Symmetry is a tidy and attractive idea that falls apart in our untidy Universe. Indeed, since the 1960s, some kind of broken symmetry has been required to explain why there is more matter than antimatter in the Universe — why, that is, that any of this exists at all. But pinning down the source behind this existential symmetry violation, even finding proof of it, has been impossible. Yet in a new study in the Monthly Notices of the Royal Astronomical Society, astronomers found the first evidence of this necessary violation of symmetry at the moment of creation. They studied a whopping million trillion 3D galactic quadruplets in the Universe and discovered that the Universe at one point preferred one set of shapes over their mirror images.
Parity symmetry violation points to an infinitesimal period in our Universe’s history when the laws of physics were different than they are today, with enormous consequences for how the Universe evolved.
The finding, established with a high level of statistical confidence, has two primary consequences.
First, this parity violation could only have imprinted itself on the future galaxies during a period of extreme inflation in the earliest moments of the Universe, confirming a central component of the Big Bang theory of the origin of the cosmos.
Parity violation would also help answer perhaps the most crucial question in cosmology: why is there something instead of nothing?
That’s because parity violation is required to explain why there is more matter than antimatter, an essential condition for galaxies, stars, planets and life to form in the way they have.
“I’ve always been interested in big questions about the Universe,” said University of Florida’s Professor Zachary Slepian.
“What is the beginning of the Universe? What are the rules under which it evolves? Why is there something rather than nothing? This work addresses those big questions.”
Parity symmetry is the idea that physical laws shouldn’t…
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