spiral cloud structure
31Galaxy morphological classification — Artist s concept illustrating bulge no bulge spiral galaxies. Galaxy morphological classification is a system used by astronomers to divide galaxies into groups based on their visual appearance. There are several schemes in use by which galaxies… …
32Andromeda Galaxy — The Andromeda Galax …
33literature — /lit euhr euh cheuhr, choor , li treuh /, n. 1. writings in which expression and form, in connection with ideas of permanent and universal interest, are characteristic or essential features, as poetry, novels, history, biography, and essays. 2.… …
34Saturn — /sat euhrn/, n. 1. an ancient Roman god of agriculture, the consort of Ops, believed to have ruled the earth during an age of happiness and virtue, identified with the Greek god Cronus. 2. Astron. the planet sixth in order from the sun, having an …
35Formation and evolution of the Solar System — Artist s conception of a protoplanetary disk The formation and evolution of the Solar System is estimated to have begun 4.568 billion years ago with the gravitational collapse of a small part of a giant molecular cloud …
36Rings of Saturn — The full set of main rings, imaged as Saturn eclipsed the Sun from the vantage of the Cassini spacecraft on 15 September 2006 (brightness is exaggerated). The pale blue dot at the 10 o clock position, outside the main rings and just inside the G… …
37Dark matter — Not to be confused with antimatter, dark energy, dark fluid or dark flow. For other uses, see Dark Matter (disambiguation) …
38Triangulum Galaxy — Messier 33 Observation data (J2000 epoch) Pronunciation /traɪˈæŋɡjʉləm/ …
39star cluster — Astron. a number of stars of common origin held together as a group by gravitational attraction. Cf. globular cluster, open cluster, stellar association. * * * ▪ astronomy Introduction either of two general types of stellar assemblages held… …
40Galaxy formation and evolution — The study of galaxy formation and evolution is concerned with the processes that formed a heterogeneous universe from a homogeneous beginning, the formation of the first galaxies, the way galaxies change over time, and the processes that have… …
