Ep 23. The Riddle of Antimatter

In the twenty-third episode of Cosmic Journeys season 1, watch as scientists explore one of the greatest mysteries of the universe: antimatter. As we know it, matter and antimatter exist in perfect symmetry, with each particle having a corresponding antiparticle. However, when matter and antimatter meet, they annihilate each other in a burst of energy. This presents a puzzle: if the Big Bang created equal amounts of matter and antimatter, why does the universe appear to consist almost entirely of matter?

To unravel this riddle, the episode delves into the history of antimatter research. In 1932, Carl Anderson discovered the positron, the antiparticle of the electron, and received the Nobel Prize for his discovery. Scientists then began to build particle accelerators to create and study other anti-particles. One of the primary goals of these experiments was to understand the balance of matter and antimatter in the universe.

The episode takes viewers through several experiments aimed at studying antimatter. First, we see the Proton-3 experiment, which sought to measure the cosmic ray flux of anti-protons. The team was able to detect a few anti-protons, confirming that antimatter does exist in the universe.

Next, the episode explores the ALPHA experiment, which is based at CERN in Switzerland. The experiment aims to create and study antihydrogen, the anti-particle of hydrogen. Scientists at ALPHA use powerful magnetic fields to trap antihydrogen atoms and study their behavior. The team has made significant progress in creating and studying these anti-atoms, but the experiments remain challenging due to the difficulty of producing and trapping antiparticles.

The episode also covers the AMS-02 instrument, which is stationed on the International Space Station. AMS-02 measures the cosmic ray flux of positrons, anti-protons, and other subatomic particles. The instrument has detected a surplus of positrons in the cosmic rays, which could be evidence of dark matter, an invisible substance thought to make up a significant portion of the universe.

Throughout the episode, scientists discuss various theories that attempt to explain the matter-antimatter asymmetry in the universe. One potential explanation is that there is a fundamental difference between matter and antimatter, which causes them to behave differently when the universe is incredibly hot and dense, as it was shortly after the Big Bang. Another theory involves CP violation, a phenomenon that involves a slight difference in how matter and antimatter particles behave under certain conditions.

By the end of the episode, viewers will have a newfound understanding of the complexity of antimatter research and the mysterious nature of the universe itself. While the riddle of antimatter remains unsolved, scientists continue to strive for new insights and discoveries that could unlock the mysteries of the universe.