The Small Magellanic Cloud (SMC) is a dwarf galaxy near the Milky Way. It is classified as a dwarf irregular galaxy. It has a diameter of about 7,000 light-years, contains several hundred million stars, and has a total mass of approximately 7 billion times the mass of the Sun. The SMC contains a central bar structure and it is speculated that it was once a barred spiral galaxy that was disrupted by the Milky Way to become somewhat irregular. At a distance of about 200,000 light-years, it is one of the Milky Way's nearest neighbors. It is also one of the most distant objects that can be seen with the naked eye.
With a mean declination of approximately −73 degrees, it can only be viewed from the Southern Hemisphere and the lower latitudes of the Northern Hemisphere. It is located mostly in the constellation of Tucana and also partly in Hydrus and appears as a hazy, light patch in the night sky about 3 degrees across, looking like a detached piece of the Milky Way. Since it has a very low surface brightness, it is best viewed from a dark site away from city lights. It forms a pair with the Large Magellanic Cloud (LMC), which lies a further 20 degrees to the east, and like the LMC is a member of the Local Group.
Image Credit: ESA/Hubble and Digitized Sky Survey 2, Davide De Martin
Explanation from: https://en.wikipedia.org/wiki/Small_Magellanic_Cloud