A glimpse of the Milky Way

The Spitzer Space Telescope’s infrared eyes have delivered the best view of our galaxy’s inner regions that we likely will see for the foreseeable future. Because infrared light penetrates dust, the composite image shows the galactic plane out to 60,000 light-years from Earth — slightly more than double the distance to the Milky Way’s center.

To create the image, Spitzer scientists stitched together more than 800,000 snapshots. The image spans approximately 130° east to west (centered on the galaxy’s core) and up to 2° north and south of the plane. “This is the highest-resolution, largest, and most sensitive infrared picture ever taken of our Milky Way,” says Sean Carey of the Spitzer Science Center at the California Institute of Technology in Pasadena. “With this data, we can learn how massive stars form, map galactic spiral arms, and make a better estimate of our galaxy’s star-formation rate.”

The data came from two separate surveys: the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) and the Multiband Imaging Photometer for Spitzer Inner Galactic Plane Survey (MIPSGAL). In the final image, blue represents light of 3.6 micrometers, green shows light of 8 micrometers, and red reveals light of 24 micrometers. In comparison, visible light ranges from 0.4 to 0.7 micrometer.

The broad swaths of green reveal organic molecules known as polycyclic aromatic hydrocarbons. They encompass regions filled with developing stellar embryos. The curved ridges in the green clouds, dubbed bubbles, contain young stars. The stars themselves appear as yellow and red dots. And the reddish wisps filling most of the bubbles reveal particles of graphite dust. The blue specks sprinkled throughout the image are relatively old stars.

This image shows the Milky Way from approximately 65° galactic longitude (at left) to 39° longitude — Vulpecula to Aquila — and within 1° galactic latitude north and south of the galaxy’s plane. Click here to see a larger view.

All images by: NASA/JPL-Caltech/University of Wisconsin

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This image shows the Milky Way from approximately 39° galactic longitude (at left) to 13° longitude — Aquila to northern Sagittarius — and within 1° galactic latitude north and south of the galaxy’s plane. The bright red-and-yellow complex at the top border and near the right edge is the Eagle Nebula (M16) in Serpens. Click here to see a larger view.

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This image shows the Milky Way from approximately 13° galactic longitude (at left) to 347° longitude — from northern to southern Sagittarius and centered on galactic center — and within 2° galactic latitude north and south of the galaxy’s plane. Click here to see a larger view.

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This image shows the Milky Way from approximately 347° galactic longitude (at left) to 321° longitude — southern Sagittarius to Circinus — and within 1° galactic latitude north and south of the galaxy’s plane. Click here to see a larger view.

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This image shows the Milky Way from approximately 321° galactic longitude (at left) to 295° longitude — Circinus to western Centaurus — and within 1° galactic latitude north and south of the galaxy’s plane. Click here to see a larger view.