Supermassive black holes, which can be billions of times the mass of the sun, are believed to have formed very early in the universe's history, possibly through direct collapse of primordial matter rather than from the remnants of stars.

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.

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.

Almost all the information in the universe is in the form of black holes; they contain significantly more information than anything else.

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.

Black holes are flawless in the sense that you can completely understand them by looking at just their charge, mass, and spin; every black hole with those properties is identical to every other black hole.

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

Inside the event horizon, the nature of space and time changes dramatically. As an object falls into a black hole, it experiences time differently, with their future leading them inevitably to the singularity, which is a point in time rather than space from their perspective.