Filamentary structures in our Milky Way galaxy are apparent at
large scales (as shown in this Planck image, on the right) and
small scales (as seen in the Herschel image on the left). This
Planck image, covering a portion of the sky about 55 degrees in
total extent, was obtained by the Planck High Frequency
Instrument at a frequency of 857 Gigahertz (corresponding to a
wavelength of 350 micrometers). The bright horizontal band
corresponds to the plane of our spiral galaxy, which is seen in
cross-section from our vantage point. The colors in the Planck
images represent the intensity of heat radiation by dust. This
Planck image was obtained during the first Planck all-sky
survey, which began in mid-August 2009. By mid-March 2010, more
than 98 percent of the sky had been observed. The second sky
scan is underway, but, because of the way Planck surveys the
sky, the first scan won't be 100 percent complete until late-May
2010. Planck is a European Space Agency mission, with
significant participation from NASA. NAS