Friday, Sept. 13, 2013
Test 1: Two weeks from today.
Astronomy Open House: Today, starts at 7:45 pm.
News: Voyager 1 left the solar system about a year ago! (NASA)
Today's Topics:
The General Picture So Far
Changes in one night, sky rotation.
Changes over longer periods of time (SkyGazer): the Sun, the Moon,
the planets (Q), stars...
What is a day? (Solar vs sidereal day.)
What about a week? A month? A year?
Next: In the early 1600s Johannes Kepler formulated his three laws of ellipses, areas, periods. But why do planets move that way? Because of gravity.
Assignment: Today's class summary.
Spaceweather; APOD; Heavens-Above; Clear Sky Clock; PhysOrg Astronomy News; The Sky at a Glance
