1. Astronomy and Cosmologies Wed.30.Mar, week 1, Spring 2005, Zita Ch.1: Astronomy & the Universe Write your question on the board Discuss questions Discuss ET workshop questions Space & Time workshop Preview Ch.1 online quiz Work some example problems

2. Distances and angles Even if we don’t know the distance to an object, angles are easy to measure. By total coincidence, the Sun and Moon happen to subtend nearly the same angle from Earth at the moment. Therefore, we can have eclipses.

3. Small-angle formula D =  d where the angle  is in radians. 360 o =2  radians D and d have the same units (e.g. both in meters).

4. Calibrate your hand and binocs In this week’s Space and Time workshop, you’ll use your hands to find angles. Also discover the field of view of your binocs.Space and Time

5. Space and Time workshop

6. Angles and distances 1 AU = 93 million miles = 150 million km 1 parsec ~ 3 light years Ly = distance light travels in one year Ly = speed * time ~ 3x10 8 m/s*3x10 7 s Ly =_______________________ 2  radians = 360 degrees 1 degree = 60 arcminutes 1 arcminute = 60 arcseconds

7. Online Quiz Ch.1 Preview

8. Looking ahead…

9. Research planning Read our Research webpage Browse past projects and candidate topics What are you especially interested in? Black holes? Jupiter’s moons? Think about What you might observe What questions you might investigate Cosmologies, modern and ancient Measurements/calculations you might do