Sentences with phrase «planet and star formation»

This portion of the spectrum, which is more energetic than most radio waves yet less energetic than visible and infrared light, holds the key to understanding a great variety of fundamental processes, including planet and star formation, and the formation and evolution of galaxies and galaxy clusters in the early Universe.

«Our result feels to me like a glimpse into a new era of planet and star formation science.

By throwing a wrench into the theories of planet and star formation, brown dwarfs may help fix them

Not exact matches

Of the trillions of stars (most of which probably have some rocky planets orbiting it from the leftovers of its formation) there are probably plenty of planets orbiting their stars at the same distance as ours with varying conditions, ours just happened to be right for humans to evolve and be here today.

British physicist P.C.W. Davies has concluded that the odds against the initial conditions being suitable for the formation of stars, which are necessary for planets and thus life, is a one followed by at least a thousand billion billion zeros.

The formation of the stars, the creation within those stars of the periodic table of elements and the formation of the planets and planetary systems can be seen as the «free will principle» of the material dimension of the universe.

He then went on to tell us about the history of the universe from the huge explosion of matter and energy (the Big Bang) through the formation of stars and then rocky planets on which complex chemicals were produced, leading to the synthesis of the first molecules of life and the emergence of the plant and animal kingdoms.

From all this, one can see that Colson's appeal to the Big Bang to show that astrophysics can not yield «natural explanations» of star and planet formation is utterly unfounded in science, philosophy, or theology.

Is it possible that a man of Barr's education really wonders why some of us would not accept a natural explanation for the formation of stars and planets in light of discoveries made possible by the Hubble telescope?

We will also apply for more observation time on the ALMA telescope to study the planet - forming discs in even higher resolution to get more detailed information about their chemical composition,» says Jes Jørgensen, associate professor in the research group Astrophysics and Planetary Science at the Niels Bohr Institute and Centre for Star and Planet Formation, University of Copenplanet - forming discs in even higher resolution to get more detailed information about their chemical composition,» says Jes Jørgensen, associate professor in the research group Astrophysics and Planetary Science at the Niels Bohr Institute and Centre for Star and Planet Formation, University of CopenPlanet Formation, University of Copenhagen.

Carr and the other research team members set out to study the protoplanetary disk around a star known as HD 100546, and as sometimes happens in scientific inquiry, it was by «chance» that they stumbled upon the formation of the planet orbiting this star.

Unlike the ATA, which was devoted primarily to finding intelligent life, the SKA will help study general relativity, star and planet formation, and more.

«If we can understand the chemical complexity of these ices in the molecular cloud, and how they evolve during the formation of a star and its planets, then we can assess whether the building blocks of life should exist in every star system,» said Melissa McClure of the Universiteit van Amsterdam, the principal investigator on a research project to investigate cosmic ices.

John Tobin of the National Radio Astronomy Observatory in Charlottesville, Virginia, and colleagues found that the disc's motion mirrors the way planets orbit stars, hinting that it has all the right moves for planet formation (Nature, doi.org/jxm).

Meanwhile, astronomers have observed the formation of organic chemicals in stellar nebulae and discovered over 70 Jupiter - sized extrasolar planets circling nearby stars.

«Ours isn't the only group looking for planets around young stars, and my hope is that astronomers can find enough of them to shed light on some of the nagging questions about planet formation,» Johns - Krull said.

«That's been called into question over the past decade, and many new ideas have been offered, but the bottom line is that we need to identify a number of newly formed planets around young stars if we hope to fully understand planet formation.»

«You build bigger, you go fainter, you go deeper, and you'll have a shot at a major discovery,» explains Pudritz, «So building these larger machines will no doubt allow us to study the birth of the first galaxies and even planet formation around distant stars.

Using data from the Hubble Space Telescope, researchers estimated the rates of past star and planet formation in the universe, which is now about 13.8 billion years old.

Scientists are looking closer at brown dwarfs to learn more about the formation of stars and planets.

Their work, which Hassanzadeh will present at the annual meeting of the American Physical Society's Division of Fluid Dynamics in Pittsburgh on November 25, also provides insight into persistent ocean eddies and vortices that contribute to star and planet formation.

Two recent studies show that the formation of planets may leave detectable chemical signatures in their host stars, a finding that could help scientists zero in on planetary systems even more quickly and speed the search for worlds similar to Earth.

The leftover material from star formation flattens out as it spins and clumps together to make planets.

«Even using just the first 16 of its 66 antennas, ALMA will already surpass the capabilities of all existing telescopes of its kind, and will provide new insights into star formation as well as the origins of galaxies and planets,» says Paola Andreani, manager of the European ALMA Regional Centre at the European Southern Observatory.

We talked about theoretical stuff to explain the planets and the stars and the formation of the universe.»

This supports the idea that a young planetary system can inherit the chemical composition of its parent star - forming cloud and opens up the possibility that organohalogens could arrive on planets in young systems during planet formation or via comet impacts.

The combined gravity of the second and third stars would have kept the gas and dust disk of the primary star at a maximum radius of 200 million kilometers — too close for the formation of giant planets.

«ALMA has shown us amazing images and never - before - seen views of the rings and gaps around young stars that could be the hallmarks of planet formation.

It will pick up the dim, highly reddened light emitted by the first stars in the universe and answer fundamental questions about galaxy formation, alien planets, and the geometry of the cosmos.

Both are thought to be important for understanding the formation and evolution of galaxies, and thus to some degree important for the formation and evolution of everything galaxies contain — including stars, planets and people.

Several years ago Loeb and two colleagues performed a speculative calculation estimating the interstellar abundance of «Oumuamua - sized space rocks based on the density of stars in the Milky Way and the vagaries of planet formation.

Today, this dust is plentiful and is a key building block in the formation of stars, planets and complex molecules; but in the early Universe — before the first generations of stars died out — it was scarce.

The resonance may date back to the planets» births and thus may yield insights into the formation of giant planets around other stars, including our sun.

This means that the disc may not be leftover debris from the formation of planets after all, and that the star may instead still be forming planets.

In research published this week in Astrophysical Journal Letters, Dr Zoe Leinhardt and colleagues from Bristol's School of Physics have completed computer simulations of the early stages of planet formation around the binary stars using a sophisticated model that calculates the effect of gravity and physical collisions on and between one million planetary building blocks.

In addition many theoretical studies of the formation of planetary systems out of contracting clouds of interstellar gas and dust imply that the birth of planets frequently if not inevitably accompanies the birth of stars.

They blazed brilliantly, but within just a few million years they burned out and exploded, spewing heavy elements that helped seed the formation of succeeding generations of stars and planets.

After the initial discovery of brown dwarfs in 1995, scientists quickly realised that they are a natural by - product of processes that primarily lead to the formation of stars and planets.

The new study suggests that the «hot Jupiter» WASP - 18b, a massive planet that orbits very close to its host star, has an unusual composition, and the formation of this world might have been quite different from that of Jupiter as well as gas giants in other planetary systems.

The formation of a stratosphere layer in a planet's atmosphere is attributed to «sunscreen» - like molecules, which absorb UV and visible radiation coming from the star and then release that energy as heat.

Planets are thought to form from discs of gas and dust left over from the formation of the parent star.

Dust plays an extremely important role in the universe — both in the formation of planets and new stars.

«Herschel has offered us a new view of the hitherto hidden universe, pointing us to a previously unseen process of star birth and galaxy formation, and allowing us to trace water through the universe from molecular clouds to newborn stars and their planet - forming discs and belts of comets,» ESA's Herschel project scientist Göran Pilbratt said in a statement.

Bohr Institute and the Centre for Star and Planet Formation at the University of Copenhagen, Denmark.

In recent years, evidence has grown that binary star systems can host planets, and observations suggest that planet formation is common around both tight and widely separated binary stars.

My research focuses on the formation of terrestrial planets in our Solar System and around other stars, especially with regards to the delivery of water and other biologically - important materials.

By the time a young star is a few million years old, this disk has largely dissipated and planet formation is mostly complete.

STScI / NASA press releases: Hubble Makes the First Precise Distance Measurement to an Ancient Globular Star Cluster Hubble Unmasks Ghost Galaxies Deepest View of Space Yields Young Stars in Andromeda Halo Hubble Identifies Source of Ultraviolet Light in an Old Galaxy ESA press releases: Hubble Unmasks Ghost Galaxies Four Unusual Views of the Andromeda Galaxy Public speaking: On the Trail of the Missing Galaxies High - Level Science Products from Large and Treasury Programs: GO - 9453: The Age of the Andromeda Halo (126 orbits) GO - 10265: The Formation History of Andromeda (107 orbits) GO - 10816: The Formation History of Andromeda's Extended Metal - Poor Halo (128 orbits) GO - 11664 / 12666: The WFC3 Galactic Bulge Treasury Program: Populations, Formation History and Planets (56 orbits) GO - 12549: The Formation History of the Ultra-Faint Dwarf Galaxies (113 orbits)

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 anticenter galactic bulge galactic center Galactic Club galactic coordinates galactic disk galactic empire galactic equator galactic habitable zone galactic halo galactic magnetic field galactic noise galactic plane galactic rotation galactose Galatea GALAXIES galaxy galaxy cannibalism galaxy classification galaxy formation galaxy interaction galaxy merger 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 Europa Mission (GEM) 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 Cassiopeiae star 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 «garbage theory», of the origin of life Gardner, Martin (1914 — 2010) Garneau, Marc (1949 ---RRB- garnet Garnet Star (Mu Cephei) Garnet Star Nebula (IC 1396) garnierite Garriott, Owen K. (1930 ---RRB- Garuda gas gas chromatography gas constant gas giant gas laws gas - bounded nebula gaseous nebula gaseous propellant gaseous - propellant rocket engine gasoline Gaspra (minor planet 951) Gassendi, Pierre (1592 — 1655) gastric juice gastrin gastrocnemius gastroenteritis gastrointestinal tract gastropod gastrulation Gatewood, George D. (1940 ---RRB- Gauer - Henry reflex gauge boson 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 ---RRB- GEM «gemination,» of martian canals Geminga Gemini (constellation) Gemini Observatory Gemini Project Gemini - Titan II gemstone gene gene expression gene mapping gene pool gene therapy gene transfer General Catalogue of Variable Stars (GCVS) general precession general theory of relativity generation ship generator Genesis (inflatable orbiting module) Genesis (sample return probe) genetic code genetic counseling genetic disorder genetic drift genetic engineering genetic marker genetic material genetic pool genetic recombination genetics GENETICS AND HEREDITY Geneva Extrasolar Planet Search Program genome genome, interstellar transmission of genotype gentian violet genus geoboard geode geodesic geodesy geodesy satellites geodetic precession Geographos (minor planet 1620) geography GEOGRAPHY Geo - IK geologic time 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 (GTO) 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 ---RRB- Giacobini - Zinner, Comet (Comet 21P /) Giaever, Ivar (1929 ---RRB- giant branch 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 ---RRB- 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 ---RRB- glass GLAST (Gamma - ray Large Area Space Telescope) Glauber, Johann Rudolf (1607 — 1670) glaucoma glauconite Glenn, John Herschel, Jr. (1921 ---RRB- Glenn Research Center Glennan, T (homas) Keith (1905 — 1995) glenoid cavity glia glial cell glider Gliese 229B Gliese 581 Gliese 67 (HD 10307, HIP 7918) Gliese 710 (HD 168442, HIP 89825) Gliese 86 Gliese 876 Gliese Catalogue glioma glissette glitch 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 ---RRB- gold - leaf electroscope Goldstone Tracking Facility Golgi, Camillo (1844 — 1926) Golgi apparatus Golomb, Solomon W. (1932 — 2016) golygon 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 ---RRB- Graham, Thomas (1805 — 1869) Graham's law of diffusion Graham's number GRAIL (Gravity Recovery and Interior Laboratory) grain (cereal) grain (unit) gram gram - atom Gramme, Zénobe Théophile (1826 — 1901) gramophone Gram's stain Gran Telescopio Canarias (GTC) 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 grass grassland gravel graveyard orbit 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 gradient stabilization Gravity Probe A Gravity Probe B gravity - assist gray (Gy) 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 Red Spot Great Rift (in Milky Way) Great Rift Valley Great Square of Pegasus Great Wall greater omentum greatest elongation Green, George (1793 — 1841) Green, Nathaniel E. Green, Thomas Hill (1836 — 1882) green algae Green Bank Green Bank conference (1961) Green Bank Telescope green flash greenhouse effect greenhouse gases 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 grike Grimaldi, Francesco Maria (1618 — 1663) Grissom, Virgil (1926 — 1967) grit gritstone Groom Lake Groombridge 34 Groombridge Catalogue gross ground, electrical ground state ground - track 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 (NGC 7552, NGC 7582, NGC 7590, and NGC 7599) GSLV (Geosynchronous Satellite Launch Vehicle) g - suit G - type asteroid Guericke, Otto von (1602 — 1686) guanine Guiana Space Centre guidance, inertial Guide Star Catalog (GSC) guided missile guided missiles, postwar development Guillaume, Charles Édouard (1861 — 1938) Gulf Stream (ocean current) Gulfstream (jet plane) Gullstrand, Allvar (1862 — 1930) gum Gum Nebula gun metal gunpowder Gurwin Gusev Crater gut Gutenberg, Johann (c. 1400 — 1468) Guy, Richard Kenneth (1916 ---RRB- guyot Guzman Prize gymnosperm gynecology gynoecium gypsum gyrocompass gyrofrequency gyropilot gyroscope gyrostabilizer Gyulbudagian's Nebula (HHstar 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 anticenter galactic bulge galactic center Galactic Club galactic coordinates galactic disk galactic empire galactic equator galactic habitable zone galactic halo galactic magnetic field galactic noise galactic plane galactic rotation galactose Galatea GALAXIES galaxy galaxy cannibalism galaxy classification galaxy formation galaxy interaction galaxy merger 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 Europa Mission (GEM) 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 Cassiopeiae star 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 «garbage theory», of the origin of life Gardner, Martin (1914 — 2010) Garneau, Marc (1949 ---RRB- garnet Garnet Star (Mu Cephei) Garnet Star Nebula (IC 1396) garnierite Garriott, Owen K. (1930 ---RRB- Garuda gas gas chromatography gas constant gas giant gas laws gas - bounded nebula gaseous nebula gaseous propellant gaseous - propellant rocket engine gasoline Gaspra (minor planet 951) Gassendi, Pierre (1592 — 1655) gastric juice gastrin gastrocnemius gastroenteritis gastrointestinal tract gastropod gastrulation Gatewood, George D. (1940 ---RRB- Gauer - Henry reflex gauge boson 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 ---RRB- GEM «gemination,» of martian canals Geminga Gemini (constellation) Gemini Observatory Gemini Project Gemini - Titan II gemstone gene gene expression gene mapping gene pool gene therapy gene transfer General Catalogue of Variable Stars (GCVS) general precession general theory of relativity generation ship generator Genesis (inflatable orbiting module) Genesis (sample return probe) genetic code genetic counseling genetic disorder genetic drift genetic engineering genetic marker genetic material genetic pool genetic recombination genetics GENETICS AND HEREDITY Geneva Extrasolar Planet Search Program genome genome, interstellar transmission of genotype gentian violet genus geoboard geode geodesic geodesy geodesy satellites geodetic precession Geographos (minor planet 1620) geography GEOGRAPHY Geo - IK geologic time 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 (GTO) 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 ---RRB- Giacobini - Zinner, Comet (Comet 21P /) Giaever, Ivar (1929 ---RRB- giant branch 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 ---RRB- 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 ---RRB- glass GLAST (Gamma - ray Large Area Space Telescope) Glauber, Johann Rudolf (1607 — 1670) glaucoma glauconite Glenn, John Herschel, Jr. (1921 ---RRB- Glenn Research Center Glennan, T (homas) Keith (1905 — 1995) glenoid cavity glia glial cell glider Gliese 229B Gliese 581 Gliese 67 (HD 10307, HIP 7918) Gliese 710 (HD 168442, HIP 89825) Gliese 86 Gliese 876 Gliese Catalogue glioma glissette glitch 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 ---RRB- gold - leaf electroscope Goldstone Tracking Facility Golgi, Camillo (1844 — 1926) Golgi apparatus Golomb, Solomon W. (1932 — 2016) golygon 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 ---RRB- Graham, Thomas (1805 — 1869) Graham's law of diffusion Graham's number GRAIL (Gravity Recovery and Interior Laboratory) grain (cereal) grain (unit) gram gram - atom Gramme, Zénobe Théophile (1826 — 1901) gramophone Gram's stain Gran Telescopio Canarias (GTC) 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 grass grassland gravel graveyard orbit 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 gradient stabilization Gravity Probe A Gravity Probe B gravity - assist gray (Gy) 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 Red Spot Great Rift (in Milky Way) Great Rift Valley Great Square of Pegasus Great Wall greater omentum greatest elongation Green, George (1793 — 1841) Green, Nathaniel E. Green, Thomas Hill (1836 — 1882) green algae Green Bank Green Bank conference (1961) Green Bank Telescope green flash greenhouse effect greenhouse gases 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 grike Grimaldi, Francesco Maria (1618 — 1663) Grissom, Virgil (1926 — 1967) grit gritstone Groom Lake Groombridge 34 Groombridge Catalogue gross ground, electrical ground state ground - track 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 (NGC 7552, NGC 7582, NGC 7590, and NGC 7599) GSLV (Geosynchronous Satellite Launch Vehicle) g - suit G - type asteroid Guericke, Otto von (1602 — 1686) guanine Guiana Space Centre guidance, inertial Guide Star Catalog (GSC) guided missile guided missiles, postwar development Guillaume, Charles Édouard (1861 — 1938) Gulf Stream (ocean current) Gulfstream (jet plane) Gullstrand, Allvar (1862 — 1930) gum Gum Nebula gun metal gunpowder Gurwin Gusev Crater gut Gutenberg, Johann (c. 1400 — 1468) Guy, Richard Kenneth (1916 ---RRB- guyot Guzman Prize gymnosperm gynecology gynoecium gypsum gyrocompass gyrofrequency gyropilot gyroscope gyrostabilizer Gyulbudagian's Nebula (HH2AND PUZZLES gamete gametophyte Gamma (Soviet orbiting telescope) Gamma Cassiopeiae Gamma Cassiopeiae star 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 «garbage theory», of the origin of life Gardner, Martin (1914 — 2010) Garneau, Marc (1949 ---RRB- garnet Garnet Star (Mu Cephei) Garnet Star Nebula (IC 1396) garnierite Garriott, Owen K. (1930 ---RRB- Garuda gas gas chromatography gas constant gas giant gas laws gas - bounded nebula gaseous nebula gaseous propellant gaseous - propellant rocket engine gasoline Gaspra (minor planet 951) Gassendi, Pierre (1592 — 1655) gastric juice gastrin gastrocnemius gastroenteritis gastrointestinal tract gastropod gastrulation Gatewood, George D. (1940 ---RRB- Gauer - Henry reflex gauge boson 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 ---RRB- GEM «gemination,» of martian canals Geminga Gemini (constellation) Gemini Observatory Gemini Project Gemini - Titan II gemstone gene gene expression gene mapping gene pool gene therapy gene transfer General Catalogue of Variable Stars (GCVS) general precession general theory of relativity generation ship generator Genesis (inflatable orbiting module) Genesis (sample return probe) genetic code genetic counseling genetic disorder genetic drift genetic engineering genetic marker genetic material genetic pool genetic recombination genetics GENETICS AND HEREDITY Geneva Extrasolar Planet Search Program genome genome, interstellar transmission of genotype gentian violet genus geoboard geode geodesic geodesy geodesy satellites geodetic precession Geographos (minor planet 1620) geography GEOGRAPHY Geo - IK geologic time 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 (GTO) 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 ---RRB- Giacobini - Zinner, Comet (Comet 21P /) Giaever, Ivar (1929 ---RRB- giant branch 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 ---RRB- 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 ---RRB- glass GLAST (Gamma - ray Large Area Space Telescope) Glauber, Johann Rudolf (1607 — 1670) glaucoma glauconite Glenn, John Herschel, Jr. (1921 ---RRB- Glenn Research Center Glennan, T (homas) Keith (1905 — 1995) glenoid cavity glia glial cell glider Gliese 229B Gliese 581 Gliese 67 (HD 10307, HIP 7918) Gliese 710 (HD 168442, HIP 89825) Gliese 86 Gliese 876 Gliese Catalogue glioma glissette glitch 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 ---RRB- gold - leaf electroscope Goldstone Tracking Facility Golgi, Camillo (1844 — 1926) Golgi apparatus Golomb, Solomon W. (1932 — 2016) golygon 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 ---RRB- Graham, Thomas (1805 — 1869) Graham's law of diffusion Graham's number GRAIL (Gravity Recovery and Interior Laboratory) grain (cereal) grain (unit) gram gram - atom Gramme, Zénobe Théophile (1826 — 1901) gramophone Gram's stain Gran Telescopio Canarias (GTC) 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 grass grassland gravel graveyard orbit 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 gradient stabilization Gravity Probe A Gravity Probe B gravity - assist gray (Gy) 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 Red Spot Great Rift (in Milky Way) Great Rift Valley Great Square of Pegasus Great Wall greater omentum greatest elongation Green, George (1793 — 1841) Green, Nathaniel E. Green, Thomas Hill (1836 — 1882) green algae Green Bank Green Bank conference (1961) Green Bank Telescope green flash greenhouse effect greenhouse gases 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 grike Grimaldi, Francesco Maria (1618 — 1663) Grissom, Virgil (1926 — 1967) grit gritstone Groom Lake Groombridge 34 Groombridge Catalogue gross ground, electrical ground state ground - track 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 (NGC 7552, NGC 7582, NGC 7590, and NGC 7599) GSLV (Geosynchronous Satellite Launch Vehicle) g - suit G - type asteroid Guericke, Otto von (1602 — 1686) guanine Guiana Space Centre guidance, inertial Guide Star Catalog (GSC) guided missile guided missiles, postwar development Guillaume, Charles Édouard (1861 — 1938) Gulf Stream (ocean current) Gulfstream (jet plane) Gullstrand, Allvar (1862 — 1930) gum Gum Nebula gun metal gunpowder Gurwin Gusev Crater gut Gutenberg, Johann (c. 1400 — 1468) Guy, Richard Kenneth (1916 ---RRB- guyot Guzman Prize gymnosperm gynecology gynoecium gypsum gyrocompass gyrofrequency gyropilot gyroscope gyrostabilizer Gyulbudagian's Nebula (HHstar 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 «garbage theory», of the origin of life Gardner, Martin (1914 — 2010) Garneau, Marc (1949 ---RRB- garnet Garnet Star (Mu Cephei) Garnet Star Nebula (IC 1396) garnierite Garriott, Owen K. (1930 ---RRB- Garuda gas gas chromatography gas constant gas giant gas laws gas - bounded nebula gaseous nebula gaseous propellant gaseous - propellant rocket engine gasoline Gaspra (minor planet 951) Gassendi, Pierre (1592 — 1655) gastric juice gastrin gastrocnemius gastroenteritis gastrointestinal tract gastropod gastrulation Gatewood, George D. (1940 ---RRB- Gauer - Henry reflex gauge boson 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 ---RRB- GEM «gemination,» of martian canals Geminga Gemini (constellation) Gemini Observatory Gemini Project Gemini - Titan II gemstone gene gene expression gene mapping gene pool gene therapy gene transfer General Catalogue of Variable Stars (GCVS) general precession general theory of relativity generation ship generator Genesis (inflatable orbiting module) Genesis (sample return probe) genetic code genetic counseling genetic disorder genetic drift genetic engineering genetic marker genetic material genetic pool genetic recombination genetics GENETICS AND HEREDITY Geneva Extrasolar Planet Search Program genome genome, interstellar transmission of genotype gentian violet genus geoboard geode geodesic geodesy geodesy satellites geodetic precession Geographos (minor planet 1620) geography GEOGRAPHY Geo - IK geologic time 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 (GTO) 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 ---RRB- Giacobini - Zinner, Comet (Comet 21P /) Giaever, Ivar (1929 ---RRB- giant branch 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 ---RRB- 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 ---RRB- glass GLAST (Gamma - ray Large Area Space Telescope) Glauber, Johann Rudolf (1607 — 1670) glaucoma glauconite Glenn, John Herschel, Jr. (1921 ---RRB- Glenn Research Center Glennan, T (homas) Keith (1905 — 1995) glenoid cavity glia glial cell glider Gliese 229B Gliese 581 Gliese 67 (HD 10307, HIP 7918) Gliese 710 (HD 168442, HIP 89825) Gliese 86 Gliese 876 Gliese Catalogue glioma glissette glitch 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 ---RRB- gold - leaf electroscope Goldstone Tracking Facility Golgi, Camillo (1844 — 1926) Golgi apparatus Golomb, Solomon W. (1932 — 2016) golygon 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 ---RRB- Graham, Thomas (1805 — 1869) Graham's law of diffusion Graham's number GRAIL (Gravity Recovery and Interior Laboratory) grain (cereal) grain (unit) gram gram - atom Gramme, Zénobe Théophile (1826 — 1901) gramophone Gram's stain Gran Telescopio Canarias (GTC) 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 grass grassland gravel graveyard orbit 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 gradient stabilization Gravity Probe A Gravity Probe B gravity - assist gray (Gy) 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 Red Spot Great Rift (in Milky Way) Great Rift Valley Great Square of Pegasus Great Wall greater omentum greatest elongation Green, George (1793 — 1841) Green, Nathaniel E. Green, Thomas Hill (1836 — 1882) green algae Green Bank Green Bank conference (1961) Green Bank Telescope green flash greenhouse effect greenhouse gases 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 grike Grimaldi, Francesco Maria (1618 — 1663) Grissom, Virgil (1926 — 1967) grit gritstone Groom Lake Groombridge 34 Groombridge Catalogue gross ground, electrical ground state ground - track 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 (NGC 7552, NGC 7582, NGC 7590, and NGC 7599) GSLV (Geosynchronous Satellite Launch Vehicle) g - suit G - type asteroid Guericke, Otto von (1602 — 1686) guanine Guiana Space Centre guidance, inertial Guide Star Catalog (GSC) guided missile guided missiles, postwar development Guillaume, Charles Édouard (1861 — 1938) Gulf Stream (ocean current) Gulfstream (jet plane) Gullstrand, Allvar (1862 — 1930) gum Gum Nebula gun metal gunpowder Gurwin Gusev Crater gut Gutenberg, Johann (c. 1400 — 1468) Guy, Richard Kenneth (1916 ---RRB- guyot Guzman Prize gymnosperm gynecology gynoecium gypsum gyrocompass gyrofrequency gyropilot gyroscope gyrostabilizer Gyulbudagian's Nebula (HHStar (Mu Cephei) Garnet Star Nebula (IC 1396) garnierite Garriott, Owen K. (1930 ---RRB- Garuda gas gas chromatography gas constant gas giant gas laws gas - bounded nebula gaseous nebula gaseous propellant gaseous - propellant rocket engine gasoline Gaspra (minor planet 951) Gassendi, Pierre (1592 — 1655) gastric juice gastrin gastrocnemius gastroenteritis gastrointestinal tract gastropod gastrulation Gatewood, George D. (1940 ---RRB- Gauer - Henry reflex gauge boson 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 ---RRB- GEM «gemination,» of martian canals Geminga Gemini (constellation) Gemini Observatory Gemini Project Gemini - Titan II gemstone gene gene expression gene mapping gene pool gene therapy gene transfer General Catalogue of Variable Stars (GCVS) general precession general theory of relativity generation ship generator Genesis (inflatable orbiting module) Genesis (sample return probe) genetic code genetic counseling genetic disorder genetic drift genetic engineering genetic marker genetic material genetic pool genetic recombination genetics GENETICS AND HEREDITY Geneva Extrasolar Planet Search Program genome genome, interstellar transmission of genotype gentian violet genus geoboard geode geodesic geodesy geodesy satellites geodetic precession Geographos (minor planet 1620) geography GEOGRAPHY Geo - IK geologic time 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 (GTO) 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 ---RRB- Giacobini - Zinner, Comet (Comet 21P /) Giaever, Ivar (1929 ---RRB- giant branch 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 ---RRB- 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 ---RRB- glass GLAST (Gamma - ray Large Area Space Telescope) Glauber, Johann Rudolf (1607 — 1670) glaucoma glauconite Glenn, John Herschel, Jr. (1921 ---RRB- Glenn Research Center Glennan, T (homas) Keith (1905 — 1995) glenoid cavity glia glial cell glider Gliese 229B Gliese 581 Gliese 67 (HD 10307, HIP 7918) Gliese 710 (HD 168442, HIP 89825) Gliese 86 Gliese 876 Gliese Catalogue glioma glissette glitch 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 ---RRB- gold - leaf electroscope Goldstone Tracking Facility Golgi, Camillo (1844 — 1926) Golgi apparatus Golomb, Solomon W. (1932 — 2016) golygon 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 ---RRB- Graham, Thomas (1805 — 1869) Graham's law of diffusion Graham's number GRAIL (Gravity Recovery and Interior Laboratory) grain (cereal) grain (unit) gram gram - atom Gramme, Zénobe Théophile (1826 — 1901) gramophone Gram's stain Gran Telescopio Canarias (GTC) 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 grass grassland gravel graveyard orbit 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 gradient stabilization Gravity Probe A Gravity Probe B gravity - assist gray (Gy) 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 Red Spot Great Rift (in Milky Way) Great Rift Valley Great Square of Pegasus Great Wall greater omentum greatest elongation Green, George (1793 — 1841) Green, Nathaniel E. Green, Thomas Hill (1836 — 1882) green algae Green Bank Green Bank conference (1961) Green Bank Telescope green flash greenhouse effect greenhouse gases 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 grike Grimaldi, Francesco Maria (1618 — 1663) Grissom, Virgil (1926 — 1967) grit gritstone Groom Lake Groombridge 34 Groombridge Catalogue gross ground, electrical ground state ground - track 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 (NGC 7552, NGC 7582, NGC 7590, and NGC 7599) GSLV (Geosynchronous Satellite Launch Vehicle) g - suit G - type asteroid Guericke, Otto von (1602 — 1686) guanine Guiana Space Centre guidance, inertial Guide Star Catalog (GSC) guided missile guided missiles, postwar development Guillaume, Charles Édouard (1861 — 1938) Gulf Stream (ocean current) Gulfstream (jet plane) Gullstrand, Allvar (1862 — 1930) gum Gum Nebula gun metal gunpowder Gurwin Gusev Crater gut Gutenberg, Johann (c. 1400 — 1468) Guy, Richard Kenneth (1916 ---RRB- guyot Guzman Prize gymnosperm gynecology gynoecium gypsum gyrocompass gyrofrequency gyropilot gyroscope gyrostabilizer Gyulbudagian's Nebula (HHStar Nebula (IC 1396) garnierite Garriott, Owen K. (1930 ---RRB- Garuda gas gas chromatography gas constant gas giant gas laws gas - bounded nebula gaseous nebula gaseous propellant gaseous - propellant rocket engine gasoline Gaspra (minor planet 951) Gassendi, Pierre (1592 — 1655) gastric juice gastrin gastrocnemius gastroenteritis gastrointestinal tract gastropod gastrulation Gatewood, George D. (1940 ---RRB- Gauer - Henry reflex gauge boson 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 ---RRB- GEM «gemination,» of martian canals Geminga Gemini (constellation) Gemini Observatory Gemini Project Gemini - Titan II gemstone gene gene expression gene mapping gene pool gene therapy gene transfer General Catalogue of Variable Stars (GCVS) general precession general theory of relativity generation ship generator Genesis (inflatable orbiting module) Genesis (sample return probe) genetic code genetic counseling genetic disorder genetic drift genetic engineering genetic marker genetic material genetic pool genetic recombination genetics GENETICS AND HEREDITY Geneva Extrasolar Planet Search Program genome genome, interstellar transmission of genotype gentian violet genus geoboard geode geodesic geodesy geodesy satellites geodetic precession Geographos (minor planet 1620) geography GEOGRAPHY Geo - IK geologic time 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 (GTO) 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 ---RRB- Giacobini - Zinner, Comet (Comet 21P /) Giaever, Ivar (1929 ---RRB- giant branch 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 ---RRB- 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 ---RRB- glass GLAST (Gamma - ray Large Area Space Telescope) Glauber, Johann Rudolf (1607 — 1670) glaucoma glauconite Glenn, John Herschel, Jr. (1921 ---RRB- Glenn Research Center Glennan, T (homas) Keith (1905 — 1995) glenoid cavity glia glial cell glider Gliese 229B Gliese 581 Gliese 67 (HD 10307, HIP 7918) Gliese 710 (HD 168442, HIP 89825) Gliese 86 Gliese 876 Gliese Catalogue glioma glissette glitch 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 ---RRB- gold - leaf electroscope Goldstone Tracking Facility Golgi, Camillo (1844 — 1926) Golgi apparatus Golomb, Solomon W. (1932 — 2016) golygon 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 ---RRB- Graham, Thomas (1805 — 1869) Graham's law of diffusion Graham's number GRAIL (Gravity Recovery and Interior Laboratory) grain (cereal) grain (unit) gram gram - atom Gramme, Zénobe Théophile (1826 — 1901) gramophone Gram's stain Gran Telescopio Canarias (GTC) 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 grass grassland gravel graveyard orbit 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 gradient stabilization Gravity Probe A Gravity Probe B gravity - assist gray (Gy) 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 Red Spot Great Rift (in Milky Way) Great Rift Valley Great Square of Pegasus Great Wall greater omentum greatest elongation Green, George (1793 — 1841) Green, Nathaniel E. Green, Thomas Hill (1836 — 1882) green algae Green Bank Green Bank conference (1961) Green Bank Telescope green flash greenhouse effect greenhouse gases 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 grike Grimaldi, Francesco Maria (1618 — 1663) Grissom, Virgil (1926 — 1967) grit gritstone Groom Lake Groombridge 34 Groombridge Catalogue gross ground, electrical ground state ground - track 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 (NGC 7552, NGC 7582, NGC 7590, and NGC 7599) GSLV (Geosynchronous Satellite Launch Vehicle) g - suit G - type asteroid Guericke, Otto von (1602 — 1686) guanine Guiana Space Centre guidance, inertial Guide Star Catalog (GSC) guided missile guided missiles, postwar development Guillaume, Charles Édouard (1861 — 1938) Gulf Stream (ocean current) Gulfstream (jet plane) Gullstrand, Allvar (1862 — 1930) gum Gum Nebula gun metal gunpowder Gurwin Gusev Crater gut Gutenberg, Johann (c. 1400 — 1468) Guy, Richard Kenneth (1916 ---RRB- guyot Guzman Prize gymnosperm gynecology gynoecium gypsum gyrocompass gyrofrequency gyropilot gyroscope gyrostabilizer Gyulbudagian's Nebula (planet 951) Gassendi, Pierre (1592 — 1655) gastric juice gastrin gastrocnemius gastroenteritis gastrointestinal tract gastropod gastrulation Gatewood, George D. (1940 ---RRB- Gauer - Henry reflex gauge boson 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 ---RRB- GEM «gemination,» of martian canals Geminga Gemini (constellation) Gemini Observatory Gemini Project Gemini - Titan II gemstone gene gene expression gene mapping gene pool gene therapy gene transfer General Catalogue of Variable Stars (GCVS) general precession general theory of relativity generation ship generator Genesis (inflatable orbiting module) Genesis (sample return probe) genetic code genetic counseling genetic disorder genetic drift genetic engineering genetic marker genetic material genetic pool genetic recombination genetics GENETICS AND HEREDITY Geneva Extrasolar Planet Search Program genome genome, interstellar transmission of genotype gentian violet genus geoboard geode geodesic geodesy geodesy satellites geodetic precession Geographos (minor planet 1620) geography GEOGRAPHY Geo - IK geologic time 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 (GTO) 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 ---RRB- Giacobini - Zinner, Comet (Comet 21P /) Giaever, Ivar (1929 ---RRB- giant branch 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 ---RRB- 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 ---RRB- glass GLAST (Gamma - ray Large Area Space Telescope) Glauber, Johann Rudolf (1607 — 1670) glaucoma glauconite Glenn, John Herschel, Jr. (1921 ---RRB- Glenn Research Center Glennan, T (homas) Keith (1905 — 1995) glenoid cavity glia glial cell glider Gliese 229B Gliese 581 Gliese 67 (HD 10307, HIP 7918) Gliese 710 (HD 168442, HIP 89825) Gliese 86 Gliese 876 Gliese Catalogue glioma glissette glitch 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 ---RRB- gold - leaf electroscope Goldstone Tracking Facility Golgi, Camillo (1844 — 1926) Golgi apparatus Golomb, Solomon W. (1932 — 2016) golygon 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 ---RRB- Graham, Thomas (1805 — 1869) Graham's law of diffusion Graham's number GRAIL (Gravity Recovery and Interior Laboratory) grain (cereal) grain (unit) gram gram - atom Gramme, Zénobe Théophile (1826 — 1901) gramophone Gram's stain Gran Telescopio Canarias (GTC) 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 grass grassland gravel graveyard orbit 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 gradient stabilization Gravity Probe A Gravity Probe B gravity - assist gray (Gy) 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 Red Spot Great Rift (in Milky Way) Great Rift Valley Great Square of Pegasus Great Wall greater omentum greatest elongation Green, George (1793 — 1841) Green, Nathaniel E. Green, Thomas Hill (1836 — 1882) green algae Green Bank Green Bank conference (1961) Green Bank Telescope green flash greenhouse effect greenhouse gases 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 grike Grimaldi, Francesco Maria (1618 — 1663) Grissom, Virgil (1926 — 1967) grit gritstone Groom Lake Groombridge 34 Groombridge Catalogue gross ground, electrical ground state ground - track 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 (NGC 7552, NGC 7582, NGC 7590, and NGC 7599) GSLV (Geosynchronous Satellite Launch Vehicle) g - suit G - type asteroid Guericke, Otto von (1602 — 1686) guanine Guiana Space Centre guidance, inertial Guide Star Catalog (GSC) guided missile guided missiles, postwar development Guillaume, Charles Édouard (1861 — 1938) Gulf Stream (ocean current) Gulfstream (jet plane) Gullstrand, Allvar (1862 — 1930) gum Gum Nebula gun metal gunpowder Gurwin Gusev Crater gut Gutenberg, Johann (c. 1400 — 1468) Guy, Richard Kenneth (1916 ---RRB- guyot Guzman Prize gymnosperm gynecology gynoecium gypsum gyrocompass gyrofrequency gyropilot gyroscope gyrostabilizer Gyulbudagian's Nebula (HH2AND HEREDITY Geneva Extrasolar Planet Search Program genome genome, interstellar transmission of genotype gentian violet genus geoboard geode geodesic geodesy geodesy satellites geodetic precession Geographos (minor planet 1620) geography GEOGRAPHY Geo - IK geologic time 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 (GTO) 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 ---RRB- Giacobini - Zinner, Comet (Comet 21P /) Giaever, Ivar (1929 ---RRB- giant branch 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 ---RRB- 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 ---RRB- glass GLAST (Gamma - ray Large Area Space Telescope) Glauber, Johann Rudolf (1607 — 1670) glaucoma glauconite Glenn, John Herschel, Jr. (1921 ---RRB- Glenn Research Center Glennan, T (homas) Keith (1905 — 1995) glenoid cavity glia glial cell glider Gliese 229B Gliese 581 Gliese 67 (HD 10307, HIP 7918) Gliese 710 (HD 168442, HIP 89825) Gliese 86 Gliese 876 Gliese Catalogue glioma glissette glitch 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 ---RRB- gold - leaf electroscope Goldstone Tracking Facility Golgi, Camillo (1844 — 1926) Golgi apparatus Golomb, Solomon W. (1932 — 2016) golygon 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 ---RRB- Graham, Thomas (1805 — 1869) Graham's law of diffusion Graham's number GRAIL (Gravity Recovery and Interior Laboratory) grain (cereal) grain (unit) gram gram - atom Gramme, Zénobe Théophile (1826 — 1901) gramophone Gram's stain Gran Telescopio Canarias (GTC) 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 grass grassland gravel graveyard orbit 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 gradient stabilization Gravity Probe A Gravity Probe B gravity - assist gray (Gy) 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 Red Spot Great Rift (in Milky Way) Great Rift Valley Great Square of Pegasus Great Wall greater omentum greatest elongation Green, George (1793 — 1841) Green, Nathaniel E. Green, Thomas Hill (1836 — 1882) green algae Green Bank Green Bank conference (1961) Green Bank Telescope green flash greenhouse effect greenhouse gases 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 grike Grimaldi, Francesco Maria (1618 — 1663) Grissom, Virgil (1926 — 1967) grit gritstone Groom Lake Groombridge 34 Groombridge Catalogue gross ground, electrical ground state ground - track 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 (NGC 7552, NGC 7582, NGC 7590, and NGC 7599) GSLV (Geosynchronous Satellite Launch Vehicle) g - suit G - type asteroid Guericke, Otto von (1602 — 1686) guanine Guiana Space Centre guidance, inertial Guide Star Catalog (GSC) guided missile guided missiles, postwar development Guillaume, Charles Édouard (1861 — 1938) Gulf Stream (ocean current) Gulfstream (jet plane) Gullstrand, Allvar (1862 — 1930) gum Gum Nebula gun metal gunpowder Gurwin Gusev Crater gut Gutenberg, Johann (c. 1400 — 1468) Guy, Richard Kenneth (1916 ---RRB- guyot Guzman Prize gymnosperm gynecology gynoecium gypsum gyrocompass gyrofrequency gyropilot gyroscope gyrostabilizer Gyulbudagian's Nebula (Planet Search Program genome genome, interstellar transmission of genotype gentian violet genus geoboard geode geodesic geodesy geodesy satellites geodetic precession Geographos (minor planet 1620) geography GEOGRAPHY Geo - IK geologic time 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 (GTO) 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 ---RRB- Giacobini - Zinner, Comet (Comet 21P /) Giaever, Ivar (1929 ---RRB- giant branch 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 ---RRB- 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 ---RRB- glass GLAST (Gamma - ray Large Area Space Telescope) Glauber, Johann Rudolf (1607 — 1670) glaucoma glauconite Glenn, John Herschel, Jr. (1921 ---RRB- Glenn Research Center Glennan, T (homas) Keith (1905 — 1995) glenoid cavity glia glial cell glider Gliese 229B Gliese 581 Gliese 67 (HD 10307, HIP 7918) Gliese 710 (HD 168442, HIP 89825) Gliese 86 Gliese 876 Gliese Catalogue glioma glissette glitch 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 ---RRB- gold - leaf electroscope Goldstone Tracking Facility Golgi, Camillo (1844 — 1926) Golgi apparatus Golomb, Solomon W. (1932 — 2016) golygon 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 ---RRB- Graham, Thomas (1805 — 1869) Graham's law of diffusion Graham's number GRAIL (Gravity Recovery and Interior Laboratory) grain (cereal) grain (unit) gram gram - atom Gramme, Zénobe Théophile (1826 — 1901) gramophone Gram's stain Gran Telescopio Canarias (GTC) 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 grass grassland gravel graveyard orbit 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 gradient stabilization Gravity Probe A Gravity Probe B gravity - assist gray (Gy) 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 Red Spot Great Rift (in Milky Way) Great Rift Valley Great Square of Pegasus Great Wall greater omentum greatest elongation Green, George (1793 — 1841) Green, Nathaniel E. Green, Thomas Hill (1836 — 1882) green algae Green Bank Green Bank conference (1961) Green Bank Telescope green flash greenhouse effect greenhouse gases 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 grike Grimaldi, Francesco Maria (1618 — 1663) Grissom, Virgil (1926 — 1967) grit gritstone Groom Lake Groombridge 34 Groombridge Catalogue gross ground, electrical ground state ground - track 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 (NGC 7552, NGC 7582, NGC 7590, and NGC 7599) GSLV (Geosynchronous Satellite Launch Vehicle) g - suit G - type asteroid Guericke, Otto von (1602 — 1686) guanine Guiana Space Centre guidance, inertial Guide Star Catalog (GSC) guided missile guided missiles, postwar development Guillaume, Charles Édouard (1861 — 1938) Gulf Stream (ocean current) Gulfstream (jet plane) Gullstrand, Allvar (1862 — 1930) gum Gum Nebula gun metal gunpowder Gurwin Gusev Crater gut Gutenberg, Johann (c. 1400 — 1468) Guy, Richard Kenneth (1916 ---RRB- guyot Guzman Prize gymnosperm gynecology gynoecium gypsum gyrocompass gyrofrequency gyropilot gyroscope gyrostabilizer Gyulbudagian's Nebula (planet 1620) geography GEOGRAPHY Geo - IK geologic time 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 (GTO) 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 ---RRB- Giacobini - Zinner, Comet (Comet 21P /) Giaever, Ivar (1929 ---RRB- giant branch 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 ---RRB- 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 ---RRB- glass GLAST (Gamma - ray Large Area Space Telescope) Glauber, Johann Rudolf (1607 — 1670) glaucoma glauconite Glenn, John Herschel, Jr. (1921 ---RRB- Glenn Research Center Glennan, T (homas) Keith (1905 — 1995) glenoid cavity glia glial cell glider Gliese 229B Gliese 581 Gliese 67 (HD 10307, HIP 7918) Gliese 710 (HD 168442, HIP 89825) Gliese 86 Gliese 876 Gliese Catalogue glioma glissette glitch 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 ---RRB- gold - leaf electroscope Goldstone Tracking Facility Golgi, Camillo (1844 — 1926) Golgi apparatus Golomb, Solomon W. (1932 — 2016) golygon 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 ---RRB- Graham, Thomas (1805 — 1869) Graham's law of diffusion Graham's number GRAIL (Gravity Recovery and Interior Laboratory) grain (cereal) grain (unit) gram gram - atom Gramme, Zénobe Théophile (1826 — 1901) gramophone Gram's stain Gran Telescopio Canarias (GTC) 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 grass grassland gravel graveyard orbit 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 gradient stabilization Gravity Probe A Gravity Probe B gravity - assist gray (Gy) 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 Red Spot Great Rift (in Milky Way) Great Rift Valley Great Square of Pegasus Great Wall greater omentum greatest elongation Green, George (1793 — 1841) Green, Nathaniel E. Green, Thomas Hill (1836 — 1882) green algae Green Bank Green Bank conference (1961) Green Bank Telescope green flash greenhouse effect greenhouse gases 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 grike Grimaldi, Francesco Maria (1618 — 1663) Grissom, Virgil (1926 — 1967) grit gritstone Groom Lake Groombridge 34 Groombridge Catalogue gross ground, electrical ground state ground - track 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 (NGC 7552, NGC 7582, NGC 7590, and NGC 7599) GSLV (Geosynchronous Satellite Launch Vehicle) g - suit G - type asteroid Guericke, Otto von (1602 — 1686) guanine Guiana Space Centre guidance, inertial Guide Star Catalog (GSC) guided missile guided missiles, postwar development Guillaume, Charles Édouard (1861 — 1938) Gulf Stream (ocean current) Gulfstream (jet plane) Gullstrand, Allvar (1862 — 1930) gum Gum Nebula gun metal gunpowder Gurwin Gusev Crater gut Gutenberg, Johann (c. 1400 — 1468) Guy, Richard Kenneth (1916 ---RRB- guyot Guzman Prize gymnosperm gynecology gynoecium gypsum gyrocompass gyrofrequency gyropilot gyroscope gyrostabilizer Gyulbudagian's Nebula (HH2AND 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 (GTO) 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 ---RRB- Giacobini - Zinner, Comet (Comet 21P /) Giaever, Ivar (1929 ---RRB- giant branch 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 ---RRB- 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 ---RRB- glass GLAST (Gamma - ray Large Area Space Telescope) Glauber, Johann Rudolf (1607 — 1670) glaucoma glauconite Glenn, John Herschel, Jr. (1921 ---RRB- Glenn Research Center Glennan, T (homas) Keith (1905 — 1995) glenoid cavity glia glial cell glider Gliese 229B Gliese 581 Gliese 67 (HD 10307, HIP 7918) Gliese 710 (HD 168442, HIP 89825) Gliese 86 Gliese 876 Gliese Catalogue glioma glissette glitch 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 ---RRB- gold - leaf electroscope Goldstone Tracking Facility Golgi, Camillo (1844 — 1926) Golgi apparatus Golomb, Solomon W. (1932 — 2016) golygon 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 ---RRB- Graham, Thomas (1805 — 1869) Graham's law of diffusion Graham's number GRAIL (Gravity Recovery and Interior Laboratory) grain (cereal) grain (unit) gram gram - atom Gramme, Zénobe Théophile (1826 — 1901) gramophone Gram's stain Gran Telescopio Canarias (GTC) 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 grass grassland gravel graveyard orbit 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 gradient stabilization Gravity Probe A Gravity Probe B gravity - assist gray (Gy) 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 Red Spot Great Rift (in Milky Way) Great Rift Valley Great Square of Pegasus Great Wall greater omentum greatest elongation Green, George (1793 — 1841) Green, Nathaniel E. Green, Thomas Hill (1836 — 1882) green algae Green Bank Green Bank conference (1961) Green Bank Telescope green flash greenhouse effect greenhouse gases 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 grike Grimaldi, Francesco Maria (1618 — 1663) Grissom, Virgil (1926 — 1967) grit gritstone Groom Lake Groombridge 34 Groombridge Catalogue gross ground, electrical ground state ground - track 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 (NGC 7552, NGC 7582, NGC 7590, and NGC 7599) GSLV (Geosynchronous Satellite Launch Vehicle) g - suit G - type asteroid Guericke, Otto von (1602 — 1686) guanine Guiana Space Centre guidance, inertial Guide Star Catalog (GSC) guided missile guided missiles, postwar development Guillaume, Charles Édouard (1861 — 1938) Gulf Stream (ocean current) Gulfstream (jet plane) Gullstrand, Allvar (1862 — 1930) gum Gum Nebula gun metal gunpowder Gurwin Gusev Crater gut Gutenberg, Johann (c. 1400 — 1468) Guy, Richard Kenneth (1916 ---RRB- guyot Guzman Prize gymnosperm gynecology gynoecium gypsum gyrocompass gyrofrequency gyropilot gyroscope gyrostabilizer Gyulbudagian's Nebula (planet giant star Giant's Causeway Giauque, William Francis (1895 — 1982) gibberellins Gibbs, Josiah Willard (1839 — 1903) Gibbs free energy Gibson, Edward G. (1936 ---RRB- 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 ---RRB- glass GLAST (Gamma - ray Large Area Space Telescope) Glauber, Johann Rudolf (1607 — 1670) glaucoma glauconite Glenn, John Herschel, Jr. (1921 ---RRB- Glenn Research Center Glennan, T (homas) Keith (1905 — 1995) glenoid cavity glia glial cell glider Gliese 229B Gliese 581 Gliese 67 (HD 10307, HIP 7918) Gliese 710 (HD 168442, HIP 89825) Gliese 86 Gliese 876 Gliese Catalogue glioma glissette glitch 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 ---RRB- gold - leaf electroscope Goldstone Tracking Facility Golgi, Camillo (1844 — 1926) Golgi apparatus Golomb, Solomon W. (1932 — 2016) golygon 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 ---RRB- Graham, Thomas (1805 — 1869) Graham's law of diffusion Graham's number GRAIL (Gravity Recovery and Interior Laboratory) grain (cereal) grain (unit) gram gram - atom Gramme, Zénobe Théophile (1826 — 1901) gramophone Gram's stain Gran Telescopio Canarias (GTC) 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 grass grassland gravel graveyard orbit 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 gradient stabilization Gravity Probe A Gravity Probe B gravity - assist gray (Gy) 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 Red Spot Great Rift (in Milky Way) Great Rift Valley Great Square of Pegasus Great Wall greater omentum greatest elongation Green, George (1793 — 1841) Green, Nathaniel E. Green, Thomas Hill (1836 — 1882) green algae Green Bank Green Bank conference (1961) Green Bank Telescope green flash greenhouse effect greenhouse gases 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 grike Grimaldi, Francesco Maria (1618 — 1663) Grissom, Virgil (1926 — 1967) grit gritstone Groom Lake Groombridge 34 Groombridge Catalogue gross ground, electrical ground state ground - track 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 (NGC 7552, NGC 7582, NGC 7590, and NGC 7599) GSLV (Geosynchronous Satellite Launch Vehicle) g - suit G - type asteroid Guericke, Otto von (1602 — 1686) guanine Guiana Space Centre guidance, inertial Guide Star Catalog (GSC) guided missile guided missiles, postwar development Guillaume, Charles Édouard (1861 — 1938) Gulf Stream (ocean current) Gulfstream (jet plane) Gullstrand, Allvar (1862 — 1930) gum Gum Nebula gun metal gunpowder Gurwin Gusev Crater gut Gutenberg, Johann (c. 1400 — 1468) Guy, Richard Kenneth (1916 ---RRB- guyot Guzman Prize gymnosperm gynecology gynoecium gypsum gyrocompass gyrofrequency gyropilot gyroscope gyrostabilizer Gyulbudagian's Nebula (HHstar Giant's Causeway Giauque, William Francis (1895 — 1982) gibberellins Gibbs, Josiah Willard (1839 — 1903) Gibbs free energy Gibson, Edward G. (1936 ---RRB- 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 ---RRB- glass GLAST (Gamma - ray Large Area Space Telescope) Glauber, Johann Rudolf (1607 — 1670) glaucoma glauconite Glenn, John Herschel, Jr. (1921 ---RRB- Glenn Research Center Glennan, T (homas) Keith (1905 — 1995) glenoid cavity glia glial cell glider Gliese 229B Gliese 581 Gliese 67 (HD 10307, HIP 7918) Gliese 710 (HD 168442, HIP 89825) Gliese 86 Gliese 876 Gliese Catalogue glioma glissette glitch 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 ---RRB- gold - leaf electroscope Goldstone Tracking Facility Golgi, Camillo (1844 — 1926) Golgi apparatus Golomb, Solomon W. (1932 — 2016) golygon 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 ---RRB- Graham, Thomas (1805 — 1869) Graham's law of diffusion Graham's number GRAIL (Gravity Recovery and Interior Laboratory) grain (cereal) grain (unit) gram gram - atom Gramme, Zénobe Théophile (1826 — 1901) gramophone Gram's stain Gran Telescopio Canarias (GTC) 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 grass grassland gravel graveyard orbit 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 gradient stabilization Gravity Probe A Gravity Probe B gravity - assist gray (Gy) 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 Red Spot Great Rift (in Milky Way) Great Rift Valley Great Square of Pegasus Great Wall greater omentum greatest elongation Green, George (1793 — 1841) Green, Nathaniel E. Green, Thomas Hill (1836 — 1882) green algae Green Bank Green Bank conference (1961) Green Bank Telescope green flash greenhouse effect greenhouse gases 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 grike Grimaldi, Francesco Maria (1618 — 1663) Grissom, Virgil (1926 — 1967) grit gritstone Groom Lake Groombridge 34 Groombridge Catalogue gross ground, electrical ground state ground - track 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 (NGC 7552, NGC 7582, NGC 7590, and NGC 7599) GSLV (Geosynchronous Satellite Launch Vehicle) g - suit G - type asteroid Guericke, Otto von (1602 — 1686) guanine Guiana Space Centre guidance, inertial Guide Star Catalog (GSC) guided missile guided missiles, postwar development Guillaume, Charles Édouard (1861 — 1938) Gulf Stream (ocean current) Gulfstream (jet plane) Gullstrand, Allvar (1862 — 1930) gum Gum Nebula gun metal gunpowder Gurwin Gusev Crater gut Gutenberg, Johann (c. 1400 — 1468) Guy, Richard Kenneth (1916 ---RRB- guyot Guzman Prize gymnosperm gynecology gynoecium gypsum gyrocompass gyrofrequency gyropilot gyroscope gyrostabilizer Gyulbudagian's Nebula (HH2and 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 ---RRB- gold - leaf electroscope Goldstone Tracking Facility Golgi, Camillo (1844 — 1926) Golgi apparatus Golomb, Solomon W. (1932 — 2016) golygon 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 ---RRB- Graham, Thomas (1805 — 1869) Graham's law of diffusion Graham's number GRAIL (Gravity Recovery and Interior Laboratory) grain (cereal) grain (unit) gram gram - atom Gramme, Zénobe Théophile (1826 — 1901) gramophone Gram's stain Gran Telescopio Canarias (GTC) 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 grass grassland gravel graveyard orbit 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 gradient stabilization Gravity Probe A Gravity Probe B gravity - assist gray (Gy) 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 Red Spot Great Rift (in Milky Way) Great Rift Valley Great Square of Pegasus Great Wall greater omentum greatest elongation Green, George (1793 — 1841) Green, Nathaniel E. Green, Thomas Hill (1836 — 1882) green algae Green Bank Green Bank conference (1961) Green Bank Telescope green flash greenhouse effect greenhouse gases 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 grike Grimaldi, Francesco Maria (1618 — 1663) Grissom, Virgil (1926 — 1967) grit gritstone Groom Lake Groombridge 34 Groombridge Catalogue gross ground, electrical ground state ground - track 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 (NGC 7552, NGC 7582, NGC 7590, and NGC 7599) GSLV (Geosynchronous Satellite Launch Vehicle) g - suit G - type asteroid Guericke, Otto von (1602 — 1686) guanine Guiana Space Centre guidance, inertial Guide Star Catalog (GSC) guided missile guided missiles, postwar development Guillaume, Charles Édouard (1861 — 1938) Gulf Stream (ocean current) Gulfstream (jet plane) Gullstrand, Allvar (1862 — 1930) gum Gum Nebula gun metal gunpowder Gurwin Gusev Crater gut Gutenberg, Johann (c. 1400 — 1468) Guy, Richard Kenneth (1916 ---RRB- guyot Guzman Prize gymnosperm gynecology gynoecium gypsum gyrocompass gyrofrequency gyropilot gyroscope gyrostabilizer Gyulbudagian's Nebula (HH2and Climate Experiment) graceful graph gradient Graham, Ronald (1935 ---RRB- Graham, Thomas (1805 — 1869) Graham's law of diffusion Graham's number GRAIL (Gravity Recovery and Interior Laboratory) grain (cereal) grain (unit) gram gram - atom Gramme, Zénobe Théophile (1826 — 1901) gramophone Gram's stain Gran Telescopio Canarias (GTC) 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 grass grassland gravel graveyard orbit 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 gradient stabilization Gravity Probe A Gravity Probe B gravity - assist gray (Gy) 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 Red Spot Great Rift (in Milky Way) Great Rift Valley Great Square of Pegasus Great Wall greater omentum greatest elongation Green, George (1793 — 1841) Green, Nathaniel E. Green, Thomas Hill (1836 — 1882) green algae Green Bank Green Bank conference (1961) Green Bank Telescope green flash greenhouse effect greenhouse gases 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 grike Grimaldi, Francesco Maria (1618 — 1663) Grissom, Virgil (1926 — 1967) grit gritstone Groom Lake Groombridge 34 Groombridge Catalogue gross ground, electrical ground state ground - track 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 (NGC 7552, NGC 7582, NGC 7590, and NGC 7599) GSLV (Geosynchronous Satellite Launch Vehicle) g - suit G - type asteroid Guericke, Otto von (1602 — 1686) guanine Guiana Space Centre guidance, inertial Guide Star Catalog (GSC) guided missile guided missiles, postwar development Guillaume, Charles Édouard (1861 — 1938) Gulf Stream (ocean current) Gulfstream (jet plane) Gullstrand, Allvar (1862 — 1930) gum Gum Nebula gun metal gunpowder Gurwin Gusev Crater gut Gutenberg, Johann (c. 1400 — 1468) Guy, Richard Kenneth (1916 ---RRB- guyot Guzman Prize gymnosperm gynecology gynoecium gypsum gyrocompass gyrofrequency gyropilot gyroscope gyrostabilizer Gyulbudagian's Nebula (HH2and Interior Laboratory) grain (cereal) grain (unit) gram gram - atom Gramme, Zénobe Théophile (1826 — 1901) gramophone Gram's stain Gran Telescopio Canarias (GTC) 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 grass grassland gravel graveyard orbit 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 gradient stabilization Gravity Probe A Gravity Probe B gravity - assist gray (Gy) 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 Red Spot Great Rift (in Milky Way) Great Rift Valley Great Square of Pegasus Great Wall greater omentum greatest elongation Green, George (1793 — 1841) Green, Nathaniel E. Green, Thomas Hill (1836 — 1882) green algae Green Bank Green Bank conference (1961) Green Bank Telescope green flash greenhouse effect greenhouse gases 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 grike Grimaldi, Francesco Maria (1618 — 1663) Grissom, Virgil (1926 — 1967) grit gritstone Groom Lake Groombridge 34 Groombridge Catalogue gross ground, electrical ground state ground - track 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 (NGC 7552, NGC 7582, NGC 7590, and NGC 7599) GSLV (Geosynchronous Satellite Launch Vehicle) g - suit G - type asteroid Guericke, Otto von (1602 — 1686) guanine Guiana Space Centre guidance, inertial Guide Star Catalog (GSC) guided missile guided missiles, postwar development Guillaume, Charles Édouard (1861 — 1938) Gulf Stream (ocean current) Gulfstream (jet plane) Gullstrand, Allvar (1862 — 1930) gum Gum Nebula gun metal gunpowder Gurwin Gusev Crater gut Gutenberg, Johann (c. 1400 — 1468) Guy, Richard Kenneth (1916 ---RRB- guyot Guzman Prize gymnosperm gynecology gynoecium gypsum gyrocompass gyrofrequency gyropilot gyroscope gyrostabilizer Gyulbudagian's Nebula (HH2AND GRAPH THEORY graptolite grass grassland gravel graveyard orbit 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 gradient stabilization Gravity Probe A Gravity Probe B gravity - assist gray (Gy) 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 Red Spot Great Rift (in Milky Way) Great Rift Valley Great Square of Pegasus Great Wall greater omentum greatest elongation Green, George (1793 — 1841) Green, Nathaniel E. Green, Thomas Hill (1836 — 1882) green algae Green Bank Green Bank conference (1961) Green Bank Telescope green flash greenhouse effect greenhouse gases 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 grike Grimaldi, Francesco Maria (1618 — 1663) Grissom, Virgil (1926 — 1967) grit gritstone Groom Lake Groombridge 34 Groombridge Catalogue gross ground, electrical ground state ground - track 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 (NGC 7552, NGC 7582, NGC 7590, and NGC 7599) GSLV (Geosynchronous Satellite Launch Vehicle) g - suit G - type asteroid Guericke, Otto von (1602 — 1686) guanine Guiana Space Centre guidance, inertial Guide Star Catalog (GSC) guided missile guided missiles, postwar development Guillaume, Charles Édouard (1861 — 1938) Gulf Stream (ocean current) Gulfstream (jet plane) Gullstrand, Allvar (1862 — 1930) gum Gum Nebula gun metal gunpowder Gurwin Gusev Crater gut Gutenberg, Johann (c. 1400 — 1468) Guy, Richard Kenneth (1916 ---RRB- guyot Guzman Prize gymnosperm gynecology gynoecium gypsum gyrocompass gyrofrequency gyropilot gyroscope gyrostabilizer Gyulbudagian's Nebula (HH2AND 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 (NGC 7552, NGC 7582, NGC 7590, and NGC 7599) GSLV (Geosynchronous Satellite Launch Vehicle) g - suit G - type asteroid Guericke, Otto von (1602 — 1686) guanine Guiana Space Centre guidance, inertial Guide Star Catalog (GSC) guided missile guided missiles, postwar development Guillaume, Charles Édouard (1861 — 1938) Gulf Stream (ocean current) Gulfstream (jet plane) Gullstrand, Allvar (1862 — 1930) gum Gum Nebula gun metal gunpowder Gurwin Gusev Crater gut Gutenberg, Johann (c. 1400 — 1468) Guy, Richard Kenneth (1916 ---RRB- guyot Guzman Prize gymnosperm gynecology gynoecium gypsum gyrocompass gyrofrequency gyropilot gyroscope gyrostabilizer Gyulbudagian's Nebula (HH2and NGC 7599) GSLV (Geosynchronous Satellite Launch Vehicle) g - suit G - type asteroid Guericke, Otto von (1602 — 1686) guanine Guiana Space Centre guidance, inertial Guide Star Catalog (GSC) guided missile guided missiles, postwar development Guillaume, Charles Édouard (1861 — 1938) Gulf Stream (ocean current) Gulfstream (jet plane) Gullstrand, Allvar (1862 — 1930) gum Gum Nebula gun metal gunpowder Gurwin Gusev Crater gut Gutenberg, Johann (c. 1400 — 1468) Guy, Richard Kenneth (1916 ---RRB- guyot Guzman Prize gymnosperm gynecology gynoecium gypsum gyrocompass gyrofrequency gyropilot gyroscope gyrostabilizer Gyulbudagian's Nebula (HHStar Catalog (GSC) guided missile guided missiles, postwar development Guillaume, Charles Édouard (1861 — 1938) Gulf Stream (ocean current) Gulfstream (jet plane) Gullstrand, Allvar (1862 — 1930) gum Gum Nebula gun metal gunpowder Gurwin Gusev Crater gut Gutenberg, Johann (c. 1400 — 1468) Guy, Richard Kenneth (1916 ---RRB- guyot Guzman Prize gymnosperm gynecology gynoecium gypsum gyrocompass gyrofrequency gyropilot gyroscope gyrostabilizer Gyulbudagian's Nebula (HH215)

Learn about the formation and origin of the Solar System and go beyond our neighborhood to investigate exoplanets (planets around other stars) in this video of class 11 of Bruce Betts» Introduction to Planetary Science and Astronomy class.