Scientists look back to first 100 years after Big Bang
To make sense of the mysteries surrounding the universe, scientists are trying to look as far as possible to the Big Bang.
Washington: To make sense of the mysteries surrounding the universe, scientists are trying to look as far as possible to the Big Bang.
A new analysis of cosmic microwave background (CMB) radiation data by researchers with the Lawrence Berkeley National Laboratory (Berkeley Lab) has taken the furthest look back through time yet - 100 years to 300,000 years after the Big Bang - and provided tantalizing new hints of clues as to what might have happened.
Eric Linder, a theoretical physicist with Berkeley Lab`s Physics Division and member of the Supernova Cosmology Project, said that they found that the standard picture of an early universe, in which radiation domination was followed by matter domination, holds to the level that they can test with the new data, but there are hints that radiation didn`t give way to matter exactly as expected.
He said that there appears to be an excess dash of radiation that is not due to CMB photons.
Linder asserted that the 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.
He explained that these measurements revealed that the CMB`s influence on the growth and development of the large-scale structure we see in the universe today.
Linder, working with Alireza Hojjati and Johan Samsing, who were then visiting scientists at Berkeley Lab, analyzed 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.
Linder said that with the Planck and WMAP data they are pushing back the frontier and looking further back in the history of the universe, to regions of high energy physics that previously could not be accessed.
He said that while the analysis showed that 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.
Linder said that 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.
He explained that the early dark energy is a class of explanations for the origin of cosmic acceleration that arises in some high energy physics models.
Linder said that while conventional dark energy, like 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."
Linder says early dark energy could have been the driver that seven billion years later caused the present cosmic acceleration. Its actual discovery would not only provide new insight into the origin of cosmic acceleration, but perhaps also provide new evidence for string theory and other concepts in high energy physics.
The study has been published in journal Physical Review Letters.