Nearly 400 science lovers from middle schools, universities and research institutes across Beijing joined in the international celebration of Dark Matter Day on November 5^th, in an event held at the China Science & Technology Museum. The Beijing event was also broadcast live to over 52000 viewers across the country.

Researchers from top Chinese universities and research institutions explained to the public how the concept of dark matter originated, what the evidence is for its existence, and how and why they are looking for it. The dark matter-themed event was ended with a free showing of a full dome film: Phantom of the Universe—The Hunt for Dark Matter.

Dark matter explains how galaxies spin at a faster-than-expected rate without coming apart. Scientists know from these and other space observations that there is “missing” mass—something we can’t see—that makes up an estimated 95 percent of the total mass and energy of the universe. So a big part of the universe is largely unknown to us. Finding out what dark matter is made of is a pressing pursuit in physics.

This first-ever Dark Matter Day campaign was conceived by the Interactions Collaboration, a group of science communicators representing the world’s particle physics laboratories. The Institute of High Energy Physics, Chinese Academy of Sciences, is a member of the Collaboration.

This year, 101 events were held in 25 countries and regions around the world, including the USA, UK, China, India, France, and Germany. Thirteen live virtual events were open to the public. The China events included one in Shanghai on October 28th and one in Beijing on November 5^th. Over 1200 people in Beijing, Shanghai and Jilin province joined the on-site celebration, and over 50000 online fans joined the virtual celebration.

The Beijing event was co-hosted by the Institute of High Energy Physics, China Science & Technology Museum, and Capital Science Forum, and was supported by the Tsung-Dao Lee Institute, Shanghai Jiaotong University.

On November 5^th, the dark matter-themed event was held at the China Science & Technology Museum. Nearly 400 science lovers joined in the onsite celebration. (Image by Liu Jie, IHEP)

Prof. Chen Hesheng, Member of Chinese Academy of Sciences delivered a speech in which he elaborated on the concept and origin of the dark matter.(Image by Liu Jie, IHEP)

Prof.Wu Xiangping, Member of Chinese Academy of Sciences explained the evidence of the existence of dark matter to the public.(Image by Liu Jie, IHEP)

Prof. Bi Xiaojun, researcher from the Institute of High Energy Physics, started his talk from the indirect detecting method of the dark matters in the current studies. (Image by Liu Jie, IHEP)

Prof. Yue Qian, from Tsinghua University introduced the current experiment in Jinpin, China, which is the deepest underground experiment to detect dark matter in the world.(Image by Liu Jie, IHEP)

At the end of the event, four lecturers went on the stage where they encourage more young students to join in the exploration of dark matter, physics and science in the future. (Image by Liu Jie, IHEP)

People were recording the interesting talks they listened during the event and sharing with the families and friends who can not make to the onsite event. (Image by Liu Jie, IHEP)

Young people are making notes of what they have learned during the event.(Image by Liu Jie, IHEP)

 Public were lining up to enter the auditorium in China Science & Technology Museum in the morning. (Image by Liu Jie, IHEP)

Father and daughter were enjoying the talks together. They are both the fans of dark matter. (Image by Liu Jie, IHEP)