Interesting websites ( OPEN SUBJECTS)

Discussions in the vein that would most interest those looking for the "meat and potatoes" of Townsend Brown's scientific work.

Re: Interesting websites ( OPEN SUBJECTS)

Postby ecker2011 » Fri Apr 07, 2017 1:29 pm

This is for fun.

Commentary: In defense of Crazy Ideas

David Stevenson
(djs@gps.caltech.edu) California Institute of Technology, Pasadena

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Unless we change direction,
we are likely to wind up
where we are headed.
—Ancient Chinese proverb

Like many of you, I get unsolicited manuscripts that make startling and revolutionary claims. In years past they arrived by snail mail and were often handwritten or typed with copious use of capital letters, exclamation marks, and hand-drawn diagrams. More recently they come by email and look more like conventional scientific literature. (Even crackpots know how to use word processors and PowerPoint.) Denials of Einstein’s special relativity seem especially popular.

Although the shortcomings of those efforts are often readily apparent, there is much to admire about the passion and dedication with which they are constructed. Occasionally they merit attention, if only because their authors’ thought processes are not fettered by conventional thinking. Sadly, their deficiencies are often fundamental and betray a lack of understanding of the nature of science and its interconnectivity. They are what I call Crazy Ideas of the First Kind—the most common and least interesting.

Most published science is mundane. It is the easiest to get published and the easiest to get funded at a modest, sustainable level—though no funding is easy to get these days. It is also more likely to be right, precisely because it is incremental. Just as rock-solid financial investments are an important part of any balanced portfolio, so the mundane science is an important part of the science portfolio. But I suspect many scientists, even some who are recognized as leaders in their field, are unwilling to acknowledge their lack of adventurousness. They will protest that they are inventive, innovative scientists, but their measure of that is probably quite constricted because of the fine-scale partitioning that characterizes the modern scientific world. In the landscape of scientific knowledge, most of us are digging deeper holes and maybe an occasional trench to link up with a neighboring hole, but few are venturing across the ridges to the next valley.

Crazy Ideas of the Second Kind come when well-established scientists venture out from their holes and up to the ridges and peaks to survey the landscape. Inevitably, such excursions can look like the actions of a dilettante since it takes less effort to dash up a ridge than to dig a really deep hole. One is then accused of speculation. I occasionally sense from colleagues some disdain for scientific speculation, perhaps because it is cheap: It seems to require relatively little effort and commitment. Indeed, bad speculation is easy, and you can do it at the local bar or Starbucks or while riding a bike. Poor experimental or observational work also often requires less effort than good work. In fact, good speculation is hard, judging by the evident rarity of examples. Good speculation is also not always easy to recognize immediately, because part of what makes it good is something that may be hidden: the failures of alternative speculations, the crumpled sheets of paper in the wastebasket.

Richard Feynman once said that the essence of science is (or should be) “the belief in the ignorance of experts.”1 I think he meant that outsiders may provide an important breakthrough because they are unfettered. The “ignorance” that he refers to, though, must not be complete. It still must allow an appreciation of how science works and the rules that apply, and so it is the ignorance of areas of science other than your own. Residents of deep holes know very well the stuff they have excavated and the walls that surround them but know less well what novelty may lie elsewhere.

And then there are Crazy Ideas of the Third Kind, the most interesting and least common. They arise from a leading eminence in some field who has decided that something is rotten in that field’s fundamentals. In essence, they have decided that their hole is a false claim or has been mined out, even though it may be capacious and well populated.

Importantly, good crazy ideas do not have to be true to be valuable. Distinguished astrophysicist Fred Hoyle and colleagues had the crazy idea that influenza came from space.2 The more general concept of panspermia—of which Hoyle’s idea is a special case—is, however, of considerable interest.

Perhaps an even better example of that line of thinking is Hoyle’s wonderful science fiction novel The Black Cloud (Harper, ca. 1957), wherein an intelligent life-form exists as a dispersed but organized globule that wanders into our solar system. That is a truly engaging though crazy idea: Could life take the form of something that we normally think of as having high entropy? Indeed, some fluid dynamical systems display order—consider Jupiter’s Great Red Spot—and the question of what form life could take remains an open one.

Another distinguished astrophysicist, Thomas Gold, had the crazy idea that natural gas was part of Earth’s starting material rather than arising from biological processes much later in Earth history.3 Geochemists might laugh (some did), and yet the possible delivery of large amounts of reduced carbon to Earth at formation is not such a ridiculous idea. We still do not know Earth’s total reservoir of carbon, since some of it may be very deep. Gold was wrong about natural gas, but the idea is provocative, and that’s good.

More famously, Lord Kelvin had the crazy idea that you could figure out the age of Earth by solving the diffusion equation for heat conduction in a half-space. He knew that Earth is a sphere, but the diffusion time for the whole Earth is so large that a half-space suffices. (For more on Lord Kelvin’s mistake, see my letter, Physics Today, November 2010, page 8.)

Kelvin’s idea is a particularly interesting example because it was not regarded as crazy at the time but would be viewed as crazy now, for reasons that could have been explained to him back then. He was ignoring the geological evidence for the great expanses of time that must have passed, but there were as yet no good clocks for geologic time. He was also ignoring the possibility of convection, and that should not have been acceptable. Crazy ideas are often ephemeral: What was crazy then can be “natural” now and vice versa.

As for Crazy Ideas of the Third Kind, opinions will vary, but perhaps one is the idea that gravity is an emergent phenomenon, an idea often attributed to Andrei Sakharov. The extension of a rubber band, which roughly obeys Hooke’s law, is purely entropic and has nothing to do with the forces between the atoms that make up the material, so one could say that in that case a force law emerges from Boltzmann’s definition of entropy. Or perhaps Roger Penrose and his fundamental discretization of spacetime would be one of the Third Kind. Many great developments in physics began encumbered with ideas that we have now shed—for example, Maxwell’s molecular vortices.

My thesis adviser, Ed Salpeter, would occasionally say to me, “Is it crazy enough to be true?” I think what he meant is that when you’re attempting to explain something important and it has resisted solution for a significant time, then the mundane explanation is unlikely to work, so you should be seeking the “crazy” answer. Although Salpeter almost invariably wrote papers of great solidity and impact, he did coauthor a paper with Carl Sagan on life in the atmosphere of Jupiter.4 It was a good crazy paper, I think. Life in the atmosphere of Jupiter figures prominently in a science fiction novel, The Algebraist (Orbit, 2004), by Iain Banks.

In a somewhat similar spirit, Niels Bohr, responding to a lecture by Wolfgang Pauli, said, “We are all agreed that your theory is crazy. The question which divides us is whether it is crazy enough to have a chance of being correct.” The hard part lies in figuring out what is crazy enough.

References

1. R. Feynman, Phys. Teach. 7, 313 (1969), p. 319. https://doi.org/10.1119/1.2351388, Google ScholarCrossref
2. F. Hoyle, C. Wickramasinghe, J. Watkins, Viruses from Space and Related Matters, U. College Cardiff Press (1986). Google Scholar
3. T. Gold, The Deep, Hot Biosphere, Copernicus Books (1999). Google ScholarCrossref
4. C. Sagan, E. Salpeter, Astrophys. J. Suppl. Ser. 32, 737 (1976). https://doi.org/10.1086/190414, Google ScholarCrossref, CAS

http://physicstoday.scitation.org/doi/10.1063/PT.3.3507
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Re: Interesting websites ( OPEN SUBJECTS)

Postby ecker2011 » Mon Apr 10, 2017 3:48 pm

Physicist discovers strange forces acting on nanoparticles
by Aaron Hilf

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Credit: University of New Mexico

A new scientific paper published, in part, by a University of New Mexico physicist is shedding light on a strange force impacting particles at the smallest level of the material world.

The discovery, published in Physical Review Letters, was made by an international team of researchers lead by UNM Assistant Professor Alejandro Manjavacas in the Department of Physics & Astronomy. Collaborators on the project include Francisco Rodríguez-Fortuño (King's College London, U.K.), F. Javier García de Abajo (The Institute of Photonic Sciences, Spain) and Anatoly Zayats (King's College London, U.K.).

The findings relate to an area of theoretical nanophotonics and quantum theory known as the Casimir Effect, a measurable force that exists between objects inside a vacuum caused by the fluctuations of electromagnetic waves. When studied using classical physics, the vacuum would not produce any force on the objects. However, when looked at using quantum field theory, the vacuum is filled with photons, creating a small but potentially significant force on the objects.

"These studies are important because we are developing nanotechnologies where we're getting into distances and sizes that are so small that these types of forces can dominate everything else," said Manjavacas. "We know these Casimir forces exist, so, what we're trying to do is figure out the overall impact they have very small particles."

Manjavacas' research expands on the Casimir effect by developing an analytical expression for the lateral Casimir force experienced by nanoparticles rotating near a flat surface.

Imagine a tiny sphere (nanoparticle) rotating over a surface. While the sphere slows down due to photons colliding with it, that rotation also causes the sphere to move in a lateral direction. In our physical world, friction between the sphere and the surface would be needed to achieve lateral movement. However, the nano-world does not follow the same set of rules, eliminating the need for contact between the sphere and the surface for movement to occur.

"The nanoparticle experiences a lateral force as if it were in contact with the surface, even though is actually separated from it," said Manjavacas. "It's a strange reaction but one that may prove to have significant impact for engineers."
While the discovery may seem somewhat obscure, it is also extremely useful for researchers working in the always evolving nanotechnology industry. As part of their work, Manjavacas says they've also learned the direction of the force can be controlled by changing the distance between the particle and surface, an understanding that may help nanotech engineers develop better nanoscale objects for healthcare, computing or a variety of other areas.

For Manjavacas, the project and this latest publication are just another step forward in his research into these Casimir forces, which he has been studying throughout his scientific career. After receiving his Ph.D. from Complutense University of Madrid (UCM) in 2013, Manjavacas worked as a postdoctoral research fellow at Rice University before coming to UNM in 2015.


https://phys.org/news/2017-04-physicist ... icles.html
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Re: Interesting websites ( OPEN SUBJECTS)

Postby ecker2011 » Wed Apr 12, 2017 12:53 pm

Physicists discover hidden aspects of electrodynamics

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LSU Department of Physics & Astronomy Assistant Professor Ivan Agullo's new research advances knowledge of a classical theory of electromagnetism. Credit: LSU

Radio waves, microwaves and even light itself are all made of electric and magnetic fields. The classical theory of electromagnetism was completed in the 1860s by James Clerk Maxwell. At the time, Maxwell's theory was revolutionary, and provided a unified framework to understand electricity, magnetism and optics. Now, new research led by LSU Department of Physics & Astronomy Assistant Professor Ivan Agullo, with colleagues from the Universidad de Valencia, Spain, advances knowledge of this theory. Their recent discoveries have been published in Physical Review Letters.

Maxwell's theory displays a remarkable feature: it remains unaltered under the interchange of the electric and magnetic fields, when charges and currents are not present. This symmetry is called the electric-magnetic duality.

However, while electric charges exist, magnetic charges have never been observed in nature. If magnetic charges do not exist, the symmetry also cannot exist. This mystery has motivated physicists to search for magnetic charges, or magnetic monopoles. However, no one has been successful. Agullo and his colleagues may have discovered why.

"Gravity spoils the symmetry regardless of whether magnetic monopoles exist or not. This is shocking. The bottom line is that the symmetry cannot exist in our universe at the fundamental level because gravity is everywhere," Agullo said.
Gravity, together with quantum effects, disrupts the electric-magnetic duality or symmetry of the electromagnetic field.

Agullo and his colleagues discovered this by looking at previous theories that illustrate this phenomenon among other types of particles in the universe, called fermions, and applied it to photons in electromagnetic fields.
"We have been able to write the theory of the electromagnetic field in a way that very much resembles the theory of fermions, and prove this absence of symmetry by using powerful techniques that were developed for fermions," he said.
This new discovery challenges assumptions that could impact other research including the study of the birth of the universe.

The Big Bang

Satellites collect data from the radiation emitted from the Big Bang, which is called the Cosmic Microwave Background, or CMB. This radiation contains valuable information about the history of the universe.
"By measuring the CMB, we get precise information on how the Big Bang happened," Agullo said.

Scientists analyzing this data have assumed that the polarization of photons in the CMB is not affected by the gravitational field in the universe, which is true only if electromagnetic symmetry exists. However, since this new finding suggests that the symmetry does not exist at the fundamental level, the polarization of the CMB can change throughout cosmic evolution. Scientists may need to take this into consideration when analyzing the data. The focus of Agullo's current research is on how much this new effect is.

https://phys.org/news/2017-04-physicist ... amics.html
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Re: Interesting websites ( OPEN SUBJECTS)

Postby ecker2011 » Fri Apr 14, 2017 12:30 pm

A battery prototype powered by atmospheric nitrogen

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Artistic illustration of Zhang and colleagues' proof-of-concept experiment, which successfully implements a reversible nitrogen cycle based on rechargeable Li-N2 batteries with promising electrochemical faradic efficiency. Credit: Zhang et. al.

As the most abundant gas in Earth's atmosphere, nitrogen has been an attractive option as a source of renewable energy. But nitrogen gas—which consists of two nitrogen atoms held together by a strong, triple covalent bond—doesn't break apart under normal conditions, presenting a challenge to scientists who want to transfer the chemical energy of the bond into electricity.

In the journal Chem on April 13, researchers in China present one approach to capturing atmospheric nitrogen that can be used in a battery.

The "proof-of-concept" design works by reversing the chemical reaction that powers existing lithium-nitrogen batteries. Instead of generating energy from the breakdown of lithium nitride (2Li3N) into lithium and nitrogen gas, the researchers' battery prototype runs on atmospheric nitrogen in ambient conditions and reacts with lithium to form lithium nitride. Its energy output is brief but comparable to that of other lithium-metal batteries.

"This promising research on a nitrogen fixation battery system not only provides fundamental and technological progress in the energy storage system but also creates an advanced N2/Li3N (nitrogen gas/lithium nitride) cycle for a reversible nitrogen fixation process," says senior author Xin-Bo Zhang, of the Changchun Institute of Applied Chemistry, part of the Chinese Academy of Sciences. "The work is still at the initial stage. More intensive efforts should be devoted to developing the battery systems."

https://techxplore.com/news/2017-04-bat ... rogen.html
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Re: Interesting websites ( OPEN SUBJECTS)

Postby ecker2011 » Mon Apr 17, 2017 12:25 pm

This is really not new! First per-posted in the 1970's.

Could Moon Miners Use Railguns to Launch Ore into Space?

By Leonard David, Space.com's Space Insider Columnist

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Electromagnetic mass drivers using solar power could provide low-cost transportation of materials to space construction sites.
Credit: Space Studies Institute

The United States Navy fired a projectile at Mach 6 during a recent test with an electromagnetic railgun, suggesting that early ideas about using such tech to launch payloads from the lunar surface might not be so sci-fi after all.

Mach 6 (six times the speed of sound) is 4,567 mph (7,350 km/h). The escape velocity at the moon is just a shade faster than that — 5,300 mph (8,530 km/h).

The Office of Naval Research work on the EM Railgun launcher is being pursued as a long-range weapon that fires projectiles using electricity instead of chemical propellants. [The Most Dangerous Space Weapons Ever]

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The U.S. Navy's electromagnetic railgun in action during a recent test.
Credit: Office of Naval Research

Magnetic fields created by high electrical currents accelerate a sliding metal conductor, or armature, between two rails to launch projectiles.

In 1974, Princeton professor and space visionary Gerard O’Neill first proposed using an electromagnetic railgun to lob payloads from the moon.

"Mass drivers" based on a coilgun design could be adapted to accelerate a nonmagnetic object, O'Neill suggested. One application he proposed for mass drivers: tossing baseball-size chunks of ore mined from the surface of the moon into space, where they could be used as raw material for building space colonies and solar power satellites.

O'Neill worked at the Massachusetts Institute of Technology with Henry H. Kolm and a group of student volunteers to construct a mass driver prototype. Backed by grants from the Space Studies Institute, later prototypes improved on the concept, showing that a mass driver only 520 feet (160 meters) long could launch material off the surface of the moon.

An official at the Office of Naval Research, contacted by Inside Outer Space, said this of O'Neill's seminal work on mass drivers: "Very interesting proposal to use electromagnetic launchers for space vehicles. Considering the fact that the railgun is working with a small hypervelocity projectile, and requires significant power and thermal management, I suspect working out the details for movement of larger space vehicles/payloads is a long way off.

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Deflection plates near the end of the mass driver would make minute adjustments to the trajectory of the launched ore to ensure it reaches its target — a mass catcher at the Earth-moon Lagrange Point 2.
Credit: Space Studies Institute

"But I also believe that current efforts will be successful, and electromagnetic thrust will eventually be considered for other applications, including space," the official added.

You can check out a video showing work on the U.S. Navy's EM Railgun here: http://www.youtube.com/watch?v=5imlcR0CuJ0

O'Neill, who died in 1992, founded the Space Studies Institute (SSI) in 1977 with the hope of opening the vast wealth of space to humanity. For more information on SSI’s ongoing work, go to: http://ssi.org/

http://www.space.com/36442-could-moon-m ... ium=social
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Re: Interesting websites ( OPEN SUBJECTS)

Postby ecker2011 » Mon Apr 17, 2017 2:13 pm

Physicists create 'negative mass'
by Eric Sorensen

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Experimental TOF images of the effectively 1D expanding SOC BEC for expansion times of 0, 10, and 14 ms.

Washington State University physicists have created a fluid with negative mass, which is exactly what it sounds like. Push it, and unlike every physical object in the world we know, it doesn't accelerate in the direction it was pushed. It accelerates backwards.

The phenomenon is rarely created in laboratory conditions and can be used to explore some of the more challenging concepts of the cosmos, said Michael Forbes, a WSU assistant professor of physics and astronomy and an affiliate assistant professor at the University of Washington. The research appears today in the journal Physical Review Letters, where it is featured as an "Editor's Suggestion."

Hypothetically, matter can have negative mass in the same sense that an electric charge can be either negative or positive. People rarely think in these terms, and our everyday world sees only the positive aspects of Isaac Newton's Second Law of Motion, in which a force is equal to the mass of an object times its acceleration, or F=ma.In other words, if you push an object, it will accelerate in the direction you're pushing it. Mass will accelerate in the direction of the force.

"That's what most things that we're used to do," said Forbes, hinting at the bizarreness to come. "With negative mass, if you push something, it accelerates toward you."

Conditions for negative mass

He and his colleagues created the conditions for negative mass by cooling rubidium atoms to just a hair above absolute zero, creating what is known as a Bose-Einstein condensate. In this state, predicted by Satyendra Nath Bose and Albert Einstein, particles move extremely slowly and, following the principles of quantum mechanics, behave like waves. They also synchronize and move in unison as what is known as a superfluid, which flows without losing energy.

Led by Peter Engels, WSU professor of physics and astronomy, researchers on the sixth floor of Webster Hall created these conditions by using lasers to slow the particles, making them colder, and allowing hot, high energy particles to escape like steam, cooling the material further.

The lasers trapped the atoms as if they were in a bowl measuring less than a hundred microns across. At this point, the rubidium superfluid has regular mass. Breaking the bowl will allow the rubidium to rush out, expanding as the rubidium in the center pushes outward.

To create negative mass, the researchers applied a second set of lasers that kicked the atoms back and forth and changed the way they spin. Now when the rubidium rushes out fast enough, if behaves as if it has negative mass."Once you push, it accelerates backwards," said Forbes, who acted as a theorist analyzing the system. "It looks like the rubidium hits an invisible wall."

Avoiding underlying defects

The technique used by the WSU researchers avoids some of the underlying defects encountered in previous attempts to understand negative mass.

"What's a first here is the exquisite control we have over the nature of this negative mass, without any other complications" said Forbes. Their research clarifies, in terms of negative mass, similar behavior seen in other systems.This heightened control gives researchers a new tool to engineer experiments to study analogous physics in astrophysics, like neutron stars, and cosmological phenomena like black holes and dark energy, where experiments are impossible."It provides another environment to study a fundamental phenomenon that is very peculiar," Forbes said.

https://phys.org/news/2017-04-physicist ... -mass.html
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