The early universe may chirp about unknown physics. A University of Helsinki research team has demonstrated how an early universe phase transition will lead to gravitational wave signals potentially visible in the upcoming satellite missions. The research results were recently published in the journal Physical Review Letters.
Phase transitions, such as the boiling of water or the melting of a metal, are commonplace but fascinating phenomena that spur surprises decades after decades. They often occur as the temperature of a substance is changed, through the nucleation of bubbles of the new phase which then expands. In the end, the new phase has taken over the whole container.
The early universe was composed of a hot plasma whose temperature decreased as the universe expanded. It is speculated by many physicists that a phase transition may have occurred soon after the Big Bang. This would then had lead to nucleation of bubbles and their subsequent collisions. Such collisions would create powerful ripples in spacetime which could be observed in planned gravitational wave detectors. The Laser Interferometer Space Antenna (LISA), with a provisional launch date in 2037, is one such probe that may be able to detect these early Universe spacetime ripples.
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