on Eclipses

Today, a total solar eclipse will pass over the United States, from Oregon to Georgia, cutting a path that will dim the Sun an appreciable amount for everyone in the Continental United States. It’s something that hasn’t happened in 38 years, since an eclipse in 1979. It’s going to be an event shared by an…

Astronomy on Tap

One of the great things I’ve been able to do in New York City is take part in Astronomy on Tap, a public lecture/happy hour series organized by Emily Rice (CUNY-CSI), Summer Ash (Columbia), Brian Levine (AMNH), and their less-mild-mannered alter egos. Astronomy on Tap takes place in bars in Manhattan and Brooklyn and consists…

on the Doppler effect

The Doppler effect was discovered by Christian Doppler in 1842, and describes how waves seem to change with motion.  With sound waves, the Doppler effect describes the familiar shift in pitch as a car passes by you (ask any five-year-old the noise a car makes, and you’ll hear the NEEEEOUUUUWWWWW of the Doppler Effect.) With…

In which I explain Kirchoff’s Laws of Spectroscopy

Kirchoff’s Laws are the laws that govern the behaviors of light passing through a gas.  They explain the behavior of the spectra of stars, require a basic understanding of quantum mechanics.  The powerpoint explains it with examples. 1.) A heated solid object produces a continuous (blackbody) spectrum. This governs everything from stars to light bulb…

On Proper Motion

I’ve made a Powerpoint Animation (and the above animated gif, click to see it move) that demonstrate stellar proper motion.  Note that the animation is quite complex, and can only run for about 20 seconds before the various layers stop moving. Proper* Motion is the apparent angular motion of stars across the sky, due to…

In which I explain the Hertzprung-Russel diagram

Here’s a powerpoint animation that explains the Hertzprung-Russel diagram, step by step. The Hertzprung-Russel diagram is one of those great organizational schemes, like the Periodic Table, that manage to have great predictive and associative power.  It’s not perfect (neither is the Periodic Table), but it CAN explain a great number of things about stars.

Concerning Parallax

I’ve made a powerpoint presentation here that demonstrates the astronomical principle of trigonometric parallax. For the uninitiated, parallax is a fancy term for triangulation, which we humans naturally do in the form of depth perception – your eyes are separated by a small distance from each other so they see slightly different views of the world….

on the Rules of Powerpoint

I know I’m not the first person to suggest this, but I’ve come around to the idea (which was probably the original idea, anyway) that your powerpoint slides should ILLUSTRATE your talk, not BE your talk.  I think everyone’s seen powerpoint presentations where the person just reads their own slides and has written an entire…