E
Glossary and Acronyms
1-D | one-dimensional |
3-D | three-dimensional |
ABL | Automated Biological Laboratory |
accretion (astronomical) | the growth of a massive object by gravitationally attracting more matter, typically gaseous matter, in an orbiting accretion disk, causing the object to grow larger, hotter, and more luminous. |
accretion (meteorological) | the process of accumulation of frozen water as precipitation over time as it descends through the atmosphere, the basis of cloud formation |
adaptive optics | a technology used to improve the performance of optical systems by reducing the effect of incoming wavefront distortions by deforming a mirror in order to compensate for the distortion |
aeolian processes | abrasion, erosion, transportation, and deposition by wind |
AI | artificial intelligence |
ALH | Allan Hills |
ALMA | Atacama Large Millimeter Array |
APF | Automated Planet Finder |
ARC | Ames Research Center |
Archean | the second geologic eon on Earth, occuring after the Hadean and lasting from 4 billion to 2.5 billion years ago |
ARIEL | Atmospheric Remote-sensing Infrared Exoplanet Large-survey |
ASTERIA | Arcsecond Space Telescope Enabling Research in Astrophysics |
AU | Astronomical unit, one Earth-Sun distance |
Bayesian | a statistical framework in which Bayes’ theorem is used to update the probability for a hypothesis as more evidence or information becomes available, e.g., the probability of X, given the presence of Y |
biosignature | a detectable sign, e.g., chemical or morphological, that supports the likelihood of the presence of life |
biosphere | the layer of a planet where life exists; the sum total of a planet’s ecological systems |
carbonaceous chondrites | a rare and primitive type of meteorites. In addition to carbon, silicates, oxides, and sulfides, most contain water or minerals that have been altered in the presence of water and some contain organic compounds |
cementation | the process in which ions carried in groundwater chemically precipitate to form new crystalline minerals between sedimentary grains, thereby binding the grains together |
CERN | European Organization for Nuclear Research |
chemoautotroph | an organism, typically bacteria or archaea, that is able to derive energy from chemical reactions of inorganic molecules |
CHNOPS | carbon, hydrogen, nitrogen, oxygen, phosphorus, sulfur |
chromatography | the collective term for a set of laboratory techniques for the separation of mixtures. For example, in gas chromatography, the sample mixture is vaporized, injected into a stream of carrier gas, and separated into its component compounds |
COSPAR | Committee on Space Research |
Cretaceous | the geological period ranging from 145-72 Mya, a subset of the Mesozoic era, ending with the the extinction of the non-Avian dinosaurs |
cryovolcano | colloquially known as an ice volcano, a geologic feature which erupts volatiles such as water, ammonia, or methane instead of molten rock |
diagenesis | the change of sedimentary rock during and after rock formation at temperatures and pressures less than what is required for the formation of metamorphic rocks but excludes surface alteration (weathering). |
diapirism | a type of geologic intrusion in which a more mobile and ductily deformable material is forced into brittle overlying rocks |
diurnal cycle | any pattern that recurs every 24 hours |
DNA | deoxyribonucleic acid; the genetic biopolymer of most terran organisms |
DRD | Dual Reciprocating Drilling |
dynamic habitability | the relationship between the likelihood of the presence of life, the age of the stellar system and the age of the planet. Planets may only be habitable during certain stages of their lifetime. Also known as punctuated habitability |
E-ELT | European Extremely Large Telescope |
ELT | Extremely Large Telescope |
enantiomer | one of an isometric pair of crystalline forms or chemical compounds whose molecules are a nonsuperimposable mirror image of the other, like right and left hands |
ESA | European Space Agency |
ESI | Earth Similarity Index |
ESPRESSO | Echelle Spectrograph for Rocky Exoplanet and Stable Spectroscopic Observations |
eutectic | a mixture of chemical compounds or elements that have a single chemical composition that solidifies at a lower temperature than any other composition made up of the same ingredients. |
exoring | a ring system around an exoplanet |
fabrics | the spatial and geometric configuration of all the elements that make up a rock |
FAST | Five-hundred-meter Aperture Spherical radio Telescope |
FDL | Frontier Development Lab |
felsic | igneous rocks enriched in lighter elements (e.g., silicon, oxygen, aluminum, sodium, and potassium) that form feldspar and quartz |
FNIH | Foundation for the National Institutes of Health |
fractionation (geochemical) | separation of a complex mixture in successive stages into fractions, each of which is enriched in one of the components of the mixture |
fractionation (isotopic) | the enrichment of one isotope, relative to another isotope, changing their ratios; can occur during a phase transition |
Ga | Gigayear, one billion years |
GCM | general circulation model |
GCMS | gas chromatography-mass spectrometry |
geodynamics | a subfield of geophysics dealing with forces, torques, and motions of Earth. It applies chemistry and mathematics to the understanding of how mantle convection leads to plate tectonics and other geologic phenomena |
geosphere | the solid layers of a planet, including its core |
Gibbs free energy | a measure of the maximum available work that can be derived from any system under conditions of constant temperature and pressure |
GMT | Giant Magellan Telescope |
GOE | Great Oxidation Event |
GPR | ground-penetrating radar |
GPS | global positioning system |
GSMT | giant segmented mirror telescope |
HabEx | Habitable Exoplanet Observatory |
Hadean | the first geologic eon on Earth, lasting from the planet’s formation 4.540 billion years ago to 4 billion years ago |
halophile | an organism that thrives in salty environments |
HITE | habitability index for transiting exoplanets |
homologation | any chemical reaction that converts the reactant into the next member of the homologous series. A homologous series is a group of compounds that differ by a constant unit, generally a CH2 group. |
HST | Hubble Space Telescope |
hydrogenation | to treat with hydrogen; a chemical reaction between molecular hydrogen and another compound or element |
ICSU | International Council for Science |
in situ | Latin for “in place,” referring to an analysis where the phenomenon of study occurred, in contrast to a remote or a sample return analysis |
informational heteropolymer | A polymer, containing more than one type of subunit, capable of encoding genetic information. |
InSight | Interior Exploration using Seismic Investigations, Geodesy and Heat Transport |
irradiance | See “Radiation flux;” also see “Spectral or Stellar Irradiance” |
ITER | International Thermonuclear Experimental Reactor |
JAXA | Japan Aerospace Exploration Agency |
jovian | pertaining to the planet Jupiter, or similar in size to a gas giant |
JUICE | Jupiter Icy Moons Explorer |
JWST | James Webb Space Telescope |
Ka | one thousand years |
KPF | Keck Planet Finder |
LC-MS/MS | liquid-chromatography tandem mass spectrometry |
LDMS | laser desorption-mass spectrometry |
LHS | Luyten Half-Second catalog |
LIBS | laser-induced breakdown spectroscopy |
lithology | the study of rocks’ physical characteristics and formation |
lithosphere | the outermost shell of a rocky planet; on Earth, the lithosphere is the crust and the relatively elastic portion of the upper mantle |
LUVOIR | Large UV/Optical/IR Surveyor |
Ma | one million years |
machine learning | a technique used in artificial intelligence computer science, in which programs are statistically trained on known data and gain the ability to correctly analyze new data |
main sequence | the stage of stellar evolution in which a star spends the majority of its lifetime, characterized by gradually increasing temperature until it becomes a red giant |
MALDI-TOF | matrix-assisted laser desorption/ionization time-of-flight |
MarCO | Mars Cube One |
MEPAG | Mars Exploration Program Analysis Group |
metabolism | a set of chemical reactions in a cell by which food is built up (anabolism) into living protoplasm and by which protoplasm is broken down (catabolism) into simpler compounds with the exchange of energy; needed by life to maintain structure and grow |
ML | machine learning |
MOMA | Mars Organic Molecular Analyzer |
monomer | a subunit of a polymer, when bonded to other identical subunits |
Monte Carlo methods | a computational algorithm that uses repeated random sampling to reach deterministic results |
motility | the ability of an organism to move independently |
MSR | Mars Sample Return |
NAI | NASA Astrobiology Institute |
NASA | National Aeronautics and Space Administration |
NASEM | National Academies of Sciences, Engineering, and Medicine |
neural network | a type of machine learning characterized by the presence of interconnected adjustable nodes, each which take an input and deterministically produce an output. The programmer is not necessarily able to interpret the intermediate “hidden layer” logics used by the program, as only its outputs are measurable |
NExSS | Nexus for Exoplanet System Science |
ngVLA | Next Generation Very Large Array |
NIH | National Institutes of Health |
nitrile | an organic compound containing a cyanide group bound to an alkyl group |
NOAA | National Oceanic and Atmospheric Administration |
Noachian | a span in Martian geologic history approximately 4100 to 3700 Mya characterized by heavy asteroid bombardment and possibly abundant liquid water |
NOAO | National Optical Astronomy Observatory |
NRAO | National Radio Astronomy Observatory |
NRC | National Research Council |
NSF | National Science Foundation |
nucleobase | the heterocycles (i.e., ring structures made of two elements) guanine, cytosine, adenine, and thymine that form the base pairs between the two polymers of a DNA double helix |
occultation | an event that occurs when one object is hidden by another object that passes between it and the observer; contrast with a transit, when a smaller object passes in front of a larger one |
one-lid planet | a type of tectonics thought to exist on Mars, in which a single stagnant crust sits atop the mantle, rather than the active plates on modern Earth |
OPAG | Outer Planets Assessment Group |
OPP | Office of Planetary Protection |
OSIRIS-REx | Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer |
OST | Origins Space Telescope |
PCR | polymerase chain reaction |
photolysis | the decomposition of a chemical substance into simpler units as a result of the action of light |
photometry | the measurement of the brightness or intensity of light, as perceived by the human eye |
phyllosilicates | a family of minerals featuring parallel sheets of silicate; examples include clays, mica, and serpentine |
piezophile | an organism adapted to living in high-pressure environments, such as hydrothermal vents |
polymerize | of molecules, combine to form large chains and networks |
Proterozoic | the third geologic eon on Earth, occuring after the Archean and lasting from approximately 2.4 billion to 0.5 billion years ago. It was the last eon within the Precambrian supereon |
pseudo fossil | inorganic objects, markings, or impressions that might be mistaken for a fossil |
radiation flux | the flow of radiant energy per unit time onto unit area (typically measured in watts per square meter) |
radiolysis | the breakdown of molecules as a result of exposure to ionizing radiation |
Raman spectroscopy | a technique for determining the composition of a material by measuring the change in energy of laser light scattered off the sample |
rheology | the branch of physics that deals with the deformation and flow of matter, especially the non-Newtonian flow of liquids and the plastic flow of solids |
RNA | ribonucleic acid |
ROC | receiver-operator characteristic |
RSL | recurring slope lineae |
saltation | from Latin saltus “jump,” a type of particle transport occurring when loose materials are removed from a bed and carried by a fluid |
scarp | a steep slope that occurs from erosion or faulting, leaving two relatively level areas of differing elevations |
Schreibersite | a iron nickel phosphide mineral with an (Fe, Ni)3P repeating unit. It is found in metallic meteorites and in only one-known location on Earth. |
seep | a place where water, usually groundwater, reaches the Earth’s surface from an underground aquifer. |
serpentinization | a metamorphic process in which ultrabasic rocks react with water to create a variety of hydrous, magnesium-iron phyllosilicate minerals known collectively as serpentine; the process is endothermic and results in the liberation of hydrogen, methane, and hydrogen sulfide |
SETI | Search for Extraterrestrial Intelligence |
SPARCS | Star-Planet Activity Research CubeSat |
spectral irradiance or stellar irradiance | the flux of radiant energy per unit area per unit frequency or unit wavelength (typically measured in watts per square meter per hertz or watts per cublic meter, respectively) |
SSB | Space Studies Board |
starlight suppression | an astronomical technique which blocks the light from a star in order to see the much less luminous exoplanets orbiting it, related to the use of coronagraphs and starshades |
stellar type | a classification of a star based on characteristics such as temperature, luminosity, composition, and size; ranges from the rare type O, the largest and hottest, to the common type M, far smaller |
stromatolites | layered growth structures formed by the trapping, binding, and cementation of sedimentary grains by microorganisms, especially cyanobacteria; stromatolites provide records of life on Earth more than 3.5 billion years ago |
synchrotron radiation | the electromagnetic radiation emitted when charged particles are accelerated radially; usable as a source for X-ray spectroscopy |
taphonomic | the branch of paleontology that deals with the processes of fossilization |
technosignature | a detectable sign of technologically advanced life |
TESS | Transiting Exoplanet Survey Satellite |
TGO | Trace Gas Orbiter |
TMT | Thirty Meter Telescope |
TRAPPIST | Transiting Planets and Planetesimals Small Telescope |
uniformitarianism | the foundational theory that changes in Earth’s crust throughout geological history have resulted from the same continuous and uniform processes |
USB | universal serial bus |
UV | ultraviolet |
VLT | Very Large Telescope |
WFIRST | Wide Field Infrared Survey Telescope |
WIYN | Wisconsin-Indiana-Yale-NOAO |
XUV | X-ray ultraviolet |
This page intentionally left blank.