Figure 1
In visible light, the bulk of our Milky Way galaxy's stars are eclipsed
behind thick clouds of galactic dust and gas. But to the infrared eyes of
NASA's Spitzer Space Telescope, distant stars and dust clouds shine with
unparalleled clarity and color.
In this panoramic image (center row, fig. 1) from the Galactic Legacy
Infrared Mid-Plane Survey Extraordinaire project, a plethora of stellar
activity in the Milky Way's galactic plane, reaching to the far side of
our galaxy, is exposed. This image spans 9 degrees of sky (approximately
the width of a fist held out at arm's length).
The red clouds indicate the presence of large organic molecules (mixed
with the dust), which have been illuminated by nearby star formation. The
patches of black are dense obscuring dust clouds impenetrable by even
Spitzer's super-sensitive infrared eyes. Bright arcs of white throughout
the image are massive stellar incubators.
With over 160 megapixels, the full detail in this panorama cannot be
appreciated without zooming in to various areas of interest (top and
bottom rows, fig. 1). Bubbles, or holes, in the red clouds are formed by
the powerful outflows from massive groups of forming stars. Wisps of green
indicate the presence of hot hydrogen gas. Star clusters can also be seen
as the groupings of blue, yellow, and green specks inside some of the red
nebulae, or star-forming clouds.
In contrast to the plentiful examples of stellar youth in this montage,
Spitzer also sees an object called a planetary nebula (top row, middle,
fig. 1). Such nebulae are the final gasp of dying stars like our sun,
whose outer layers are blown into space, leaving a burnt out core of a
star, called a white dwarf, behind.
Although this panoramic image captures a large range of the galaxy, it
represents only 7.5 percent of the primary Glimpse survey, which will
image most of the star formation regions in our galaxy.
The infrared images were captured with the Spitzer's infrared array
camera. The pictures are 4-channel false-color composites, showing
emission from wavelengths of 3.6 microns (blue), 4.5 microns (green), 5.8
microns (orange), and 8.0 microns (red).
Caution: Images are best resolution available and are very large.
