Unraveling the Mysteries of Matter and Anti-Matter in the Universe
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Chapter 1: The Annihilation Puzzle
In the universe, matter and anti-matter obliterate each other upon contact, transforming into pure energy. This raises a perplexing question: if the universe initially contained equal quantities of both, why does matter still exist? The answer may reside with the most fundamental particles.
Gravitational waves, which are ripples in spacetime, might hold the key to understanding why anti-matter in the early universe didn't completely annihilate matter. According to established Big Bang theories, the immense energy from the explosion quickly cooled and froze into subatomic particles. As the universe expanded and cooled further, matter and anti-matter were believed to have formed in roughly equal proportions. If this were the complete narrative, these particles should have ultimately annihilated each other.
Anti-matter is detectable on the Sun's surface, where it collides with matter, leading to mutual annihilation. So, the question arises: why is matter so dominant in the universe while anti-matter remains scarce? Image credit: NASA
Section 1.1: A Transformative Phase
One explanation for the abundance of matter today is that early in the universe's history, a minuscule fraction of anti-matter converted into matter. A mere one in a billion particles would have sufficed to create the universe as we observe it, yet the mechanism behind this transformation has remained enigmatic.
Matter and anti-matter pairs, such as electrons and positrons, are nearly identical except for their opposing electrical charges. This similarity would typically preclude the conversion of anti-matter into matter (or the reverse).
As the universe evolved, a phase transition may have enabled matter to prevail over anti-matter. This phase shift could have given rise to cosmic strings, which are theorized to have produced gravitational waves that upcoming detectors might reveal. According to an international research team, this phase transition resembles the process of water turning into ice, allowing neutrino particles to convert some anti-matter into ordinary matter.
“When certain metals are cooled to low temperatures, they can lose all electrical resistance due to a phase transition, becoming superconductors. This principle underlies technologies like Magnetic Resonance Imaging (MRI) for cancer diagnostics and maglev trains that can travel at 300 miles per hour without causing discomfort. Similarly, the early universe's phase transition may have led to the formation of cosmic strings—thin tubes of magnetic fields,” explains Hitoshi Murayama, MacAdams Professor of Physics at UC Berkeley.
These cosmic strings would have attempted to “simplify themselves,” resulting in fluctuations in spacetime observable today as gravitational waves.
Section 1.2: The Role of Neutrinos
“When the universe was between a trillion and quadrillion times hotter than the hottest regions today, neutrinos likely behaved in ways that ensured our survival. We have shown that they probably left behind detectable gravitational ripples,” states Graham White, a postdoctoral fellow at Canada’s TRIUMF particle accelerator.
“For every billion anti-matter particles, there was one billion and one particles of matter. After mutual annihilation, one billionth of the matter remained—this is our current universe.” — Albert Einstein
Cosmic strings were initially proposed to explain density variations that led to the formation of stars and galaxies, although earlier theories about the early universe's matter development took precedence.
Anti-matter, theorized by physicist Paul Dirac, was first observed in 1932 and synthesized in a lab in 1955. Gravitational waves from these cosmic strings would differ from other spacetime ripples caused by events like black hole mergers.
Recently, advancements in technology have allowed astronomers to detect gravitational waves. Several new observatories are set to become operational, opening a new frontier in astronomy. This development, akin to the introduction of radio telescopes over sixty years ago, could provide insights into the reasons behind the widespread presence of matter in the universe.
The analysis of this groundbreaking theory was published in Physical Review Letters.
James Maynard, founder and publisher of The Cosmic Companion, is a New England native now residing in Tucson with his wife, Nicole, and their cat, Max.
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