Image: Hubble sees a spiral in good company

This image, taken with Hubble's Wide Field Camera 3, features the spiral galaxy NGC 4680. Two other galaxies, at the far right and bottom center of the image, flank NGC 4680. NGC 4680 enjoyed a wave of attention in 1997, ...

Hubble images a galaxy in dazzling detail

This image features the spiral galaxy NGC 691, imaged in fantastic detail using Hubble's Wide Field Camera 3 (WFC3). This galaxy is a member of the NGC 691 galaxy group named after it, which features a group of gravitationally ...

Image: Hubble captures a captivating spiral

This image shows the spiral galaxy NGC 5037, in the constellation of Virgo. First documented by William Herschel in 1785, the galaxy lies about 150 million light-years away from Earth. Despite this distance, we can see the ...

Does the Milky Way move like a spinning top?

An investigation carried out by the astrophysicists of the Instituto de Astrofísica de Canarias (IAC) Žofia Chrobáková, a doctoral student at the IAC and the University of La Laguna (ULL), and Martín López Corredoira, ...

Hubble gazes at a galactic menagerie

This packed image taken with the NASA/ESA Hubble Space Telescope showcases the galaxy cluster ACO S 295, as well as a jostling crowd of background galaxies and foreground stars. Galaxies of all shapes and sizes populate this ...

ALMA discovers the most ancient galaxy with spiral morphology

Analyzing data obtained with the Atacama Large Millimeter/submillimeter Array (ALMA), researchers found a galaxy with a spiral morphology by only 1.4 billion years after the Big Bang. This is the most ancient galaxy of its ...

Hubble takes a spiral snapshot

The luminous heart of the galaxy M61 dominates this image, framed by its winding spiral arms threaded with dark tendrils of dust. As well as the usual bright bands of stars, the spiral arms of M61 are studded with ruby-red ...

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Spiral galaxy

A spiral galaxy is a galaxy belonging to one of the three main classes of galaxy originally described by Edwin Hubble in his 1936 work “The Realm of the Nebulae” and, as such, forms part of the Hubble sequence. Spiral galaxies consist of a flat, rotating disk containing stars, gas and dust, and a central concentration of stars known as the bulge. These are surrounded by a much fainter halo of stars, many of which reside in globular clusters.

Spiral galaxies are named for the (usually two-armed) spiral structures that extend from the center into the disk. The spiral arms are sites of ongoing star formation and are brighter than the surrounding disk because of the young, hot OB stars that inhabit them. Roughly half of all spirals are observed to have an additional component in the form of a bar-like structure, extending from the central bulge, at the ends of which the spiral arms begin. Our own Milky Way has been recently (in the 1990s) been confirmed to be a barred spiral, although the bar itself is difficult to observe from our position within the Galactic disk. The most convincing evidence for its existence comes from a recent survey, performed by the Spitzer Space Telescope, of stars in the Galactic center.

Together with irregulars, spiral galaxies make up approximately 60% of galaxies in the local Universe. They are mostly found in low-density regions and are rare in the centers of galaxy clusters.

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