Astronomers have discovered an important piece of the puzzle of how supermassive black holes were able to grow so quickly in the early universe: a special kind of active galactic nucleus so ...

Quantum calorimeters are opening this new window on the Universe. First promised four decades ago, the quantum-calorimeter era of X-ray astronomy has finally dawned. A quantum calorimeter is a device ...

What Is a Light-Year? A light-year is the distance light travels in one year. Light moves incredibly fast — about 186,000 miles (300,000 kilometers) per second, covering 5.88 trillion miles (9.46 ...