Milky Way - Structure

Structure

A false-color infrared image of the core of the Milky Way Galaxy taken by NASA's Spitzer Space Telescope. Older cool stars are blue, dust features lit up by large hot stars are shown in a reddish hue, and the bright white spot in the middle marks the site of Sagittarius A*, the super-massive black hole at the center of the Galaxy.

The Galaxy consists of a bar-shaped core region surrounded by a disk of gas, dust and stars. The gas, dust and stars are organized in roughly logarithmic spiral arm structures (see Spiral arms below). The mass distribution within the Galaxy closely resembles the SBc Hubble classification, which is a spiral galaxy with relatively loosely wound arms. Astronomers first began to suspect that the Milky Way is a barred spiral galaxy, rather than an ordinary spiral galaxy, in the 1990s. Their suspicions were confirmed by the Spitzer Space Telescope observations in 2005 that showed the Galaxy's central bar to be larger than previously suspected.

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Famous quotes containing the word structure:

    “The structure was designed by an old sea captain who believed that the world would end in a flood. He built a home in the traditional shape of the Ark, inverted, with the roof forming the hull of the proposed vessel. The builder expected that the deluge would cause the house to topple and then reverse itself, floating away on its roof until it should land on some new Ararat.”
    —For the State of New Jersey, U.S. public relief program (1935-1943)

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    —Karl Wilhelm Von Humboldt (1767–1835)

    “When a house is tottering to its fall,
    The strain lies heaviest on the weakest part,
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    —Ovid (Publius Ovidius Naso)