We reconvened in the familar windowless basement lecture hall on Wednesday, to hear Dr. Mike Brotherton give us a long and detailed lecture on Newton's laws, Kepler's laws and how combining them gives us the basics of orbital mechanics. We also discussed Lagrange points and transfer orbits, all good crunchy stuff.
After the lunch break Dr. Mike resumed with an account of the Solar System and the planets, which touched on how planets form and how the greenhouse effect works.
For the early afternoon session Dr. Mike continued the theme that everything we know about the Universe is based on collecting light. He walked us through how astronomers measure the temperature of stars (based on their spectra), their composition (from absorption lines in the spectra), their brightness, and their distance (using parallax). Combining distance, brightness, and temperature lets them figure out the size of a star. Observing binary stars gives an estimate of the mass of the binary elements, and that in turn provides a yardstick to estimate the mass of stars without companions.
Charting temperature against luminosity creates the famous Hertzsprung-Russell Diagram, and when that is correlated with known stellar masses, it turns out that a star's brightness and temperature depend on its mass. Big stars burn hot and bright, small stars are cool and dim. Once that was known, astrophysicists could work out how long stars live, based on the amount of energy they emit and how much fuel they start with.
So just by gathering light and thinking about it, astronomers know what stars are made of, how they form, how big they are, how they burn, and how long they live. All from light.
The final lecture was by Dr. Stanley Schmidt, about turning astronomical information into actual science fictional settings. He focused on Hal Clement's legendary feat of worldbuilding in the novel Mission of Gravity. With just a few bits of data about an extrasolar planet (which turned out to be bogus, as it happens), Hal Clement created a strange and fantastic world, bizarre inhabitants, and their weird cultures.
He didn't quite come out and say "Go thou and do likewise," but we got the message.
After a break for dinner, we piled into vans and drove through an apocalyptic thunderstorm to the Wyoming Infrared Observatory (WIRO) atop Jelm Mountain west of Laramie. Happily the rain was going east as we went west, so by the time we reached the summit the sky above the observatory was partly clear, and we had a spectacular view of the lightning storm over Laramie, with bright moonlight highlighting the clouds.
The observatory has the taped-together atmosphere of most working scientific facilities I've seen. The control room is a bunch of workstations all linked to a big open electronics rack. And through the door is the dome itself, housing the observatory's 2-meter telescope. When I say a 2-meter telescope, I don't mean that it's slightly longer than I am. That's the width of its main mirror. The actual instrument is about 20 feet long, mounted on a titanic steel framework which can rotate to compensate for the turning of the Earth.
We got to look at the main mirror, thos with cameras took lots of pictures, and I admired the instrument's combination of scientific precision and industrial heft. When the graduate student setting up the scope for that night's observing asked for volunteers to work the dome controls, Chris Rowe won the scramble to push the button.
While the observatory team did their setup work, Dr. Brotherton talked about the telescope and the advantages of being in a small department with a big instrument. With the fatigue of a long day catching up to us, the Launch Pad workshoppers headed back down the mountain for some sleep.
The Cambias Digression 