The Magellanic Clouds were recognized early in the 20th century as companion objects to the Galaxy. When American astronomer Edwin Hubble established the extragalactic nature of what we now call galaxies, it became plain that the Clouds had to be separate systems, both of the irregular class and more than 100,000 light-years distant. (The current best values for their distances are 160,000 and 190,000 light-years for the Large and Small Clouds, respectively.) Additional close companions have been found, all of them small and inconspicuous objects of the dwarf elliptical class. The nearest of these is the Sagittarius dwarf, a galaxy that is falling into the Milky Way Galaxy, having been captured tidally by the Galaxy’s much stronger gravity. Other close companions are the well-studied Carina, Draco, Fornax, Leo I, Leo II, Sextans, Sculptor, and Ursa Minor galaxies, as well as several very faint, less well-known objects. Distances for them range from approximately 200,000 to 800,000 light-years. The grouping of these galaxies around the Milky Way Galaxy is mimicked in the case of the Andromeda Galaxy, which is also accompanied by several dwarf companions.
Milky-Way-Galaxy-as-seen-from-EarthMilky Way Galaxy as seen from Earth[Credits : © Dirk Hoppe]
Bright-nebulosity-in-the-Pleiades-distance-490-light-yearsBright nebulosity in the Pleiades (M45, NGC 1432), distance 490 light-years.[Credits : Hale Observatories ©1961]
Centre-of-the-Orion-Nebula-Astronomers-have-identified-some-700Centre of the Orion Nebula (M42).[Credits : Photo AURA/STScI/NASA/JPL (NASA photo # STScI-PRC95-45a)]
Composite-picture-of-the-Cats-Eye-Nebula-combining-three-imagesComposite picture of the Cat’s Eye Nebula (NGC 6543), combining three images taken by the Hubble …[Credits : Photo AURA/STScI/NASA/JPL (NASA photo # STScI-PRC95-01a)]
The-Crab-Nebula-which-was-formed-by-a-supernova-explosionThe Crab Nebula, which was formed by a supernova explosion recorded in 1054. This image was made by …[Credits : NASA]
The-Eagle-NebulaThe Eagle Nebula. Stars are forming in this column of cold dust and gas, which is 9.5 light-years …[Credits : NASA, ESA, and The Hubble Heritage Team (STScI/AURA)]
Horsehead-NebulaHorsehead Nebula[Credits : © Anglo-Australian Observatory]
Globular-cluster-NGC-1850-in-the-Large-Magellanic-CloudGlobular cluster NGC 1850 in the Large Magellanic Cloud.[Credits : Photo AURA/STScI/NASA/JPL (NASA photo # STScI-PRC94-40)]
Our solar system is just a miniscule part of a much larger system called the Milky Way Galaxy.[Credits : Acquired from Vast Video]
The universe is made up of many stars, solar systems, and galaxies.[Credits : Acquired from Vast Video]
Using their telescope, the brother and sister team of William and Caroline Herschel discovered the …[Credits : Acquired from Vast Video]
We welcome your comments. Any revisions or updates suggested for this article will be reviewed by our editorial staff. Contact us here.
Regular users of Britannica may notice that this comments feature is less robust than in the past. This is only temporary, while we make the transition to a dramatically new and richer site. The functionality of the system will be restored soon.