I Could Not Resist!

While I was walking my dog at 5:45 am this Friday morning, 10-12-12, I looked up and a saw two heavenly bodies and went back for my camera.  I could not resist!

waning crescent moon with Venus, other pics on Flicker

The waning crescent moon is slowly disappearing and will completely hide from view on October 14, new moon.  Meanwhile Venus, the morning star will remain bright.  The moon is approximately  374,000 km away while Venus is 169,000,000 km.  The question for my students on Monday who are currently learning about light waves is how does it take the light to reach us for both objects.  The solution is to convert the lengths to meters and divide them by the speed of light (3.0e8 m/s).
[answers: 1.2 seconds - moon, 9.4 minutes - Venus]