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

 greatest-discoveries-shorts-halleys- comet.html 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  from-space-shorts-asteroid-belt.html 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