Dwarf spheroidal galaxy (dSph) is a term in astronomy applied to the nine low luminosity dwarf elliptical galaxies that are companions to the Milky Way and to the similar systems that are companions to the Andromeda Galaxy M31. Jargon redirects here. ... A giant Hubble mosaic of the Crab Nebula, a supernova remnant Astronomy (also frequently referred to as astrophysics) is the scientific study of celestial objects (such as stars, planets, comets, and galaxies) and phenomena that originate outside the Earths atmosphere (such as the cosmic background radiation). ... Dwarf elliptical galaxies are elliptical galaxies that are much smaller than others, classified as dE. They are quite common, and are usually companions to other galaxies. ... Look up companion in Wiktionary, the free dictionary. ... It has been suggested that Andromeda-Milky Way collision be merged into this article or section. ... M31 in a small telescope The Andromeda Galaxy (IPA: , also known as Messier 31, M31, or NGC 224; older texts often called it the Andromeda Nebula) is a spiral galaxy approximately 2. ...

Recently, as growing evidence has indicated that the vast majority of dwarf ellipticals have properties that are not at all similar to elliptical galaxies, but are closer to irregular and late-type spiral galaxies, this term has been used to refer to all of the galaxies that share the properties of those above.

According to the best evidence, these are the most common type of galaxies in the universe (although they may not dominate its luminosity).

See also

• Active galaxy
• Barred spiral galaxy
• Dwarf galaxy
• Dwarf elliptical galaxy
• Elliptical galaxy
• Galaxy morphological classification
• Galaxy formation and evolution
• Groups and clusters of galaxies
• Irregular galaxy
• Lenticular galaxy
• List of galaxies
• List of nearest galaxies
• Ring galaxy
• Spiral galaxy
• Starburst galaxy
• Seyfert galaxy
• Timeline of galaxies, clusters of galaxies, and large scale structure

An active galaxy is a galaxy where a significant fraction of the energy output is not emitted by the normal components of a galaxy: stars, dust and interstellar gas. ... NGC 1300, viewed nearly face-on. ... A dwarf galaxy is a small galaxy composed of up to several billion stars, a small number compared to our own Milky Ways 200-400 billion stars. ... Dwarf elliptical galaxies are elliptical galaxies that are much smaller than others, classified as dE. They are quite common, and are usually companions to other galaxies. ... An elliptical galaxy is a type of galaxy in the Hubble sequence characterized by the following physical properties: The giant elliptical galaxy NGC 4881 (the spherical glow at upper left) lies at the edge of the Coma Cluster of Galaxies. ... Astronomers classify galaxies based on their overall shape (elliptical, spiral or barred spiral) and further by the specific properties of the individual galaxy (for example degree of ellipse, number of spirals or definition of bar). ... In astrophysics, the questions of galaxy formation and evolution are: How, from a homogeneous universe, did we obtain the very heterogeneous one we live in? How did galaxies form? How do galaxies change over time? A spectacular head-on collision between two galaxies is seen in this NASA Hubble Space... Galaxy groups and clusters are super-structures in the spread of galaxies of the cosmos. ... This article or section does not adequately cite its references or sources. ... The Spindle Galaxy (NGC 5866), a lenticular galaxy in the Draco constellation. ... List of galaxies: Abell 1835 IR1916 AM 0644-741 Andromeda Galaxy (M31/NGC 224) Andromeda I Andromeda II Andromeda III Aquarius Dwarf Barnards Galaxy (NGC 6822) Black Eye Galaxy (M64/NGC 4826) Bodes Galaxy (M81/NGC 3031) Canis Major Dwarf Galaxy Carina Dwarf Centaurus A Galaxy Draco Dwarf Fornax... The reader should be aware that there are certain unavoidable difficulties with this list. ... A ring galaxy is a galaxy with a ring-like appearance. ... It has been suggested that spiral nebula be merged into this article or section. ... [[Image: Antennae the collision of NGC 4038/NGC 4039. ... Seyfert galaxies are spiral or irregular galaxies containing an extremely bright nucleus, most likely caused by a supermassive black hole, that can sometimes outshine the surrounding galaxy. ... Timeline of galaxies, clusters of galaxies, and large-scale structure of the cosmos 964 - Al Sufi, a Persian astronomer makes the first preserved recording of the Large Magellanic Cloud. ...

External links

• A popular overview