[[File:M101 hires STScI-PRC2006-10a.jpg|thumb|Contoh galaksi spiral, An example of a spiral galaxy, the [[PinwheelGalaksj Galaxykincir]] (alsodipinandui jua knownlawan asngaran Messier 101 oratawa NGC 5457)|285x285px]]
'''SpiralGalaksi galaxiesspiral''' form amambantuk [[galaxyklasifikasi morphologicalmorfologi classificationgalaksi|classkelas ofmatan galaxygalaksk]] originallynang describedpamulaannya bydijalasakan ulih [[Edwin Hubble]] indi hisbuku nang ditulisnya pas tahun 1936 worknang bajudul ''The Realm of the Nebulae''<ref name="Hubble-1936">{{cite book|url=https://books.google.com/books?id=kgiXdDGLpFUC|title=The realm of the nebulae|last=Hubble|first=E.P.|publisher=[[Yale University Press]]|year=1936|isbn=9780300025002|series=Mrs. Hepsa Ely Silliman memorial lectures, 25|location=New Haven|oclc=611263346|author-link=Edwin Hubble}} [https://archive.org/details/TheRealmOfTheNebulae Alt URL](pp. 124–151)</ref> and, as such, form part of the [[Hubble sequence]]. Most spiral galaxies consist of a flat, rotating [[Disc (galaxy)|disk]] containing [[star]]s, [[Interstellar medium|gas and dust]], and a central concentration of stars known as the [[Bulge (astronomy)|bulge]]. These are often surrounded by a much fainter [[Galactic halo|halo]] of stars, many of which reside in [[globular cluster]]s.
Spiral galaxies are named by their spiral structures that extend from the center into the galactic disc. The spiral arms are sites of ongoing star formation and are brighter than the surrounding disc because of the young, hot [[OB star]]s that inhabit them.
