What they are Where the are They and Us

Comet – A body that produces a coma of gas and dust; a small, icy body that orbits the Sun

Made of ice and dust Comets form tails when they pass

through the inner solar system because solar radiation turns ice into gas

A comets tail always points away from the Sun

Range in size from 1 mile (think the distance from EWA to the Walmart) to 200 miles (think the distance from the bottom of NC to the top of NC) wide

Most comets are found in the Kuiper Belt (about 50 AU from the Sun) and the Oort Cloud (about 50,000 AU from the Sun)

A few comets orbit in the inner solar system due to gravitational tug

Comets may or may not orbit the Sun in the same direction as the planets

Scientists believe comets originated from the leftover debris from the creation of the solar system about 4.6 billion years ago

When comets are in the Kuiper Belt or the Oort Cloud, they are balls of ice

The comet head (coma) forms when the comet enters the inner solar system. The tail forms as a result of soar radiation turning the ice directly into gas and dust.

Comets lose ice and dust when they pass through the inner solar system

Eventually comets lose too much ice and break apart

Comets are usually undetectable to the naked eye, but may become visible when passing through the inner solar system

Meteor showers occur when Earth passes through a stream of particles left behind by a comet in its orbit

A notable comet: Halley’s comet

http://science.discovery.com/videos/100-greatest-discoveries-shorts-halleys-comet.html

Halley’s Comet can be seen from Earth about every 75 years

It is the only short period comet clearly visible with the naked eye

Asteroid – A small, solid, rocky body that orbits the Sun.

Asteroids are made of rocks and metals They do not form tails Range in size from 1000 km (the width

of North Carolina) to less than 1 km (halfway from EWA to the Walmart).

Irregular shapes due to weak gravitational pull

Surfaces covered with craters, broken rock and dust

Asteroids are found in the asteroid belt, located between Mars and Jupiter

They orbit the Sun in the same direction as the planets

There are over 4,000 asteroids in the asteroid belt

http://dsc.discovery.com/videos/fireballs-from-space-shorts-asteroid-belt.html

Asteroids are almost always undetectable to the naked eye

Asteroids produce meteors (streaks of light) upon entering Earth’s atmosphere and produce meteorites if they survive the trip through the atmosphere and hit the ground

Leave impact craters when they hit the Earth