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Showing posts from May, 2013

On Weinstein and Ouellette and Theories of Everything or "Can't We Just All Get Along???"

I tried, I tried really really hard not to write this post. I failed though, so here goes.  A few months ago I came across what looked like it should be a great little column about physics, "Cocktail Physics" by +Jennifer Ouellette. Reading one of her week in review articles, I was led to a couple of interesting stories before I came across one that looked great! I enjoy a good science yarn so I was excited to see a headline:

"...Mark Chu-Carroll took on new dimensions of crackpottery:..."
I was shocked to wind up reading an extremely mean spirited article written about another internet posting, (one very few people would have ever seen otherwise), that waxed philosophical and speculatively about special relativity, (think Einstein meets karma and self-actualization) . Worst of all, the author, Mark Chu-Carroll, a computer scientist didn't have a necessarily complete grasp on the science himself. So, that was a bummer. I wrote up a little article about the s…

Clouds Eats Mountain! Film at 7

I came across this picture of Sierra Blanca near Ruidoso, NM last night.  The peak of Sierra Blanca sits at 11,981 feet, above sea level more than 4,000 feet above Alto, NM where the picture was taken.  As a kid, growing up in Ruidoso, we'd say things like, "Wow, that cloud just hunkered down on top of the mountain." just assuming the cloud had come from somewhere else.  Looking at how the cloud above seemed to be literally streaming into the peak, I wondered if there was some kind of sciencey correlation between clouds and mountains.  I found the answer in an article from the February, 1901 issue of "The School World" by George Chisholm[1] that explained mountains actually help to form clouds, not attract them from afar.

Here's how it works.  Wind carries air saturated with water vapor into the mountain where it is forced up the slope.  As the air rises it expands due the lower air pressure, and as it expands, it becomes colder.  As it cools, the temperat…

Cool Science Locales: Saint-Pierre-de-Chartreuse

In a previous life, you're an electronics engineer who was rushed out to Grenoble, France to visit with ST Microelectronics.  Hopping off the plane in Lyon, you make the quick two hour drive southeast.  Realizing that you smell a bit funky after 8 hours on a plane, you drop into the local H&M, then pop into a pay toilet/changing room and pop out ready to engineer!   Six hours later, you finally emerge and start to look for places to stay, but to your  dismay, everywhere in Grenoble is fully booked.  You pull out your map and notice that there are mountains to the north.  Why not commute to one of the little towns up there?  You pull out the laptop and start calling hotels in each little town up the road until you finally find an available room in Saint-Pierre-de-Chartreuse. The room is only $60 a night, the travel folks at the home office should be pleased!  It's dark already when you head out of town on the D512.  You wind your way through narrow mountain roads and final…

Beta Decay Parity Violation And A Few Fischbach Notes

And now, in the ongoing series inspired by the Fischbach article on the seasonal variation of radioactive decay rates, a few more notes on beta decays.  Today, will be about beta decay and parity, (aka mirror image symmetry), violation.  In 1957[5], C.N. Yang and T.D. Lee performed a survey of the existing experiments involving beta decay and found that there was no experimental evidence showing that beta decays maintained mirror symmetry, (parity), something that had been simply assumed until then because there was experimental evidence that electromagnetic and strong interactions did maintain mirror symmetry.  A short time after Yang and Lee's report, Wu[6] completed an experiment that showed that in fact, electrons emitted from a polarized Cobalt 60 source violated mirror image symmetry.  The article following Dr. Wu's by Garwin et al[7]. showed that muon decay, (another weak force interaction), also violated mirror image symmetry.

Vectors and Axial Vectors and What it all …

A Little News, Two Approximations, And A Few Graphical Derivatives To Go With Your Coffee

Good Morning!  While drinking my coffee after getting a full night's sleep, (hooray for happily sleeping seven month olds!!!), I came across a cute little satellite and some useful approximations.

ESTCUBE 1
The Estonian University of Tartu has successfully placed a student built and student operated cubesat into orbit.  The satellite will deploy an electrodynamic tether and test the ability of the device to propel the space craft by exploiting the force between the electric charge placed on the tether by the satellite and charged particles in the solar wind.  For those that didn't know, the electronic tether propulsion concept was patented by Robert Forward, a physicist who worked for Hughes research during the '60s and went on to become a famous scifi author[5][6].  Folks with ham radios can listen in on the satellite at 437.250 MHz and 437.505 MHz.  M5AKA did a great write up on the little cubesat[1].  The satellite tracker here at Copasetic Flow has been updated to track…

Beta Decay and Neutrinos over Cocktails

This was going to be so much longer and more detailed, but as you may or may not be aware, seven month olds occasionally decide of their own volition to pull all nighters, (much like grad students).  So, I leave you with a few somewhat less than scattered thoughts, and an incredible video on the topic of neutrinos.

After yesterday's post on the possibility of the variation of radioactive decay rates with neutrino activity from the sun, I spent my free time today reading about beta decay and neutrinos.  The references I mention below are very complete, but this post won't be.  I present to you a series of notes and factoids about beta decay and the history of the neutrino, kind of a backgrounder for cocktail party level discussions of the topic if you will.

Beta Decay
I wanted to look into beta decay first because it's the type of radioactive decay, (as opposed to alpha or gamma), that involves neutrinos.  It seemed like the natural place to start.  Since we're talking…

Gran Sasso, Solar Neutrinos, and Radioactive Decay Rates

We interrupt your normal coverage of magnetic monopole searches today to bring you something much more cool from well.. the same location!  I was jazzed to find out yesterday that the next monopole project I was going to write about was done at a stunningly pretty location Gran Sasso, Italy. (picture 1)


Then, thanks to +Oliver Thewalt I found out about a very interesting study done regarding a possible time dependence of the decay rates of radioactive isotopes.  So much for the pretty location I thought, but the science is incredibly interesting.  Then, while reading up on the research this morning I found out that one of the studies[2] was performed at none other than the very same lab in Gran Sasso.  And we're back to where we started and I get to include a pretty picture with the post!  OK, OK enough with the cool coincidences and the small world of science for today.

So, here's what's going on in a nutshell.  Radioactive elements decay in a random fashion, but at a ver…

The Valentine's Day Magnetic Monopole

There's an assymetry to the form of the two Maxwell's equations shown in picture 1.  While the divergence of the electric field is proportional to the electric charge density at a given point, the divergence of the magnetic field is equal to zero.  This is typically explained in the following way.  While we know that electrons, the fundamental electric charge carriers exist, evidence seems to indicate that magnetic monopoles, the particles that would carry magnetic 'charge', either don't exist, or, the energies required to create them are so high that they are exceedingly rare.  That doesn't stop us from looking for them though!

Keeping with the theme of Fairbank[1] and his academic progeny over the semester break, today's post is about the discovery of a magnetic monopole candidate event by one of the Fairbank's graduate students, Blas Cabrera[2].  Cabrera was utilizing a loop type of magnetic monopole detector.  Its operation is in concept very simpl…

Some Quantized Flux History

In  1961, William Fairbank and Bascomb Deaver experimentally verified that magnetic flux can be quantized.  This week I read an excellent paper on the history of the experiment[1].  For those who aren't close to a library with access to the journal, (and for my own notes), here are a few of the highlights.  For more info on the Fairbank/Deaver experiment see[4] .

The Other Experiment The first interesting thing you should know is that there was a similar experiment  performed in Southern Germany by Robert Doll and Martin Näbauer in the same year, (1961)[2].  Their apparatus was different,  instead of  vibrating a superconducting cylinder to determine the value of the magnetic field at had trapped as Deaver and Fairbank did, they used a superconducting cylinder attached to a torsion pendulum (picture 1).  By measuring the amount of time it took the oscillations of the pendulum to die off they were able to determine the strength of the trapped magnetic field.  Their results showed th…

GIGO and Lightning Formation (GIGO: Gammas In, Gammas Out)

Two recent lightning studies provide interesting insight into the formation of lightning and the terrestrial gamma flashes, (also known as dark lightning),  that sometimes accompany it[1][2][4].  While both studies make use of the radio pulses created during lightning formation they seem to differ in their explanations of how the radio pulses are created.


First a little background on lightning formation.  The following great summary is from a recent post by +John Baez.[3]
"Lightning happens in stages. First, a streamer of electricity travels from one charged area to another, say, from a cloud to the ground, or from one layer within a cloud to another. This prompts a return stroke with the reverse charge to go in the opposite direction. The initial streamer electrified the air it moved through, creating a path of least resistance that allows the return stroke to carry a much greater current."
Both of the studies indicate that radio pulses associated with lightning are emitted…

Thoughts on Fairbank's Quantized Flux Discovery and the Quantum Hall Effect

William Fairbank might be most famous for experimentally demonstrating that magnetic flux is quantized[1].  In 1961 he published the results of an experiment that exposed very small cylinders of superconducting tin to a magnetic field and then measured the magnetic flux trapped by the cylinder after the applied magnetic field was turned off.  For more detail on why the flux was trapped, see [2].  He arrived at the following graph of trapped flux vs. applied field strength. (picture 1)


The data points are clustered around magnetic flux levels on the y axis that correspond to the values predicted for the magnitude of quantized magnetic flux.  The apparatus for the experiment is similar in several ways to the apparatus for the fractional charge experiment I mentioned yesterday [3].  A superconductor was exposed to an external magnetic field and results were analyzed by measuring properties of an induced vibration of the superconductor through a magnetometer, (an inductive pickup coil).
A…

The Strange Story of Free Fractional Charge

The currently widely held wisdom is that quarks, the subatomic constituents that make up protons and neutrons, cannot be found in an unbound state, (i.e. roaming freely outside of a proton, neutron, or other particle made up of quarks).  The reasoning goes that the attractive force due to the strong force between two quarks is so powerful that if they are separated far enough apart, there will be enough energy stored in the  strong field to create two additional quarks that will immediately glom on to the two you were trying to separate in the first place, hence, no independent unbound quarks.

In 1977, however, Larue, Fairbank[1], and Hebard reported that they had found evidence indicating that free quarks did in fact exist[2].  Their experiment involved suspending a 1/4 mm superconducting niobium sphere in a magnetic field gradient[7] and causing it to oscillate in a vertical direction.  The researchers measured the effects reversing the polarity of an applied electric field had on …