IT CAME FROM Asteroids, comets, and YOU

Formation of the Solar System

Formation of the Moon

Luna

The Asteroid Belt is not like this

Chicxulub 65 million years ago 180 km wide

Barringer Meteor Crater (Arizona) 49,000 years ago km diameter (0.737 miles)

Area surrounding the 1908 Tunguska Event, circa 1927

Artist’s Conception, just before impact

When will the next collision occur?

Asteroid Apophis Size: 300 meters Probabilty of Collision in 2036: 1 in 45,000 (as of last year) 2029 Orbit-changing encounter

Factors important in asteroid collisions Planetary Gravity g planet = 9.8 m/s

Target Density Rocky Crust: ρ = 2700 kg/m 3 (Water: ρ = 1000 kg/m 3 )

Impactor Density Density: ρ = 3000 kg/m 3 max Comet: ρ = kg/m 3

Kinetic Energy KE = ½mv 2 v meteor = km/s (assume 30) Angle of Impact Most common: 45°

Equation for Radius of Impactor from De Pater and Lissauer (2001) R meteor = 0.401( ρ planet ) 0.42 (D crater ) 1.28 (v meteor ) 0.56 (g planet ) 0.28 ( ρ meteor ) 0.42 (2700) 0.42 (9.805) 0.28 (3000) 0.42 (30000) × 10 -3