An artist's conception of the James Webb Space Telescope orbiting the sun, 1 million miles from Earth. Credit: NASA-GSFC / Adriana M. Gutierrez (CI Lab) In the year 1054 CE, astronomers saw a strange ...

The standard candle is the famous Crab Nebula, which evolved from the “guest star” recorded by the imperial astronomers of China’s Song Dynasty. LHAASO has also discovered a photon with an energy of 1 ...