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.

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.

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 first generation of LIGO detected nothing, but the team persevered, demonstrating remarkable resilience and determination in the face of challenges.

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

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.

The construction of LIGO took 50 years, showcasing the tenacity and commitment of the scientists involved, many of whom dedicated their lives to the project.

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.

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.