Dan Marrone, Event Horizon Telescope (EHT) co-investigator and an associate professor of Astronomy at the University of Arizona, attends a press conference held by the EHT project and the U.S. National Science Foundation (NSF) in Washington D.C., the United States, on April 10, 2019. Astronomers said here Wednesday that they captured the first image of a black hole, unveiling the first direct visual evidence of an unseeable cosmic object and its shadow. (Xinhua/Liu Jie)