Page 72 - (DK) Eyewitness - Mars

Glossary

AMAZONIAN AGE The most recent Martian ELLIPSE The egg-shaped orbit of a planet, JOVIAN PLANET Any one of the four
historical period, beginning about 2.5 billion moon, or a man-made satellite. The orbits of gaseous outer planets: Jupiter, Saturn,
years ago and continuing until today. the planets are ellipses, not circles. Uranus, and Neptune.

ASH Fine-grained material produced by a EROSION The wearing away of soil or rock as LABYRINTHUS An intersecting network
volcanic eruption and thrown into the a result of the action of wind and water. of valleys.
atmosphere in a cloud.
EXPLOSIVE ERUPTION A violent volcanic LANDER Part of a spacecraft that detaches
ASTEROID Any of the small celestial bodies eruption that throws debris high into the air. and lands on a planet.
with orbits between Mars and Jupiter. The resulting fast-flowing lava often builds up
a steep cone. LAVA Molten rock that flows from
ASTRONOMY Generally, the study of the underground onto the surface.
planets and stars, and the laws that govern FLYBY The flight of a spacecraft, generally
their movements. termed a probe, which passes a planet without LIMB The outer edge, or horizon, of a
attempting to land or to orbit. celestial body, usually as viewed from
above the surface.
GEOCENTRIC Earth-centered: the theory
that the Earth is the center of the Solar MAGMA Molten rock within the crust of a
System, and the planets and Sun revolve planet that can push through to the surface
around the Earth. and become lava.
HELIOCENTRIC Sun-centered: the theory MANTLE The area inside a planet, below the
that the Sun is the center of the Solar System, crust and surrounding the core.
and the planets revolve around it.
METEOR The glow seen when a meteoroid
HESPERIAN AGE The middle period in burns in the atmosphere, often termed
Olympus Mons caldera Martian history, beginning about 3.5 billion a shooting star.
years ago and lasting until about 2.5 billion
BIOSPHERE A natural system that contains years ago. METEORITE The part of a meteoroid that
all the elements required for life, including rain survives the fall through a planet’s atmosphere
and warmth and the capacity for producing air HOT SPOT A point on a planet’s surface and strikes the surface.
that can be breathed. that is warmer than its surroundings and
could be heat from a rising plume in the METEOROID A small rock in space.
CALDERA A large depression at the top of a planet’s mantle.
volcano. Volcanic calderas are produced by the MONS A mountain, often a volcano.
collapse of a magma chamber or by an ICE TOWERS Frozen formations created by
explosive eruption the venting of steam from under the Antarctic NOACHIAN The first Martian historical
that removes the surface ice; inside temperatures are warmer period, beginning about 4.5 billion years ago
upper part of than the outside air. and lasting until about 3.5 billion years ago.
the volcano.
IMPACT CRATER A basinlike depression OPPOSITION The relationship when a
CHASMA A gash caused by the crash of an object falling from celestial body passes between another body
in the land’s space; usually surrounded by a rim and by and the Sun. The Earth and Mars are in
surface, often a ejecta that lands all around. opposition when Earth passes between Mars
deep canyon. and the Sun, placing Mars on the opposite
side of the Earth from the Sun.
CONE The peak of
a volcano, formed
by lava pouring
Ganges Chasma down the sides
and cooling into
steep slopes.
CORE The center of a planet; the cores of
Earth and Mars are mostly iron.
CRATER A depression, usually with a rim,
formed by the impact of a meteorite. Also, a
depression around the opening or vent of
a volcano.
CRUST The outer layer of a planet, above the
mantle and core.
DUST DEVIL A twisting updraft of wind that
raises dust and soil into a small cyclone and
moves across the ground.

EJECTA Material, such as mud or fragmented
rock, that is thrown out of an impact crater
during its formation. Painting of Noctis Labyrinthus

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