First glimpse of Planck all-sky survey

ESA have today released this image of data from the first year of the Planck microwave survey. The bright blue and white swirls across the centre of the image is from dust in the milky way, but the most interesting part of the image is the red and orange effects around the top and bottom. This is a clear view of the cosmic microwave background left over from the big bang seen at resolutions never possible before.

Planck is space-based telescope launched in 2009. For the last year it has been sitting at the L2 Lagrangian point away from the Earth’s interference. Two instruments are used to measure microwave radiation at 9 different frequencies. The image released today is a composite of reduced resolution designed to show off what Planck is capable of for the media without giving away the data that will be used for scientific analysis. It is no conincidence that the resolution is just right to use as your desktop wallpaper. The real data is three times more detailed and the different frequencies can be combined to subtract out most of the foreground galactic radiation which for the purposes of large scale cosmology is just noise. We will probably have to wait another two years before we are allowed to see the full results.

Another feature of the Planck survey that was not available with the earlier COBE and WMAP surveys is measurement of the polarisation of the microwaves. This will add another dimension to the data that will help to tell us about features of the background radiation. The images from Planck will improve our understanding of the parameters of the expanding universe (Hubble and Cosmological constants) and the formation of galaxies and galactic clusters in the early universe. In fact it should be possible to produce a detailed catalogue of galactic clusters because of the distortion of the background due to high energy electrons. Another goal of the Planck mission is to observe the gravitational lensing of the background due to dark matter.


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