Planck paints a dusty masterpiece
This week, the European Space Agency (ESA) released glorious maps of the dust in the Milky Way. These maps were created by the Planck satellite, which was launched last year. Its main mission is to map the cosmic microwave background, the radiation that was released when the universe was about 370,000 years old.
So, what’s dust got to do with the CMB?
Well, the thermal emissions of dust can obscure some of the CMB radiation. So, in order to precisely map the CMB, you need to characterize the dust in the Milky Way. The dust is extremely cold – just about 12 degrees above absolute zero in some places, and tens of degrees above absolute zero at its warmest (in the maps, the whiter regions are hotter, and the darker pinks are colder).
But the CMB at 2.75 K is even colder. So, this dust can be a nuisance.
NASA’s WMAP satellite – the gold standard for mapping the CMB until Planck came along – did not have the high frequency coverage necessary to map the dust effectively.
Planck can do that, and it’s doing exactly that as can be seen in this image.
See some pictures of Planck being assembled before launch here.