The document compares and contrasts comets and asteroids. It notes that comets are made of ice and dust while asteroids are made of rocks and metals. Comets form tails when passing through the inner solar system, while asteroids do not form tails. Comets typically have more elliptical and tilted orbits than asteroids and planets, and originate from the Kuiper Belt or Oort Cloud, while asteroids typically remain in the asteroid belt between Mars and Jupiter.

1. Graphic Organizer
Comparison of comets and asteroids
Comets Asteroids
Comet Hyakutake Asteroid: Artist’s concept
Made up of ice and dust Made up of rocks and metals
Form tails when they pass through Do not form tails
the inner solar system
Typically have orbits that are very Typically have orbits that are much
much more elliptical and tilted than more elliptical and tilted than those
those of the planets of the planets
Usually orbit the Sun in two regions: Usually orbit the Sun in the asteroid
the Kuiper Belt (about 30 to 50 AU belt, a region between Mars and
from the Sun) and the Oort Cloud Jupiter
(extending outward to about 50,000
AU from the Sun)
Typically remain in the outermost Typically remain in the asteroid belt,
regions of the solar system (beyond a region between Mars and Jupiter
the orbit of Neptune), but can pass
through the inner solar system if their
orbits are elliptical enough
May or may not orbit the Sun in the Orbit the Sun in the same direction
same direction as the planets as the planets
(Table continued, next page)
www.nasa.gov Page 1

2. Graphic Organizer
Comparison of comets and asteroids (cont’d)
(Continued from previous page)
Comets Asteroids
Usually undetectable to the Virtually undetectable to the
naked eye; may become visible naked eye
while passing through the inner
solar system
Meteor showers usually occur when Produce meteors (streaks of light)
Earth passes through a stream of upon entering Earth’s atmosphere;
particles left behind by a comet in produce meteorites if they survive
its orbit. the trip through Earth’s atmosphere
(either whole or in part) and hit
the ground
www.nasa.gov
amazing-space.stsci.edu
Page 2