- colorless gaseous compound composed of nitrogen and hydrogen
Asteroid Belt
- collection of asteroids orbiting between Mars and Jupiter
asteroids
- rocky remains from the formation of the solar system
atmosphere
- gaseous layer surrounding a planet
C
carbon dioxide
- colorless, odorless gas; when frozen, known as dry ice
century
- 100-year interval
Ceres
- largest asteroid in the asteroid belt, now considered a dwarf planet
circumference
- distance around a circular shape similar to a perimeter
climate
- general patterns of weather over time in a given region
coma
- cloudy envelope of dust and gas around the nucleus of a comet
comet
- Body of gas, ice, and dust that orbits the sun
compound
- a molecule made of atoms of different elements; two or more atoms joined together chemically
D
Dawn
- NASA space mission to investigate the asteroids Ceres and Vesta
debris
- scattered remains of something broken down or destroyed
decade
- 10-year interval
diameter
- the distance through a circle or sphere from one side to the other
dwarf planet
- small planet-like object orbiting the sun
E
environment
- the surroundings or conditions in which an organism lives
extinction
- the complete disappearance of a type of organism
F
friction
- rubbing of one surface against another
G
gravitational pull
- pull of gravity between masses
I
impact crater
- depression in the ground created by the impact of an asteroid, meteoroid or comet
irregular
- not even or uniform in shape
K
Kuiper Belt
- region of space on the edge of our solar system where comets originate
M
meteor
- a meteoroid that has entered the earth's atmosphere
meteorite
- The remains of a meteoroid that has fallen to the earth
meteoroid
- small rocky body traveling through space
methane
- simple hydrocarbon gas released during decomposition
mitigate
- to lessen or reduce the effect
N
nucleus
- a collection of materials at center of a comet
O
Oort Cloud
- region of space beyond Pluto where comets lie
P
Perseid Meteor Shower
- In August the earth moves through a field of debris and the resulting meteors that burn up in the atmosphere can be seen
R
radar
- a system for detecting the presence, distance and speed of objects such as ships, aircraft, or space bodies, by sending out radio waves that are reflected off the object back to the source
Rosetta Mission
- International mission between ESA and NASA to study a comet
S
solar system
- the sun, planets, moons, asteroids, meteoroids, comets and additional matter between
spherical
- shaped like a sphere or a ball
T
tail
- The venting of gases that show following the heating of a comet by the sun's energy
trough
- a ditch or long shaped depression
V
Vesta
- second most massive asteroid in the asteroid belt
