The large scale of the Universe, galaxy clusters and interstellar dust revealed the European Planck satellite some of their secrets.
Launched in 2009 to observe the anisotropies of the cosmic microwave background (CMB), Planck observed the entire sky in millimeter and submillimeter wavelengths. Before the release of its first ultra precise map of the ‘first light of the Universe’, planned for 2013, Planck revealed precious information about objects in the foreground.
Rotating dust
The origin of the mysterious unusual microwave emission, discovered in the 1990s, is now explained. The observed excess of radiation between 10 and 60GHz would be caused by interstellar grains made of 10 to 50 atoms, rapidly rotating, up to 10 billion times per second. This emission (red in the picture below) is more particularly observed in the interstellar cloud Rho Ophucius.
More gas in the Galaxy
Planck detected and measured an important, hitherto unknown fraction of interstellar gas; up to half the molecular hydrogen in the Galaxy, probably located in the envelope of the interstellar clouds, has just been ‘recovered’.
Evolving cosmic background
The infrared background of the Universe has been mapped by Planck with an unseen precision. The satellite observed it up to frequencies never seen before, in great details. It is now possible to see the cosmic web changing through time, up to 11 billion years in the past (see the animation below).
Early Release Compact Sources Catalogue
The Early release Compact Sources Catalogue (ERCSC) from Planck’s data was also published yesterday. Consisting of nine lists, one for each observation frequency, it contains more than 15,000 objects, of which 189 are clusters of galaxies discovered by Sunyaev-Zel’dovich effect, and 915 are molecular clouds with a temperature below -259°C (the average temperature of dusts in the Galaxy). This is a real gold mine at the disposal of all researchers.
