Wednesday, Sept. 18, 2013
The Sky: Tonight we will have a full moon night. It is the Harvest Moon (NASA).
Reminder: Test 1 is next Friday. Please bring a scantron sheet (letter-size purple form).
Homework #1: Answer 5 questions in writing; due Mon 9/23 (see also the homework policy).
Solar Observation? Possibly, on Friday.
Today's Topics: Top Hat review question, then finish
Gravity
then, the Nature of Light:
• What is light? Waves of different wavelenths.
• How do we know? Interference and diffraction.
• The electromagnetic spectrum.
• How fast does it travel? Always at the
same speed c = 300,000 km/sec!
Reading: Chapter 5; See also the lecture notes and today's class summary.
Spaceweather; APOD; Heavens-Above; Clear Sky Clock; PhysOrg Astronomy News; The Sky at a Glance
