PHYSICS Content

Making light bend backwards

2008-12-10T08:22:00.004+05:30

Negative refraction compared to natural refraction. In natural refraction, light going from one material to another bends in some direction to the opposite side of the "normal," an imaginary line perpendicular to the surfaces. In negative refraction, light bends back from the normal.

While developing new types of lenses, researchers have crafted a layered material that makes light bend in a way nature never intended.Light naturally bends, or refracts, in a specific way when it travels from one material to another. This creates, for example, the illusion of a drinking straw looking bent when placed in water.But the new material, crafted from alternating layers of semiconductors, refracts light backwards—a phenomenon called negative refraction, researchers say.

Negatively refracting materials have been made before. But this is the first that’s fully three-dimension and made totally of semiconductors, the investigators said. Semiconductors are substances that can switch between electrically conducting and non-conducting states, which makes them key components of electronic devices.

The negative-refraction semiconductor structure could be useful in instruments such as chemical threat sensors, communications equipment and diagnostics tools, the scientists said. Semiconductors “are extremely functional materials. These are the things from which true applications are made,” said engineer Claire Gmachl of Princeton University in New Jersey, one of the researchers.

Natural refraction is why lenses have to be curved, a trait that limits image resolution. The new material makes flat lenses possible, Gmachl and colleagues said—theoretically allowing for the creation of microscopes that can focus on objects as small as DNA strands.A limitation of the new material, though, is that it works only with infrared light, a type of light with slightly lower energy than the visible. But the researchers said they hope the technology will expand to other wavelengths in the future.

The substance is in a class of materials called metamaterials, made of traditional substances, such as metals or semiconductors, arranged in very small alternating patterns that modify their collective properties. This enables metamaterials to manipulate light in ways that normal materials cannot. Scientists are also investigating the possibility that certain metamaterials could form invisibility cloaks

At Long Last, Physicists Calculate the Proton's Mass

2008-11-24T18:56:00.000+05:30

By Adrian Cho ScienceNOW Daily News 21 November 2008 It's one thing to know a fact, but it's another to explain it, as a curious advance in particle physics shows. Ever since the proton was discovered 89 years ago, physicists have been able to measure the mass of the particle--which, along with another called the neutron, makes up the atomic nucleus. But even with the best computers, theorists had not been able to start with a description of the proton's constituent parts and calculate its mass from scratch. Now, a team of theorists has reached that goal, marking the arrival of precision calculations of the ultracomplex "strong force" that binds nuclear matter. "It's a really big deal," says John Negele, a theorist at the Massachusetts Institute of Technology in Cambridge. "It's the first time that we've really had this kind of confidence that everything is being done right." Like a troubled teenager, the proton is a mess inside and just about impossible to figure out. In the 1970s, experimenters discovered that the proton and the neutron, known collectively as nucleons, consist of more-fundamental particles called quarks and gluons, which are the basic elements of a theory called quantum chromodynamics (QCD). In the simplest terms, a proton contains two "up" type quarks and one "down" type quark, with gluons zipping among them to bind them with the strong nuclear force. (The neutron contains two downs and an up.) In reality, a nucleon is much more complicated. Thanks to the uncertainties of quantum mechanics, myriad gluons and quark-antiquark pairs flit in and out of existence within a nucleon. All of these "virtual" particles interact in a frenzy of pushing and pulling that's nearly impossible to analyze quantitatively. "Everything interacts with everything," says Laurent Lellouch, a theorist with the French National Center for Scientific Research at the Center for Theoretical Physics in Marseille and one of 12 physicists from France, Germany, and Hungary who performed the new calculations. Ninety-five percent of the mass of a nucleon originates from these virtual particles. To simplify matters, the team took a tack pioneered in the late 1970s called lattice QCD. Within their computer programs, the researchers modeled space not as continuous but as a three-dimensional array of points. They also modeled time as passing in discrete ticks, as opposed to flowing smoothly. This turns space and time into a lattice of points. The researchers then confined the quarks to the points in the lattice and the gluons to the links between the points. The lattice sets a shortest distance and time for the interactions, greatly simplifying the problem. Still, the computation involves millions of variables and requires supercomputers. Only since about 2000 have researchers attempted to include not just all of the gluons but the fleeting quark-antiquark pairs as well. The latest work, reported today in Science, incorporates a variety of conceptual improvements to obtain estimates of the mass of the nucleon and nine other particles made of up, down, and slightly heavier "strange" quarks accurate to within a couple of percent. This isn't the first computational tour de force for particle physicists. Five years ago, others made equally precise calculations of more esoteric quantities--somewhat easier to calculate--such as those that govern the decay of a particle called a D+ meson, which contains a down antiquark and a heavy "charm" quark, notes Christine Davies, a theorist at the University of Glasgow in the U.K. Still, she says, the calculation of the well-known masses highlights the ability of lattice QCD to make accurate predictions for the strong force. "This is all good news for lattice QCD," Davies says, "because there are lots of things that we want to calculate that experimenters haven't already measured." For example, Negele says, physicists still don't know distribution of the virtual particles inside the proton or the origin of its spin. --------------------------------------------------------------------------------

Chandrayaan-1 Probe Lands On Moon

2008-11-15T08:18:00.002+05:30

India’s first unmanned moon mission touched down on the moon on Friday, according to Indian Space Research Organization officials.

The Moon Impactor probe detached itself from the Chandrayaan-1 (moon vehicle) about 100 km from the moon's surface and crash-landed on the south pole of the moon at 10:01 a.m. EST, making India the fourth nation to have a presence on the Moon.

Miniature Indian flags painted on four sides of the MIP signaled the country's symbolic entry into moon to coincide with the birth anniversary of the country's first Prime Minister Jawaharlal Nehru, observed as Children's Day.

"It will signify the entry of India on Moon," an ISRO official said.

The MIP consists of a C-band Radar Altimeter for continuous measurement of altitude of the probe, a video imaging system for acquiring images of the surface of moon from the descending probe and a mass spectrometer for measuring the constituents of extremely thin lunar atmosphere during its 20-minute descent to the lunar surface.

During its 20-minute descent to the moon's surface, MIP took pictures and transmitted them back to the ground. The first pictures are expected to be made public on Saturday.

This Week in Physics History: Nov. 3 - 9

2008-11-06T06:26:00.002+05:30

Nov. 7, 1492 - A meteorite crashes to Earth around noon in a wheat field near Ensisheim, Alsace. The Ensisheim Meteorite is the oldest meteorite with a known date of impact.

Nov. 8, 1854 - Johannes Rydberg, discovery of the Rydberg State of an atom, is born.

Nov. 7, 1867 - Maria Sklodowska is born, remembered to posterity as Marie Curie, pioneer in the study of radioactivity. To date, she is the only person to have earned Nobel prizes in two different fields - physics & chemistry.

Nov. 7, 1878 - Lise Meitner is born. Meitner did ground-breaking work on the discovery of nuclear fission, but was controversially not included in the 1944 Nobel award for the discovery.

Nov. 5, 1879 - Scottish physicist James Clerk Maxwell dies. Maxwell is best known for unifying electricity and magnetism through Maxwell's Laws into electromagnetic theory.

Nov. 7, 1888 - Indian physicist Sir Chandrasekhara Venkata Raman is born. Raman received the 1930 Nobel Prize in Physics for work in molecular scattering of light, specifically the discovery of the Raman effect which bears his name.

Nov. 9, 1921 - Albert Einstein is awarded the Nobel Prize in Physics, primarily for his work in explaining the photoelectric effect.

Nov. 9, 1934 - Carl Sagan, American astronomer and author, is born. Sagan became best known as a populizer of science through television specials, and both fiction and non-fiction writing. He was the author of the science fiction novel Contact, which was later made into a film starring Jodie Foster.

Nov. 6, 1944 - The Hanford Atomic Facility first produces plutonium.

Nov. 5, 1948 - American physicist William Daniel Phillips is born. Phillips won the 1997 Nobel Prize in Physics for his work in laser cooling, which uses lasers to slow the motion of gaseous molecules.

Chandrayaan-1 Camera Tested

2008-11-01T08:51:00.006+05:30

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The Terrain Mapping camera (TMC) on board Chandrayaan-1 spacecraft was successfully operated on October 29, 2008 through a series of commands issued from the Spacecraft Control Centre of ISRO Telemetry, Tracking and Command Network (ISTRAC) at Bangalore. Analysis of the first imagery received by the Indian Deep Space Network (IDSN) at Byalalu and later processed by Indian Space Science Data Centre (ISSDC) confirms excellent performance of the camera.The first imagery (image 1) taken at 8:00 am IST from a height of 9,000 km shows the Northern coast of Australia while the other (image 2) taken at 12:30 pm from a height of 70,000 km shows Australia’s Southern Coast.

TMC is one of the eleven scientific instruments (payloads) of Chandrayaan-1. The camera can take black and white pictures of an object by recording the visible light reflected from it. The instrument has a resolution of about 5 metres.

Besides TMC, the other four Indian payloads of Chandrayaan-1 are the Hyper spectral Imager (HySI), Lunar Laser Ranging Instrument (LLRI), High Energy X-ray Spectrometer (HEX) and the Moon Impact Probe (MIP). The other six payloads of Chandrayaan-1 are from abroad.

It may be recalled that the 1380 kg Chandrayaan-1 was successfully launched into an initial elliptical orbit around the Earth by PSLV-C11 on October 22, 2008. This was followed by four orbit raising manoeuvres, which together raised Chandrayaan-1’s orbit to a much higher altitude. The spacecraft is now circling the Earth in an orbit whose apogee (farthest point to Earth) lies at 267,000 km (Two lakh sixty seven thousand km) and perigee (nearest point to Earth) at 465 km. In this orbit, Chandrayaan-1 takes about six days to go round the Earth once. The spacecraft performance is being continuously monitored and is normal.

This Week in Physics History: Oct. 27 - Nov. 2

2008-10-29T08:19:00.003+05:30

Nov. 2, 1929 - Canadian-American physicist Richard E. Taylor is born. Taylor shared the 1990 Nobel Prize in physics for work in particle scattering that helped lead to the quark model of particle physics.

Oct. 30, 1941 - German physicist Theodor Wolfgang Hansch is born. He shared half of the 2005 Nobel Prize in Physics for his work on laser-based precision spectroscopy, which involves something called the "optical frequency comb technique."

Nov. 1, 1950 - American physicist Robert B. Laughlin is born. Laughlin's explanation of the fractional quantum Hall effect earned him the 1998 Nobel Prize in Physics.

Oct. 27, 1968 - Austrian-born physicist Lise Meitner dies. Meitner was involved in work that lead to the discovery of nuclear fission, but was not named when her collaborator Otto Hahn received the 1944 Nobel Prize in Physics.

Oct. 30, 1975 - German experimental physicist Gustav Ludwig Hertz dies. Hertz, along with James Franck, conducted the Franck-Hertz experiments regarding inelastic collisions in gases, which earned the pair the 1925 Nobel Prize in Physics. Gustav was the nephew of famed physicist Heinrich Rudolph Hertz, for whom the SI unit of frequency - the hertz - is named.

Oct. 27, 1980 - American physicist John Hasbrouck Van Vleck dies. Van Vleck received the 1977 Nobel Prize in physics for work understanding the behavior of electrons in magnetic materials.

Oct. 31, 1986 - American physicist & chemist Robert Mullikan dies. His work in molecular orbital theory earned him the 1966 Nobel Prize in Chemistry.

Oct. 27, 1992 - David Bohm, American physicist, dies at age 75. Bohm contributed to theoretical physics, introducing a controversial alternative to traditional quantum physics interpretations involving hidden variables, which has gained some measure of support in recent years, though is still considered a marginal theory. He also worked with the Manhattan Project. He left the United States in 1951, after being released from jail for refusing to answer questions to the House Un-American Activities Committee regarding previous connections with Communists.

Oct. 27, 1999 - American physicist Robert Mills dies. Mills is best known for his work Chen Ning Yang in developing the Yang-Mills field equations, crucial in quantum field theory and the principles of gauge fields.

CHANDRAYAAN-1

2008-10-20T16:35:00.004+05:30

CHANDRAYAAN-1: India's first mission to the Moon

"THE MOON" with the history of the early solar system etched on it beckons mankind from time immemorial to admire its marvels and discover its secrets. Understanding the moon provides a pathway to unravel the early evolution of the solar system and that of the planet earth. Through the ages, the Moon, our closest celestial body has aroused curiosity in our mind much more than any other objects in the sky. This led to scientific study of the Moon, driven by human desire and quest for knowledge. This is also reflected in the ancient verse. Exploration of the moon got a boost with the advent of the space age and the decades of sixties and seventies saw a myriad of successful unmanned and manned missions to moon.Following this, a hiatus of about one and a half-decade followed. During this period we refined our knowledge about the origin and evolution of the moon and its place as a link to understand the early history of the Solar System and of the earth.

This Week in Physics History: Oct. 13 - 20

2008-10-14T08:42:00.001+05:30

Monday October 13, 2008

Oct. 15, 1878 - The Edison Electric Light Company begins operation.

Oct. 17, 1887 - German physicist Gustav Kirchhoff dies. Kirchhoff worked extensively in the fields of electricity, spectroscopy, and thermal radiation. He coined the term black body radiation. He is probably best known for the Kirchhoff's Laws in electronics. There is also a Kirchhoff's law of thermal equilibrium, which states "At thermal equilibrium, the emissitivity of a body (or surface) equals its absorptivity."

Oct. 20, 1891 - English physicist Sir James Chadwick is born. Chadwick discovered the neutron and led the way for the discovery of nuclear fission.

Oct. 19, 1910 - American astrophysicist Subrahmanyan Chandrasekhar is born in Lahore, British India (now Pakistan). His work on stellar evolution earned him the 1983 Nobel Prize in Physics.

Oct. 14, 1914 - American chemist & physicist Raymond Davis Jr. is born. Davis received the 2002 Nobel Prize in Physics for his work in astrophysics, especially related to cosmic neutrino detection.

Oct. 17, 1933 - Fleeing Nazi Germany, Albert Einstein immigrates to the United States.

Oct. 19, 1937 - New Zealand physicist Ernest Rutherford dies. His discovery of Rutherford scattering led to the orbital theory of the atom, which helped earn him the 1908 Nobel Prize in Chemistry.

Oct. 20, 1984 - British theoretical physicist Paul Adrien Maurice Dirac dies. Dirac is one of the founders of quantum physics. He made many mathematical innovations that helped with analysis of physical systems ranging from electromagnetic phenomena to quantum physics. He earned the 1933 Nobel Prize in physics, along with Erwin Schroedinger, "for the discovery of new productive forms of atomic theory." The "Dirac equation" that he developed describes the behavior of fermions.

Oct. 13, 1987 - American physicist Walter Brattain dies. Brattain, along with Bell Labs coworkers John Bardeen and William Shockley, invented the transistor, for which the trio received the 1956 Nobel Prize in Physics.

Oct. 13, 2003 - Canadian physicist Bertram Brockhouse dies. Brockhouse received the 1994 Nobel Prize in Physics for the discovery of neutron scattering techniques to probe the structure of matter.

The Nobel Prize in Physics 2008

2008-10-08T18:25:00.007+05:30

“Discovery of Broken Symmetries”

This year’s Nobel Prize in Physics is awarded to Yoichiro Nambu, USA and jointly to Makoto Kobayashi, Japan and Toshihide Maskawa, Japan for their “discovery of Broken Symmetries”. This year’s Nobel Laureates in Physics have presented theoretical insights that give us a deeper understanding of what happens far inside the tiniest building blocks of matter.

Yoichiro Nambu

1/2 of the prize

USA

Enrico Fermi Institute, University of Chicago Chicago, IL, USA

"for the discovery of the mechanism of spontaneous broken symmetry in subatomic physics"

Makoto Kobayashi

1/4 of the prize

Japan

High Energy Accelerator Research Organization (KEK) Tsukuba, Japan

"for the discovery of the origin of the broken symmetry which predicts the existence of at least three families of quarks in nature"

Toshihide Maskawa

1/4 of the prize

Japan

Kyoto Sangyo University; Yukawa Institute for Theoretical Physics (YITP), Kyoto University Kyoto, Japan

"for the discovery of the origin of the broken symmetry which predicts the existence of at least three families of quarks in nature"

CERN: European Organization for Nuclear Research

2008-09-23T16:54:00.005+05:30

The Large Hadron Collider
Our understanding of the Universe is about to change... The Large Hadron Collider (LHC) is a gigantic scientific instrument near Geneva, where it spans the border between Switzerland and France about 100 m underground. It is a particle accelerator used by physicists to study the smallest known particles – the fundamental building blocks of all things. It will revolutionise our understanding, from the minuscule world deep within atoms to the vastness of the Universe. Two beams of subatomic particles called 'hadrons' – either protons or lead ions – will travel in opposite directions inside the circular accelerator, gaining energy with every lap. Physicists will use the LHC to recreate the conditions just after the Big Bang, by colliding the two beams head-on at very high energy. Teams of physicists from around the world will analyse the particles created in the collisions using special detectors in a number of experiments dedicated to the LHC. There are many theories as to what will result from these collisions, but what's for sure is that a brave new world of physics will emerge from the new accelerator, as knowledge in particle physics goes on to describe the workings of the Universe. For decades, the Standard Model of particle physics has served physicists well as a means of understanding the fundamental laws of Nature, but it does not tell the whole story. Only experimental data using the higher energies reached by the LHC can push knowledge forward, challenging those who seek confirmation of established knowledge, and those who dare to dream beyond the paradigm.

LHC Shuts Down For Two Months Due To Helium Leak

2008-09-23T16:48:00.002+05:30

Just a week ago, the transformer failed and now a new hardware, due to its malfunction, has stopped the LHC, dead in its tracks. This time a magnet quench event has occurred due to failure of the electrical link between two of the particle accelerator's massive 30-ton superconducting magnets. The complex rectifying process will take approximately two months. The section of the tunnel will have to be warmed up, which contains the magnet. Then it will have to be cooled down to its -271°C operating temperature.

Stephen Hawking: Big Bang experiment could finally earn me a Nobel Prize

2008-09-09T19:48:00.005+05:30

Daily Mail Reporter:09th September 2008

Experts around the world are eagerly awaiting the switch on of the world's biggest scientific experiment, and none more so than Professor Stephen Hawking. The £5billion Large Hadron Collider aims to recreate the conditions moments after the Big Bang that created the universe. It could offer Professor Hawking his best chance so far of winning a Nobel prize if it confirms his theory that black holes give off radiation. He told the BBC: 'If the LHC were to produce little black holes, I don't think there's any doubt I would get a Nobel prize, if they showed the properties I predict. 'However, I think the probability that the LHC has enough energy to create black holes, is less than 1 per cent, so I'm not holding my breath.' The British physicist put forward his idea in the 1970s but it proved controversial because many scientists believed nothing could escape the gravitational pull of a black hole. Although Hawking's theory has become accepted by the profession is remains unproven. Nobel prizes in physics are awarded only when there is experimental evidence for a new phenomenon. The Large Hadron Collider (LHC) at Cern may produce microscopic black holes that could evaporate in a flash of Hawking radiation. To do this, a massive 27km tunnel has been constructed under countryside in France and Switzerland near Geneva, which will be used to smash protons together at 99.99 per cent of the speed of light. Tomorrow morning, it will be switched on and the first attempt to send the particle beam around its entire 27km length will be made. Experts say the LHC is probably the most complex and challenging scientific endeavour since the Apollo programme put astronauts on the moon. One of the aims of the LHC is to hunt for the Higgs boson, the so-called "God particle". The Higgs is said to be the so-far undetected key to mass. If scientists can prove its existence, it could pave the way for manipulating the gravity which exists in all mass - rather like Star Trek 'tractor' beams.

Multibillion-dollar experiment to probe nature's mysteries

2008-09-08T22:18:00.002+05:30

Deep underground on the border between France and Switzerland, the world's largest particle accelerator complex will explore the world on smaller scales than any human invention has explored before. The Large Hadron Collider will look at how the universe formed by analyzing particle collisions. Some have expressed fears that the project could lead to the Earth's demise -- something scientists say will not happen. Still, skeptics have filed suit to try to stop the project. Scientists say the collider is finally ready for an attempt to circulate a beam of protons the whole way around the 17-mile tunnel. The test, which takes place Wednesday, is a major step toward seeing if the the immense experiment will provide new information about the way the universe works. "It's really a generation that we've been looking forward to this moment, and the moments that will come after it in particular," said Bob Cousins, deputy to the scientific leader of the Compact Muon Solenoid experiment, one of six experiments inside the collider complex. "September 10 is a demarcation between finishing the construction and starting to turn it on, but the excitement will only continue to grow." The collider consists of a particle accelerator buried more than 300 feet near Geneva, Switzerland. About $10 billion have gone into the accelerator's construction, the particle detectors and the computers, said Katie Yurkewicz, spokewoman for CERN, the European Organization for Nuclear Research, which is host to the collider.

Big Bang Machine 'Absolutely Safe'

2008-09-08T22:00:00.006+05:30

Big bang machine 'absolutely safe'

Scientists insist the most powerful particle accelerator ever built is "absolutely safe".

Concerns have been voiced over the £5 billion Large Hadron Collider (LHC) which will be switched on this Wednesday

The machine, to be based underground on the Swiss-French border, will smash protons - one of the building blocks of matter - into each other at energies up to seven times greater than any achieved before.

In the flashes from the collisions, they expect to reproduce conditions that existed during the first billionth of a second after the Big Bang at the dawn of creation.

Professor Otto Rossler, a German chemist from a group of scientists mounting a last-minute court challenge to the project, has expressed worries about the creation of black holes.

Scientists believe microscopic black holes might be generated in the machine. But according to the predictions, they will blink in and out of existence before anything scary happens.

Prof Rossler believes it is quite possible that the black holes made in the LHC will grow uncontrollably and "eat the planet from the inside".

But Particle physicist Dr James Gillies, a spokesman for the project, said: "We have received a lot of worried calls from people about it.

"There's nothing to worry about, the LHC is absolutely safe, because we have observed nature doing the same things the LHC will do. Protons regularly collide in the earth's upper atmosphere without creating black holes."

The experiments could help scientists find answers to some of the biggest questions in physics, such as why the universe looks the way it does, and how to explain mass, gravity and mysterious "dark matter".

Japanese physicists aim to unlock universe's mysteries

2008-09-03T13:06:00.003+05:30

A worker shows the facilties of the world's largest scale synchrotron 500m in diameter which produces neutrons and neutrino and can be used for research materials and life science at the Japan Atomic Energy Agency (JAEA) Tokai Research and development center at Tokai village in Ibaraki prefecture As the world's scientists try to unzip mysteries about the universe, Japan is set to open its largest atomic science park to study the world at its smallest level

Electrons discover their individuality

2008-09-03T12:55:00.004+05:30

Electrons between cooperative (coherent) and egocentric behaviour: If an electron is catapulted out of a nitrogen molecule at relatively low speed, it behaves cooperatively. The waves are sent out like a pseudo pair from both atoms and are superimposed (a). This also remains the case so if one of these electron waves is scattered off the atom (b). On the other hand, an electron behaves egocentrically or like an individual if it leaves the molecule quickly (c). If the electron now hits the adjacent atom and is scattered by it, it recognizes from which atom it started and superimposes itself on its scattered wave. Image: Fritz Haber Institute / Uwe Becker

This Week in Physics History: September 1 - 7

2008-09-03T05:35:00.001+05:30

Sept. 1, 1804 -

German astronomer Karl Ludwig Harding discovers Juno, one of largest asteroids in the asteroid belt.

Sept. 3, 1905 -

American experimental physicist Carl David Anderson is born. Anderson would receive the 1936 Nobel Prize in Physics for his discovery of the positron.

Sept. 5, 1906 -

Austrian physicist Ludwig Boltzmann dies. Part of the illustrious Boltzmann family, which permeated nineteenth century European intellectual life in mathematics & the sciences, Ludwig is best known for his work in statistical mechanics and thermodynamics. He strongly advocated atomic theory, well before it was popular to do so.

Sept. 3, 1976 -

U.S. spacecraft Viking II arrived on Mars, landing at Utopia Planitia, and took the first pictures of the planet's surface. Viking II was, of course, an unmanned spacecraft.

Sept. 2, 1992 -

The first automobile powered by natural gas is purchased. Fifty of these alternative fuel vehicles were purchased and put into service by the Southern California Gas Company

This Week in Physics History: August 18 - 24

2008-08-22T18:06:00.006+05:30

Aug. 19, 1662 -

French mathematician, philosopher, & physicist Blaise Pascal dies. Pascal was best known for his mathematical work, especially the formation of Pascal's Triangle (although he was not the first to develop it) as well as work in probability. In physics, Pascal is known for his impassioned defense of the scientific method, studies of fluids, and early work in thermodynamics, most notably pressure and vacuum experiments.

Aug. 23, 1806 -

French physicist Charles Augustin de Coulomb dies. His best-known achievement is the discovery of Coulomb's law for electrostatic force. The SI unit of charge, the coulomb, was named after him.

Aug. 21, 1814 -

Early American physicist and inventor Sir Benjamin Thompson, Count Rumford, dies. Thompson's work in questioning the orthodox physical theories of the time helped lay the foundation for revolutions in thermodynamics, especially in the realms of specific heats, heat transfers and thermal conducitivity. His views on heat as a form of motion helped lead to the kinetic theory and also the laws of conservation of energy.

Aug. 20, 1961 -

American physicist Percy Williams Bridgman dies. Bridgman won the 1946 Nobel Prize in Physics for his work in high-pressure physics. Aug. 21, 1993 - The Mars Observer spacecraft signal is lost by NASA.

Aug. 21, 1995 -

American astrophysicist (born in British India) Subrahmanyan Chandrasekhar dies. Chandrasekhar's theoretical work in cosmology and stellar evolution earned him the 1983 Nobel Prize in physics. The Chandra X-Ray Observatory satellite, deployed into space by the Space Shuttle Columbia in 1999, was named in his honor after a contest with 6,000 proposed names.

Aug. 24, 2006 -

The International Astronomical Union comes to the conclusion that they will redefine the term "planet" so that Pluto is no longer a planet

Scientists Create World's Thinnest Balloon

2008-08-18T08:20:00.001+05:30

Scientists have developed the world's thinnest balloon that is impermeable to even the smallest gas molecules. Above is a multi-layer graphene membrane that could be used in various applications, including filters and sensors. Credit: Jonathan Alden

The Light and Matter Series

2008-08-03T09:42:00.010+05:30

The Light and Matter Series of six books is intended for a introductory course.

Newtonian Physics

http://www.lightandmatter.com/area1book1.html

Conservation Laws

http://www.lightandmatter.com/area1book2.html

Vibrations and Waves

http://www.lightandmatter.com/area1book3.html

Electricity and Magnetism

http://www.lightandmatter.com/area1book4.html

Optics

http://www.lightandmatter.com/area1book5.html

The Modern Revolution in Physics

http://www.lightandmatter.com/area1book6.html

The Light and Matter Series

2008-08-03T09:34:00.003+05:30

The Light and Matter series of introductory physics textbooks is designed for the type of one-year survey course taken by biology majors.

Newtonian Physics

Conservation Laws Vibrations and Waves Electricity and Magnetism Optics The Modern Revolution in Physics Simple Nature - engineering physics Conceptual Physics

Student Devises Solar Energy ECG Useful In Developing Countries And Troubled Areas

2008-08-01T18:25:00.001+05:30

ScienceDaily (July 24, 2008): Electrotechnology student Felix Adamczyk has devised an ECG machine that runs on solar energy. This especially lends itself to use in developing countries or troubled areas. Adamczyk christened it “Kadiri”, which means “make possible” in the Tanzanian language Kiswahili.

http://www.sciencedaily.com/releases/2008/07/080720220017.htm

Send your name to the Moon

2008-07-28T18:09:00.001+05:30

Hydrogen Vehicles Coming Soon

2008-07-26T08:48:00.001+05:30

Hydrogen Vehicles Coming Soon? Two Million Could Be On Roads By 2020

ScienceDaily (July 18, 2008) — A transition to hydrogen vehicles could greatly reduce U.S. oil dependence and carbon dioxide emissions, says a new congressionally mandated report from the National Research Council, but making hydrogen vehicles competitive in the automotive market will not be easy. While the development of fuel cell and hydrogen production technology over the past several years has been impressive, challenges remain.

'Man-made' Water Has Different Chemistry

2008-07-16T08:35:00.001+05:30

ScienceDaily (June 20, 2008) — As population growth, food production and the regional effects of climate change place greater stress on the Earth’s natural water supply, “man-made” water – created by removing salt from seawater and brackish groundwater through reverse osmosis desalination – will become an increasingly important resource for millions of humans, especially those in arid regions such as the Middle East, the western United States, northern Africa and central Asia.

Amorphous Materials: How Some Solids Flow Like Liquids

2008-07-14T08:26:00.001+05:30

ScienceDaily (July 7, 2008): Scientists at CNRS-affiliated laboratories(1) in Bordeaux, Lyon and Paris have provided the first proof that amorphous materials, also known as soft glasses, deform and flow through a collective movement of their particles. These materials (which include chocolate mousse, shaving cream, mayonnaise, metallic glasses, granular materials and mud) are amorphous solids, in other words, they are resistant like solids but, like liquids, lack a crystalline structure. This discovery, published in the journal Nature, should make it possible to better understand deformation and fracturing in metallic glasses(2) and the spreading of thin layers of fragile materials (such as face creams) used in the cosmetics, food-processing and lubrication industries.

Planetary science: The early Moon was rich in water

2008-07-13T08:25:00.001+05:30

Planetary science: The early Moon was rich in water

Marc Chaussidon1

Abstract

Analyses of lunar volcanic glasses show that they are rich in volatile elements and water. If parts of the lunar mantle contain as much water as Earth's, does this imply that the water has a common origin? The Moon's chemical composition differs from Earth's. It is enriched by a factor of two to three in refractory elements (those that condense first from a high-temperature gas) such as aluminium, calcium and titanium; most easily vaporized (that is, volatile) elements, such as sodium and potassium, are rare; and it is considered to be almost devoid of water1.

Nature 454, 170-172 (10 July 2008)

Hammer And Feather On Moon

2008-06-20T19:19:00.001+05:30

Hammer And Feather On Moon

Optical Illusion

2008-06-20T18:41:00.001+05:30

Optical Illusion

Solutions to IIT - JEE – 2008

2008-06-19T17:58:00.001+05:30

Solutions to IIT - JEE – 2008(Paper – 1, Code−7)

Solutions to IIT - JEE – 2008 (Paper – 1, Code−7)

2008-06-19T17:15:00.003+05:30

Solutions to IIT - JEE – 2008 (Paper – 1, Code−7)

OPTICAL ILLUSIONS

2008-06-18T22:40:00.001+05:30

OPTICAL ILLUSION

METALS IN NUTRITION

2008-05-20T09:48:00.001+05:30

METALS IN NUTRITION

Metals in the diet

A variety of metals are found in a range of foods in the diet, and in this context, are termed minerals, along with some non-metals, such as iodine and fluorine. The minerals are grouped in to either: Macro minerals – those that are needed by the body in relatively large amounts (e.g. sodium, potassium, chlorine, calcium, phosphorus, magnesium) Micro/trace minerals – those needed in small amounts (e.g. selenium, iron, zinc, copper, manganese, molybdenum, chromium, arsenic, germanium, lithium, rubidium, tin). Many of these minerals have been classed as essential elements, necessary for utilisation by the body to ensure good health, but the function of these minerals and their benefits to the body is still uncertain and has been widely speculated. This has given scope for arguing the justification of taking supplements. Much research has been carried out, concerning the role of minerals in the body, but in many cases, difficulties in investigating their individual effects has been expressed because intake is often in combination with other vitamins and minerals, e.g. fruit and vegetables contain several minerals. There is, however, strong evidence that supplementation of certain minerals would benefit those suffering from deficiency disorders. It is also important to note though that intake of minerals does not necessarily correlate with absorption and a balance must be obtained. There are many suggested essential elements – here, we have highlighted some of those which have been most speculative, primarily the micro minerals.

Macro minerals

Macro minerals are present in virtually all cells of the body, maintaining general homeostasis and required for normal functioning. Acute imbalances of these minerals can be potentially fatal, although nutrition is rarely the cause of these cases. Diet can affect levels of macronutrients in the body, but effects are generally chronic, e.g. a high intake of sodium can lead to hypertension.

Micro minerals

Micro minerals contribute to good health if they originate from an organic source because they have essentially been processed. Plants take up minerals from the ground, digest them, making them ionic so that when consumed by humans, assimilation into the body occurs much more easily, and toxicity by accumulation does not occur. However, micro minerals from inorganic sources, such as heavy metals, can not be used by the body as they tend to build up in the tissues.

Understanding of superconductivity may be closer

2008-05-20T09:08:00.002+05:30

Understanding of superconductivity may be closer
Physicists have long debated the causes of superconductivity, a phenomenon in which normal resistance to a flow of electrical current vanishes in certain materials when extremely cold. This allows hyper-efficient current transmission—offering the promise of a new electrical golden age with high-powered computers, magnetically levitating trains and super-efficient power lines. But to put this effect to practical use, scientists have to understand it better, especially why it seems to occur only in such cold and whether that can be changed. A new study may help clarify these questions, according to researchers who have found that superconductivity works differently in two slightly different temperature ranges. Superconductivity was discovered by the Dutch physicist Heike Kamerlingh Onnes when in 1911 when he cooled mercury to barely above absolute zero, the lowest temperature theoretically possible. Scientists later concluded that superconductivity at such rock-bottom temperatures occurs when vibrations of the grid-like atomic arrangement of the material affects its electrons, subatomic particles that carry electric charge. These, which normally repel each other because they have the same charge, then join up as pairs that glide effortlessly through the material without scattering off its atoms. In 1986 came the discovery of a class of materials that allow superconductivity at somewhat less frigid temperatures: up to about 150 Kelvin (minus 253 F or minus 123 C), considerably higher than the 4 degrees Kelvin (minus 452F or minus 269 C) required in the original Onnes tests. This advance allowed the materials to be cooled with liquid nitrogen, which costs less than the liquid helium needed to cool lower-temperature superconductivity. Since that finding, scientists have debated whether in these higher-temperature superconductors—also called copper oxide superconductors—electrons bond in the same ways as in the lower-temperature superconductors. The mechanism turns out to be different, according to the new study. Rather than atomic vibrations driving the electrons to join as pairs, the researchers said, higher-temperature superconductivity depends on electrons’ ability to take advantage of their natural repulsion in a complex situation. This conclusion, investigators said, was based on experiments showing that the places in a sample where electrons form the most strongly bound pairs, are the same as where they show signs of stronger repulsion at higher, non-superconducting temperatures. Surprisingly, in other words, it seems “the electrons with the strongest repulsion in one situation are the most adept at superconductivity in another,” said Princeton University physicist Ali Yazdani, one of the researchers. That’s unlike the behavior of electrons in lower-temperature superconductive materials, according to the group, which studied a compound made of strontium, bismuth, calcium and copper oxide and reported the findings in the April 11 issue of the research journal Science. Although much remains to be explained, the researchers said their work may be a a useful step. “The data is a gold mine which we’re only beginning to exploit,” agreed Princeton physicist Philip Anderson, who won a physics Nobel in 1977 and wasn’t involved in the research. The investigators used a specially rigged form of a device known as scanning tunneling microscope, which let them examine a single atom as electrons there went from repelling each other to pairing up. The microscope analyzes atoms by measuring current that flows between the surface of a sample, and a specially designed probe on the microscope. The probe, with a fine tip just one atom wide, is placed a hair’s breadth above the sample, and can move in increments smaller than an atom over the surface to take measurements. April 10, 2008,Courtesy Princeton University and World Science staff

Superinsulator - New State of Matter

2008-05-01T10:54:00.001+05:30

Superinsulator - New State of Matter Physicists have known about superconductors since 1911, but now it looks like the opposite - a superinsulator - might also exist, unnoticed until recently. An international team led by Argonne National Laboratory's Valerii Vinokur has published their findings in the April 3 issue of the journal Nature. The superinsulator requires a very delicate balance to be achieved. Thin films of titanium nitride (normally a superconductor) apparently drop to zero electrical conductance when lowered below a certain critical temperature and placed in the presence of a magnetic field, the exact opposite of what occurs in standard superconductivity (which yields zero electrical resistance below a critical temperature). Scientists have known that superconductors can turn into insulators, but only due to quantum phase transitions very near absolute zero. This new form of insulator extends over a range of temperatures up to nearly 70 millikelvin in a magnetic field of 0.9 tesla. The theory behind these results poses some curious properties of quantum physics, as is usually the case. Essentially, they posit that electrical current and electrical voltage swap roles in the quantum system under these conditions. Plotting phase diagrams of current vs. magnetic field for superconductors and voltage vs. magnetic field for superinsulators result in a pair of phase diagrams which appear to be virtually identical, in fact! In an analysis of the findings, Italian physicist Rosario Fazio says, "Vinokur and colleagues' observation and theory of superinsulation are crucial advances in our understanding of the collective properties of low-dimensional systems." Fazio goes on to speak about the extent to which further investigation into these topics needs to be performed. One does have to wonder what technological insights we might gain from the intense study of how to create materials which can completely block the flow of electrical impulses

Power goes wireless

2008-05-01T10:39:00.002+05:30

A new system for transmitting power could get rid of the tangle of cables that keep alive our cell phones, laptops and other devices, researchers report. Physicists at the Massachusetts Institute of Technology in Cambridge, Mass. found that power could be transmitted without wires using special “resonant” antennas. The researchers used the system to power a 60-watt light bulb more than two meters (about two yards) from a wireless transmitter at 40 percent efficiency. Two images of a 60-watt bulb lit from 2 meters away by a power-transmitting coil. Note the obstruction in the lower image.One known method uses electromagnetic radiation, like radio waves. More commonly used for wireless transmission of information, these can also transmit power. But not very effectively. Since radiation spreads in all directions, almost all the power would end up being wasted into space. An alternative strategy is to beam the radiation specifically toward the electronic device to be charged—but then problems can arise if some other object gets in the way, or if you move the device. The MIT concept, called “WiTricity” for wireless electricity, involves using so-called coupled resonators. These are objects that, if struck or disturbed, tend to naturally oscillate at a definite rhythm. If two of them tend to have matching rhythms, they actually enhance each others’ oscillations. One example is a child on a swing. If she swings her legs in synch with the natural rhythm of the swing itself, the swing will soon be briskly in motion. The type of resonance behind such a push-pull system is called mechanical, but other types of resonances are possible. There are acoustic resonances, for example. Imagine a room with 100 identical wine glasses, each filled with different amounts of wine. This gives each glass a different “resonant frequency,” or natural rhythm of vibration. If a singer then sings a loud enough note in the room, a glass of the corresponding frequency might accumulate enough energy to explode, while the other glasses sit undisturbed. The MIT team focused on yet another type of resonance, magnetic. They set up two copper coils, each a self-resonant system. One coil, attached to a power source, is the “sending” unit. Instead of sending out electromagnetic waves, it fills its surroundings with an oscillating magnetic field. This leads to a power exchange with the other, “receiving” coil. Because the magnetic field, unlike radio waves, never gets too far from the sending unit, the energy isn’t lost into space. And extraneous objects entering the field have no impact because they normally don’t resonate along with the system. With such a design, power transfer has a limited range, and the range would be shorter for smaller-size receivers. Still, for laptop-sized coils, power levels more than enough for a laptop can be transferred over room-sized distances nearly omni-directionally and efficiently, regardless of what’s between the objects, researchers said. “As long as the laptop is in a room equipped with a source of such wireless power, it would charge automatically, without having to be plugged in,” said MIT’s Peter Fisher. Although the power transfer efficiency remains below the ideal, team member Andre Kurs said in an email that he’s optimistic it can be improved. He also acknowledged that inefficiency raises environmental concerns, but argued that the new system on balance might actually help the environment. That’s because the batteries that it would replace also tend to lose efficiency over time, and contain toxic chemicals.

This Week in Physics History: April 21 – 27

2008-04-27T12:35:00.003+05:30

This Week in Physics History: April 21 – 27 April 27, 2008 • Apr. 23, 1858- German physicist & Nobel laureate Max Planck is born. Planck is credited as the father of quantum physics, because his solution to the ultraviolet catastrophe in blackbody radiation involved assuming that energy traveled in discrete packets, which he termed quanta. He derived a value, later called Planck's constant, which is crucial to performing quantum physics calculations. Out of this finding, Albert Einstein was able to explain the photoelectric effect and, subsequently, the field of quantum physics was born. He received the 1918 Nobel Prize in Physics for this work. • Apr. 25, 1900 - Austrian physicist Wolfgang Ernst Pauli is born. Pauli is best known for discovering the "Pauli Exclusion Principle" and extensive work in the concept of spin in particle physics and chemistry. He received the 1945 Nobel Prize in Physics for this work, having been nominated for it by Albert Einstein. • Apr. 22, 1904 - American physicist J. Robert Oppenheimer was born. Oppenheimer is sometimes called "the father of the atomic bomb" because he was the director of the Manhattan Project to develop the first nuclear bomb. • Apr. 25, 1953 - Francis Crick & James D. Watson publish their paper describing the double helix structure of DNA, which was determined largely with the use of x-ray crystallography. • Apr. 24, 1960 - German physicist & Nazi oppositionist Max von Laue died in Berlin. He was awarded the Nobel Prize in Physics in 1914 for his work in discovering the crystial diffraction of x-rays. • Apr. 21, 1994 - Astronomer Alexander Wolszczan announces the first discoveries of extrasolar planets (i.e. planets circling stars other than our Sun). • Apr. 26, 1994 - Physicists announce the first evidence of the top quark, a previously theoretical subatomic particle

Atomic Clock

2008-04-24T09:23:00.001+05:30

Atomic Clock The mechanical clock served the needs of people for many centuries. Most people were satisfied with reckonings of time that gained or lost only a minute or two each day, and more accurate timepieces were available where greater precision was necessary, as with the operation of railroads or the determination of longitude at sea. In the course of the 20th century, however, the need for much greater accuracy arose. At the same time, recently discovered scientific principles made possible the building of clocks with almost unimaginable accuracy. In the 1920s, the rapidly expanding radio industry generated a need for the precise allocation of broadcast frequencies. Since frequency is by definition the number of cycles per second, the ability to broadcast on an exact frequency required an exact division of time. In the United States, the task of assigning radio frequencies was given to the National Bureau of Standards (NBS), an agency of the federal government's Department of Commerce. In response to the need for better time measurement, in the 1920s the NBS invented a clock based on a quartz crystal. When electrically stimulated, a quartz crystal vibrates at a fixed rate determined by its size and shape. This attribute allowed the construction of timepieces that were accurate to 1 second every 3 years. Quartz-crystal clocks were used to set radio frequency standards for 3 decades, but they suffered from a serious defect: Each clock ran at a slightly different rate. For most applications the differences were so small as to be irrelevant, but for others they were of crucial importance. Much more accurate clocks became possible in the late 1940s as a result of fundamental discoveries regarding the behavior of atoms. In particular, quantum physics had determined that atoms absorbed and emitted energy only at certain frequencies. In 1948, three physicists at the NBS—Harold Lyons, Benjamin Husten, and Emory Heberling—used this principle to build the first atomic clock. The clock used microwaves that were directed into ammonia gas. When the microwave frequency (about 24 billion hertz) was the same as the natural frequency of the hydrogen atoms in the ammonia, the atoms absorbed them. If the frequency was different, the microwaves hit a detector that triggered an electrical current. The current in turn adjusted the microwave frequency, which was then used to keep a crystal vibrating at a uniform rate. The clock was accurate to 1 second every 8 months. This was not as good as the best conventional quartz crystal clock, but there was ample room for further development. The next generation of atomic clocks was built around the element cesium. These clocks used vaporized cesium that had been magnetically divided so that one beam of atoms had identical energy states. When a microwave signal matched a cesium atom's natural frequency, it changed the atom's energy state. The atoms with a changed energy state were magnetically segregated and sent to a detector. As with the first atomic clock, the signal from the detector was used to stabilize the vibration frequency of a quartz crystal. In this way, it became possible to tell time that was accurate by 1 second every 300 hundred years. Development continued, and by 1970 the latest cesium clock operated with an accuracy of 1 second in 6,000 years. This made it more accurate than our natural timepiece, the Earth, which spins erratically due to axial wobbling caused by tides, the movement of the interior molten core, and even heavy snowfalls. Because atomic time slowly gets out of synch with Earth time, the Paris-based International Bureau of Time occasionally has to add or subtract a "leap second" to bring the two back together. Atomic clocks gain or lose only a few millionths of a second annually, yet the quest for even more accurate clocks continues. Increasingly accurate clocks are vital to a variety of scientific and technological ventures. Elementary-particle physicists are concerned with the detection of subatomic particles that may exist for a fraction of a nanosecond (a nanosecond is 10-9 seconds), while geologists study tiny movements of the Earth's tectonic plates in order to learn more about the cause of earthquakes. Television and radio broadcasting still require precise reckonings of time, especially as the airwaves get increasingly crowded and frequencies have to be kept within very narrow limits. Atomic clocks are also vital to the operation of sophisticated navigation technologies, where an error of a fraction of a second can throw an airplane several miles off course. References: 1.Margaret Coel, "Keeping Time by Atom," American Heritage of Invention and Technology, (1988)

Timeline: Physics[2007]

2008-04-19T13:48:00.001+05:30

Timeline: Physics[2007] January 11: Scientists find three black holes in close proximity to each other.Astronomers spot a rare phenomenon: a trio of black holes. The black holes, called quasars, are about 10.5 billion light years from Earth and about 100 thousand light years from each other, about the width of our Milky Way Galaxy—a rare astronomical discovery. Each quasar emits more light than an average galaxy. Light now reaching Earth from the quasars is nearly as old as the universe; researchers hope to learn more about the chaotic nature and composition of the early universe by studying these quasars. February 2: Physicists discover way to measure extra dimensions, which provides evidence for string theory.A group of theoretical physicists have found that by looking at the universe moments after the big bang, they may find evidence to support string theory and the existence of extra dimensions. In addition to three dimensions of space and the fourth dimension of time, string theory proposes that there are six additional dimensions that make up the universe. It is thought that these six extra dimensions are hidden within the tiny strings that make up all matter and energy in the universe. The concept is difficult for most people to visualize, and until now, experimentally proving string theory was thought to be impossible. By comparing detailed measurements of cosmic background radiation—faint energy traces left over from the big bang—and comparing it to results predicted by string theory, researchers are hoping to discover the shape and nature of the six unseen dimensions within the tiny strings. February 14: Engineering professor resolves Einstein's twin paradox.Subhash Kak, an engineering professor from Louisiana State University, finds a solution to the twin paradox, a problem introduced in 1905 with the publication of Albert Einstein's theory of relativity. The paradox attempts to answer questions that arise when traveling at near the speed of light. The paradox is as follows: one twin leaves Earth on a spaceship traveling near the speed of light. The ship travels several light years away. When the ship returns to Earth, because of the phenomenon of time dilation—a consequence of relativity—the twin left behind on Earth is now older than his brother. The paradox is that, in this situation, it is the earthbound twin who is considered to be in motion relative to the spaceship and thus should be the one aging more slowly (which is not the case). Kak solved the paradox by measuring the motion of the Earth and the spaceship against a third, fixed point, rather than against each other. By employing high level mathematics, Kak also assumed that the spaceship travels through an anisotropic universe to come to his conclusion. The long-standing paradox here is resolved so that after the flight, there is no age difference between the twins. March 1: Scientists create coating made of nanoparticles that reflects virtually no light.Researchers have developed the world's most nonreflective material. The new coating has a refractive index, which controls how much light a material reflects, of 1.05, which is comparable to that of air. To achieve the low reflectivity state, the silica nanorods are placed on a coating of aluminum nitride at an angle of about 45°. Physicists are hoping to use the new antireflective coating to improve performance of light emitting diodes (LEDs), solar cells, and other optical hardware. 2007 April 2: NASA mission proves one of Einstein's relativity predictions.Astronomers determine that data collected from NASA's Gravity Probe B satellite proves that one of Albert Einstein's predictions about curved space is correct to within 1 percent. In his theory of relativity, Einstein predicted the geodesic effect, in which space is curved by the mass of an object. The effect is often illustrated by placing a heavy ball on a sheet of rubber. The depression that the ball makes in the sheet represents the distortion created by the Earth's mass on the space beneath it. Gravity Probe B is currently testing another of Einstein's predictions, called frame-dragging, in which a massive spinning object, such as the Earth, would drag the surrounding space and time with it as it rotates, just as the ball on the rubber sheet would drag the rubber if it were twisted. April 4: Scientists measure details of electrons tunneling out of atom.Researchers at the Max Planck Institute in Germany have performed experiments that measure the time it takes for an electron to "tunnel" out of an atom. Tunneling occurs when an electron escapes from the atom without additional energy, a feat that would be impossible if electrons obeyed the rules of classical physics. Electrons, however, follow the rules of quantum mechanics. The tunneling was measured to take less than 400 attoseconds, or 4 × 10−16 seconds. Scientists hope that the finding could be used to improve the X-ray laser, which would be instrumental in the early diagnosis of cancer. April 16: The highest frequency signal ever is produced.Engineers at UCLA produce the highest frequency electromagnetic signal ever produced: 324 gigahertz, or 324 billion cycles per second, 70 percent faster than previously attained. The device that created the record-breaking signal is a complementary metal oxide semiconductor (CMOS) device similar to the type used in computer processors. This range of frequencies, called "submillimeter" because the wavelength is just under one millimeter (0.04 inch), can be used to see through clouds and fog, and also in high-resolution sensors on spacecraft. Engineers also hope to use the higher frequency limit to increase available bandwidth of communication systems, which would lead to speedier and more efficient voice, data, and video transmissions. May 3: Mercury's core may be liquid.The results of a five-year study reveal Mercury has a liquid core of molten iron, rather than a solid core, as previously believed. By bouncing radio signals sent from a ground telescope in California off of the planet, then receiving them again at a facility in West Virginia, astronomers were able to measure small twists in Mercury's rotation that were twice as high as expected for a planet with a solid core. This supports data taken by Mariner 10 in 1974, which measured a weak magnetic field on Mercury's surface—a key indicator of a liquid core. May 15: Hubble Telescope detects ring of dark matter.NASA's Hubble Space Telescope has detected a ripple around two collided galaxies that adds compelling evidence for the existence of dark matter. Astronomers believe that dark matter makes up a majority of the matter in the universe. The ring is 2.6-million-light-years wide and bends the light around it to create a ripple effect, which researchers claim is dark matter's "calling card." The ring surrounds cluster ZwCl0024+1652, which comprises the remnants of two galaxies that collided over a billion years ago. May 21: Researchers find new production method for hydrogen fuel.A new type of fuel, in the form of aluminum and gallium pellets, may offer an efficient way to produce and store hydrogen, which many scientists hope is the clean fuel that will replace gasoline and oil. Until now, the major roadblock to producing hydrogen-powered cars has been the absence of an efficient method of producing hydrogen. In the new procedure, gallium is added to aluminum pellets causing the aluminum to react with water. This splits the hydrogen and oxygen in the water, releasing pure hydrogen. The pellets are easily stored and transported and researchers say the cost of the new fuel would be competitive with that of gasoline. June 12: Scientists demonstrate quantum communication with light.Scientists working at the European Space Agency (ESA) have shown that a strange property of light, called quantum entanglement, can be used for communications over long distances. In the study, a laser beam was transmitted across a distance of 89 miles (144 km) to a remote satellite. Quantum entanglement hinges on the fact that when light is emitted from one source, such as a laser, it retains information about all of the photons that it interacted with, so if two photons are separated after they interact, they can retain information about the other, even if they are miles apart. Quantum entanglement held steady even through Earth's atmosphere. Researchers also showed that making a measurement anywhere along the path of the signal will be noticed, so eavesdroppers would be detected. Therefore, these lines of communications would be perfect for sending and receiving confidential information. June 28: Nano-sized light source invented.Researchers at the University of California at Berkeley have invented a nano-sized light source able to emit light across the visible spectrum. This light source could have profound implications in the development of nanophotonic technology, bioimaging, and cybercryptography. July 12: New lens device will shrink huge light waves to pinpoints.University of Michigan scientists have constructed a new lens that can break light waves into much smaller points than is possible with a standard lens. This new technology could be used to increase data storage on media such as CDs, which are currently limited by the size of the electromagnetic wave (and thus the number of bits they can hold). September 12: Spin measured on individual atoms.Scientists at the University of California, Berkeley, succeed in measuring the spin of individual iron atoms place atop a film of copper atoms. While scientists have long known that the electrons of individual atoms have one of two spin qualities ("up" or "down"), until recently these have only been measured in a film of orderly arranged atoms. Researchers hope that someday atomic spin could be used as a digital switch in smaller, more efficient computers. September 12: New particle created by uniting matter and antimatter.A team of scientists from the University of California creates molecules of di-positronium, a particle predicted in 1946, by bonding electrons with positrons. The particles have remained elusive due to the scarcity of antimatter positrons in the universe. Scientists solved this problem by trapping and gradually accumulating 20 million positrons, before releasing them into a silica sponge. Before annihilating, many positrons bonded to electrons, forming di-positronium molecules. The molecules also annihilated within a quarter of a nanosecond (one billionth of a second). The team speculates that the new molecule could possibly be incorporated into the design of a powerful gamma ray laser. September 12: Russians test fuel-air bomb.The Russian air force tests a fuel-air bomb, claiming that it is larger than the American MOAB (Massive Ordinance Air Burst) bombs. If claims are correct, the fuel-air bomb is the largest non-nuclear bomb in the world. The fuel-air bomb operates in two stages. First, a primary charge disperses ignitable material into the surrounding atmosphere, which is then exploded by a larger, secondary charge. Russia has stated that the explosion has the force of 44 tons of TNT, sufficient to demolish a four-story building at the test site. September 24: An experiment aboard the European Space Agency's Foton satellite confirms liquid fluctuation.An experiment on board the European Space Agency's Foton satellite has confirmed scientific theories about fluid fluctuation. Fluctuations in temperature and concentration are an intrinsic property of liquids, but the changes are so small as to be difficult to observe using traditional methods. In microgravity's strong temperature gradient—great differences across a small distance—the satellite is able to photograph visible fluctuations and transmit the images to Earth, less than a week after launch. October 2: Scientists develop a two-dimensional, microscopic "invisibility cloak."A team of physicists from the United States have created a visible light "invisibility cloak" 10 micrometers in diameter. By injecting polarized cyan light onto a film of gold, the light is transformed into plasmons that redirect light around the gold, effectively making it invisible in two dimensions. Another American team created a three-dimensional microwave invisibility cloak in October 2006. In the visual light cloak, dimensionality was decreased to accommodate the much smaller wavelength. October 22: Microscopic nanoantenna laser developed.Engineers at Harvard have designed a laser capable of producing detailed images on a nanometric scale. The laser, called a quantum cascade laser nanoantenna, is comprised of two gold rods separated by a gap of one nanometer. By focusing light of a certain spectrum through the gap, the laser is able to scan across samples at a resolution much higher than that of the wavelength of the light itself. The new technology enables researchers to see, in great detail, the chemical composition of the interiors of cells and other nanoscopic materials. October 29: Magnetic separation technique developed.A new magnetic separation technique called magnetophoresis has been developed by a joint team of researchers at Duke University and Perdue University. The process involves using a magnetic field and microchip to separate and sort magnetic beads according to size. The beads could be attached to a substance, such as a suspected pathogen, and then separated from the sample by the magnet. The technique could have applications in medicine, as a method for testing for multiple pathogens at once. October 31: Scientists develop functioning nanoradio.A team of researchers from the University of California Berkeley and the Lawrence Berkeley National Laboratory has developed a working radio from a single fiber of carbon nanotube less than one micrometer long. The device is powered by a battery and functions by running a stream of electrons along the tube and across a vacuum to a negatively charged copper anode. Radio waves disrupt the flow of electrons, and the signal is relayed and broadcast through a speaker. The technology could have broad applications, since any system in which a nanoradio is embedded could potentially be controlled by radio. November 12: Scientists discover a new method for storing hydrogen.Scientists at the University of Virginia have found a new class of materials for storing hydrogen. The material doubles, from seven to fourteen percent, the storage capacity by weight for hydrogen. Earlier materials required extremely low temperatures for storage while the new material is functional at room temperature. The technology could have applications in energy storage and transportation. December 7: New oil-repelling technology allows for the creation of self-cleaning materials. Researchers from MIT and the U.S. government have designed a material that is repellent to oils. This new material is known as superoleophobic because oil bounces off, making it essentially self-cleaning. Oleophobic materials are much more complicated than water-repellant materials as oil tends to spread quickly and cling to surfaces. Possible applications are self-cleaning displays on cell-phones. December 7: Scientists gain new insight on solar wind. Information recorded by the NASA telescope Hinode provides a clearer picture as to the effect of magnetic waves called Alfvén waves, on solar winds. The understanding of solar winds is important, as they can disrupt power grids and satellite communications. December 13: Physicists discover "rogue" optical waves. Scientists, using waves of light to understand aquatic waves, have pinpointed the cause of rogue waves. Rogue waves are large oceanic waves that seem to happen irrespective of tides. The effect was reproduced in a lab by hitting a light wave with sound in what scientists are calling a "sweet spot." Further investigation will follow on the effects of sound on aquatic waves.

'Power shirt' generates watts as you walk

2008-04-19T13:33:00.001+05:30

'Power shirt' generates watts as you walk Two sets of zinc oxide nanowires meet teeth-to-teeth, allowing the gold-coated microfibres to scrub those not coated with gold. This generates electricity by the so-called piezoelectric effect, the fundamental concept behind a 'power shirt' A microfibre fabric that generates enough of its own electricity to recharge a mobile phone or ensure that an mp3 player never runs out of power has been developed by US scientists. If made into a shirt, the fabric could harness power from its wearer simply walking around or even from a slight breeze, they report today in the journal Nature. "The fibre-based nanogenerator would be a simple and economical way to harvest energy from the physical movement," says Professor Zhong Lin Wang of the Georgia Institute of Technology, who led the study. The nanogenerator takes advantage of the semiconductive properties of zinc oxide nanowires, tiny wires 1000 times smaller than the width of a human hair, embedded in the fabric.The wires are formed into pairs of microscopic brush-like structures, shaped like a baby-bottle brush. One of the fibres in each pair is coated with gold and serves as an electrode. As the bristles brush together through a person's body movement, the wires convert the mechanical motion into electricity. "When a nanowire bends it has an electric effect," Wang says. "What the fabric does is it translates the mechanical movement of your body into electricity." Coating the fibres His team made the nanogenerator by first coating fibres with a polymer and then a layer of zinc oxide. They then dunked this into a warm bath of reactive solution for 12 hours. This encouraged the wires to multiply, coating the fibres. "They automatically grow on the surface of the fibre," Wang says. "In principle, you could use any fibre that is conductive." They then added another layer of polymer to prevent the zinc oxide from being scrubbed off. And they added an ultra-thin layer of gold to some fibres, which works as a conductor. Could it be static? To ensure all that friction was not just generating static electricity, the researchers conducted several tests. The fibres produced current only when both the gold and the zinc oxide bristles brushed together. So far, Wang says the researchers have demonstrated the principle and developed a small prototype. "Our estimates show we can have up to 80 milliwatts per square metre of this fabric. This is enough to power a little iPod or charge a [mobile] phone battery," he says. "What we've done is demonstrate the principle and the fundamental mechanism

Recent Physics News

2008-04-16T11:06:00.002+05:30

Recent Physics News [2008] January 8: Scientists create the most light-absorbent material yet. Scientists have created a material that absorbs more than 99.9 percent of light. It is composed of tiny carbon tubes standing on end and is more than three times darker than the current record holder (a nickel-phosphorous alloy), and 30 times darker than the current benchmark, which is also made of carbon. Practical applications include usage on solar panels. January 9: Researchers use silicon nanowires to convert heat into electricity. U.S. scientists have discovered that by using rough, rather than smooth, nanowires they can more efficiently turn heat into electricity. Scientists hope to eventually be able to build on this technology to improve the efficiency of energy production. February 13: Scientists create a theoretical "periodic table" of black hole orbit patterns.The shape of the orbital pattern an object traces is largely influenced by its proximity to the black hole. The farthest objects trace standard elliptical paths, whereas the nearest objects trace more complex paths that could be essentially different each time. The table of patterns was compiled using computational models of idealized situations and will be used

Physicists create superinsulators

2008-04-16T10:09:00.002+05:30

Physicists create superinsulators U.S. and European scientists have discovered a fundamental state of matter that they say opens new directions of inquiry in condensed matter physics. Researchers at the U.S. Department of Energy's Argonne National Laboratory, in collaboration with several European institutions, have created superinsulators that they say might result in a new generation of microelectronic devices. Led by Argonne senior scientist Valerii Vinokur and Russian scientist Tatyana Baturina, the researchers from Belgium, Germany, Russia and the United States fashioned a thin film of titanium nitride that they then chilled to near absolute zero. When they tried to pass a current through the material, the researchers noticed its resistance suddenly increased by a factor of 100,000 once the temperature dropped below a certain threshold. The same sudden change also occurred when the researchers decreased the external magnetic field. Like superconductors, which have applications in many different areas of physics, the scientists say superinsulators could eventually find their way into a number of products, including circuits, sensors and battery shields.

2008-04-15T08:45:00.000+05:30

Optical Illusions & Visual Phenomena These pages demonstrate visual phenomena, and »optical« or »visual illusions«. The latter is more appropriate, because most effects have their basis in the visual pathway, not in the optics of the eye. http://www.michaelbach.de/ot/

2008-04-15T08:39:00.001+05:30

Flash Animations for Physics Flash animations for illustrating Physics content. This page provides access to those animations which may be of general interest. The animations will appear in a separate window. http://www.upscale.utoronto.ca/GeneralInterest/Harrison/Flash

2008-04-15T08:28:00.000+05:30

Making Sound: Voice Coil The voice coil is a basic electromagnet. An electromagnet is a coil of wire, usually wrapped around a piece of magnetic metal, such as iron. Running electrical current through the wire creates a magnetic field around the coil, magnetizing the metal it is wrapped around. The field acts just like the magnetic field around a permanent magnet: It has a polar orientation -- a "north" end and and a "south" end -- and it is attracted to iron objects. But unlike a permanent magnet, in an electromagnet you can alter the orientation of the poles. If you reverse the flow of the current, the north and south ends of the electromagnet switch. This is exactly what a stereo signal does -- it constantly reverses the flow of electricity. If you've ever hooked up a stereo system, then you know that there are two output wires for each speaker typically a black one and a red one. http://electronics.howstuffworks.com/speaker5.htm

2008-04-15T08:22:00.000+05:30

SPEAKER-PHONE Got some old boom box, computer or stereo speakers? The RECYCLED SPEAKERS PHONE is an easy to make intercom. http://www.sciencetoymaker.org/SpeakPhone/index.html

2008-04-12T21:54:00.000+05:30

The Floating Water Bridge

J. Phys. D: Appl. Phys. 40 P.6112-61149(2007)

Water undoubtedly is the most important chemical substance in the world.When two beakers (100 mL) set on an even plane, one was fixed,the other movable and controlled by a step motor, and both beakers were separated by 1 mm. The beakers were filled with triply deionized water such that the water surface was about 3mm below the beaker’s edge.Now one electrode was charged with 15 kV, the other was set to ground potential.Since the voltage generators provide a limited current output was stable at 0.5 mA. After a short electric discharge, which was build up between the two water surfaces,a water connection formed spontaneously between the two beakers; the water moved up the glass walls and built a water bridge.