Practical Physics News

These days physics often seems far removed from reality-black holes, worm holes, particles being in two places at once, 10 spatial dimensions. So its a pleasant surprise that physicists at UCLA have found a new dramatic application for the scotch tape in your kitchen drawer: generating x-rays.

When the tape is peeled removing the adhesive-electrons are released generating electric currents. In the photo to the left you're seeing visible light emission from these electrons. It turns out they also emit x-rays, so many that its possible to x-ray a human finger. I was about to try an experiment and x-ray my painful tooth but that's on hold because apparently you have to do this in a vacuum.

OK here is the kicker-physicist Seth Putterman says the process could be used for nuclear fusion. I'm a bit skeptical about that given the history of table top fusion attempts so far. You can read the details here:

From a Strip of Scotch Tape, X-rays

Models or Reality?

When I was a naive student first getting interested in physics, I was awed by its predictive power and took the theories themselves to be reality. On the blog Cosmic Variance Sean Carroll promotes this viewpoint when he writes:

"Right and wrong aren’t parts of the fundamental description of reality. That description has to do with wave functions and Hamiltonian dynamics, not with ethical principles. That is what the world is made of, at a deep level."

This is exactly how I used to think about things. Lately though, I have become more of a positivist. This is the viewpoint that scientific theories are just models. A good model makes predictions that agree with experiment. The fact that the models often change with time as better data or ideas come to the fore shows that its naive to take the models as absolute descriptions of reality. For a simple example you might consider the Bohr atom. If you recall, Bohr thought of the atom as a little solar system, with the nucleus playing the role of the sun and electrons occupying fixed orbits at different distances from the nucleus. As they jumped from one orbit to another, they emitted or absorbed photons of light.

We now know an atom isn't quite like that, and that instead the wave function of the electron allows us to make probabilistic predictions as to where the electron will be found. Each orbit is described by a different wave function, giving the "electron cloud" picture of the atom. The Bohr model of the atom, even though it agrees with a lot of experimental data, isn't real.

The positivist would say that the electron cloud is no more reality than Bohr's atom was. It simply makes better predictions. At our current level of technology and predictive capability, it seems to work perfectly. But that doesn't mean that in the future a better model of the atom won't come about. And-despite its drawbacks-the Bohr model of the atom actually works quite well in many circumstances. In nuclear engineering its often if not always adequate enough to think of the atom in terms of Bohr's picture. On the other hand, if you're doing quantum chemistry then you need to think in terms of the electron cloud model.

This goes to show that taking "wave functions" and "Hilbert space" to be reality itself is a naive viewpoint. Wave functions and Hilbert space are just tools that allow scientists to make predictions. They are good tools to be sure, but confusing a good tool that exists on paper and only in the minds of arrogant physics professors to be fundamentally real is an extremely naive approach to life.

The positivist viewpoint makes a lot more sense. Stephen Hawking summed it up well in his best seller A Brief History of Time when he wrote:

"Any sound scientific theory, whether of time or of any other concept, should in my opinion be based on the most workable philosophy of science: the positivist approach put forward by Friedrich Hayek and Karl Popper and others. According to this way of thinking, a scientific theory is a mathematical model that describes and codifies the observations we make. A good theory will describe a large range of phenomena on the basis of a few simple postulates and will make definite predictions that can be tested… If one takes the positivist position, as I do, one cannot say what time actually is. All one can do is describe what has been found to be a very good mathematical model for time and say what predictions it makes."

At the time I read this back in 1990, I was disappointed Hawking felt this way. Now with some maturity under my belt I realize that this is a far better description of what science does than taking some equations on a blackboard-which are good, useful tool to be sure-to really be reality itself.

Progress in ALS Research

Lou Gherig's disease is a horrible illness. The best science fiction writer couldn't come up with something as bad as losing your ability to move everything except maybe your eyeballs, while you stay locked-up, fully conscious in your prison of a body. Offering any kind of treatment for this debilitating disease would be a big breakthrough in medical science that would help people who really suffer-so this story caught my attention.

Swamping Bad Cells With Good In ALS Animal Models Helps Sustain Breathing

ScienceDaily (Oct. 20, 2008) — In a disease like ALS - one that's always fatal and that has a long history of research-resistant biology - finding a proof of principle in animal models is significant.

This week, Johns Hopkins researchers report that transplanting a new line of stem cell-like cells into rat models of the disease clearly shifts key signs of neurodegenerative disease in general and ALS in particular - slowing the animals' neuron loss and extending life.

The new work supports the hypothesis that artificially outnumbering unhealthy cells with healthy ones in targeted parts of the spinal cord preserves limb strength and breathing and can increase survival.

Read the rest on Science Daily

Opera about the making of the Atomic Bomb

The Terror and Attraction of Science, Put to Song
By DENNIS OVERBYE

Is it the horror or the beauty that makes science cool?

Sometimes it seems as if horror is the only story that science has to tell, or the only one we want to hear. Somebody has a gadget they have to build, an experiment too sweet to resist, forces they need to probe, regardless of the consequences. Think of Eve with her apple, Frankenstein with his monster, a stock trader with a foolproof get-rich-quick scheme.

I shouldn’t have to tell you that it usually ends badly.

The tug of war between beauty and horror is the theme of “Doctor Atomic,” the opera by John Adams and Peter Sellars about the building of the atomic bomb, which opened last week at the Metropolitan Opera. It stars Gerald Finley as J. Robert Oppenheimer, the brilliant philosopher-king of the secret society of scientists and engineers who were plucked from academia and assembled on a New Mexico mesa during World War II and told to make a bomb before the Germans did — a man as sung by Mr. Finley equally in love with the Bomb and his own inscrutability.

The opera follows events on two nights — one in June and then on the eve of July 16 during the countdown to the first test explosion at Alamogordo amid lightning and rain — as the scientists wrestle with doubts about whether “the Gadget,” as they refer to the bomb, will work, or work too well, setting the atmosphere on fire, and whether it should be dropped on humans.

As a love-starved Kitty Oppenheimer, sung by Sasha Cooke, sings, “Those who most long for peace now pour their lives on war.”

“Doctor Atomic” was surely born on the dark side of science mythology. Pam Rosenberg, then director of the San Francisco Opera, wanted to do an opera about an American Faust, namely Oppenheimer, whose life certainly seemed to follow a tragic trajectory. Wealthy, articulate and effortlessly fluent in far-flung domains of learning and culture, he was the young American prince of the new science of quantum mechanics as well as a bohemian and a pal of communists (his brother Frank and his ex-lover Jean Tatlock). Less than a decade after he was hailed as the deliverer of Promethean fire and the symbol of American science, Oppenheimer was stripped of his security clearance and banished from government circles.

Read the rest on the NY Times

It from Bit Speculations

Last night after watching some B. Allan Wallace lectures, I was wondering about the nature of consciousness. I am wondering if in some sense our consciousness (or the consciousness of anything) simply fundamentally exists in some sense, at least as information. Let's imagine a thought experiment. Suppose for the sake of argument that the technology existed where you could scan the atoms that make up a person, and any other information that might be relevant like say their energy states. Who knows how this could be done, lets say quantum computers turn out to be workable and that someday they have this capability. Furthermore lets say for the sake of argument that a memory device (maybe a quantum memory) is capable of storing all of this information for retrieval later.

So in the year 2050 a woman (we'll call her Betty) is scanned and her data saved. Now suppose that technology has also advanced enough so that we could read the information and assemble the atoms together into the same state as Betty in 2050. Suppose this is done in the year 2150 long after Betty has died.

It would seem to me that for all intensive purposes, if you could do this-arrange the same types of atoms/molecules together in the same state as Betty in 2050, the recreated Betty 100 years later would be completely indistinguishable from the original. I can't think of any scientific test that could be done even in principle that would tell you it wasn't really Betty, just a copy. So why not just say it is the original Betty? This would be a scientifically implemented resurrection.

What this says is that consciousness is more of an informational phenomenon, and in some sense it already exists in the universe and always exists provided the energy is there to do these sorts of things (i.e. arrange atoms together in the right way). In other words, the woman I've named Betty in the particular state she is in at some moment in 2050 including her conscious awareness is a packet of information. Rearrange the right atoms into the same state at any time in the history of the universe where it is plausible (not in the distant future when everything has decayed away though), that state is recreated and so is the consciousness that goes along with it.

You could ask what if we recreate Betty on the spot. Of course you couldn't do it instantly, no matter how advanced technology got there would be some finite time required to scan an organism and then construct the duplicate. So what would happen to Betty's consciousness then? Would it somehow split? Or is consciousness distinct and evolving, in other words you aren't really the same consciousness you were 2 seconds ago.

Maybe in the distant future it would be possible to even recreate previous states of the universe in some kind of quantum simulation. Then it might be possible for an infinitely advanced civilization to resurrect the past including its living inhabitants. Where would all this information be stored? In Hilbert space of course.

B. Allan Wallace on Consciousness

SPEAKING OF CONSCIOUSNESS one of my favorite scholars in the area is B. Allan Wallace. The guy simply blows me away with his genius. He has a degree in physics and has studied neurosciences and is also a Buddist monk. A brilliant man with a lot of thoughts regarding the ultimate problem in science: consciousness.

John Hagelin on Consciousness

One of my favorite subjects is consciousness. I think it is the ultimate question in science. I actually spent some time in neuropsychology and worked in a research lab-and came away thinking that neuroscientists have no idea whatsoever what consciousness is about. Saying its "emergent" from "complexity" is a big non-explanation.

Anyway so the debate over John Hagelin (TM Fame) over on Not Even Wrong led me to these YouTube videos which include interviews with Hagelin. Honestly I don't think Hagelin is all that wacky. Some of his thoughts actually make more sense than reductionist biology which has completely failed to explain how consciousness has arisen from the brain (hint: explaining what brain cells are responsible for vision does not explain why there is an entity inside my head WATCHING the show).