On this day, 36 years ago, on November 13, 1989 (October 16, 1989, the world's largest electron-positron collider was completed. On November 13, 1989, Professor Emilier Picasso, executive director of the preparation plan for the European "Leiper" electron-positron collider, the world's largest particle accelerator, handed over the key at the official inauguration ceremony of the aircraft. It was handed over to Professor Carlo Rubia, Chairman of the European Center for Nuclear Research. The Leiper electron-positron collider is located in an underground tunnel under the Jura Mountains on the French-Swiss border. The tunnel is 50 to 150 meters deep, 3.8 meters in diameter and 27,000 meters in circumference. It can simulate the scene of the universe at the Big Bang hundreds of millions of years ago, allowing electrons and electrons to travel in opposite directions and collide at the speed of light in the collider. Scientists explore the most basic structure of matter and reveal the mystery of the birth of the universe by observing various new phenomena that occur when electrons and positrons collide. The construction of the "Leiper" collider began in 1983, two years after the preparation plan was approved by CERN. The entire project was completed in July 1989 and cost a total of 1.3 billion Swiss francs. The three-week test results show that the maximum energy of the "Leiper" particle accelerator can reach more than 100 billion electron volts, and can produce a large number of "Z" particles, allowing scientists to study the quality, lifetime, decay and other characteristics of the particle itself, and further understand the basic laws of the motion of the universe. Dr. Rubia, director of CERN and Nobel Prize winner in Physics, pointed out at the ceremony that the operation of the "Raiper" machine is the result of the unity and efforts of the 14 European member states of CERN. It marks Europe's leading position in the field of basic research in particle physics. The completion of the "Leiper" machine is also the product of years of cooperation between European scientists and more than 1500 scientists from all over the world, including scientists from China, the United States, the Soviet Union and other countries.