Copasetic Flow

A pink cloud was reported in the early morning, (pre-sunrise), sky over Arizona on Wednesday [1]. NASA and the DOD soon thereafter took credit for the cloud.  They had launched a rocket into the ionosphere where it released a vapor that created the cloud.  The purpose of the experiment was to study the effects of the vapor on the ionosphere itself.  The article, referenced above from ABC, said: "The experiment, which also involved using ground stations to take measurements of the ionosphere, was intended to develop scientific explanations for ionospheric disturbances and their effects on modern technology, officials said." This has all been done before [2] as it turns out!  In 1956 the Air Force launched two missiles from White Sands Missile Range with payloads of nitric oxide.  The gas released in the ionosphere created a glowing cloud described as being ' yellow-red '[3] in color.  They were studying the ionosphere as well, which, back in 195...

Did you ever wonder if there was any 'real science' behind the subject matter of shows like 'Ancient Aliens'? There is! Yesterday I came across these two articles[1][2] by Dr. Virginia Trimble: UC Irvine astronomy professor and science historian. The first article was written by Dr. Trimble when she was still an undergrad at UCLA. It detailed her calculations showing that the constellation Orion was visible through the 'so called air shaft' of Cheops pyramid when it was constructed. The second article was an excellently written and fun to read review of the a 1979 "Symposium on the Implications of Our Failure to Observe Extraterrestrials " The symposium was attended by luminaries such as Freeman Dyson and Bracewell. Among other topics, there were discussions of how many planets were available that could support life. It gives a nice historical perspective on today's post from John Baez [3] References 1. "Astronomical Investigation Conc...

Work is proceeding on testing the systems that will be used in the experiment.  While the glass Dewar’s silvering blocks gamma radiation in the 22 keV range substantially, it fits nicely inside the yoke magnet whose field can be easily measured.  A temperature gauge was located; vacuum testing was started for the inner Dewar and lid, (including the instrumentation ports.)  Scroll to the bottom for the background of the experiment. All about the temperature gauge Today, just pictures of the gauge.  For an idea of scale, its rectangular footprint is about the size of a nickel.  The four wire sockets on the left are for attaching a four point probe to measure the resistance of the gauge. The Dewar lid with all the attachments The easiest way to seal the Dewar lid was to put the instrumentation stick back in place.  An experimental stage to hold the Pb sample still needs to be designed. Testing the vacuum pump before testing the D...

How a car accident in 1936 turned physicist, David Tressel Griggs, into WWII radar test pilot who ferried other scientists to the European front to capture Nazi atom bomb scientists. Here's what I already knew: Agnew Hunter Bahnson Jr., in a rather indirect manner, provided both the airplane and the test pilot used by MIT's Radiation Lab to test a new WWII technology, radar.  In 1936, Bahnson, who was a resident of a Harvard dormitory, took one of his geophysicist dorm-mates, David Tressel Griggs on a hiking trip through the Caucasus Mountains.  The Caucasus range connects the Black Sea with the Caspian Sea.  Bahnson's and Grigg's hiking trip ended before it even began, however, when Agnew swerved off the road to miss a bicyclist and struck a tree[1].  Griggs narrowly missed losing both of his legs to amputation. Hunter's father had taken out an insurance policy for the trip.  Grigg's used his payment to purchase a Luscombe airplane.  His injured legs ...

Our cosmology course is well under way and it's  a lot of fun so far!  The class direction overall is towards describing the inflationary universe by means of quantum field theory, but this week we're focused on relativity.  We're allowed to work on our homework together, however, I'm spending most of my time in the lab this semester, so I'll be posting my homework notes here.  If you'd like to grab bits and pieces, make suggestions, or contribute, the whole shooting match will also be archived on github . Our first homework contains a problem that involves accelerating reference frames.  The question is, given the transformation between the lab and the accelerating reference frame, figure out if the line element $ds^2$ is preserved.  There are a few interesting aspects to this problem.  First, while the transform looks similar to Rindler coordinates, it's not, (as ar as I can tell.)  Second, looking into Rindler coordinates a bit, they seem to ...

For background on the experiment, please scroll down. We can get a cheap piece of 3/4 inch diameter Pb from Rotometals .  Here are the details 3/4 17.14 per foot Nuclead has the same thing.  Check for purity and price. Also there’s Mayco . Next question, how pure does pure have to be? Pb purity data: The following are reference articles about superconductors.  Each of them describes the purity of the Pb samples used.  The lower bar is set by the RMP article referenced below, as well as one other that mentions the use of ‘commercial’ grade material and the evidence of a transition to a superconducting state for this material.  The final reference from 1886 in the section defines commercial level material to have a quality not lower than 99% pure.  This information is being researched to determine what purity of sample we should use.  It would seem that a higher purity sample will produce fewer unexpected experimental results, as we...

I ran into a rather abstruse question in today's first mechanics recitation.  The question gave the one dimensional position of a particle with respect to time as $x = 10 - 4t + 2t^3$ It then asked for the distance traveled by the particle between t = 0 and t = 2.  The suggested answer, (from the prof in charge of TAs), was to plot the trajectory of the particle, thereby demonstrating the distance and displacement were different.  Here's the plot: The idea is that you can see that the particle travelled form 10 to 8 and then back to 18, so the total distance is more than the displacement from 10 to 18 i.e. 8. The question came up as to how to do this to get the exact answer.  Here goes What we want to do is add up all the small, (read infinitesimal), distances travelled by the particle between time 0 and time 2.  The phrases, 'adding up', and infinitesimal provide the tip off that we'll do an integral, so: Getting to the Integral the ...