Ancient Life on Mars
Glossary
achondrite
- A stony meteorite that lacks chondrules, which are small round
granules of extraterrestrial origin found in most meteorites.
anorthite - A feldspar mineral, rich in calcium, that occurs
in igneous rocks.
ANSMET
- The Antarctic Search for Meteorites, a group of meteorite
hunters sponsored annually by the U.S., with funding provided
by the National Science Foundation and NASA. The first ANSMET
team joined Japanese explorers to hunt for meteorites in Antarctica
in 1976, and more than 7500 meteorite samples have been collected
since then.
archaeon
- A type of bacteria that has different chemicals from common
bacteria.
basalt
- A common type of fine-grained, volcanic rock, composed primarily
of the minerals pyroxene and plagioclase.
chondrite
- A meteorite that contains chondrules, which are small round
granules of extraterrestrial origin found in most meteorites.
chromite
- An opaque black mineral containing iron and chromium, FeCr2O4.
dendritic
- In the shape of a tree, with many sets of smaller and smaller
branches.
eucaryote
- Also spelled eukaryote; a single-celled or multicellular organism
whose cells contain a distinct membrane-bound nucleus.
fusion
crust - A thin glassy coating, usually black
and rarely exceeding one millimeter in thickness, formed on
the surface of a meteorite by frictional heating during atmospheric
flight.
greigite
- A dark mineral with spinel-like structure, Fe3S4.
igneous
- Term used to describe a rock or mineral that solidified from
molten or partly molten material, i.e., from a magma; also used
to describe processes leading to, related to, or resulting from
the formation of such rocks.
iron
meteorite
- A general name for meteorites consisting primarily of an alloy
of iron and nickel metal.
magnesite
- A white to grayish, yellow, or brown mineral, MgCO3.
magnetite
- A black, cubic, strongly magnetic, opaque mineral, Fe3O4.
meteorite
- An extraterrestrial rock that has fallen to Earth. Most meteorites
are pieces of asteroids; a few meteorites are known to come
from the Moon or from Mars.
polycyclic
aromatic hydrocarbons - Commonly referred to
as PAHs, these compounds form easily by heating almost any organic
or carbon-rich material; for example, PAHs form when red meat
is burnt, and they have been found to be linked to cancer. Aromatic
hydrocarbons contain flat rings of carbon atoms, usually six
carbons arranged in a hexagon; polycyclic means that the molecules
contain more than one "aromatic" ring.
pyrrhotite
- A yellow-tan iron sulfide mineral, approximately FeS.
siderite
- An orangish to black or brown mineral, FeCO3.
SNC
meteorite
- One of the 12 meteorites thought to have come from Mars. The
letters SNC stand for the three types of meteorites: Shergottites,
Nakhlites, and Chassigny.
stony
meteorite - Meteorites consisting largely or
entirely of silicate minerals (chiefly olivine, pyroxene, and
plagioclase); e.g., chondrites and achondrites. Stony meteorites
constitute more than 90% of all meteorites that have been found
on Earth.