1. Asteroids, Meteors & Comets, Oh My!

3. Asteroids & the Asteroid Belt:
An asteroid is a planetesimal left over from the beginning of the solar system.
The majority of asteroids are found within the asteroid belt, between Jupiter and Mars.
The gravitational pull of Jupiter is so big that a planet could not form there.

4. Meteors, Meteoroids, Meteorites
Meteoroid: A chunk of iron and rock in space that is NOT part of the asteroid belt
Meteor: A chunk of iron & rock that is in Earth’s atmosphere (usually burning up)
Meteorites: A chunk of iron & rock that has hit the Earth’s surface
Most are smaller than a grain of corn!

5. Meteorite:
Meteorites are bits of the solar system that have fallen to the Earth.
Most come from collisions of asteroids within the asteroid belt, few come from comets, or from the other planets

6. Impact Craters Throughout the Solar System

7. Meteor Showers:
Happen the same time each year when Earth’s atmosphere intersects debris left by a comet. Comet debris burns in the Earth’s atmosphere.
When meteors burn up in the atmosphere, they create a trail of light.

8. Tanguska Event June 30, 1908, a comet exploded at Tanguska
There was no crater--it exploded above ground
Explosion flattened hundreds of trees

9. Trees have been flattened, by the explosion.

10. Tanguska Event
Dust found in Antarctic ice, showing global spreading of the dust
One degree cooling in Northern Hemisphere in years following 1908 have been attributed to impact.
Shows that even small events like Tanguska can cause global temperature change--causing global cooling.

11. Barringer Meteorite Crater, Arizona:
One-mile wide, 570 feet deep
50,000 years old
Meteorite 45 meters (~135 ft) in diameter
Most of the meteorite vaporized on impact
Small meteorite fragments found around crater

12. Chicxulub Crater Located near the port city of Progreso, Mexico
Scientist believe that this may be the crater that wiped out the dinosaurs
Formed 65 million years ago
Meteorite 10 km in diameter
Dates coincide with iridium layer on Cretaceous
Called an astrobleme

13. Chicxulub Crater