Comets, Asteroids, and MeteorsSection 14.5

Standard6.e. Students know the appearance, general composition, relative position and size, and motion of objects in the solar system.

IntroductionThe sun, planets, and moons are the only objects in the solar system. There are other smaller objects moving through the solar system as well.

CometsComet: a “dirty snowball”

about the size of a mountain.Comets are loose collections

of ice and dust, and small rocky particles whose orbits are usually very long, narrow ellipses.

CometsA Comet’s Head

Clouds of gas and dust form a fuzzy outer layer called the coma.

Nucleus: the inner core of a comet

The brightest part is the nucleus and the coma

CometsA Comet’s Tail

Comet means “long-haired star”

Has a gas and a dust tail. Gas tail is always away from the sun.

CometsOrigin of Comets

Kuiper Belt: doughnut shaped region that extends beyond Neptune’s orbit

Oort Cloud: spherical region of comets that surrounds the solar system

AsteroidsAsteroids are too small and

too numerous to be considered planets or dwarf planets.

Most asteroids revolve around the sun in circular orbits between Mars and Jupiter.Called the asteroid belt

AsteroidsAstronomer have found more

than 100,000 asteroids.They hypothesize these

asteroids were leftover pieces of the early solar system that never came together to form a planet

AsteroidsSome asteroids have

extremely elliptical orbits that cross paths with other planets. This is what happened with the dinosaurs. An asteroid in orbit hit earth, causing a mass extinction.

MeteorsWhen there is a meteor shower, you often see a meteor at least once every 10 minutes

Meteoroid is a chunk of rock or dust in space

MeteoroidsMeteoroids come from comets

or asteroidsWhen a meteoroid enters

Earth’s atmosphere, it is called a meteor. It burns up and creates a streak in the sky (SHOOTING STAR.

Meteors

When meteoroids enter the atmosphere and strikes Earth’s surface, it is called a meteorite.