Astronomical Dictionary on Letter #G

Galaxy

Vast star systems containing thousands of billions of stars, dust and gas, held together by gravity....

Galilean Moons

Jupiter's four largest moons: Io, Europa, Ganymede and Callisto. ...

Galileo

(1564-1642) Italian mathematician, astronomer, and physicist. First to use a telescope to observe th...

Geosynchronous Orbit

Sometimes known as a geostationary orbit, in which a satellite's orbital velocity is matched to the ...

Globular Cluster

A spherical cluster of older stars, often found in galaxies. These clusters form a sphere surroundin...

Granulation

The mottled, orange peel, appearance of the Sun's surface; caused by convection within the Sun and o...

Geomorphology

The study of the external structure, form, and arrangement of rocks in relation to the development o...

Geyser

A type of hot spring that intermittently erupts jets of material. ...

Giotto

Giotto di Bondone (1267?-1337) Italian medieval painter, architect, and sculptor....

Graben

A long, relatively depressed crustal unit or block that is bounded by faults along its sides; a tro...

Gula

One of the primary goddesses of the Akkadian and Babylonian peoples. The mother-goddess and great ph...