Friday, September 20, 2013
Change: HW #1 is now due Monday.
Today's Topics:
The Nature of Light
• What is light? Waves of different wavelenths.
• How do we know? Interference and diffraction.
• The parts of the electromagnetic spectrum.
• How fast does it travel? Always at the
same speed c = 300,000 km/sec!
Matter and Light
• What is matter made of? Atoms and molecules.
• How does light interact with bulk matter?
• How does light interact with atoms? Photons.
Spectroscopy
• Kinds of spectra and information:
– Emission line [composition].
– Continuous [temperature,
all objects].
– Absorption [composition and temperature].
• Doppler effect [radial velocity] – demo.
So, what do we get on Earth from space?
Reading: Ch. 5, and today's class summary.
Spaceweather; APOD; Heavens-Above; Clear Sky Clock; PhysOrg Astronomy News; The Sky at a Glance
