### Virginia Trimble on Pyramids and Missing Extraterrestrials

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 Concerning the so-called Air-Shafts of Cheops's Pyramid"

2. "Where Are They? A Report on a Symposium on the Implications of Our Failure to Observe Extraterrestrials "
http://www.bigear.org/CSMO/PDF/CS06/cs06p20.pdf

3. John Baez on Earth-like planets near Red Dwarfs

### Cool Math Tricks: Deriving the Divergence, (Del or Nabla) into New (Cylindrical) Coordinate Systems

The following is a pretty lengthy procedure, but converting the divergence, (nabla, del) operator between coordinate systems comes up pretty often. While there are tables for converting between common coordinate systems, there seem to be fewer explanations of the procedure for deriving the conversion, so here goes!

What do we actually want?

To convert the Cartesian nabla

to the nabla for another coordinate system, say… cylindrical coordinates.

What we’ll need:

1. The Cartesian Nabla:

2. A set of equations relating the Cartesian coordinates to cylindrical coordinates:

3. A set of equations relating the Cartesian basis vectors to the basis vectors of the new coordinate system:

How to do it:

Use the chain rule for differentiation to convert the derivatives with respect to the Cartesian variables to derivatives with respect to the cylindrical variables.

The chain rule can be used to convert a differential operator in terms of one variable into a series of differential operators in terms of othe…

### 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…

### The Javascript Google URL Shortener Client API

I was working with the Google API Javascript Client this week to shorten the URLs of Google static maps generated by my ham radio QSL mapper. The client interface provided by Google is very useful. It took me a while to work through some of the less clear documentation, so I thought I'd add a few notes that would have helped me here. First, you only need to authenticate your application to the url shortener application if you want to track statistics on your shortened urls. If you just want the shortened URL, you don't need to worry about this. The worst part for me was that the smaple code only showed how to get a long url from an already shortened rul. If you follow the doucmentaiotn on the insert method, (the method for getting a shortened url from a long one), there is a reference to a rather nebulous Url resource required argument. It's not at all clear how to create one of these in Javascript. The following example code shows how:
var request = gapi.clie…