Archive for the 'Physics' Category

Hearing The Sound Of Quantum Drums

Published
by
billycuts
on February 10, 2008
in Music, Nanotechnology and Physics
. 0 Comments

Forty years ago, mathematician Mark Kac asked the theoretical question, “Can one hear the shape of a drum?”

If drums of different shapes always produce their own unique sound spectrum, then it should be possible to identify the shape of a specific drum merely by studying its spectrum, thus “hearing” the drum’s shape (a procedure analogous to spectroscopy, the way scientists detect the composition of a faraway star by studying its light spectrum).

But what if two drums of different shapes could emit exactly the same sound? If so, it would be impossible to work backward from the spectrum and uniquely surmise the physical structure of the drum, because there would be more than one correct answer to the question.

It took until the 1990s for mathematicians to prove that, in fact, two drums of different shapes could produce the same sound. In other words, you can’t hear the shape of a drum. That outcome, which was physically verified in one instance with vibrations on the surface of soap bubbles, raised theoretical questions about spectroscopy.

“This revolutionized our conception of the fundamental connections between shape and sound, but also had profound implications for spectroscopy in general, because it introduced an ambiguity,” according to Stanford physicist Hari Manoharan.

Science Daily

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Exploding Nanowires

Published
by
billycuts
on January 6, 2008
in Art, Nanotechnology and Physics
. 0 Comments

f07firstplace-fannyberon_1.jpg

Gizmodo via Patrick

Gamma Ray Lasers? Positronium Created In The Lab

Published
by
billycuts
on September 13, 2007
in Energy/Fuel, Nature of Reality and Physics
. 0 Comments

Physicists at UC Riverside have created molecular positronium, an entirely new object in the laboratory. Briefly stable, each molecule is made up of a pair of electrons and a pair of their antiparticles, called positrons.

The research paves the way for studying multi-positronium interactions—useful for generating coherent gamma radiation—and could one day help develop fusion power generation as well as directed energy weapons such as gamma-ray lasers. It also could help explain how the observable universe ended up with so much more matter than “antimatter.”

The researchers made the positronium molecules by firing intense bursts of positrons into a thin film of porous silica, which is the chemical name for the mineral quartz. Upon slowing down in silica, the positrons were captured by ordinary electrons to form positronium atoms.

Science Daily

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Wireless Power Transfer Here At Last

Published
by
d3ftonic
on June 19, 2007
in Energy/Fuel, Physics and Technology
. 0 Comments

A new way of transmitting electricity wirelessly has been discovered by U.S. researchers. It could pave the way for the wireless charging of portable electronic devices, rendering power cords obsolete in the process.

Devised by physicists at the Massachusetts Institute of Technology (MIT), in Boston, the new technology is detailed today in the U.S. journal Science.

At the turn of the 20th century, famed physicist and inventor Nikola Tesla devoted considerable effort towards achieving large scale wireless power transfer. Success proved elusive, however, and the demand for such schemes declined.

Now, the revolution in consumer technology has re-ignited the interest of researchers.

cosmos

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The Antikythera Mechanism: A 2000 Year Old Computer

Published
by
DrQuickbeam
on May 9, 2007
in Computers, History/Archaeology, Mathematics, Physics and Technology
. 0 Comments

Antikythera Mechanism

One day last month, I paid a visit to Michael Wright, in his book-and-clock-cluttered home, in West London. Wright was reading Xenophon, the Greek historian, in ancient Greek. He put the book down and brought out his model of the Mechanism from a cabinet underneath the stairs. In size, it is startlingly similar to a laptop computer, though a bit thicker. On the front dial, in addition to the pointers for the sun and the moon that Price posited, Wright added pointers for the planets and a separate pointer for the day of the year. On the back dial were two hundred and twenty-three divisions, marking months in the saros cycle; a similar dial above that showed months in the Metonic cycle. The gears were hidden inside a wooden casing, which had a large wooden knob on one side.

Wright took his model apart to showed me how all the gears fitted together. Then Wright put the machine back together and turned the hand knob that drives the solar gear. It engaged with the smaller gears, through the various gear trains, and the pointers began to spin around the dials. The day-of-the-year pointer moved forward at a regular pace, but the lunar and planetary pointers traced eccentric orbits, sometimes reversing course and going backward, just as the planets occasionally appear to do in the night sky. Meanwhile, the pointers on the back dials crept through the months in the saros and Metonic cycles; eclipses came and went. I noticed that as long as he kept turning the knob Wright himself seemed, for once, perfectly unmuddled.

Until this moment, I had, like many others, continued to puzzle over why, if the Greeks were capable of building such a technically sophisticated device, they used that capacity to construct what is essentially a toy—an intellectual amusement. But as I beheld this whirring, whirling symphony of metal, a perfect simulation of a mechanistic and logical universe, I realized that my notions of practicality were foolish and shortsighted. This machine was much more than a toy; it embodied a whole world view, and it must have been, for the ancients, wonderfully reassuring to behold.

NewYorker

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High School Student Builds Fusion Reactor

Published
by
DrQuickbeam
on March 18, 2007
in Hacks and Physics
. 0 Comments

High school student Thiago Olson has gone beyond basic physics class. Way beyond. Using parts and materials scrounged from the local hardware story and eBay, Olson built a working fusion reactor. In November 2006, a few tiny bubbles in his neutron dosimeter told him that he’d achieved success: Fusing hydrogen nuclei into helium.

While it takes far more energy to run than it produces, Olson’s nuclear reactor is pretty bad-ass, producing 200 million-degree plasma at its core—or, as Olson points out, “several times hotter than the core of the sun.”

Discover

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Minerals In Birds’ Beaks May Be Their Compass

Published
by
DrQuickbeam
on March 18, 2007
in Biology and Physics
. 0 Comments
It has long been recognized that birds possess the ability to use the Earth’s magnetic field for their navigation, although just how this is done has not yet been clarified. However, the discovery of iron-containing structures in the beaks of homing pigeons in a new study by Gerta Fleissner and her colleagues at the University of Frankfurt offers a promising insight into this complex topic. The article will be published online mid-March in Springer’s journal Naturwissenschaften.

In histological and physicochemical examinations in collaboration with HASYLAB, the synchrotron laboratories based in Hamburg, Germany, iron-containing subcellular particles of maghemite and magnetite were found in sensory dendrites of the skin lining the upper beak of homing pigeons. A dendrite is a branched extension a nerve cell (neuron).

This research project found that these dendrites are arranged in a complex three-dimensional pattern with different spatial orientation designed to analyze the three components of the magnetic field vector separately. They react to the Earth’s external magnetic field in a very sensitive and specific manner, thus acting as a three-axis magnetometer.

physorg

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Light Measured For First Time As Both Wave AND Particle

Published
by
DrQuickbeam
on March 15, 2007
in Physics
. 1 Comment

Work completed by a visiting research professor at Rowan University, physics professors and a student from the institution shows that light is made of particles and waves, a finding that refutes a common belief held for about 80 years.

Shahriar S. Afshar, the visiting professor who is currently at Boston’s Institute for Radiation-Induced Mass Studies (IRIMS), led a team, including Rowan physics professors Drs. Eduardo Flores and Ernst Knoesel and student Keith McDonald, that proved Afshar’s original claims, which were based on a series of experiments he had conducted several years ago.

An article on the work titled “Paradox in Wave-Particle Duality” recently published in Foundations of Physics, a prestigious, refereed academic journal, supports Albert Einstein’s long-debated belief that quantum physics is incomplete. For eight decades the scientific community generally had supported Niels Bohr’s ideas commonly known as the Copenhagen Interpretation of Quantum Mechanics. In 1927, in his “Principle of Complementarity,” he asserted that in any experiment light shows only one aspect at a time, either it behaves as a wave or as a particle. Einstein was deeply troubled by that principle, since he could not accept that any external measurement would prevent light to reveal its full dual nature, according to Afshar. The fundamental problem, however, seemed to be that one has to destroy the photon in order to measure either aspects of it. Then, once destroyed, there is no light left to measure the other aspect.

In this modified double-slit experiment, a laser beam hits a screen with two small pinholes. As a particle, light goes through one of the pinholes. Through a lens system, the light is then imaged onto two detectors, where a certain detector measures only the photons, which went through a particular pinhole. In this way, Afshar verified the particle nature of light. As a wave, light goes through both pinholes and forms a so-called interference pattern of bright and dark fringes.

“Afshar’s experiment consists of the clever idea of putting small absorbing wires at the exact position of the dark interference fringes, where you expect no light,” Knoesel said. “He then observed that the wires do not change the total light intensity, so there are really dark fringes at the position of the wires. That proves that light also behaves as a wave in the same experiment in which it behaves as a particle.”

NewsWise

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The Elephant and The Event Horizon

Published
by
DrQuickbeam
on October 28, 2006
in Physics and Space
. 0 Comments

Let’s say Alice is watching a black hole from a safe distance, and she sees an elephant foolishly headed straight into gravity’s grip. As she continues to watch, she will see it get closer and closer to the event horizon, slowing down because of the time-stretching effects of gravity in general relativity. However, she will never see it cross the horizon. Instead she sees it stop just short, where sadly Dumbo is thermalised by Hawking radiation and reduced to a pile of ashes streaming back out. From Alice’s point of view, the elephant’s information is contained in those ashes.

There is a twist to the story. Little did Alice realise that her friend Bob was riding on the elephant’s back as it plunged toward the black hole. When Bob crosses the event horizon, though, he doesn’t even notice, thanks to relativity. The horizon is not a brick wall in space. It is simply the point beyond which an observer outside the black hole can’t see light escaping. To Bob, who is in free fall, it looks like any other place in the universe; even the pull of gravity won’t be noticeable for perhaps millions of years. Eventually as he nears the singularity, where the curvature of space-time runs amok, gravity will overpower Bob, and he and his elephant will be torn apart. Until then, he too sees information conserved.

Neither story is pretty, but which one is right? According to Alice, the elephant never crossed the horizon; she watched it approach the black hole and merge with the Hawking radiation. According to Bob, the elephant went through and floated along happily for eons until it turned into spaghetti. The laws of physics demand that both stories be true, yet they contradict one another. So where is the elephant, inside or out?

The answer Susskind has come up with is – you guessed it – both.

NS Space

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Visual History Of The Universe

Published
by
DrQuickbeam
on October 8, 2006
in Art, Physics and Space
. 0 Comments

universe.jpg

New Evidence Indicates The Universe Egg-shaped

Published
by
billycuts
on October 6, 2006
in Nature of Reality, Physics and Space
. 0 Comments

Using a microwave probe of U.S. space agency NASA, scientists said they have evidence that the universe has a shape somewhat akin to an egg, rather than the expected round.


This would explain some curious anomalies over the universe’s expanse, the scientists reported in the journal Physical Review Letters.


The researchers reached the conclusion by observing the universe with the Wilkinson Microwave Anisotropy Probe, which was launched by NASA in 2001 to measure fluctuations in the cosmic microwave background radiation.


Xinhua


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Scientists Teleport Macroscopic Object 1/2 Meter

Published
by
DrQuickbeam
on October 5, 2006
in Physics and Technology
. 0 Comments

Beaming people in “Star Trek” fashion is still in the realms of science fiction, but physicists in Denmark have teleported information from light to matter bringing quantum communication and computing closer to reality.Until now scientists have teleported similar objects such as light or single atoms over short distances from one spot to another in a split second.

But Professor Eugene Polzik and his team at the Niels Bohr Institute at Copenhagen University in Denmark have made a breakthrough by using both light and matter.

“It is one step further because for the first time it involves teleportation between light and matter, two different objects. One is the carrier of information and the other one is the storage medium,” Polzik explained in an interview on Wednesday.

The experiment involved for the first time a macroscopic atomic object containing thousands of billions of atoms. They also teleported the information a distance of half a meter but believe it can be extended further.

cnn

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China Claims Successful Fusion Power Test

Published
by
DrQuickbeam
on September 28, 2006
in Energy/Fuel and Physics
. 0 Comments

China claims to have carried out a successful test of its experimental thermonuclear fusion reactor. But what exactly made this test ‘successful’ is not clear. From the article: ‘Xinhua cited the scientists as saying that deuterium and tritium atoms had been fused together at a temperature of 100 million degrees Celsius for nearly three seconds. The report did not specify whether the device… had succeeded at producing more energy than it consumed, the main obstacle to making fusion commercially viable.

China is a participant in the 10-nation ITER project to build a fusion reactor in the south of France by 2015. The article quotes the research head of ITER as saying, “It was important for China to show that it is part of the club.

routers

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Impermanence and the Bliss of Self-Realiztion

Published
by
DrQuickbeam
on June 28, 2006
in Consciousness/Psych/Brain, Nature of Reality, Philosophy and Physics
. 0 Comments

As I explore the subtle changes in each moment, endless varieties of bliss are revealed to me. The richness of these experiences is too vast to ever articulate it justly. But what I have learned over the past few years since mastering this process, is that beyond the mind and body, attachments, ego fixations, and other cognitive constructs known as the “self”, lies a freedom of consciousness that is overwhelmingly blissful, confirming, and reassuring to our deepest being. From these experiences I know there is no such thing as “death” as we might understand it. There is no oblivion, or void outside of what we make it. Existence itself is already perfection incarnate, and any concept we harbor in conflict with this basic reality, is our own “make-wrong”, “karma”, or whatever you want to call it. When we let go of our attachments, and surrender to the experience of each moment, the true universe reveals itself to us. This universe is utter perfection beyond our wildest imaginings. Any notion/experience I’ve ever had that doesn’t align with this always turned out to be one of my own impermanent creations. When “I” get out of the way, this bliss of self-realization reveals itself again long enough for to run into my next “make-wrong”, etc.

by fromfuturehi

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Labs Compete to Build New Nuclear Bomb

Published
by
DrQuickbeam
on June 14, 2006
in Big Brother, Military and Physics
. 0 Comments

Yahoo! News is reporting that two labs are currently competing to design the first new nuclear bomb in twenty years. The new bomb was approved as a part of the 2006 defense spending bill. From the article: ‘Proponents of the project say the U.S. would lose its so-called “strategic deterrent” unless it replaces its aging arsenal of about 6,000 bombs, which will become potentially unreliable within 15 years. A new, more reliable weapon, they say, would help the nation reduce its stockpile.

yahoo

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