HKUST-Harvard Scientists Discover Ways toClock the Beginning of the Universe
Scientistsfrom HKUST and Harvard-Smithsonian Center for Astrophysics discovered a methodto observationally distinguish different theories of how the universe firstbegan at its very early stage. The findings were accepted by the Journal ofCosmology and Astroparticle Physics.
Theexpansion of our current universe has been established for almost a century.However, concerning much earlier stages of our universe as how it began hasalways been a topic of contention among scientists. The most widely-acceptedtheory of the primordial universe is cosmic inflation, during which the universewas expanding at an extremely fast and mounting rate. On the other hand, thereare also contending theories which believe that our infant stage universe wasfast contracting, slowly contracting, static or slowly expanding.
Whileit is known that the above scenarios of how the early stage universe began allexist, there has not been a clear way to distinguish those scenarios fromobservations. Without a chronological way to label the primordial stages of theuniverse, scientists could not know whether the primordial universe wasexpanding or contracting.
ProfYi Wang, Assistant Professor of HKUST’s Department of Physics and hiscollaborators Prof Xingang Chen and Mohammad Hossein Namjoo from theHarvard-Smithsonian Center for Astrophysics note that some heavy particles thatare known existing at the birth of the universe can be used as standard clocks;and with the time reference set by the clocks, the primordial stages of theuniverse can be labeled with time and thus the expansion or contraction historyof the primordial universe can be reconstructed.
Theresearch paper proposes that the time of every primordial era can be labeled,such that new observations shall be like a movie, which shows in time order howour universe comes from.
“Fromobserving the oscillation of the massive particles, we are able to reconstructwhen fluctuations are created in the primordial universe,” says Prof Wang.“Soon, we may be able to verify the evolutionary history towards how ouruniverse was created, which has remained a myth for so long.”