Motions in the Sky

A. Motion of the Stars through one night a. How can you describe the motion of the stars when you’re facing west? b. Describe the motion of the stars when you’re facing east. c. How can you describe the motion of the stars when you’re facing north? Is there any star that is not moving (or moving very little)? B. Observing from different latitudes a. Change the location to Mexico City closer to the equator. i. What do you see that is different from what you saw when you were looking from San Diego? b. Change to Seattle. i. Again describe what is different about the night sky. ii. How can you use Polaris to determine how far north you are standing? C. Motion of the Stars through one year. a. Return to San Diego. How long will it take for the stars to make one complete circle around polaris? b. Set the step to 24 hours. Click the step forward button to advance the time by 24 hours. Are the stars in exactly the same position they were 24 hours previously? Have they gone more than or less than a full circle in 24 hours? D. Wandering Stars a. Set step to 5 minutes and the date to January 1st. Aim on mars. How can you describe the motion of mars over one night? b. Is mars moving differently than the stars?. Describe the motion of mars. c. Are there any other objects that move differently than the stars? d. When you see the wandering stars, where are they located? Are they scattered all over the sky? Or are they always in a predictable location? E. More about wandering stars a. Set date to june 1st 2003. Set time to 24 hours. i. From one night to the next, which direction do the stars move? ii. Which direction is Mars moving relative to the stars in the background? iii. In the first part of September, which direction is mars movinig relative to the stars in the background? iv. What happens to the motion of mars around the beginning of October? v. Draw a sketch of mars motion relative to the background stars. F. Conclusions a. Can you come up with a model that explains all these motions? b. Is it likely that ancient peoples would come up with the same model as yours?