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.

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.

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.

One of the most incredible things humans have accomplished is detecting gravitational waves through LIGO, which allows us to observe events from the early universe.

Gravitational waves, while detected by LIGO and predicted to carry energy, present a challenge in general relativity because covariant definitions based on stress energy yield zero energy for pure gravitational waves.

When two black holes merge, they emit gravitational waves, and the final black hole's mass is less than the sum of the original black holes due to energy radiated away as gravitational waves.

LIGO is like a gigantic musical instrument designed to record the shape of the ringing drum of spacetime, allowing scientists to listen to gravitational waves rather than just taking snapshots of them.

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.

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.