Researchers from the Lawrence Berkeley National Laboratory (Berkeley Lab) have further analyzed cosmic
microwave background (CMB) radiation data to take a look back through time yet - 100 years to 300,000 years
after the Big Bang.
"We found that the standard picture of an early universe, in which radiation domination was followed by
matter domination, holds to the level we can test it with the new data, but there are hints that radiation
didn't give way to matter exactly as expected," says Eric Linder, a theoretical physicist with Berkeley
Lab's Physics Division and member of the Supernova Cosmology Project.
"There appears to be an excess dash of radiation that is not due to CMB photons."
Click on image to enlarge
The microwave sky as seen by Planck. Mottled structure of the CMB, the oldest light in the universe, is
displayed in the high-latitude regions of the map. The central band is the plane of our galaxy,
the Milky Way. Courtesy of European Space Agency
Our knowledge of the Big Bang and the early formation of the universe stems almost entirely from measurements
of the CMB, primordial photons set free when the universe cooled enough for particles of radiation and
particles of matter to separate.
These measurements reveal the CMB's influence on the growth and development of the large-scale structure
we see in the universe today.
"With the Planck and WMAP data we're really pushing back the frontier and looking further back in the
history of the universe, to regions of high energy physics we previously could not access," said Linder
who along with colleagues analysed the latest satellite data from the European Space Agency's Planck mission
and NASA's Wilkinson Microwave Anisotropy Probe (WMAP).
"While our analysis shows the CMB photon relic afterglow of the Big Bang being followed mainly by dark
matter as expected, there was also a deviation from the standard that hints at relativistic particles beyond
The most accurate map yet of the light released shortly after the Big Bang, when the universe was just 380,000
years old - the universe is now thought to be 13.8 billion years old. Credits: ESA
"New experiments for measuring CMB polarization that are already underway, such as the
POLARBEAR and SPTpol telescopes, will enable us to further explore primeval physics, Linder says.