The final mass of a merged black hole is less than the sum of the two original black holes due to the energy radiated away in the form of gravitational waves, which is not detectable as light but rather as ripples in spacetime.

Black holes curve space and time around them, creating a gravitational field that affects the movement of objects nearby. When two black holes orbit each other, they create waves in the shape of space that follow their movement, eventually merging into a larger black hole that emits gravitational waves as it settles down.

Gravitational waves are not light; they are emitted in the rippling of spacetime and can be likened to sound, as they can be detected in the human auditory range if one is close enough to colliding black holes.

The relationship between black holes and galaxies is complex, with supermassive black holes likely playing a critical role in the formation and evolution of galaxies, possibly influencing their growth through jets of material they emit.

Gravitational waves are created when massive objects like black holes move, causing ripples in the fabric of spacetime that can be detected on Earth.

On September 14, 2015, after years of work, LIGO detected its first gravitational wave, a signal from a collision of black holes that occurred over a billion years ago.

When observing Hawking radiation, one can notice entanglement between the radiation and the interior of a black hole, indicating that information is not lost.

The experience of falling into a black hole varies with its size. For larger black holes, the curvature of spacetime is less noticeable, making the crossing of the event horizon less dramatic compared to smaller black holes, where the effects are more pronounced.

In principle, if one could collect all the Hawking radiation from a black hole, it would contain details about the black hole's interior, suggesting that information is not destroyed.