Every Type of Black Hole Explained

Added: 2026-05-13

[00:00:00]Stellar black hole. You've heard that black holes are the most destructive objects in the universe. That's not quite right. The most common kind, the one that forms when a massive star dies, isn't destructive at all. It's just gravity doing exactly what gravity has always done, just with nothing left to stop it. When a star runs out of fuel, its core collapses. For most stars, something stops that collapse. Electron pressure, neutron pressure, the quantum refusal of matter to be compressed any further.

[00:00:29]>> [music] >> But for stars above roughly 25 times the mass of our sun, nothing stops it. The core keeps falling inward past every known boundary until it [music] reaches a single point of infinite density, a singularity. And the region of space around it where gravity is strong enough to trap light permanently becomes the event horizon. The black hole. There are an estimated 100 million stellar black holes in the Milky Way alone. We have [music] directly confirmed roughly 20.

[00:00:57]They don't glow. They don't announce themselves. [music] Most sit in perfect silence in the dark between stars. The only ones we find are the ones caught in the act of eating a nearby companion star. The infalling gas heated so violently it screams in X-rays before crossing the edge. But stellar black holes are just the [music] beginning. They top out at around 100 solar masses. What sits at the center of almost every galaxy in the observable universe is something incomparably larger. Super massive black hole.

[00:01:27]At the center of the Milky Way, 26,000 light-years from where you're sitting, there is an object 4 million times the mass of our sun. It is called Sagittarius A star. And for most of its life, it has been completely quiet, patient, waiting. Super massive black holes range from 1 million to tens of billions of solar masses. The largest ever found, Ton 618, contains 66 billion suns compressed into a single point. If you replaced our sun with ton 618, its event horizon would extend past the orbit of Neptune, swallowing every planet in the solar system without noticing. We don't fully understand how they got so large so fast. The universe is only 13.8 billion [music] years old.

[00:02:09]Finding a super massive black hole weighing tens of billions of solar masses when the universe was less than a billion years old is like finding a fully grown elephant inside an egg. The math doesn't work cleanly. [music] The leading theories involve rapid early mergers or seed black holes formed [music] directly from collapsing gas clouds without going through a star phase at all. We don't know which. Maybe both, maybe neither. What we do know is that super massive black holes aren't just passengers in their galaxies. They are the engine. When they feed, jets of plasma and energy erupt from their poles at close to the speed of [music] light, blasting material across hundreds of thousands of light years, regulating how fast their entire host galaxy can form new stars. The black hole shapes the galaxy. The galaxy shapes the black hole. Each one sculpted the other over billions of years. And the ones that are actively feeding, those are something else entirely. Quazar. For 20 years after their discovery, no one knew what quazars were. They looked like stars, but their light was so bizarrely shifted that if the shift meant what physicists thought it meant, they had to be impossibly far away. And if they were that far away, the amount of energy they were producing was so enormous that every explanation physics had fell apart. A quasar is a super massive black hole in the act of consuming so much material that the accretion disc around it outshines every star in its host galaxy combined. The brightest known quazar produces 450 trillion times more light than our sun. The entire Milky Way with its 200 billion stars produces roughly twice what the sun does per star. This single black hole in its feeding frenzy outshines our entire galaxy by a factor of 25,000. The energy comes not from the black hole itself, but from the material falling toward it.

[00:03:56]Gravity accelerates that material to a significant fraction of the speed of light. Friction heats it to billions of degrees and up to 40% of the infalling mass is converted directly into energy before it ever crosses the event horizon. Nuclear fusion, the process that powers every star, converts less than 1%. Black holes are 40 times more efficient than stars at converting matter into energy. Quazars are ancient.

[00:04:20]Most burned brightest in the early universe when gas was plentiful and everything was closer together. Our own galaxy likely had one. The quiet black hole at its center is what a quazar looks like after the meal is finished.

[00:04:32]Intermediate mass black hole. Here is a gap that should not exist. [music] Stellar black holes cap out around 100 solar masses. Super massive black holes start at a million. For decades, nothing had been confirmed in between. Not because they shouldn't exist, but because we couldn't find them.

[00:04:50]Intermediate mass black holes [music] range from 100 to 100,000 solar masses.

[00:04:55]They are large enough that individual [music] stellar collapses can't explain them, but small enough that they don't dominate the center of a galaxy the way super massive ones do. They hide in globular clusters, the dense ancient balls of stars that orbit galaxies like satellites. [music] Finding them requires watching a star move in a way that only something enormously massive and completely invisible could cause. In 2020, astronomers confirmed one by catching a star being torn apart at the center of a globular cluster. the [music] characteristic flare of a tidal disruption event. A star getting too close and being stretched into a thin stream of gas spiraling inward. The black hole responsible was estimated at around 50,000 solar masses. Not a rounding error. Real. They matter because they might be the missing link, [music] the seeds, the thing that eventually merges and grows into the super massive black holes that anchor [music] galaxies. Without intermediates, the evolutionary story has a chapter missing. Finding them is how we fill it in. Primordial black hole.

[00:05:55]Every type of black [music] hole covered so far forms from something. A dying star, a growing galaxy, a emerging cluster. Primordial black holes are different. They didn't form from anything that came after the Big Bang.

[00:06:08]They are older than stars, [music] older than atoms. They may have formed in the first fractions of a second of existence itself. In the earliest moments of the universe, density fluctuations in the hot plasma of the Big Bang could have been extreme enough that regions of space simply collapsed into black holes before any structure formed. A universe of black holes being born in silence before the first star ever ignited. They could range from microscopic, smaller than an atom, all the way up to hundreds of thousands of solar masses. The tiny ones, if they exist, would have already evaporated through Hawking radiation. But the larger ones could still be out there.

[00:06:46]And here is the part that changes everything. If primordial black holes exist in the right size range, they might account for dark matter. That invisible substance making up 27% of the universe that we have never directly detected. Not a particle, not a field, just black holes, small and ancient and everywhere, formed before light itself existed. We haven't confirmed them, but we haven't ruled them out either. And if they are real, we have been searching for dark matter with the wrong instruments, looking for particles when the answer was gravity all along.

[00:07:18]Rotating black hole. Every black hole you have heard about in any classroom or documentary is almost certainly a lie.

[00:07:25]Not wrong, exactly, just incomplete, because no real black hole is perfectly still. [music] Every object in the universe rotates. Stars rotate. When they collapse, that rotation is conserved and amplified the way a spinning skater pulls in their arms and suddenly blurs. Real black holes spin.

[00:07:43]And a spinning black hole is a fundamentally different object than a stationary one. A rotating black hole described by the curr solution to Einstein's equations doesn't just have an event horizon. It has an ergosphere, a region of space outside the event horizon where spacetime itself is being dragged around so [music] fast that nothing, not even light, can remain stationary relative to the outside universe. You would be forced to rotate with the black hole just by existing in [music] that region. Not because something is pulling you, because space itself is moving and you are inside it.

[00:08:15]The fastest spinning black hole ever measured completes one full rotation in roughly a millisecond. At its equator, spacetime is moving at nearly the speed of light. And this spinning creates a loophole, a theoretical escape route that a non-rotating black hole doesn't have. Inside a cur black hole, the singularity isn't a point. It's a ring.

[00:08:35]A ring singularity that in principle [music] you could pass through without being destroyed and emerge somewhere or somewhere else entirely. In principle, the inside of a black hole remains the one [music] place in the universe where our equations give answers we cannot verify because nothing that crosses the horizon ever tells us what it found. If you found this video interesting, please consider liking and subscribing. It helps more than you