EASC 108 Lecture Notes - Lecture 14: Galilean Moons, Kuiper Belt, Impact Crater

• School: Simon Fraser University
• Department: Earth Sciences
• Course: EASC 108
• Professor: Glyn Williams- Jones

Document Summary

Most of large and medium-sized moons ( density > 2g/cm3) probably formed in the accretion disks of the planets. All spherical, rotate and revolve in the respective ecliptic plane" of each planet in same direction of plane" rotations. Composed of ~50/50 rocky materials & large water ice (no h or he, why?) Small moons have irregular shape, and no orbital pattern. Terrestreial planets: 75-90% of craters caued by asteroid impact. Few asteroids reach jupiter, and virtually none reach saturn cratering rates should be very low. Jupiter"s gravity parity shields the inner solar system from comets. So more cometary impacts in the outer solar system. Jupiter: most impacts come from jupiter family, comets: objects diverted from kuiper belt (30-50 au) Saturn: most impacts come from long-period comets from the oort cloud. Impact rates: jupiter ~50% of earth; saturn ~25% of earth. Gravity of planet: pull comets inward, bigger the planet, stronger the effect.