Showing posts with label physics. Show all posts
Showing posts with label physics. Show all posts

2012-03-24

The Vortex Cannon

The Vortex Cannon - Student Science - YouTube

After weeks of pestering, we finally give in and let George build a vortex cannon - with surprisingly spooky cup flying results. For more information on the physics behind this head on over to http://www.urn1350.net/thescienceshow to listen to the full podcast!



Vortex ring - Wikipedia, the free encyclopedia


A vortex ring, also called a toroidal vortex, is a region of rotating fluid moving through the same or different fluid where the flow pattern takes on a toroidal (doughnut) shape. The movement of the fluid is about the poloidal or circular axis of the doughnut, in a twisting vortex motion. Examples of this phenomenon are a smoke ring or a microburst[1][2]

Vortex ring toy - Wikipedia, the free encyclopedia

A vortex ring toy generates vortex rings – rolling torus-shapes of fluid – that move through the fluid (most often air, and sometimes water). [...] A vortex cannon generates vortex rings, typically using acetylene-air or hydrogen–oxygen explosions.[1]

Vortex Cannon! - Bang Goes the Theory Preview - BBC One - YouTube


Jem Stansfield builds a vortex cannon to blow a house of bricks over.



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2012-03-18

Neutrinos Communication Through the Earth

Short Sharp Science: Neutrinos send wireless message through the Earth


A team at Fermilab in Batavia, Illinois have successfully used a beam of the near-massless particles to transmit the word "neutrino" to a detector 1 km away, including a 240-metre journey through solid rock.

Neutrinos rarely interact with other forms of matter, so pass through most objects unimpeded - including the Earth's core. That makes them potentially useful as messengers. Previous suggestions include using these ghostly particles to send messages across the planet without wires, cables or satellites, to communicate with hidden submarines or even to sync alien clocks. This latest experiment is the first demonstration that the principle actually works.

Neutrinos used for communication | TG Daily


The most intriguing thing about using neutrinos to communicate is that they can penetrate almost anything they encounter. This could be a particularly useful feature for submarines, for example, or for sending messages in space, allowing them to travel straight through a planet.

Neutrinos are extremely tiny particles with almost zero mass and neutral charge. Thus they are impervious to electromagnetic forces and respond very weakly to gravity. They almost never collide with other particles, generally passing straight through the atoms that make up matter.

Now, scientists have successfully harnessed neutrinos to send a message from one place to another, spelling out the word "neutrino" in a particle binary code. [Nature's Tiniest Particles Dissected (Infographic)]




Researchers Send "Wireless" Message Using Elusive Particles : Rochester News

The communication test was done during a two-hour period when the accelerator was running at half its full intensity due to an upcoming scheduled downtime. Regular MINERvA interaction data was collected at the same time the communication test was being carried out.

[...]

The message that the scientists sent using neutrinos was translated into binary code. In other words, the word "neutrino" was represented by a series of 1's and 0's, with the 1's corresponding to a group of neutrinos being fired and the 0's corresponding to no neutrinos being fired. The neutrinos were fired in large groups because they are so evasive that even with a multi-ton detector, only about one in ten billion neutrinos are detected. After the neutrinos were detected, a computer on the other end translated the binary code back into English, and the word "neutrino" was successfully received.

"Neutrinos have been an amazing tool to help us learn about the workings of both the nucleus and the universe," said Deborah Harris, Minerva project manager, "but neutrino communication has a long way to go before it will be as effective."

Minerva is an international collaboration of nuclear and particle physicists from 21 institutions that study neutrino behavior using a detector located at Fermi National Accelerator Laboratory near Chicago. This is the first neutrino experiment in the world to use a high-intensity beam to study neutrino reactions with nuclei of five different target materials, creating the first side-by-side comparison of interactions. This will help complete the picture of neutrinos and allow data to be more clearly interpreted in current and future experiments.


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2012-03-08

Black Hole Simulations

Black hole - Wikipedia, the free encyclopedia

A black hole is a region of spacetime from which nothing, not even light, can escape.[1] The theory of general relativity predicts that a sufficiently compact mass will deform spacetime to form a black hole. Around a black hole there is a mathematically defined surface called an event horizon that marks the point of no return. It is called "black" because it absorbs all the light that hits the horizon, reflecting nothing, just like a perfect black body in thermodynamics.[2] Quantum mechanics predicts that black holes emit radiation like a black body with a finite temperature. This temperature is inversely proportional to the mass of the black hole, making it difficult to observe this radiation for black holes of stellar mass or greater.

Simulated view of a black hole (center) in front of the Large Magellanic Cloud. Note the gravitational lensing effect, which produces two enlarged but highly distorted views of the Cloud. Across the top, the Milky Way disk appears distorted into an arc.
Simulation of gravitational lensing by a black hole, which distorts the image of a galaxy in the background


Inside Black Holes


This is not an artist's impression.
It is a general relativistic volume-rendering
of a super-computed simulation.


  • Journey into the simplest kind of black hole, a black hole with mass, but no charge and no spin — a Schwarzschild black hole.
  • Journey into and through a charged black hole — a Reissner-Nordström black hole. This one has a wormhole and a white hole connecting to a new universe.
  • How to understand black holes — a black hole is a waterfall of space.
  • How does a scene appear when you pass through it at near the speed of light? — The rules of 4-dimensional perspective.
  • How to find your way inside black holes — Penrose diagrams.
  • Journey into a realistic (well, kind of) black hole — the wormhole is destroyed by the mass inflation instability.
  • The movies on this site were made with the Black Hole Flight Simulator.



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2011-12-15

The Physics Behind Great White Shark Attacks

How Great White Sharks Hide in Plain Water | Motherboard

A group led by UM assistant professor Dr. Neil Hammerschlag studied the techniques employed by the great whites in their hunting of Cape fur seals in False Bay, South Africa. The study helps confirm a notion, long held by surfers whose silhouettes look somewhat like a seal’s, that great whites always stalk their prey from below. While that in itself isn’t surprising, Hammerschlag’s research, published in Marine Biology Research, showed that the sharks camouflage themselves by taking advantage of water’s light-scattering properties. In low light conditions, when sunlight is hitting the water at a sharp angle, light does not penetrate deep into the water, and what light does is heavily distorted, essentially hiding the shark in otherwise clear water.

New Study Illustrates the Physics Behind Great White Shark Attacks on Seals | The Rosenstiel School of Marine and Atmospheric Science at the University of Miami

Scientists use basic principles of underwater optics, physics to understand predator-prey interactions


Sharks typically search, stalk and strike their prey from below. The vast majority of predatory strikes by sharks and Cape fur seals occur against small groups of young-of-the-year seals. Predatory activity by sharks is most intense within two hours of sunrise and quickly decreases as light penetration in the water column increases.

“Stealth and ambush are key elements in the white shark's predatory strategy,” said Hammerschlag.

Cape fur seals also have unique techniques to detect, avoid, outmaneuver and in some cases injure the white shark in order to avoid predation by sharks.

According to the authors, if a seal is not disabled during the shark’s initial shark, the small seal can use its highly maneuverable body to leap away from the shark’s jaws to evade a second strike.

Taylor & Francis Online :: Marine predator–prey contests: Ambush and speed versus vigilance and agility - Marine Biology Research - Volume 8, Issue 1

Differences in relative strengths and weaknesses between predators and prey under tactical contexts result in complex and dynamic contests between them. These contests are often brief and difficult to observe in marine systems. Here, we employ basic principles of underwater optics and physics to provide a conceptual understanding of mechanisms underlying predator–prey interactions between white sharks (Carcharodon carcharias) and Cape fur seals (Arctocephalus pusillus pusillus) that have been previously described at Seal Island in False Bay, South Africa.



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2011-11-21

Fast 3-D Current Disruptions in Magnetic Reconnection Experiments

A 3-D way to release magnetic energy... fast!

Experiments discover a 3-D process by which magnetic reconnection can release energyfaster than expected by classical theories.
Scientists at the U.S. Department of Energy's Princeton Plasma Physics Laboratory (PPPL) have discovered a new process at work in a mysterious magnetic phenomenon that occurs both in the earth's atmosphere and in space, playing a role in events such as the aurora borealis and .

In a series of experiments on a device known as the Magnetic Reconnection Experiment (MRX), which replicates magnetic reconnection in the laboratory, a team of researchers found that many important plasma quantities are found to have strong variations in very early in the process. This variation may aid in the formation of regions of high with characteristics similar to what have been called "flux ropes."

Experiments show that when the reconnection rate spikes in this 3-D configuration, the high current ropes are ejected out of the reconnection region, leading to a sudden decrease in the current density. The researchers have termed this process a "current layer disruption."

NASA Magnetic Reconnection - YouTube

This science visualization shows a magnetospheric substorm, during which, magnetic reconnection causes energy to be rapidly released along the field lines in the magnetotail, that part of the magnetosphere that stretches out behind Earth. This released energy is focused down at the poles and the resulting flood of solar particles into the atmosphere, causes the auroras at the North and South Poles. 



Princeton University - PPPL scientists bring mysterious magnetic process down to earth


Scientists believe that magnetic reconnection is behind the extraordinary bursts of radiation that have emerged from the center of the Crab nebula, the remains of an exploded star. The device allows PPPL researchers to recreate the magnetic reconnection process in a controlled setting. (Photo by Elle Starkman)

William Slavin (center), head of PPPL's safety division, gives graduate students a tour of the MRX device, which resembles a large steel barrel attached to arrays of tubes and wires. The device allows PPPL researchers to recreate the magnetic reconnection process in a controlled setting. (Photo by Elle Starkman)



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2011-10-22

Quantum Levitation Demonstration and Explanation

Looks like magic: quantum levitation – Light Years - CNN.com Blogs

It looks like something out of a magic show, where the magician is able to defy gravity and float or levitate an object in midair with no apparent explanation. Check out this really cool video which is not a Vegas show, but an example of something called quantum levitation:


It’s not magic at all, but a very cool demonstration from the Association of Science-Technology Centers. It’s a demo from Tel-Aviv University on what happens when a superconductor gets trapped in a magnetic field. What you’re witnessing is something similar to the Meissner Effect.

Meissner effect - Wikipedia, the free encyclopedia

The Meissner effect is the expulsion of a magnetic field from a superconductor during its transition to the superconducting state. [...] The samples, in the presence of an applied magnetic field, were cooled below what is called their superconducting transition temperature. Below the transition temperature the samples canceled nearly all magnetic fields inside. They detected this effect only indirectly; because the magnetic flux is conserved by a superconductor, when the interior field decreased the exterior field increased. The experiment demonstrated for the first time that superconductors were more than just perfect conductors and provided a uniquely defining property of the superconducting state.
Diagram of the Meissner effect. Magnetic field lines, represented as arrows, are excluded from a superconductor when it is below its critical temperature.


Quantum_Levitation

 

Our mission
We are dedicated to teach and educate young and adults of superconductivity through the unique and counter-intuitive phenomena of ‘quantum trapping’ and ‘quantum levitation’.




The physics behind

Superconductivity and magnetic field do not like each other. When possible, the superconductor will expel all the magnetic field from inside. This is the Meissner effect. In our case, since the superconductor is extremely thin, the magnetic field DOES penetrates. However, it does that in discrete quantities (this is quantum physics after all! ) called flux tubes.

Inside each magnetic flux tube superconductivity is locally destroyed. The superconductor will try to keep the magnetic tubes pinned in weak areas (e.g. grain boundaries). Any spatial movement of the superconductor will cause the flux tubes to move. In order to prevent that the superconductor remains “trapped” in midair.


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2011-06-13

Towards Thorium Nuclear Power

New age nuclear | COSMOS magazine

Nuclear energy produces no greenhouse gases, but it has many drawbacks. Now a radical new technology based on thorium promises what uranium never delivered: abundant, safe and clean energy - and a way to burn up old radioactive waste.

Named after Thor, the warlike Norse god of thunder, thorium could ironically prove a potent instrument of peace as well as a tool to soothe the world's changing climate. With the demand for energy on the increase around the world, and the implications of climate change beginning to strike home, governments are increasingly considering nuclear power as a possible alternative to burning fossil fuels.

But nuclear power comes with its own challenges. Public concerns over the risk of meltdown, disposal of long-lived and highly toxic radioactive waste, the generation of weapons grade by-products, and their corresponding proliferation risks, all can make nuclear power a big vote-loser.

A thorium reactor is different. And, on paper at least, this radical new technology could be the key to unlocking a new generation of clean and safe nuclear power. It could prove the circuit-breaker to the two most intractable problems of the 21st century: our insatiable thirst for energy, and the warming of the world's climate.

YouTube - Thorium Remix 2009 - LFTR in 16 Minutes

Thorium is readily available & can be turned into energy without generating transuranic wastes. Thorium's capacity as nuclear fuel was discovered during WW II, but ignored because it was unsuitable for making bombs. A liquid-fluoride thorium reactor (LFTR) is the optimal approach for harvesting energy from Thorium, and has the potential to solve today's energy/climate crisis. This 16 minute video summarizes 197 minutes worth of Google Tech Talks on the subject of Thorium & LFTR.



Accelerator Driven System

Fission occurs in thorium when atoms absorb a neutron to become a heavier isotope and quickly decay into an isotope of the element protactinium and then an isotope of uranium, which is fissioned when struck by an additional neutron. The number of neutrons produced is not sufficient for a self-sustained chain reaction.

A particle accelerator could be used to provide the necessary neutrons for fission to occur in thorium and a nuclear reactor making use of such an outside neutron source would be known as an 'accelerator driven system' (ADS).

Electron Model of Many Applications: Technology which could save the world | Mail Online

Cryogenics engineer Rachael Buckley inside the 'Emma' (the Electron Model of Many Applications) accelerating ring at Daresbury

And this is Emma’s special significance. Making particle accelerators affordable means they could be built and used in practical, everyday settings – such as thorium power stations. The key to thorium energy is likely to be the further development of ‘pocket-sized’ machines – precisely the kind of accelerator that looks and behaves like Emma.
[...]
Last year, ThorEA published a report, Towards An Alternative Nuclear Future, which concluded it should be possible to build the first 600MW power plant fuelled by thorium with three attached ‘pocket-sized’ NS-FFAG accelerators within 15 years, at a cost of about £2 billion – making it highly competitive in relation to fossil-fuel or conventional nuclear alternatives.

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2011-06-06

Fun with Blender 3D Physics Animations




Blender (software) - Wikipedia, the free encyclopedia

Blender is a free open source 3D graphics application, available under the GNU General Public License for the Linux, Mac OS X, FreeBSD, OpenBSD and Microsoft Windows operating systems.

Blender's features include 3D modeling, UV unwrapping, texturing, rigging, water and smoke simulations, skinning, animating, rendering, particle and other simulations, non-linear editing, compositing, and the ability to create interactive 3D applications, video games, animated film, or visual effects. More advanced tools include rigid, realistic body, fluid, cloth and softbody dynamics simulation, modifier-based modeling, character animation, a node-based material and compositing system, and embedded scripting in Python.



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2011-03-18

The LHC Could Cause Matter to Travel in Time

Large Hadron Collider could be world’s first time machine | Research News @ Vanderbilt | Vanderbilt University



If the latest theory of Tom Weiler and Chui Man Ho is right, the Large Hadron Collider – the world’s largest atom smasher that started regular operation last year – could be the first machine capable of causing matter to travel backwards in time.

“Our theory is a long shot,” admitted Weiler, who is a physics professor at Vanderbilt University, “but it doesn’t violate any laws of physics or experimental constraints.”

One of the major goals of the collider is to find the elusive Higgs boson: the particle that physicists invoke to explain why particles like protons, neutrons and electrons have mass. If the collider succeeds in producing the Higgs boson, some scientists predict that it will create a second particle, called the Higgs singlet, at the same time.

According to Weiler and Ho’s theory, these singlets should have the ability to jump into an extra, fifth dimension where they can move either forward or backward in time and reappear in the future or past.

“One of the attractive things about this approach to time travel is that it avoids all the big paradoxes,” Weiler said. “Because time travel is limited to these special particles, it is not possible for a man to travel back in time and murder one of his parents before he himself is born, for example. However, if scientists could control the production of Higgs singlets, they might be able to send messages to the past or future.”

Illustration of singlet time travel theory. When a pair of protons collide in the Large Hadron Collider, the resultant explosion may create a special type of particle, called a Higgs singlet, that is capable of traveling forward and back in time. It would do so by leaving familiar three-dimensional space to travel in an extra dimension. (Jenni Ohnstad / Vanderbilt)

Weiler and Ho’s theory is based on M-theory, a “theory of everything.” A small cadre of theoretical physicists have developed M-theory to the point that it can accommodate the properties of all the known subatomic particles and forces, including gravity, but it requires 10 or 11 dimensions instead of our familiar four. This has led to the suggestion that our universe may be like a four-dimensional membrane or “brane” floating in a multi-dimensional space-time called the “bulk.”


Higgs boson - Wikipedia, the free encyclopedia

The Higgs boson is a hypothetical massive elementary particle predicted to exist by the Standard Model of particle physics. The existence of the particle is postulated as a means of resolving inconsistencies in current theoretical physics, and attempts are being made to confirm the existence of the particle by experimentation, using the Large Hadron Collider (LHC) at CERN and the Tevatron at Fermilab.
A simulated event, featuring the appearance of the Higgs boson


Introduction to M-theory - Wikipedia, the free encyclopedia

[...]
In the 1980s, a new mathematical model of theoretical physics called string theory emerged. It showed how all the particles, and all of the forms of energy in the universe, could be constructed by hypothetical one-dimensional "strings", infinitely small building-blocks that have only the dimension of length, but not height nor width. Further, string theory suggested that the universe is made up of multiple dimensions. Height, width, and length constitute three-dimensional space, and time gives a total of four observable dimensions; however, string theories initially supported the possibility of ten dimensions – the remaining six of which we cannot detect directly. This was later increased to 11 dimensions based on various interpretations of the ten dimensional theory that led to five partial theories as described below. Super-gravity theory also played a significant part in establishing the existence of the 11th dimension.
[...]
In the mid-1990s, a string theorist named Edward Witten of the Institute for Advanced Study and other important researchers considered that the five different versions of string theory might be describing the same thing seen from different perspectives. They proposed a unifying theory called "M-theory", in which the "M" is not specifically defined, but is generally understood to stand for "membrane".



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2011-01-18

Quantum Entanglement Allows Time Teleportation

arXiv blog

New Type Of Entanglement Allows 'Teleportation in Time,' Say Physicists

Conventional entanglement links particles across space. Now physicists say a similar effect links particles through time.

To see how, imagine an experiment that Ralph and Olson describe in which a qubit is sent into the future. The idea is that a detector acts on a qubit and then generates a classical message describing how this particle can be detected. Then, at some point in the future, another detector at the same position in space, receives this message and carries out the required measurement, thereby reconstructing the qubit.

But there's a twist. Olson and Ralph show that the detection of the qubit in the future must be symmetric in time with its creation in the past. "If the past detector was active at a quarter to 12:00, then the future detector must wait to become active at precisely a quarter past 12:00 in order to achieve entanglement," they say. For that reason, they call this process "teleportation in time".

Time travel - Wikipedia, the free encyclopedia

Time travel is the concept of moving between different points in time in a manner analogous to moving between different points in space, either sending objects (or in some cases just information) backwards in time to some moment before the present, or sending objects forward from the present to the future without the need to experience the intervening period (at least not at the normal rate).

Although time travel has been a common plot device in fiction since the 19th century, and one-way travel into the future is arguably possible given the phenomenon of time dilation based on velocity in the theory of special relativity (exemplified by the twin paradox), as well as gravitational time dilation in the theory of general relativity, it is currently unknown whether the laws of physics would allow backwards time travel.
Any technological device, whether fictional or hypothetical, that is used to achieve time travel is commonly known as a time machine.


Quantum entanglement - Wikipedia, the free encyclopedia

Quantum entanglement is a property of the quantum mechanical state of a system containing two or more objects, where the objects that make up the system are linked in such a way that the quantum state of any member of the system cannot be adequately described without full mention of the other members of the system, even if the individual objects are spatially separated. Quantum entanglement is at the heart of the EPR paradox that was described by Albert Einstein, Boris Podolsky, and Nathan Rosen in 1935, and it was experimentally verified for the first time in 1972 by Stuart Freedman and John Clauser[1].


Quantum teleportation - Wikipedia, the free encyclopedia

Quantum teleportation, or entanglement-assisted teleportation, is a technique used to transfer quantum information from one quantum system to another. It does not transport the system itself, nor does it allow communication of information at superluminal (faster than light) speed. Neither does it concern rearranging the particles of a macroscopic object to copy the form of another object. Its distinguishing feature is that it can transmit the information present in a quantum superposition, useful for quantum communication and computation.


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2010-11-27

Before the Big Bang -- Roger Penrose's Conformal Cyclic Cosmology

"We Can Glimpse the Universe Before the Big Bang": One of World's Leading Physicists



The circular patterns within the cosmic microwave background suggest that space and time did not come into being at the Big Bang but that our universe in fact continually cycles through a series of "aeons," according to University of Oxford theoretical physicist Roger Penrose, who says that data collected by NASA's WMAP satellite supports his idea of "conformal cyclic cosmology".


Black hole encounters would have repeated themselves several times, with the center of each event remaining at almost exactly the same point in the CMB sky, even when occurring in different aeons. The huge amounts of energy released would appear as spherical, low-variance radiation bursts in the CMB. Image credit: Gurzadyan and Penrose.



Penrose claims to have glimpsed universe before Big Bang - physicsworld.com




Seeing through the Big Bang

According to Penrose and Gurzadyan, these circles allow us to "see through" the Big Bang into the aeon that would have existed beforehand. The circles, they say, are the marks left in our aeon by the spherical ripples of gravitational waves that were generated when black holes collided in the previous aeon. And they say that these circles pose a problem for inflationary theory because this theory says that the distribution of temperature variations across the sky should be Gaussian, or random, rather than having discernable structures within it.

arXiv.org > astro-ph > arXiv:1011.3706

Concentric circles in WMAP data may provide evidence of violent pre-Big-Bang activity

Authors: V.G.Gurzadyan, R.Penrose
(Submitted on 16 Nov 2010)

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