2007-12-12 06:10:17 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Astronomy & Space
http://images.search.yahoo.com/search/images;_ylt=A0geu7YTNGBHwwAAdvZXNyoA?ei=UTF-8&p=galaxies&fr2=tab-web&fr=ush-ans
2007-12-12 06:20:10 · answer #1 · answered by michaell 6 · 1⤊ 0⤋
Spiral galaxies consist of a flat, rotating disk of stars, gas and dust, and a central concentration of stars known as the bulge. These are surrounded by a much fainter halo of stars, many of which reside in globular clusters. Elliptical galaxies have smooth, featureless light-profiles and range in shape from nearly spherical to highly flattened, and in size from hundreds of millions to over one trillion stars. In the outer regions, many stars are grouped into globular clusters. Most elliptical galaxies are composed of older, low-mass stars, with a sparse interstellar medium and minimal star formation activity They are often chaotic in appearance, with neither a nuclear bulge nor any trace of spiral arm structure. Collectively they are thought to make up about a quarter of all galaxies. Most irregular galaxies were once spiral or elliptical galaxies but were deformed by gravitational action.
2016-05-23 06:00:28 · answer #2 · answered by Anonymous · 0⤊ 0⤋
The center of each galaxy has a black hole in the middle which furnishes the gravity of all the solar systems around it.
2007-12-12 06:50:41 · answer #3 · answered by JOHNNIE B 7 · 0⤊ 0⤋