1. Wednesday September 5, 2012 (Lab – Hubble’s Law – The Expanding Universe - Day 2)

2. The Launch Pad Wednesday, 9/5/12 Define the terms “Doppler effect” and “redshift.” The Doppler Effect is the change in the observed frequency of a wave, as of sound or light, occurring when the source and observer are in motion relative to each other, with the frequency increasing when the source and observer approach each other and decreasing when they move apart. Redshift is a shift toward longer wavelengths caused by an object that is receding from an observer and stretching out the light waves behind the object. This results in longer wavelength visible light waves, which are toward the red end of the spectrum.

3. Announcements Please remember that we will have our next Quiz this Friday.

4. Assignment Currently Open Summative or Formative? Date IssuedDate Due Date Into GradeSpeed Final Day ESS Class Information Sheet F18/278/28 ESS Class Procedures and Expectations F28/278/29 Quiz 1S18/31 9/14 Lab - Hubble’s Law - the Expanding Universe F39/49/6

5. ?? Recent Events in Science The Milky Way Now Has a Twin (or Two): Astronomers Find First Group of Galaxies Just Like Ours. Read all about it! This image shows one of the two ‘exact matches’ to the Milky Way system found in the survey. The larger galaxy, denoted GAMA202627, which is similar to the Milky Way clearly has two large companions off to the bottom left of the image. In this image bluer colours indicate hotter, younger, stars like many of those that are found in our galaxy. (Credit: Dr. Aaron Robotham, ICRAR/St Andrews using GAMA data) http://www.sciencedaily.com/releases/2012/ 08/120822221342.htm