Most of the dust seen by Planck is very cold, at temperatures as low as around −260 C, and as a result glows in Planck's high frequencies (particularly 353 GHz and above). It is cold, dense clumps of dust and gas that mark the earliest stages of the birth of stars.

Although the dust is concentrated in the disc of our Galaxy, Planck has mapped its distribution all over the sky, showing structure at high Galactic latitudes (looking up or down out of the plane) of the Galaxy. Many other galaxies also contain similar dust, but most of them have been removed from the map of dust shown here.

The emission from the dust seen by Planck must be removed from the maps before cosmological analysis, but is of great interested to astronomers studying star formation in our own Milky Way.

Dust Polarisation

The cold dust grains in our galaxy are aligned to the magnetic field, and this causes the light it emits to be slightly polarised. The direction of this polarisation tells us the orientation of the Galaxy's magnetic field.

The texture used to display the polarisation direction was originally produced by Marc-Antoine Meville-Deschenes, at IAS (Paris).