NASA | Swift Finds 'Missing' Active Galaxies

The video explores the presence of supermassive black holes in galaxies, which emit X-rays. It highlights the role of NASA's Swift satellite in discovering hidden black-hole-powered galaxies that contribute to the cosmic X-ray background. The video explains how viewing angles affect the detection of these black holes and discusses the historical context of galaxy mergers that activated black holes, leading to a peak in the X-ray background when the universe was younger.

Explain the significance of galaxy mergers in activating black holes.

What evidence supports the idea that the X-ray background peaked around seven billion years ago?