Wednesday, November 24, 2010

Error: Divide by Zero

I recently came across this car on the road.

This struck me as (1) inaccurate and (2) ineffective. But then I didn't know it would be better if it said "undefined mpg", "infinite mpg," or something else entirely?

Thursday, November 11, 2010

Pulsar music

Speaking of globular clusters, some work has been done to convert the electromagnetic pulses of pulsars near the core of globular cluster 47 Tucanae into audible sounds for our listening pleasure. 

More info here.

A lovely video of this cluster:

Tuesday, November 2, 2010

Autumn leaves as globular clusters?

As I looked at the red leaves falling around a maple tree in my yard, I was reminded of an appendix in Pickover's Chaos in Wonderland called "Build Your Own Globular Cluster".  I dug it out and found the equation
p = 1/(1+r²)^n
where p is the density of stars in the cluster, r is the radius, and n is a so-called polytrophic index, "typically 2.5<n<3.2".  The index also provided a program for plotting globular clusters, but I found it difficult to understand, so I went about creating my own from the equation.  I used the inverse function r(p), and let p be a random number between 0 and 1.  The result looked very similar to the pattern of leaves I saw on the ground, but I still wonder if this was the right equation to us, or if a normal distribution would be more appropriate.