For some time, I’ve contemplated the nature of these mysterious behemoths, and I feel they have been somewhat misrepresented in their public image. Possibly misunderstood even among the scientific community. I’d like to address them from the stance that rather than being a place where “physics breaks down” as we often hear, they are instead a place where we observe “physics at its most extreme.”
Specifically, it has always bothered me to hear people say “when this object falls in…” This is, and always has been, physically impossible. Relativity insists that it will never be possible to cross the border of a black hole. Yet this is something we have actually observed – we’ve seen stars “fall in”. I am going to point out that we aren’t seeing them “fall in”. Not at all.
Relativity has several things to say about objects falling into a black hole, how the distortion of spacetime caused by gravitational acceleration will twist things up – let’s address each of the effects, and then I’ll go over how those effects then imply the formative moments of a black hole’s birth. Finally, a brief summation.
OK, so let’s deal with the first, and easiest to view, aspect. That aspect is time. We’ll use an astronaut in our example to keep things “classic” – Major Tom (thanks, Mr. Bowie). He’s falling towards a black hole. A big one, a “gentle” one to use the phrase from the character Romily in “Interstellar”, so he’s not going to be spaghettified. (If it were a smaller hole, then yes, he’d get torn up and yadda yadda yadda all down to atoms or subatomics if you carry it to that extreme. That’s an aside.)
The apocryphal story is that if it’s a big enough hole, he could conceivably cross the surface without being killed and possibly see what’s inside, but like an astronomical Cassandra, Major Tom will never be able to get the message out as to what’s in there.
That image is, to put it bluntly, false. He’s never going to pass the horizon. The border he’s never going to cross is in actuality a surface, rather than a “horizon”. It has been represented in popular media as a non-physical boundary that simply represents where light can no longer escape. In actually what it is, is a solid surface upon which Major Tom – or at least, what’s left of him – will impact and merge. And we’ll get to that in a little while.
Back to what I started with – time. Let’s begin by looking at how time represents itself as a dimension of space. Hermann Minkowski first twigged to the nature of time in this fashion back in the late 1800s, while studying Maxwell’s laws of electrodynamics. He represented time as an additional dimension on top of the three we are already familiar with, which helped to explain why Maxwell’s laws came out looking so elegant. He posited that if you were to lay out a 2-dimensional diagram of X and Y coordinates, by “rotating” one’s perspective those axes could represent length, width, breadth, and time. When you use X being one of the space axes and Y being a time axis, then a thing which is at rest in space would be represented by a vertical column as it “traverses” time. Any motion within space would tilt that line of traverse to an angle.
And when one reaches c, then in practical experience time ceases to pass, because there’s no wiggle-room for the object to make any progress on the time axis (or, as it turns out, on any other). On the graph it would look like a 45-degree angle, but from an experiential perspective time just stops.
There’s absolutely no place for Major Tom to move in time. Space has been compacted to its fullest extent – in effect, all four dimensions are compacted into a point (if you drew it on a chart, any X or Y axis would only allow a single value, with no “range” to maneuver on). But it does not rip. That’s one of the kickers here, which conflicts with what you often hear when people say “Oh, the laws of physics break down inside a black hole.” No, they don’t. They reach their limits, but there’s no break-down. First off, because there really is no “inside” the black hole. Externally, it’s not really a hole, it’s a ball to our perception, it’s a solid piece of matter – for all intents and purposes space has compacted to a one-dimensional point that happens to have perceptible size to us, and what we have been calling its “horizon” is the solid surface of that point – and the accumulation of black hole matter upon it.
What kind of matter is that? That I couldn’t tell you. But Einstein’s relativity makes it quite clear that everything halts at the surface, where acceleration reaches c and space-time becomes completely compacted and clogged. And we’ll get to why soon. First things first. As we said, time this is the easiest one to conceive of – and because of the enormous gravitational acceleration, time locally drops to nil.
From Major Tom’s point of view, time is ambling merrily forward for him as if nothing abnormal were happening. However, the universe around him speeds up and up and up. As he falls towards the surface of the hole, his perception of the universe experiences a dramatic change.
The rest of the universe is ticking forward as expected from outside of the effect of the hole. So as Major Tom’s experience of the universe swiftly tightens, light and matter continue to fall into the hole, and any of it that comes from a vector that intersects Major Tom will line up right behind him. Depending on how the hole twists space up, there may only be one vector from which things approach the center of gravity.
All of that stuff falling on the hole throughout the lifetime of the universe, or at least the lifetime of the hole, hits him all at once. It’s been energized by the gravitational acceleration, and it all lands on his ass as he goes in. So basically as he’s falling, as he reaches the surface, he gets blasted with the most powerful pulse laser ever invented or ever to occur in nature. In effect, an X-ray laser nuke has just gone off behind him. Whatever internal structure hasn’t been torn asunder by tidal forces is going to be completely annihilated by the influx of a lifetime’s worth of matter-energy hitting him all at once.
Remember, looking at him from the outside, there’s no time going on. So there’s no time to stretch this event out in. It all piles up to occur in a single moment, a now, which comprises the lifespan of the hole. So he floats in thinking it’s going to be a gentle ride and he’s going to cross the surface to get a peek inside, and just as he reaches it, bam, he gets blown away by the biggest space laser ever. I guess we’ve discovered those space lasers.
Back to the discussion. Major Tom also represents an element of mass and/or an element of energy. When he reaches the hole, what happens to his mass? “What happens” is kind of a misnomer, since there’s no time for things to happen, but linguistically it’s what we have to work with. As a result of relativistic effect his mass rapidly ratchets up to infinity. Now this is impossible from the perspective of someone outside of the hole’s reach. We know he weighs 80kg, his suit weighs 120kg, so he’s 200kg of “stuff”. His mass can’t be more, according to conservation of energy, so obviously he can’t be of infinite mass. We’ve measured black holes. They have specific masses (usually expressed as a number of solar masses), we can see them dance with solar partners, we can see what happens to orbiting material. And we can calculate their overall mass, so obviously they don’t reach an infinite mass.
But according to relativity, as he approaches lightspeed, his mass literally reaches a state of infinity. And now that I’m looking at how this works, I can see why physicists hate infinities so much, because they really shouldn’t exist. But yes, he does reach an infinite mass. It is unavoidable – he is approaching lightspeed, and the math is undeniable. What’s more, we’ve observed mass changes in objects which follow the changes predicted by relativity. It really is happening.
But we have two measurements here, one from outside the hole’s effect and one from within it. Both are equally valid, according to relativity.
Recently, we’ve had validation of the Higgs field being responsible for granting mass to matter. As matter passes through space, it meets resistance in the form of inertia, which increases as the relative velocity increases, and the Higgs field is responsible for that resistance.
Call this a prediction – someone might have already posited this, I don’t know, I haven’t read 100% of the literature – but prediction nonetheless: with objects subject to the intense gravitation close to the surface of a black hole, the Higgs field will be bound up so tightly that it causes a localized mass of effectively infinite magnitude. I think we’re going to find that the Higgs field “spreads out” over the four dimensions, such that when time flows at its most free in deep space and uninhibited by objects of mass, one’s experience of the Higgs will be at its most minimal, “at rest” as it were. As spacetime gets constricted, however, there will be less “room” for the Higgs to spread out in, and as a result any matter within constricted spacetime will have to contend with a compressed Higgs field. It would follow that the Higgs bozon which was recently discovered at the LHC, might appear to us at different energy levels depending on how loosely or tightly local space is constricted. If we were to set up a properly-sized collider in zero-G, then the Higgs particle will be observed at an energy lower than the 127GeV we see it when performing detection on the surface of the earth.
So to boil it down, the effect of the Higgs field will be inversely proportional to the availability of the various dimensions, including time. That would mean that the Higgs field expresses itself across all four spatial dimensions, and when those dimensions are compacted in the presence of a large attractor, the normally constant effect of the Higgs field is applied in a smaller space, thereby it is concentrated into whatever remains of them. This then grants a layman’s explanation for why mass increases for objects approaching lightspeed (Einstein was far better at math than I am, and his expressions are a much more accurate version of this).
Back to Major Tom – as we watch him slow down and fade away, his space becomes more constricted, and as a result his mass takes a sudden, steep increase as he gets nearer and nearer the surface. And as a result, he begins to exert more and more gravity upon himself. Of course, time is dropping away too, so the acceleration of this gravity is less and less notable to him, its per-second-per-second affect being peeled away by the very dilation that is amping up his local mass. It may become sufficient to overcome his internal structural integrity, much as there could be tidal forces that spaghettify an object. Except in this case, the object might collapse upon itself.
This is observed in the accretion disk, where fusion from stellar gas continues to happen, despite the star(s) being ripped apart and their own internal gravity no longer sufficient to maintain fusion of their material. The pressure within the disk builds up not only because of the volume of the material, but because the material itself is becoming more massive.
From outside, the material approaches the hole, becoming more massive but at the same time running more slowly, so as we see it the light emitted from the material begins to fade. It doesn’t emit as rapidly (photons per second) because less time is passing, and the emissions that do occur are red-shifted due to acceleration, thereby dimming what does get emitted, so overall it is steadily disappearing from view. From its own perspective, the material is compacting, going through fusion well beyond iron (at which point it stops emitting energy and consumes it instead) and into the compaction of atomic nuclei into neutronium, and possibly deeper into quark material. This will happen in the milliseconds before reaching the surface, but it will happen to all material falling in.
So it’s likely that Major Tom is going to compress locally to a point where his atoms will begin fusing. But externally his 200kg still adds to the mass of the hole (minus what gets converted into emissions that escape as he accretes). He will likely turn into at least a ball of tin foil with a hot mess of biological matter inside it as it descends.
Now that’s all great. However, we’re we’ve got one more effect that we haven’t talked about yet.
Relativity’s conservation of angular momentum demands something particularly curious (which yes, has been observed) in addition to the dilation of time and escalation of mass. As it approaches c, an object’s length begins to compress, to the point where it will approach zero.
At lightspeed, its length is nil.
Along the axis of gravitation, Major Tom steadily becomes thinner and thinner, to a point where at the surface he achieves two-dimensionality.
As if his problems weren’t enough already.
We’ve already seen above, as his mass ratchets up and time slows, he gets compressed as his suit collapses around him, becoming a gross mess inside a tin-foil ball. But because of relativistic warping of his length, it appears more like a tinfoil plate. It will be a roughly flat one, its curvature matching that of the hole’s surface, as the force of gravitation will be straight towards the center of gravity.
Time has stopped. His mass has skyrocketed to Infinity. His length has lessened to close to zero. He has become a two-dimensional, infinite mass for which time has ceased – and this is where the really interesting part happens, he never crosses the surface.
At some point that mass and its attendant gravitation, along with his vanishingly small length, will exceed the Chandrasekhar limit on its own in the direction of the axis of gravitation. Major Tom becomes, all by himself, a black hole. He becomes the surface.
Our observations of stars vanishing “into” a black hole, I submit, are not transits of a boundary. That stellar material is quite literally becoming black hole stuff, plastered on the surface of the existing hole. The Chandrasekar limit isn’t describing where the boundary is – it’s describing where the beginning of maximal compression takes place, the surface of an object. Unfortunately, determining that requires mathematics beyond my capacity.
I submit here, that a black hole is not some “empty space” with a teeny tiny singularity inside – it is a solid body. It is made up of all the maximally compressed matter and energy that has ever fallen into it, bound up in maximally compressed spacetime. What we see as city- or solar-system-sized “holes” are solid objects whose surface exists spread upon a medium of spacetime that has been compacted as far as it will go. Just as a neutron star is a solid body of compressed matter, a black hole is simply the most compacted form of matter and energy there is, within the most compacted form of space-time there can be. Rather than breaking down the laws of physics, a black hole is the embodiment of them. It represents those physical constraints at their most extreme. Within it, we have achieved some phase of matter beyond what we know – matter and energy have become a single homogeneous material.
I don’t know this for sure, I obviously can’t look. I can’t see that closely. This phase of matter may be a fluid, it may be a solid, I don’t think such qualifications can be applied here.
But we’re still dealing with a form of matter that has been maximally compressed. And rather than being a rip in space-time or a hole in space-time, what we are seeing is the expression of matter and space-time at its most extreme. And no, the laws of physics do not break down inside a black hole. They reach their limit, their theoretical maximum of whatever measurement we’re trying to imply or measure, but they do not break.
Space being stretched to its maximum in this instance, we will have the result of what amounts to a spherical “pit”, which when graphed will look like the classical “stretched cone” diagrams everyone sees when talking about black holes. But in at least two dimensions the thing will have a property of motion, as it will be rotating – and continuing to accelerate in its rotation, if it has an active accretion disk. That rotation will steadily decrease over time, as it bleeds rotational energy into a steady, monotonous gravitational wave.
These all have implications on the formation of a hole, how it occurs at its initial moment.
I keep calling it a hole simply because the terminology has been there since I was a child. It’s not a hole, it’s a ball. It’s a solid ball, solid all the way through (which can appear deceptively large). From the moment that the maximal compression was reached, in the heart of a dying star. Or the moment that the primordial soup at the Big Bang reached maximum compression.
Which, when one considers it, may lead to the question of why isn’t everything already a black hole? During the bang, things were compressed pretty tightly, and it seems logical that things should have just remained together as a black hole. But then we get into “inflation”, wherein expansion exceeded the speed of light, which would certainly explain how we turned black hole matter inside-out and spewed out a universe.
(I put quotes around inflation for a reason – there is a clarification that can be done there, that what we consider “inflation” is actually evidence of a collision between two universes, one of space-time and one of matter-energy, but that’s a topic for a different essay.)
That spewage of universe back at the beginning doesn’t necessarily have to mean that all matter escaped black-holedom. There may very well be quite a bit of our universe still bound up in black hole material, fragments of the original impactor sailing around through space.
These original fragments may explain where some of the biggest holes originated from – superdense clumps that formed during an uneven expansion in the first moments of the universe. Who knows? Maybe the Great Attractor is simply a black hole so enormous that it would completely overwhelm our concept of size. We wouldn’t see it, because it’s not feeding, there’s nothing for it to feed upon. I don’t know. There would probably be some sort of residual image of it that JWST or a later telescope would be able to see, or a hint of it in the cosmic background, perhaps a lensing effect around it, or a greater red-shift directly before it and a blue-shift to the light lensed around it.
All of this black hole matter, the maximally compacted matter and energy, this exists in what is likely to be a homogeneous purest state of the stuff we consider to be “normal” matter. This stuff forms when gravitation – the warpage of space-time – compresses that matter to the point where it overcomes all of its own interacting forces.
When a star goes into collapse, gravity finally winning out over fusile pressure, all that mass cramming down towards the center, sooner or later some small pocket goes into maximal compaction. The atomic nuclei get pressed together, fusing far past iron and creating an energy vacuum, completely off the periodic table and into neutronium, that tiny core neutron star with overlapping gravitation not just of itself but from all the other crushing material coming in, the accumulation of forces finally reaching the tipping point of c.
Maybe it’s only a few atoms in size, maybe it’s the size of a full neutron star, but spacetime as well as matter achieves that maximal compression. From here, we end up with layer upon layer being forced onto the hole, each atom or molecule or quark plastering itself upon the surface, relativistic effects forcing them to each become black matter like a quasi-stellar onion.
And that star’s death continues to force-feed the hole, layer after layer of stuff being put down. It all goes through the same process we described for Major Tom previously. Space scrunches up and Its time slams to zero, the Higgs field goes crazy and its local mass explodes into infinity, and its length renders it effectively two-dimensional as it settles onto the horizon. Within its own Schwarzschild radius, the spacetime completely locks up, it crystallizes for all intents and purposes.
And as a side note, this is probably the only place in the universe where “vibration” cannot occur, and therefore perhaps the temperature would be considered to be absolute zero.
I want to term this stuff “black matter”, rather than dark matter, because it’s important not to confuse the two. Dark matter doesn’t interact with normal matter, whereas black matter interacts like a drunken undergraduate on spring break. Get too close to the door, and you’re going to get dragged into the party, never to escape the same again.
To synopsize, the popular conception of a black hole as a hole, as somewhere that physics breaks, is a false image. It may be due to the naming of it, the conceptual implication of the use of our language resulting in people viewing these as largely empty spaces. But Einstein laid out the rules very clearly – there can be no “hole” there, no demarcation border to be crossed.
Within our universe, we have limits – and a black hole does not exceed or break these limits, rather it embodies them. It is a solid form, of similar nature as other “strange” stars such as neutron stars and quark stars. Its black matter is the ultimate expression of the laws of gravitation being applied to “normal” matter and energy, maximally compacting that material into a homogenous ball.
With space having frozen in place in endless layers, this ‘cosmic onion’ also ends up preserving the matter which has fallen upon it – but any such matter has itself already been annihilated by the additionally infalling matter-energy, and maximally compressed into black matter itself.