractive-index materials are two of the hottest topics in physics -- but one might not think they have much in common. Now, however, physicists in the UK and US have proposed that graphene could be used to make a tiny lens to focus electrons through negative refraction. Although the lens has not yet been made, it could someday be used to focus electrons with much more precision than existing electron lenses (Science 315 5816 ).
Nanorods make "ideal" anti-reflection coatings
Physicists in the US claim to have created the first thin optical film with a refractive index close to that of air. The film consists of an array of obliquely-deposited nanorods, which can collectively have a refractive index as low as 1.05. The physicists also claim several graded layers of the films can produce an optical coating that "virtually eliminates" reflection at all wavelengths (Nature Photonics to be published).
Microscope "fingerprints" atoms
Physicists in Japan, Spain and the Czech Republic have developed a new type of atomic force microscope (AFM) that can "fingerprint" the chemical identity of individual atoms on a material's surface. This is one step ahead of existing AFMs, which can only detect the position of atoms.
Quantized magnetoresistance observed for the first time
Researchers in the US and France have shown that the electrical resistance of a magnetic wire just a few atoms thick can be changed in a stepwise manner by varying an applied magnetic field. The result is claimed to be the first experimental verification of "ballistic anisotropic magnetoresistance", which was first predicted in 2005. The breakthrough could someday be exploited to boost the capacity of magnetic data-storage devices (Nature Nanotechnology doi:10.1038/nnano.2007.36).
European Research Council launched today
Scientists in Europe are set to benefit from a massive new source of research money following the official launch of the European Research Council (ERC) at a conference in Berlin today. The ERC -- the first pan-European funding agency to cover all fields of science -- will award grants to individual researchers worth a total of Euro 7.5bn over the next seven years.
Limits set on size of dark matter clumps
If dark matter really does reside only in large clumps, these cannot be any bigger than one-tenth the mass of the Earth. This is the claim of physicists from Germany and the UK, who have studied gravitational lensing data from almost 300 distant supernovae.
"Chemical origami" shrinks 2D discs into 3D objects
Physicists in Israel have invented a neat method of making elaborate 3D structures from flat 2D discs. The trick is to pre-treat a gel disc half the size of a beer coaster with a monomer solution "blueprint" that selectively shrinks when heated. The technique, which cleverly demonstrates the link between 2D and 3D geometry, could be used by engineers to create self-assembling prototypes (Science 315 1116). It's quite easy to see how simple 3D objects could be created using the principle.
Islamic "quasicrystals" predate Penrose tiles
Islamic architects and mathematicians were creating quasi-crystalline patterns some 500 years before similar patterns were described in the West, claim two physicists in the US. Peter J Lu of Harvard University and Paul Steinhardt of Princeton University say that sets of special tiles developed around the 13th century allowed artisans to use complex mathematics to create the fantastic geometric patterns that adorn mosques, palaces and other buildings in the Muslim world.
Magnetic fields put the heat on neutron stars
Magnetic heating could be playing a much more prominent role in the evolution of neutron stars than previously expected, claim astrophysicists in Spain and the US. The researchers looked at data describing the surface temperature and magnetic field of about 30 neutron stars and found a mathematical relationship between the two properties that suggests that the stars are being heated by their own magnetic fields.
Physicists peer into ultrashort laser pulses
Researchers in the UK have unveiled a new technique for characterizing the light within ultrashort infrared laser pulses. The method determines the phase of the light relative to the pulse envelope, and could improve scientists' ability to probe the electrons in atoms and molecules and lead to a better understanding of how chemical reactions occur (Nature Physics doi:10.1038/nphys463).
Ultrafast electron microscope makes movies
Physicists have created a new form of electron microscopy that can make "movies" of atoms as they undergo ultra-rapid chemical or structural transitions. Ahmed Zewail and colleagues at the California Institute of Technology in the US have used coincident electron and laser pulses to follow vanadium and oxygen atoms as they rearranged themselves on a vanadium oxide surface over the course of several picoseconds.
Water flows on Mars
Water could be flowing somewhere on Mars right now and it certainly flowed sometime in the last seven years, according to the latest analysis of images from NASA’s Mars Global Surveyor spacecraft. Michael Malin and colleagues of Malin Space Systems in California claim that images of the Martian surface, taken several years apart, clearly show evidence for liquid water flowing down gullies in the walls of impact craters (Science to be published).
Optical clocks strike again
Physicists in the US have created a highly-stable optical clock that could push the precision of these new timekeepers beyond that of conventional atomic clocks. Optical clocks keep time by using visible light to probe the unwavering energy levels within atoms. While they have the potential to be much more precise than microwave-based atomic clocks, they have suffered from stability problems due to the motion of the atoms.
Binary star pulsates with high-energy gamma rays
The first astronomical source of very high-energy gamma-ray pulses has been discovered by an international team of researchers. The gamma rays, which have energies greater than 100 giga electron volts (GeV), are at least 100 000 times more energetic than other known periodic signals. (Astronomy & Astrophysics in press). The pulses are produced in binary star system called LS 5039, which is a well-known source of x-rays.
Categories: News
A sticky problem
Physicists in the US have made a peculiar discovery about how a small object slides over a rapidly rotating lubricated disk. They have found that if the object is tilted so that it only touches the disk at its corner, then the friction is greater when the disk rotates in one direction rather than the other.
Fish cells swim circles around physics lab
What do stampeding elephants and flocks of birds have in common with living cells from a goldfish? They can all be described by a new model of "flocking" devised by biophysicists in Hungary. The model is based on observations of live cells that begin to move in unison as their numbers reach a critical level. It is the first to explain how such simple organisms can do this without being "aware" of their neighbour's collective motion. (Phys. Rev. E to be published).
Metamaterial bridges the terahertz gap
Researchers in the US have used an artificially-structured "metamaterial" to build a device that can control highly-elusive terahertz (THz) radiation. The modulator is claimed to be ten-times better at switching a THz beam than previous designs and could pave the way for the use of the radiation in a wide range of applications in chemistry, astronomy and even airport security (Nature 444 597).
Thinning thermosphere gives satellites a boost
Carbon dioxide released through the burning of fossil fuels is cooling the upper atmosphere, says a group of physicists who believe that a coherent pattern of global climate change in Earth's upper atmosphere is emerging after more than 15 years of study and debate. Falling temperatures are also lowering the density of the upper atmosphere and causing it to contract towards Earth.
To knot or not to knot
For anyone who has ever experienced the frustration of tangled cables, Jens Eggers sympathizes. His team in the UK have spent the last three years trying to understand knot formation. Now they have found that cables longer than a certain length have the same probability of getting knotted, but that the time to shake out a knot increases rapidly with cable length (Phys. Rev. E. 74 052101).
About this image
Courtesy of SOHO/EIT consortium. SOHO is a project of international cooperation between ESA and NASA. Image has been modified.
The Solar and Heliospheric Observatory (SOHO) is designed to study the internal structure of the Sun, its extensive outer atmosphere and the origin of the solar wind, the stream of highly ionized gas that blows continuously outward through the Solar System. An uninterrupted view of the Sun is achieved by operating SOHO from a permanent vantage point 1.5 million kilometers sunward of the Earth. SOHO was designed to observe the Sun continuously for at least two years.
- New quasar is the oldest yet
- Closing in on the gamma-ray sky
- Milky Way Black Hole May Be A Colossal 'Particle Accelerator'
- Cosmic Lighthouses: Astrophysicists Explain Differences In Brightness Of Supernova Explosions
- Universe Offers 'Eternal Feast,' Cosmologist Says
- Origin Of Darkest Galaxies In The Universe Elucidated
- Scientists Find High Energy Systems Hidden In 'Gas Cocoon'
- Astronomer Finds Closest Gravitational Lensing Galaxy
- First negatively charged molecule found in space
- Binary star pulsates with high-energy gamma rays
- Active galactic nuclei
- Gamma ray 'clock' found creating antimatter
- Astronomers Find First Ever Gamma Ray Clock
