A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

g (acceleration due to gravity)
G (gravitational constant)
G star
G1.9+0.3
gabbro
Gabor, Dennis (1900–1979)
Gabriel's Horn
Gacrux (Gamma Crucis)
gadolinium
Gagarin, Yuri Alexeyevich (1934–1968)
Gagarin Cosmonaut Training Center
GAIA
Gaia Hypothesis
Galactic Club
galactic coordinates
galactic disk
galactic empire
galactic habitable zone
galactic halo
galactic magnetic field
galactic noise
galactic rotation
galactose
Galatea
GALAXIES
galaxy
galaxy classification
galaxy formation
galaxy interaction
Galaxy, The
Galaxy satellite series
Gale Crater
Galen (c. AD 129–c. 216)
galena
GALEX (Galaxy Evolution Explorer)
Galilean satellites
Galilean telescope
Galileo (Galilei, Galileo) (1564–1642)
Galileo (spacecraft)
Galileo satellite navigation system
gall
gall bladder
Galle, Johann Gottfried (1812–1910)
gallic acid
gallium
gallon
gallstone
Galois, Évariste (1811–1832)
Galois theory
Galton, Francis (1822–1911)
Galvani, Luigi (1737–1798)
galvanizing
galvanometer
game
game theory
GAMES AND PUZZLES
gamete
gametophyte
Gamma (Soviet orbiting telescope)
Gamma Cassiopeiae
gamma function
gamma globulin
gamma rays
Gamma Velorum
gamma-ray burst
gamma-ray satellites
Gamow, George (1904–1968)
ganglion
gangrene
Ganswindt, Hermann (1856–1934)
Ganymede
Gardner, Martin (1914–2010)
Garneau, Marc (1949–)
garnet
Garnet Star (Mu Cephei)
Garnet Star Nebula (IC 1396)
garnierite
Garriott, Owen K. (1930–2019)
Garuda
gas
gas constant
gas giant
gas laws
gasoline
Gaspra
Gassendi, Pierre (1592–1655)
gastric juice
gastrocnemius
gastroenteritis
gastrointestinal disease
gastrointestinal tract
gastropod
gastrulation
Gauer-Henry reflex
gauge theory
gauss (unit)
Gauss, Carl Friedrich (1777–1855)
Gaussian distribution
Gay-Lussac, Joseph Louis (1778–1850)
GCOM (Global Change Observing Mission)
Geber (c. 720–815)
gegenschein
Geiger, Hans Wilhelm (1882–1945)
Geiger-Müller counter
Giessler tube
gel
gelatin
Gelfond's theorem
Gell-Mann, Murray (1929–2019)
Geminga
Gemini (constellation)
Gemini Observatory
Gemini Project
Gemini-Titan II
gemstone
gene
gene mapping
gene transfer
general theory of relativity
generation ship
generator
Genesis (inflatable orbiting module)
Genesis (sample return probe)
genetic code
genetic disorder
genetic drift
genetic engineering
genetic marker
genetic material
genetic pool
genetic recombination
GENETICS AND HEREDITY
Geneva Extrasolar Planet Search Program
genome
genome, interstellar transmission of
genotype
gentian violet
genus
geoboard
geochronology
geode
geodesic
geodesy
Geographos
geography
GEOGRAPHY
Geo-IK
geological map
geology
GEOLOGY AND PLANETARY SCIENCE
geomagnetic field
geomagnetic storm
geometric mean
geometric sequence
geometry
GEOMETRY
geometry puzzles
geophysics
GEOS (Geodetic Earth Orbiting Satellite)
Geosat
geostationary orbit
geosynchronous orbit
geosynchronous/geostationary transfer orbit
geosyncline
Geotail (satellite)
geotropism
germ
germ cells
Germain, Sophie (1776–1831)
German Rocket Society
germanium
germination
Gesner, Konrad von (1516–1565)
gestation
Get Off the Earth puzzle
Gettier problem
geyser
g-force
GFO (Geosat Follow-On)
GFZ-1 (GeoForschungsZentrum)
ghost crater
Ghost Head Nebula (NGC 2080)
ghost image
Ghost of Jupiter (NGC 3242)
Giacconi, Riccardo (1931–)
Giacobini-Zinner, Comet (Comet 21P/)
Giaever, Ivar (1929–)
Giant Magellan Telescope
giant molecular cloud
giant planet
giant star
Giant's Causeway
Giauque, William Francis (1895–1982)
gibberellins
Gibbs, Josiah Willard (1839–1903)
Gibbs free energy
Gibson, Edward G. (1936–)
Gilbert, William (1544–1603)
gilbert (unit)
Gilbreath's conjecture
gilding
gill
gill (unit)
Gilruth, Robert R. (1913–2000)
gilsonite
gimbal
Ginga
ginkgo
Giotto (ESA Halley probe)
GIRD (Gruppa Isutcheniya Reaktivnovo Dvisheniya)
girder
glacial drift
glacial groove
glacier
gland
Glaser, Donald Arthur (1926–2013)
Glashow, Sheldon (1932–)
glass
GLAST (Gamma-ray Large Area Space Telescope)
Glauber, Johann Rudolf (1607–1670)
glaucoma
glauconite
Glenn, John Herschel, Jr. (1921–2016)
Glenn Research Center
Glennan, T(homas) Keith (1905–1995)
glenoid cavity
glia
glial cell
glider
Gliese 229B
Gliese 581
Gliese 67
Gliese 710
Gliese 86
Gliese 876
glioma
glissette
Global Astrometric Interferometer for Astrophysics (GAIA)
Global Oscillation Network Group (GONG)
Globalstar
globe
Globigerina
globular cluster
globular proteins
globule
globulin
globus pallidus
GLOMR (Global Low Orbiting Message Relay)
GLONASS (Global Navigation Satellite System)
glossopharyngeal nerve
Gloster E.28/39
glottis
glow-worm
glucagon
glucocorticoid
glucose
glucoside
gluon
Glushko, Valentin Petrovitch (1908–1989)
glutamic acid
glutamine
gluten
gluteus maximus
glycerol
glycine
glycogen
glycol
glycolysis
glycoprotein
glycosidic bond
glycosuria
glyoxysome
GMS (Geosynchronous Meteorological Satellite)
GMT (Greenwich Mean Time)
Gnathostomata
gneiss
Go
Go, No-go
goblet cell
GOCE (Gravity field and steady-state Ocean Circulation Explorer)
God
Goddard, Robert Hutchings (1882–1945)
Goddard Institute for Space Studies
Goddard Space Flight Center
Gödel, Kurt (1906–1978)
Gödel universe
Godwin, Francis (1562–1633)
GOES (Geostationary Operational Environmental Satellite)
goethite
goiter
gold
Gold, Thomas (1920–2004)
Goldbach conjecture
golden ratio (phi)
Goldin, Daniel Saul (1940–)
gold-leaf electroscope
Goldstone Tracking Facility
Golgi, Camillo (1844–1926)
Golgi apparatus
Golomb, Solomon W. (1932–2016)
golygon
gömböc
GOMS (Geostationary Operational Meteorological Satellite)
gonad
gonadotrophin-releasing hormone
gonadotrophins
Gondwanaland
Gonets
goniatite
goniometer
gonorrhea
Goodricke, John (1764–1786)
googol
Gordian Knot
Gordon, Richard Francis, Jr. (1929–2017)
Gore, John Ellard (1845–1910)
gorge
gorilla
Gorizont
Gott loop
Goudsmit, Samuel Abraham (1902–1978)
Gould, Benjamin Apthorp (1824–1896)
Gould, Stephen Jay (1941–2002)
Gould Belt
gout
governor
GPS (Global Positioning System)
Graaf, Regnier de (1641–1673)
Graafian follicle
GRAB
graben
GRACE (Gravity Recovery and Climate Experiment)
graceful graph
gradient
Graham, Ronald (1935–2020)
Graham, Thomas (1805–1869)
Graham's law of diffusion
Graham's number
GRAIL (Gravity Recovery and Interior Laboratory)
grain (cereal)
gram
gram-atom
Gramme, Zénobe Théophile (1826–1901)
gramophone
Gram's stain
Gran Telescopio Canarias
Granat
Grand Tour
grand unified theory (GUT)
Grandfather Paradox
Granit, Ragnar Arthur (1900–1991)
granite
granulation
granule
granulocyte
graph
graph theory
graphene
graphite
GRAPHS AND GRAPH THEORY
graptolite
grassland
grasslands of Africa
grasses (Poaceae)
gravel
gravimeter
gravimetric analysis
Gravitational Biology Facility
gravitational collapse
gravitational constant (G)
gravitational instability
gravitational lens
gravitational life
gravitational lock
gravitational microlensing
GRAVITATIONAL PHYSICS
gravitational slingshot effect
gravitational waves
graviton
gravity
gravity gradient
Gravity Probe A
Gravity Probe B
gravity-assist
gray (unit)
gray goo
gray matter
grazing-incidence telescope
Great Annihilator
Great Attractor
great circle
Great Comets
Great Hercules Cluster (M13, NGC 6205)
Great Monad
Great Observatories
Great Rift (in Milky Way)
Great Rift Valley
Great Wall
greater omentum
greatest elongation
Greek astronomy
Greek science
Green, George (1793–1841)
Green, Nathaniel Everett (1823–1899)
Green, Thomas Hill (1836–1882)
green algae
Green Bank Observatory
Green Bank conference (1961)
Green Bank Telescope
green flash
greenhouse effect
Green's theorem
Greg, Percy (1836–1889)
Gregorian calendar
Grelling's paradox
Griffith, George (1857–1906)
Griffith Observatory
Grignard, François Auguste Victor (1871–1935)
Grignard reagent
Grimaldi, Francesco Maria (1618–1663)
Grissom, Virgil (1926–1967)
grit
gritstone
Groombridge 34
gross
ground, electrical
ground state
ground-track
groundwater and water table
group
group theory
GROUPS AND GROUP THEORY
growing season
growth
growth hormone
growth hormone-releasing hormone
growth plate
Grudge, Project
Gruithuisen, Franz von Paula (1774–1852)
Grus (constellation)
Grus Quartet
GSLV (Geosynchronous Satellite Launch Vehicle)
g-suit
G-type asteroid
Guericke, Otto von (1602–1686)
guanine
Guiana Space Centre
guidance, inertial
guided missile
guided missiles, postwar development
Guillaume, Charles Édouard (1861–1938)
Gulf Stream (ocean current)
Gullstrand, Allvar (1862–1930)
gum
Gum Nebula
gunpowder
Gurwin
Gusev Crater
gut
Gutenberg, Johann (c. 1400–1468)
Guy, Richard Kenneth (1916–2021)
guyot
Guzman Prize
gymnosperm
gynecology
gynoecium
gypsum
gyrocompass
gyrofrequency
gyropilot
gyroscope
gyrostabilizer
Gyulbudagian's Nebula (HH215)