Most distant blazar OP 313 discovered 8 billion light-years away. Astronomers discovered blazar OP 313, the most distant high-energy source powered by a supermassive black hole, located 8 billion light-years from Earth. Found using LST-1 and MAGIC telescopes in Spain, it emitted powerful gamma-rays in December 2023. Its light reveals the universe's state 5 billion years after the Big Bang.