This is an image of the Earth (the dot in the middle) as seen from 3.7 billion miles away by the Voyager 1 spacecraft. Voyager 1 is one of my favorite spacecraft- it has journeyed through our solar system for 35 years, providing wonderful pictures and data for the outer planets along the way. It is back in the news, just now finally leaving our solar system.
This picture is humbling to me - it is through electromagnetic radiation that we know the universe, and it is through electromagnetic radiation that the universe knows us, sitting here, on our pale blue dot. _________________________________________________________________

• Final exam info is now up on the "Exams and Grades" link.
• D2L site now has your updated grade info. EVERYTHING up to the final exam is now in there. (There used to be a small bug for some people in the "lab total" column, because I was missing some data from a TA, but that should be up to date now)
  Let us know if you see something that seems problematic ASAP!
  
  
• EXTRA CREDIT SURVEY: (done)
• Here is the extra lens sim I showed in class last week. (Click on the "+" sign to switch it to "-" for a diverging lens, which the phet sim does not have)
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  Earlier homepage and announcements can be found here:
  week #1, week #2/3 , week 4 , weeks 5/6, week 7, week 8, week 9, week 10, week 11, week 12