A Peek Inside

It’s been my pleasure to offer 6-week courses for the past three years. Each September we offer Astronomy 101, a broad introduction from planets and the Solar System out to galaxies and the Big Bang. Other courses include Measuring Distances in Space, Clocks/Calendars/Coordinates/Orbits, Physics in Astronomy. Currently we’re in a new course, Cosmology 101. In the Spring, we’re tackling Multi-wavelength Astronomy, also new. We try to keep to tight, crowded syllabuses in our weekly two-hour classes.

I’m impressed by the feedback and interactions that occur, from which I learn a lot. For example, while discussing the elliptical orbits of planets one member found a website with month-by-month charts of where the second focal point lies, depending on planet positions. Sometimes it’s near the sun’s surface, sometimes a million miles beyond it. Who knew this was known? The first focal point is at the sun’s center.

In discussing time zones, class members explained that they originated from the need for uniform train schedules, not from any astronomy imperative. Of course, think of it: before the telegraph, every town and city had its own time of day based on its local solar noon!

credit: Simona D’Souza
Lucca Zimmerman demonstrates his gravity model.

Lucca, a 10-year old, took several courses (with parents). Physics in Astronomy prompted him to do a school project on curved space and gravity. I merely suggested he find a video and interpret it. Instead he built a model using a stretchable cloth attached to a basketball hoop. A heavy weight in the center bent the cloth in such a way that smaller balls tossed in orbited like planets around the sun. In fact, the orbit axis repositioned (“precessed”) just as Einstein predicted in general relativity. He demonstrated this twice in our classes.

Did you know the moon’s pull creates more than ocean tides? The ground itself lifts and sinks by about 3 feet daily over continental areas. I didn’t; it came out in our discussions.