Comets, Asteroids and Meteors

Comets Comets: - visible for days, weeks and months - “dirty snowball” chunks of ice and dust; orbits are long and narrow ellipses - size of Earth’s mountains - few pass near Earth - tail hundreds or millions of Km long - 1705 Edmund Halley (English Astronomer) calculated orbits of 24 comets. He predicted one would appear every 76 years when the prediction came true the comet was named after him

Halley’s Comet

Parts of a Comet Nucleus: main body (head), solid center made of ice from water, methane and ammonia, and dust Coma: the atmosphere of the comet created as the comet evaporates. Tail: ice and dust that is melting, emerges as comet gets closer to sun, always points away from the sun, can be up to 250 million kilometers in length Comets have an elongated elliptical orbit, its tail always points away from the sun due to the force of solar winds.  

Comet Diagram

Asteroids Rocky objects too small and numerous to be called planets Found in the Asteroid Belt located between the orbits of Mars and Jupiter More then 10 000 Vary in shape and size · Some asteroids outside the asteroid belt have orbits that cross Earth’s orbit; scientists monitor the positions of these asteroids One hit Earth 65 million years ago making a crater 200 Km in diameter near the Yucatan Peninsula; hypothesized to have caused the extinction of dinosaurs.

Asteroid

Asteroid Belt

Meteors Meteors: a meteoroid that burns up as it enters Earth’s atmosphere Meteoroid: chunks of rock and dust from pieces of comets and asteroids in space Meteorite: meteor that hits the surface of a moon or planet.

Meteor Showers