By: Bill The Butcher
I’ve got a question in my mind today that just won’t go away, and this is it: What is it like inside a black hole?
With apologies to those for whom this is old hat, for those of you who aren’t really into astrophysics, a black hole is an astronomical body which results when a super-massive star (more than three times the mass of our sun) collapses on itself (the reasons for this collapse aren’t relevant to this particular discussion). Since every object in the Universe possessing mass attracts every other object with a constant force (called “gravity”) which increases four times with each halving of the distance between them (the Inverse Square Law, which you might remember from school physics), as the star collapses on itself, the gravity attracting its component parts to each other increases to the square of the amount by which the star shrinks.
For illustration, imagine a ball made of foam rubber, and squeeze it on all sides so that it is crushed on itself. Now imagine that the force that is crushing it isn’t your hand from outside, but an attraction from inside – an attraction which increases steadily the more the ball is crushed. What happens to the ball at the end?
Since the attraction increases steadily, if it keeps increasing, the ball will ultimately collapse to the point where it can collapse no more, until all the spaces in the foam rubber have vanished and the thing is no longer compressible. Yet, the force keeps increasing. Now what?
Well, if you have a large enough star, instead of a foam rubber ball, it will collapse until it no longer exists in the visible universe – it will collapse into a point smaller than the full stop at the end of this sentence – yet it still possesses the entire mass of the original super-massive star. Under those conditions, its density will be so great as to approach infinity, and its gravitational field will be rather large.
How large?
This is where it gets interesting. Gravity is an attractive force, so in order to get away from it you need to move faster than it attracts you. That’s why you need a rocket to go into space, and can’t just fly into orbit on an Airbus. Think of climbing out of a well, and you have the idea. That’s what they call it, actually, the gravity well.
Well, the gravity well of a black hole is so deep that not even light can climb out of it. According to Einstein’s General Theory of Relativity, light is the ultimate limiting factor in the Universe. Nothing – and that means nothing – can move faster than light, whose speed is 300,000 kilometres per second. The speed necessary to climb out of any given gravity well is known as that gravity well’s escape velocity, and the escape velocity of a black hole is greater than the speed of light.In fact, that’s why they call it a black hole.
This, then, is what a black hole consists of: a point of infinite density, known as the singularity, at which the laws of physics might break down; and this is which is surrounded by a region of gravity so intense that light can’t escape from it. This region is known as the event horizon, for reasons I’ll explain in a minute.
Obviously, if not even light can get out of a black hole’s gravity well, nothing else can, either. Therefore, nothing that happens inside the gravity well of a black hole can be detected from outside. No information can leave the gravity well of a black hole, and this is why the event horizon gets its name. We can’t know of any events that happen inside it.
Proceeding along this same line of thought, if anything falls into the black hole, it for all purposes vanishes from the known (and knowable) universe. Once it’s inside the event horizon, not only can it never leave, but no information about it can ever leave, either. It’s the only real, permanent, and indisputable disappearing trick.
Now, the gravity around a black hole is so intense that it sucks in everything, from gas particles to material objects, which approaches close. Take a look at this picture, for example, where the black hole sucks in a stream of hot material from another star, forming an accretion disc:
Hollywood movies apart, no astronaut would be advised to try and dive into a black hole. Let’s suppose someone fell into one feet-first. As this intrepid (and suicidal) adventurer fell, the gravity around his feet would be many times greater than the gravity at his head, because his feet are closer to the black hole and the distance between them and his head would mean that the gravity affecting his feet is greater by the square of his height (the Inverse Square Law, again). This is true of all gravity, but most gravitational fields are so weak that it doesn’t matter. However, since the gravity well of a black hole is so strong, the difference in pull along the length of his body would stretch him out like a piece of chewing gum; as he fell into the event horizon, he’d be drawn into something resembling a thread, hundreds of kilometres long.
(I’ll digress a moment to acknowledge that there’s something else predicted by the General Theory of Relativity, and proved in experiments; time moves slower the faster one travels, until it comes to a full stop at the speed of light. Yes, I know that; but for the purpose of this article, where I’m admittedly presenting a simplistic view of a black hole, that’s not relevant.)
Even if our adventurer somehow survived his trip into the black hole, nothing he saw or did there could ever become known to us outside, so we can never actually be cognisant of the conditions inside the event horizon. There might be anything there – including planets, complete with advanced civilisations, according to at least one physicist [source] – but we wouldn’t know.
But for the sake of argument, let’s say you and I managed to survive a trip to the inside of an event horizon. It’s not important that we couldn’t let anyone remaining outside know of what we saw and did, whether we kept spinning round the singularity in some complex orbit or fell into it and were instantly consumed. As long as we remained alive and functioning, what would we see?
This is precisely the question that is haunting me today, and will not go away.
I have a speculation, which I admit is unsupported so far as I am aware by mathematics and physics, and therefore is very likely wrong. But hear me out on it for the moment.
As I said, everything – be it light, radiation, or matter – that enters a black hole stays inside. It can never escape so long as the black hole lasts. Now, light or radiation never disappears, no matter how much time has passed since it was created. If it’s not absorbed, it only gets dissipated by a square of the distance it travels, again according to the Inverse Square Law. That’s why we can still detect the background radiation left over from the Big Bang which created the Universe.
But within the black hole, the light and radiation could go nowhere. It could only bounce back and forth, endlessly, inside the bubble of the event horizon, without dissipating. And as the black hole accumulated more and more radiation and light, the interior would necessarily get brighter and brighter. As long as the black hole lasted, therefore, the interior would keep gathering energy, which it could not lose. (It’s perfectly possible that this accumulated energy would cause the black hole to ultimately fall apart, but again that’s not relevant to this discussion.)
Therefore, this is what I think the inside of a black hole would be like – a region of intense light, terrific radiation levels, and considerable heat. Quite like a furnace, in fact, with elements of nuclear reactor as well.
Come to think of it, that’s not too far away from the traditional Judaeo-Christian vision of Hell, is it?
Now tell me what you think.
Subversify Staff
Great article. Love the topic. A couple of points I need to get out before I share my theory. First. Recent work has recorded neutrinos traveling faster than light. Check it out here:
http://operaweb.lngs.infn.it/spip.php?rubrique14
Discoveries such as this are continue to challenge the theories we hold as true such as the Relativity. Additionally,things do escape from black holes. We have evidence of this in the form of X rays and Gamma Rays as well as through the stunning composite photos from Hubble showing the ejection plumes of matter eminating from the black holes. Check these out:
http://images.nationalgeographic.com/wpf/media-live/photos/000/186/cache/black-holes-hold-universe_18665_600x450.jpg
Now with that out of the way I’d like to share my idea about what is at the point of singularity. I really enjoy Brian Greene’s analogy (The Elegent Universe, The Fabric of the Cosmos etc.) of our universe as a slice of bread in a stack of slices (other universes) that make up a loaf. I theorize that the black hole is, in a sense, a portal to another universe. I look forward to reading Dr. Greene’s latest book “The Hidden Universe”. I’ve always appreciated pioneers in this field who dare to explain the unexplainable.
Excellent! Bill the Butcher is the smartest smart ass I’ve ever met, for sure.
Bill, and P.Bugnacki, you are both going to hurt my head. Space, in and of itself, is so enormous, even its unlimited reach is difficult to comprehend. And then, you add its expansions and contractions, its curved dimensions, far flung Universes; and black holes.
I think i postulated once and i will timidly express it again; this compression of energy and matter appear to be as the seeds, which at the point of maximum containment, burst forth with new Universes, an eternally occurring big bang, repelling than absorbed.
In order to visualize hell, one has to visualize a heaven as well, and i don’t, really. I only visualize different planes of existence, awareness, connection and the breathing in and breathing out of Universes and life cycles. Life is the greatest miracle i see. I went to a science museum the other day that showed a simulated, eight foot strand of DNA. I marveled as i watched it twisting and vibrating, busy with its own energy, and thought, “this is life. It’s all around us. These DNA strands even accompany the vastness of space.” So, that’s how i see black holes. Not as a hell. Not as an end, but a beginning for Universes that have gotten old and tired and are drifting apart.
P, you’ve raised excellent points. I’ll address them when I get online from my computer. Of course, this is a simplistic view of black holes.
Now, Paul, while I’ve read about the neutrinos allegedly travelling faster than light, of course, I’d like to point out that it’s still not been reproduced under independent experimental circumstances, and that the same people who have reported the “phenomenon” are urging that other scientists check it out before it can be accepted. I’m reminded of the claim a few months ago that light was slowed down in denser media like glass, which turned out to be a fallacy. I’d not be too excited about that until we have independent confirmation, and then we will of course have to see if this actually means we have to throw Einsteinian relativity (with all the verified observations and proved predictions it has made, and all the physics that depend on it) out of the window or whether the theories can be adjusted to accommodate it. And you don’t need me to tell you of what happens to physics and all we know of the observable universe if we have to discard relativity in toto.
Again, black holes aren’t “black” in the strict sense of being undetectable, but the radiations you speak of aren’t actually emerging from inside the black hole as from the boundary of the event horizon. I’ve been trying to wrap my brain around Stephen Hawking’s explanation of how identical quarks pairs come into existence around the event horizon, one of which is emitted, but the more I read Hawking the less I understand what he’s talking about – and in recent days I’m beginning to wonder if he knows what he’s talking about. (Oh for the good old days of Carl Sagan, who might have been wrong but was at least comprehensible.) Also, if the black hole’s spinning, the accretion disc of material spinning round the boundary of the event horizon will be ejected (perhaps along the Lagrange points) – it has no requirement to emerge from inside the hole, which (if we are to accept Einstein for the moment), it can’t.
As a fellow science-fiction enthusiast, of course I know of the “black hole leads to white hole” hypothesis. But you’ll recognise that it’s only a hypothesis. It’s not a theory, more like wishful thinking than anything else. Unlike black holes, whose physics is fairly well understood and which were mathematically postulated long before being detected, white holes have really no scientific reason to exist. Even if they did, how can you say that a black hole would lead to one? You can’t prove it, because you can’t test it experimentally (your probe would never emerge from the black hole, nor would any signal it sent). And assume we find a white hole. Can something enter it? If nothing can, if it’s a one-way route into the universe, how can one get much more out of it than one can out of a black hole?
Thanks again for these points, though. Definitely material for thought!
Point taken on the “white hole hypothesis”. Like yourself, I too understand less the more I read some of Hawkins’ work. I must have read chapter 4 in “The Universe in a Nut Shell” 5 times and it still makes my head spin (your not alone Karlsie). But what I am accutely aware of is how little we do know the more we discover. A great example of this was the discovery that our universe is not only expanding but is expanding at an increasing rate. What is pushing or pulling our universe appart? A larger parallel universe adjacent to ours perhapse?
Einstein had proposed a “Universal Constant” which he later abandoned. A part of the expansion may be due to that. Frankly, I’m trying to find some source which will explain this stuff in terms I can understand.
Good read. A few points I would like to make. Based on research I have conducted myself by reading and watching documentaries of black holes; many have agreed that if you did go into a black hole you would see nothing. The reason is simple. If you were to spot a black hole by telescope, chances are it’s been around for awhile. With everything it has consumed and compressed, the middle wouldn’t be unlike a ball of energy cocktail. A mixture of mass, energy, and power. Light cannot escape a black hole, therefore many have suggested it wouldn’t be unrealistic to say that the black hole (being the most powerul force in the universe) also destroys light, rather then retaining. Black holes are not rips in the universe, so the theory that if you were to enter a black hole and come out on the other side of the universe is ignorant. Based on several sources, though some same and some different I think the black hole is this; A self generating power of uncalculated gravity and detructive forces. Of course that is what it is, now what’s inside? You got me.
i didn’t read any of the comments but i thought your topic was cool. but as for what is inside one i believe is quite simple, a black hole is just like a little moon with a lot of weight. and anything past a mile (for example)off the surface of the black hole is always going to fall onto it. any light (or energy) that fall onto the surface is converted to heat, i would imagine that the surface of a black hole would be very flat (and hot), anything uneven/elevated off the surface would be crushed back into place. sorry if i’m a little late on commenting. salah
I kinda thought a black hole was where you get sucked in and die, and beyond that point, nothing really matters…!