Astronomy 10 Spring 2000

Worksheet #2

1. Name the 12 constellations of the Zodiac in order (consult another group if you can’t do it all in your group). Put them in a big circle on a piece of paper, with the Sun at the center. Inside that circle, depict the Earth in March, when the Sun is "in Aries". In which sign will it be seen at the other equinox, and at the solstices?

2. In your picture for March (as viewed from the north ecliptic pole), show where a person would be standing at sunrise, noon, sunset, and midnight. Do this again for 6 months later. Discuss which constellations are visible at midnight in each case. (Remember that the stars are actually very far away)

3. Jupiter is 5 times further away from the Sun than the Earth. How long is its “year” compared to the Earth's? Halley’s comet has an orbital period of 76 years. What is its semimajor axis in AU (so again, compared to the Earth's orbit)? For these and almost all problems in this class (which will be posed as comparisons), you should use ratios to solve them, rather than plugging in all the constants and calculating each quantity separately.

4. Using the concepts of celestial equator and ecliptic, make a demonstration of why the day is longer in the summer and shorter in the winter. Explain why the day and night are equal at the equinoxes, and most different at the solstices. Does the difference increase with latitude?