1. Comets, Asteroids, and Meteoroids
SPACE

2. Learning Goals
To be able to describe comets, asteroids and meteoroids

3. Comets (Dirty Snowballs)
A comet is a large chunk of ice, rock, and dust that orbits the Sun
Comets range in diameter from less than 1 km to over 20 km
When close to the Sun, frozen gases are evaporated and a tail develops
Comets have orbital periods ranging from a few years, to thousands of years

4. Famous Comets
Comet Tempel 1 – Deep Impact Spacecraft launched into comet in 2005, Stardust flyby in 2011
Comet Shoemaker-Levy 9 – collided with Jupiter in 1994
Comet Hale-Bopp – 1997 (will return in over 4000 years)
Halley’s Comet – last seen in 1986; first comet recognized as the same object; most studied; returns every 76 years (2061)

5. Asteroids
Asteroids are small celestial objects made of rock and metals
They are irregularly shaped and range in size from 10 m to nearly 1000 km
There are millions of asteroids in the solar system, most are located in the asteroid belt, between Mars and Jupiter

6. Meteoroids, Meteors, Meteorites
A meteoroid is a piece of rock or metal that is smaller than an asteroid
Meteoroids that enter Earth’s atmosphere begin to burn up due to friction
They become a bright streak of light in the sky called a meteor (commonly called a shooting star)
A meteor that reaches the ground is called a meteorite

7. Impacts
A 10 km wide meteorite that hit Earth near Mexico is believed to have led to the extinction of the dinosaurs 65 million years ago – Chicxulub Crater
A 5 km diameter meteorite impacted northern Quebec about 212 million years ago, creating the Manicouagan Crater

8. Meteor Showers
April 22, 23 - Lyrids Meteor Shower. The Lyrids is an average shower, usually producing about 20 meteors per hour at its peak. It is produced by dust particles left behind by comet C/1861 G1 Thatcher, which was discovered in The shower runs annually from April It peaks this year on the night of the night of the 22nd and morning of the 23rd. These meteors can sometimes produce bright dust trails that last for several seconds. Unfortunately this year the glare from the full moon will block out all but the brightest meteors. If you are patient, you should still be able to catch a few good ones. Best viewing will be from a dark location after midnight. Meteors will radiate from the constellation Lyra, but can appear anywhere in the sky.
Astronomy Calendar

9. Success Criteria
I CAN compare comets, asteroids and meteoroids