Sunday, May 11, 2014

Actually at an Observatory!

My grad student Jesse Rogerson and I will be at the University of Arizona Bok 2.3-meter telescope starting tomorrow night.  Meanwhile, we visited the WIYN 3.5-meter telescope...

Sunday, April 13, 2014

The Boy Who Cried Wolf: A Bayesian Fairy Tale

When introducing Bayesian statistics to undergraduates, I have used the Monty Hall problem.  But it occurred to me last week that one of Aesop's Fables is also suited to the task.  Without further ado:

The Boy Who Cried Wolf: A Bayesian Fairy Tale

(This post is a link because Mathjax is better at displaying equations than is.)

Sunday, March 9, 2014

Universe Pie

Last time I saw a pie chart of the constituents of the universe, I thought "Why not use a real pie?"

So I went and made the above pie and pie chart.  Science is delicious!

Extra science: note that the top crust can be considered as stars and gas in galaxies and clusters of galaxies, while the bottom 'hidden' crust can be considered the warm-hot intergalactic medium.

The recipe below will likely evolve with time. I'd like to improve the proportions by doubling the blueberry content. but I'll wait for fresh blueberry season so the calories don't go even higher. And of course our ignorance of dark matter means that a chocolate brownie layer could be substituted for the current chocolate cream cheese layer...

Universe Pie

Dark Energy: 540 ml blueberry pie filling (or blackberry; who knows what dark energy is?)
Dark Matter: 200 g chocolate cream cheese, 1 egg, and 1/4 tsp vanilla
Normal Matter: two frozen pie crusts, thawed for at least 10 minutes

1. Preheat oven to 350 F and put rack in upper middle slot.
2. Prick one pie shell with fork in two dozen places and bake for 10 minutes.
3. Meanwhile, beat dark matter ingredients until smooth.
4. Pour dark matter into baked pie shell and bake until set (10 to 15 minutes).
5. Pour dark energy over dark matter.  Invert second pie shell over top.  Press edges down gently to seal.  Cut holes in top shell to let steam escape.
6. Bake for 20 minutes, then turn on broiler for 2 to 3 minutes to brown top.
7. Remove from oven and cool to room temperature on rack.
8. Refrigerate before slicing for best pie-chart effect.

Calories: 70 egg + 600 cream cheese + 840 blueberries + 1700 pie shells = 400/slice (for 8 slices) [Now I understand why most recipes don't list calories.]