New view of Universe from Planck

25 March 2013

Europe's Planck satellite has compiled the most detailed map ever of the cosmic microwave background (CMB). The map gives a picture of how the Universe looked just 380,000 years after the Big Bang, and shows the seeds of cosmic structure.

The team behind the mission, including scientists from Oxford, report results giving a more accurate recipe for the composition of the Universe and the relative amounts of dark matter and dark energy, and bolsters evidence for inflation in the early Universe.

'Part of the Oxford team's job was to use data from other experiments, such as the Atacama Cosmology Telescope, to 'clean up' the Planck signal and help us see through all the very bright objects, including our Galaxy and distant galaxies, that lie between us and this echo of the ancient Universe,' said Dr Jo Dunkley of Oxford University's Department of Physics, who led Oxford's Planck research team with post-docs Dr Erminia Calabrese and Dr Charmaine Armitage-Caplan.

The properties of the hot and cold regions of the map provide information about the composition and evolution of the Universe. Normal matter that makes up stars and galaxies contributes 4.9% of the mass/energy density of the Universe. Dark matter, which has so far only been detected indirectly by its gravitational influence, makes up 26.8%. Dark energy, thought to be responsible for accelerating the expansion of the Universe, accounts for around 69%.

The new analysis also gives strong support for theories of inflation, a very brief phase during the first tiny fraction of a second of the Universe's existence. As well as explaining many properties of the Universe as a whole, this initial expansion caused the ripples in the CMB that we see today. But because the precision of Planck's map is so high, it also reveals some peculiar unexplained features. Amongst the most surprising findings are that the fluctuations in the CMB over large scales do not quite match those predicted by the standard model.

See here for the Oxford University news story.