When the Planck probe was launched with the Herschel Infrared Space Telescope back on the 14th of May, it slowly made its way to the L2 Lagrangian point, a parking place in space created by the interaction of the Sun and the Earth’s gravitational fields, one million miles behind the Earth itself, though the orbit around L2 is so large it isn’t in the shadow of the Earth. After a six week journey, the probe spent another six weeks cooling down to a tenth of a degree above absolute zero. Then a further six weeks were spent calibrating the instruments.
All the preparations were done and dusted by the 13th of August. On this date the First Light Survey began. Planck spent a fortnight examining a fifteen degree wide strip of the night sky with all nine of its observation channels. Three channels are part of the UK built Low Frequency Instrument and six come from the High Frequency Instrument, both of which are looking at microwaves. The microwaves in question belong either to the Cosmic Microwave Background, light left over from the time the Universe became transparent to light, or they are part of the radiation from the galaxy and other sources that need to be removed for best viewing of the CMB (and vice versa). The data has now been released, the mainstream media and more traditional astronomy news sheets reported.
The probe will be searching for temperature variations in the Cosmic Microwave Background with unprecedented clarity. The team behind Planck boast that more has been learnt from the fortnight long first light strip than the five year long WMAP mission, the previous best look at the CMB.
With the first light survey completed, Planck immediately moved onto the main operational goal – fifteen months worth of scanning the sky in order to produce two all sky maps. The first will be released using the initial six months of data and the second will use the full fifteen months worth.