Planck challenges our understanding of the Universe
21st March 2013
The Planck map of the Cosmic Microwave Background. Full resolution version.
Image Credits: ESA, LFI and HFI Consortia (2013)
A false-colour image of the whole sky as seen by Planck. The dust throughout the Galaxy (as seen by HFI) is shown in blue, while hot gas (as measured by LFI) can be seen as red regions across the centre of the image. In the background, the mottled yellow features are relic radiation, called the Cosmic Microwave Background, which contains information about the earliest stages of the Universe. This image is a low-resolution version of the full data set.
Image Credits: ESA, LFI and HFI Consortia (2010)
Europe’s Planck space telescope, which University of Manchester scientists at the Jodrell Bank Observatory helped build, has compiled the most detailed map of the post-Big Bang Universe ever recorded and thrown up anomalies that current physics cannot yet explain.
But the data – released today (Thursday) by the European Space Agency – also provides the best evidence yet to support the standard model of cosmology, dates the Universe at 13.82 billion years and refines our knowledge of the Universe’s composition and evolution.
The Planck satellite telescope, a flagship mission for the UK Space Agency, has produced the most accurate values yet for the ingredients of the Universe, with normal matter – the things we see and feel around us – making up just 4.9% of the Universe’s density (mass and energy) and dark matter contributing 26.8%, nearly a fifth more than previously estimated.
Professor Richard Davis, who led the University of Manchester Planck team, said: “The information extracted from Planck’s new map provides excellent confirmation of the standard model of cosmology with unprecedented accuracy and sets a new benchmark for our knowledge of the ingredients of the Universe.
“But because the precision of Planck’s map is so high, it has also revealed some unexplained anomalies in the data that require further study. Among these interesting findings are fluctuations in the cosmic microwave background over large scales that do not match what the standard model of physics predicts, including an asymmetry in the average temperatures on opposite hemispheres of the skies.”
The Planck telescope’s image is based on the initial 15 months of data and is the mission’s first all-sky picture of the oldest light in the Universe, imprinted when the Universe was just 380,000 years old. The cosmic microwave background (CMB) the telescope has measured shows tiny temperature fluctuations that correspond to regions of slightly different densities at very early times after the Big Bang; these fluctuations represent the seeds of all future structure – the stars and galaxies – we see today.
One way to explain the anomalies is to propose that the Universe is not, in fact, the same in all directions on a larger scale than we have so far observed. In this scenario, the light rays from the CMB may have taken a more complicated route through the cosmos than previously understood, resulting in some of the unusual patterns observed by Planck.
Professor Richard Battye, from the Jodrell Bank Centre of Astrophysics at the University of Manchester, said: "Planck has provided us with a huge amount of information about the nature of the very early Universe and the fundamental processes taking place there. The data are broadly consistent with the standard picture that has emerged over the last 20 years, but there are also a number of tantalising hints that there is something missing in our understanding. It will be fun trying to figure out what is going on."
Dr Chris Castelli, Acting Director of Science, Technology and Exploration at the UK Space Agency, said: “With its ability to make such detailed and accurate observations, Planck is helping us to place the vital pieces of the jigsaw that could give us a full picture of the evolution of the Universe, rewriting the textbooks along the way.”
George Efstathiou, University of Cambridge, added: “The CMB temperature fluctuations detected by Planck confirm once more that the relatively simple picture provided by the simple model is an amazingly good description of the Universe.”
Notes for Editors:
Images and animations
UK involvement in Planck
The UK is playing a major role in the Planck mission. A number of UK institutes and companies form part of the consortium that built the two focal plane instruments, HFI and LFI. The Jodrell Bank Observatory at The University of Manchester produced critical elements of the LFI receiver modules. Cardiff University, STFC RAL and SEA were involved with hardware development for HFI, while various UK research groups including Imperial College London, University of Cambridge, and University of Oxford form the London Planck Analysis Centre and Cambridge Planck Analysis Centre. These groups are involved with data analysis and simulation for the HFI data analysis and simulation software
Jodrell Bank's role in Planck
Jodrell Bank Centre for Astrophysics (JBCA) is directly involved with the two lowest frequencies of the Low Frequency Instrument, the 30 and 44 GHz radiometers. These have 4 and 6 detectors respectively, operating at 20K (-253.15°C or -423.67°F). The resolution on the sky is 33 and 27 arc minutes, and the sensitivity 1.6 and 2.4 micro K (over 12 months). The cryogenic low noise amplifiers which are the heart of the radiometers were developed at Jodrell Bank, with help from the National Radio Astronomy Observatory in Virginia, USA.
Dr B. Maffei and Dr G. Pisano are involved in the other focal instrument, the HFI. First at Cardiff University and now at the University of Manchester, they have played a major role in the design, development and calibration of the Focal Plane Unit, in particular the cold optics, in collaboration with the Institut d'Astrophysique Spatiale - France, Maynooth University - Ireland and JPL/Caltech - USA.
The work to understand the Galactic emission seen by Planck is being co-led from Jodrell Bank by Emeritus Professor Rod Davies and Dr Clive Dickinson. A number of projects are led by Jodrell Bank scientists, including Professor Richard Davis and Dr Clive Dickinson. Each of the 14 projects focusses on one aspect of the Galaxy as seen by Planck, including the electrons that gyrate in the Galactic magnetic field, the ionized gas that pervades the interstellar medium and the dust grains that emit across the entire frequency range that Planck is sensitive to. Jodrell Bank is also leading the calibration and identifying systematics in the LFI data.
Planck all-sky image and the CMB
The all-sky picture is of the oldest light in our Universe, imprinted on the sky when it was just 380 000 years old.
At that time, the young Universe was filled with a hot dense soup of interacting protons, electrons and photons at about 2700ºC. When the protons and electrons joined to form hydrogen atoms, the light was set free. As the Universe has expanded, this light today has been stretched out to microwave wavelengths, equivalent to a temperature of just 2.7 degrees above absolute zero.
This ‘cosmic microwave background’ – CMB – shows tiny temperature fluctuations that correspond to regions of slightly different densities at very early times, representing the seeds of all future structure: the stars and galaxies of today.
According to the standard model of cosmology, the fluctuations arose immediately after the Big Bang and were stretched to cosmologically large scales during a brief period of accelerated expansion known as inflation.
Planck was designed to map these fluctuations across the whole sky with greater resolution and sensitivity than ever before. By analysing the nature and distribution of the seeds in Planck’s CMB image, we can determine the composition and evolution of the Universe from its birth to the present day.
A series of scientific papers describing the new results will be published on 22 March.
The new data from Planck are based on the first 15.5 months of its all-sky surveys. Launched in 2009, Planck was designed to map the sky in nine frequencies using two state-of-the-art instruments: the Low Frequency Instrument (LFI), which includes the frequency bands 30–70 GHz, and the High Frequency Instrument (HFI), which includes the frequency bands 100–857 GHz. HFI completed its survey in January 2012, while LFI continues to operate.
Planck’s first all-sky image was released in 2010 and the first scientific data were released in 2011. Since then, scientists have been extracting the foreground emissions that lie between us and the Universe’s first light to reveal the CMB presented in this release. The next set of cosmology data will be released in early 2014.
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