Asteroids Asteroid Belt What is an Asteroid? A large, irregularly shaped chunk or rock or metal that orbits the sun The Asteroid Belt Can Be Divided Into Two Belts The Inner Asteroid Belt- Within 250 million miles of the Sun Mostly metallic (iron and nickel) The Outer Asteroid Belt million miles from the Sun Mostly rocky and are rich in carbon What is the Largest Asteroid in the Solar System? Vesta- which is 578 km in length What happened to Ceres? When Pluto was demoted to dwarf planet, Ceres was promoted to dwarf planet status Origin of the Asteroid Belt? When the solar system was forming, there was enough material to form a planet 4 times bigger than Earth. So what happened??? Origin of the Solar System? So What Happened? The gravitational forces of the Sun were in a tug-of-war with the gravitational forces of Jupiter. Jupiter pulled away most of the material. What is left could only build a planet half the size of the Earths moon. Are All Asteroids in the Asteroid Belt? Scientists estimate that there are over 1 million asteroids in the asteroid belt More than 1 million other asteroids are scattered around the solar system. Some asteroids are near Earth Near Earth Asteroids (NEA) Any asteroid that may travel within 0.3 AU (30 million miles) of the Earth NASA has an entire department dedicated to monitoring NEAs Estimate there are NEAs over 1 Km Currently have identified and track 322 asteroids Cant identify and track all of the smaller ones Torino Scale A scale designed to measure the threat of an asteroid impact with the earth. It is base on two things: Chance of impact Size of asteroid Torino Scale Asteroid Impact Asteroid Impact and Dinosaur Extinction Large asteroid impacted Earth about 66 million years ago. Impact sent so much material into the atmosphere that it blocked out sunlight 75% of all species of plants and animals were wiped out including all of the dinosaurs Where Did the Asteroid Hit? A Dinosaurs Eye-View