Visitors are seen at a planetarium in Lhasa, southwest China's Tibet Autonomous Region, Dec. 14, 2019. An planetarium opened its door to the public for trial operation in Lhasa on Saturday. (Xinhua/Li Xin)

Visitors are seen at a planetarium in Lhasa, southwest China's Tibet Autonomous Region, Dec. 14, 2019. An planetarium opened its door to the public for trial operation in Lhasa on Saturday. (Xinhua/Li Xin)

A visitor observes through an astronomic telescope at a planetarium in Lhasa, southwest China's Tibet Autonomous Region, Dec. 14, 2019. An planetarium opened its door to the public for trial operation in Lhasa on Saturday. (Xinhua/Li Xin)

Visitors are seen at a planetarium in Lhasa, southwest China's Tibet Autonomous Region, Dec. 14, 2019. An planetarium opened its door to the public for trial operation in Lhasa on Saturday. (Xinhua/Li Xin)

Elementary school students learn astrology at a planetarium in Lhasa, southwest China's Tibet Autonomous Region, Dec. 14, 2019. An planetarium opened its door to the public for trial operation in Lhasa on Saturday. (Xinhua/Li Xin)

Visitors view a meteorite at a planetarium in Lhasa, southwest China's Tibet Autonomous Region, Dec. 14, 2019. An planetarium opened its door to the public for trial operation in Lhasa on Saturday. (Xinhua/Li Xin)

Visitors are seen at a planetarium in Lhasa, southwest China's Tibet Autonomous Region, Dec. 14, 2019. An planetarium opened its door to the public for trial operation in Lhasa on Saturday. (Xinhua/Li Xin)

Photo taken on Dec. 14, 2019 shows the exterior view of a planetarium in Lhasa, southwest China's Tibet Autonomous Region. An planetarium opened its door to the public for trial operation in Lhasa on Saturday. (Xinhua/Li Xin)

Visitors watch a movie at a dome theatre in a planetarium in Lhasa, southwest China's Tibet Autonomous Region, Dec. 14, 2019. An planetarium opened its door to the public for trial operation in Lhasa on Saturday. (Xinhua/Li Xin)

Visitors are seen at a planetarium in Lhasa, southwest China's Tibet Autonomous Region, Dec. 14, 2019. An planetarium opened its door to the public for trial operation in Lhasa on Saturday. (Xinhua/Li Xin)

Elementary school students visit a planetarium in Lhasa, southwest China's Tibet Autonomous Region, Dec. 14, 2019. An planetarium opened its door to the public for trial operation in Lhasa on Saturday. (Xinhua/Li Xin)

Visitors are seen at a planetarium in Lhasa, southwest China's Tibet Autonomous Region, Dec. 14, 2019. An planetarium opened its door to the public for trial operation in Lhasa on Saturday. (Xinhua/Li Xin)

Books are seen at a store in a planetarium in Lhasa, southwest China's Tibet Autonomous Region, Dec. 14, 2019. An planetarium opened its door to the public for trial operation in Lhasa on Saturday. (Xinhua/Li Xin)