New maps from ESA’s Planck satellite, forming the second major data release (February 2015) from the project, have unveiled the polarised light from the early Universe across the entire sky, revealing that the first stars formed much later than previously thought.
New in the 2015 release is the use of high resolution polarisation information of cosmic microwave background (CMB) data. The standard cosmological model remains an excellent fit to the data. The data have also enabled new important insights into the early cosmos and its components, including the intriguing dark matter and the elusive neutrinos.
The international Planck Collaboration which produced these results include UCL researchers in Physics & Astronomy’s Astrophysics Group and the Mullard Space Science Laboratory.
Figure: A visualisation of the polarisation of the Cosmic Microwave Background, or CMB, as detected by ESA’s Planck satellite over the entire sky. The CMB is a snapshot of the oldest light in our Universe, imprinted on the sky when the Universe was just 380 000 years old. It shows tiny temperature fluctuations that correspond to regions of slightly different densities, representing the seeds of all future structure. A small fraction of the CMB is polarised – it vibrates in a preferred direction. In this image, the colour scale represents temperature differences in the CMB, while the texture indicates the direction of the polarised light. The patterns seen in the texture are characteristic of ‘E-mode’ polarisation, which is the dominant type for the CMB. For the sake of illustration, both data sets have been filtered to show mostly the signal detected on scales around 5 degrees on the sky. However, fluctuations in both the CMB temperature and polarisation are present and were observed by Planck on much smaller angular scales, too. (Credit: ESA/Planck)