The “singularity” itself is a point of infinite density with zero size. the diameter is about the event horizon. it is the boundary beyond which nothing can escape
The singularity is the point way down in the middle, and does not have a large diameter.
What you’re thinking of is the event horizon of the black hole, which is just the sort of point of no return for getting close to the thing, and is not part of the singularity itself, just a line of gravitational effect.
They don’t. I assume you’re referring to the diameter of the event horizon which is directly proportional to the mass of the black hole, called the Schwarzschild radius.
They are a singularity but their existence influences the space around them.
A black hole has enormous gravity, the “diameter” I assume you mean the ring around it is the event horizon, the space where the gravity is so strong it bends light.
What you’re seeing is light bending around the black hole not the black hole itself.
Singularities in black holes are predicted by mathematics but there are significant reasons to believe that this is just a math oddity and not reflective of reality.
The singularity is like the small central point at the bottom of a whirlpool in a body of water. Depending on how hard the suction is, you will have an appreciable swirl of whitewater and other garbage the whirlpool has pulled in from the surrounding water (cups, plastic, dirt, leaves, etc.). All this white water and garbage helps you gauge how far out the whirlpools pull goes and the larger the whirlpool the harder the suction from the bottom (to be clear the suction creates how large the whirlpool is, not the other way round. I worded that poorly.)
It’s the same with black holes except the whitewater is space/time and the garbage is suns, planets, and microplastics from earth (jk).
Think of it like a whirlpool, the singularity is the centre of it, that is quite small compared to the total diameter of a whirlpool and the edge you see in water that starts to suck you in, there will be a point where you can no longer swim away from the centre of the whirlpool, this is the event horizon of a black hole
They probably aren’t. We don’t think physical singularities are real.
Black holes have a diameter because of the event horizon – the point at which there are no longer paths that go anywhere except inwards. No light emitted at, past, (or, realistically, near) the event horizon makes it out. However, because of how wildly space is bent around black holes, a lot of paths near the event horizon also don’t make it out (or do so at weird directions,) so when you observe a black hole, you see a shadow that’s a couple times larger than the actual event horizon.
You are probably thinking of the diameter as “the surface of a solid object”, but that’s not accurate for black holes. The diameter of a black hole is its event horizon, which is just the distance at which nothing can escape its gravity.
As other commenters have pointed out, black holes probably don’t have singularities at their center.
The maths of pure GR have singularities—points where a physical quantity (gravity, the curvature of spacetime) blows up to infinity—in them, but that’s typically taken not to mean there’s a literal singularity in reality, but as a suggestion that general relativity, for all its successes, is still not the complete picture. Usually when an equation has division by zero, it’s a sign something is missing from your model. This singularity stuff is just another reason GR and quantum mechanics, two of our best physical theories, are in irreconcilable conflict with each other.
Nobody’s ever jumped inside a black hole and taken measurements of gravity or density or spacetime curvature. Rather, the mathematical models of GR predict there’s a singularity, a terminus of spacetime at the center of black holes, but the fact that it predicts and actually requires that (at least in the Schwarzchild solutions to Enstein’s field equations) suggests something is missing from our model.
In fact, some argue that we’re interpreting it wrong. The Penrose Singularity theorem has widely been interpreted to prove that the interior spacetime region of any black hole surrounded by an event horizon must be geodesically incomplete, i.e., it must contain a singularity. But Roy Kerr (the same guy after whom the Kerr metric for rotating black holes is named) argues that’s a faulty conclusion. He argues that just because the affine parameter is bounded doesn’t mean there has to be singularities.
Comments
The “singularity” itself is a point of infinite density with zero size. the diameter is about the event horizon. it is the boundary beyond which nothing can escape
You are thinking of the event horizon, that is simply the radius from the singularity at which light cannot escape.
The singularity is the point way down in the middle, and does not have a large diameter.
What you’re thinking of is the event horizon of the black hole, which is just the sort of point of no return for getting close to the thing, and is not part of the singularity itself, just a line of gravitational effect.
They don’t. I assume you’re referring to the diameter of the event horizon which is directly proportional to the mass of the black hole, called the Schwarzschild radius.
That is the event horizon, where the effect of gravity is stronger than light. It’s not all mass, but it’s the edge of what we can see.
They are a singularity but their existence influences the space around them.
A black hole has enormous gravity, the “diameter” I assume you mean the ring around it is the event horizon, the space where the gravity is so strong it bends light.
What you’re seeing is light bending around the black hole not the black hole itself.
Singularities in black holes are predicted by mathematics but there are significant reasons to believe that this is just a math oddity and not reflective of reality.
The singularity is like the small central point at the bottom of a whirlpool in a body of water. Depending on how hard the suction is, you will have an appreciable swirl of whitewater and other garbage the whirlpool has pulled in from the surrounding water (cups, plastic, dirt, leaves, etc.). All this white water and garbage helps you gauge how far out the whirlpools pull goes and the larger the whirlpool the harder the suction from the bottom (to be clear the suction creates how large the whirlpool is, not the other way round. I worded that poorly.)
It’s the same with black holes except the whitewater is space/time and the garbage is suns, planets, and microplastics from earth (jk).
Think of it like a whirlpool, the singularity is the centre of it, that is quite small compared to the total diameter of a whirlpool and the edge you see in water that starts to suck you in, there will be a point where you can no longer swim away from the centre of the whirlpool, this is the event horizon of a black hole
“If black holes are singularities”
They probably aren’t. We don’t think physical singularities are real.
Black holes have a diameter because of the event horizon – the point at which there are no longer paths that go anywhere except inwards. No light emitted at, past, (or, realistically, near) the event horizon makes it out. However, because of how wildly space is bent around black holes, a lot of paths near the event horizon also don’t make it out (or do so at weird directions,) so when you observe a black hole, you see a shadow that’s a couple times larger than the actual event horizon.
You are probably thinking of the diameter as “the surface of a solid object”, but that’s not accurate for black holes. The diameter of a black hole is its event horizon, which is just the distance at which nothing can escape its gravity.
> If black holes are singularities
As other commenters have pointed out, black holes probably don’t have singularities at their center.
The maths of pure GR have singularities—points where a physical quantity (gravity, the curvature of spacetime) blows up to infinity—in them, but that’s typically taken not to mean there’s a literal singularity in reality, but as a suggestion that general relativity, for all its successes, is still not the complete picture. Usually when an equation has division by zero, it’s a sign something is missing from your model. This singularity stuff is just another reason GR and quantum mechanics, two of our best physical theories, are in irreconcilable conflict with each other.
Nobody’s ever jumped inside a black hole and taken measurements of gravity or density or spacetime curvature. Rather, the mathematical models of GR predict there’s a singularity, a terminus of spacetime at the center of black holes, but the fact that it predicts and actually requires that (at least in the Schwarzchild solutions to Enstein’s field equations) suggests something is missing from our model.
In fact, some argue that we’re interpreting it wrong. The Penrose Singularity theorem has widely been interpreted to prove that the interior spacetime region of any black hole surrounded by an event horizon must be geodesically incomplete, i.e., it must contain a singularity. But Roy Kerr (the same guy after whom the Kerr metric for rotating black holes is named) argues that’s a faulty conclusion. He argues that just because the affine parameter is bounded doesn’t mean there has to be singularities.