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1. Lecture 17—Milankovitch cycles Abiol 574
5. Q: What makes eccentricity vary?A: The gravitational pull of the other planets
6. Eccentricity Variations Current value: 0.017
Range: 0-0.06
Period(s): ~100,000 yrs
~400,000 yrs
9. Q: What makes the obliquity and precession vary?A: First, consider a better known example…
12. Obliquity Variations Current value: 23.5o
Range: 22o-24.5o
Period: 41,000 yrs
13. Precession Variations Range: 0-360o
Current value: Perihelion occurs on Jan. 3
? North pole is pointed almost directly away from the Sun at perihelion
Periods*: ~19,000 yrs
~23,000 yrs
20. NH Insolation vs. Time
21. O isotopes—the last 900 m.y.