Scientists have taken the furthest look back through time yet, 100 years to 300,000 years after the Big Bang, to better understand the mysteries of the universe.
The researchers from Lawrence Berkeley National Laboratory (Berkeley Lab) used a new analysis of cosmic microwave background (CMB) radiation to take a look back in time to the beginnings of our universe.
"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," said Eric Linder, a theoretical physicist with Berkeley Lab's Physics Division.
"There appears to be an excess dash of radiation that is not due to cosmic microwave background (CMB) photons," Linder said.
Our knowledge of the Big Bang and the early formation of the universe stems 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.
Linder and colleagues, analysed the latest satellite data from the European Space Agency's Planck mission and NASA's Wilkinson Microwave Anisotropy Probe (WMAP), which pushed CMB measurements to higher resolution, lower noise, and more sky coverage than ever before.
"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," Linder said.
"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 CMB light," he said.
Linder said the prime suspects behind these relativistic particles are 'wild' versions of neutrinos, the phantomlike subatomic particles that are the second most populous residents (after photons) of today's universe.
Another suspect is dark energy, the anti-gravitational force that accelerates our universe's expansion.
"Early dark energy is a class of explanations for the origin of cosmic acceleration that arises in some high energy physics models," Linder said.
"While conventional dark energy, such as the cosmological constant, are diluted to one part in a billion of total energy density around the time of the CMB's last scattering, early dark energy theories can have 1-to-10 million times more energy density," he added.
Linder said early dark energy could have been the driver that seven billion years later caused the present cosmic acceleration.