1. Activity 4- Impact Events and the Earth System

2. Barringer Crater – Northern AZ
The world’s best preserved meteorite impact site on Earth. Meteor Crater is the breath-taking result of a collision between an asteroid traveling 26,000 miles per hour and planet Earth approximately 50,000 years ago.
Meteor Crater is nearly one mile across, 2.4 miles in circumference and more than 550 feet deep.

3. Asteroids Rocky bodies left over from formation of the solar system
Orbit the sun – very eccentric orbits
Asteroids >1km hit the Earth every few hundred million years

4. Asteroids
Ceres (the largest- 950 Km across) is classified as a dwarf planet
It is widely believed that an asteroid caused extinction of the dinosaurs
NASA is currently working on a mission to have an astronaut walk on an asteroid!

5. NASA Near Earth Objects watch

6. Torino Scale Scale 1-10 1 = little effects 10 = catastrophic effects
Measures the effects of an impact
Scale 1-10
1 = little effects
10 = catastrophic effects

7. Comets Dirty snowball! Frozen gas and dust
Orbits are very eccentric and have a high inclination
Have two tails, the gas tail (blue) and the dust tail (white)
Famous periodic comet- Halley’s Comet (July 28, 2061 next perihelion)

8. Halley’s Comet Passes by Earth every 75 years
Next approach July 28, 2061 – mark your calendars!
10 miles long, 5 miles wide and 5 miles high

9. Anatomy of a Comet Tail always faces AWAY from the sun
Coma – cloud of dust and gas
Nucleus – center of the comet

10. Meteoroids, Meteors, and Meteorites
Named for where they are:
A meteoroid is in space
A meteor is passing through the Earth’s atmosphere (shooting star)
A meteorite is found on Earth