The Small Magellanic Cloud (SMC) is an irregular dwarf galaxy and a satellite of the Milky Way. It has a diameter of about 7,000 light-years (2.1 kpc) and is about 200,000 light-years (60 kpc) away from Earth. It contains a mass of approximately 10 billion solar masses, making it one of the most massive galaxies in the Local Group. The SMC is classified as an irregular galaxy because it lacks a well-defined spiral or elliptical structure.
The SMC was discovered in 1499 by Antonio Pigafetta, who accompanied Ferdinand Magellan on his voyage around the world. In 19th-century observations, the SMC appeared to be part of our Milky Way Galaxy and was thus nicknamed “the Little Cloud” or “Magellanic Stream”. However, later studies showed that the SMC is actually far beyond our own Galaxy and is one of its satellites.
The SMC is rich in star clusters and nebulae. Among the most notable are 47 Tucanae (a globular cluster), NGC 346 (an emission nebula with embedded star clusters), DEM L316A (a supernova remnant), and N11L MCPS J00452748-7259191 (a young star cluster). The Large Magellanic Cloud (LMC), another satellite galaxy of ours, lies only 50 kpc away from us and 4 times closer than the SMC; as a result, we can see many more features in detail in the LMC than we can in its smaller companion.