Asteroids are rocky airless worlds that orbit the sun and are too small to be considered planets. They come in three main types - C, S, and M - and some are potentially hazardous if they come close to Earth. While asteroid impacts were more common in the past, Earth still suffers impacts about once every 2,000 years from asteroids the size of a football field. Comets are made of ice, dust, and rock and form tails when close to the sun as their ices sublimate. Meteors are flashes of light seen when meteorids burn up in Earth's atmosphere, meteorites are meteorids that survive entry and hit the ground.

1. Comets, Meteors, Asteroids
Always duck for Comets

2. Asteroids
• Rocky Airless worlds
• Orbit our Sun
• Too small to be a planet
• Ten Need To Know Facts about Asteroids:
• https://solarsystem.nasa.gov/planets/profi
le.cfm?Object=Asteroidso small to be
called planets

3. Asteroids
• Come in three types:
• 1. C-types (Chondrites)
• 2. S-types (Stony)
• 3. M-types (metallic, nickel-iron)
• NEOs (near earth objects), PHAs,
(Potentially Hazardous Asteroids)

4. More Facts on Asteroids
• Asteroids aren’t the only things that hit Earth. Each day, more than 100 tons of
material from asteroids and comets falls toward Earth. Most of it is destroyed by
friction as it passes through our atmosphere. If something DOES hit the ground, it is
known as a meteorite.
• While asteroid impacts were more common in the past, they aren’t as frequent today.
• An asteroid impact some 65 million years ago contributed to the extinction of the
dinosaurs. (It was one of several factors that affected all life on Earth at that time.)
• Earth suffers an impact from an object the size of a football field about once every
2,000 years.
• A car-sized meteoroid (a piece of asteroid) falls into Earth’s atmosphere about once a
year. The result is a beautiful fireball, but the meteoroid usually burns up before
reaching the ground.
• Asteroids are rich in precious metals and other metals, as well as water.
• Some asteroids are actually blown-out comets. The ices are gone, and all that’s left is
the rocky material.
• Some asteroids have moons of their own!
• Most asteroids orbit the Sun in the Asteroid Belt, which lies between Mars and
Jupiter.
• Asteroids are also referred to as minor planets or planetoids.

5. Comets
• Comets are very small bodies
(astronomically speaking) that are made
of ice, dust, and rock.
• The tail: when comets come close to the
sun their nucleus heats up and the
methane and nitrogen ices sublimate to
gas. This forms a pair of tails when
solar winds blow the residuals away.

6. Comet Anatomy
• One tail is dust caused by dust particles
released from the ices of the nucleus.
• The other tail is a gas or ion tail. The is
the part caused by the solar wind.
• Coma: Atmosphere
• Nucleus: main part of comet.
• http://space-facts.com/comets/
• https://solarsystem.nasa.gov/planets/profi
le.cfm?Object=Comets

7. Comets

8. Meteors, Meteorites, Meteoroids
Meteor: Flash of light we see when some
type of interplanetary debris burns up in our
atmosphere
Meteoroid: The debris of rock that makes it
into the Earth’s atmosphere from space.
Meteorite: a meteoroid that has survived
the atmosphere and hits the Earth’s surface.

9. Meteors, Meteorites, Meteoroids
• http://space-facts.com/meteorites/
• https://solarsystem.nasa.gov/planets/pr
ofile.cfm?Object=Meteors