A Trip Inside A Black Hole: Part Two

Suicide missions are hardly unknown happenings, so presumably it wouldn’t be too hard to find a volunteer to take a long walk off a short pier and dive into the heart of a Black Hole. Well, let’s trade in the walk and the pier for a spaceship, with our suicidal pilot crewmember willing to boldly go. What might she expect? For that matter what might a chickenhearted outside observer expect to see?

Continued from yesterday’s blog…

Now for the speculation: Let us suppose that our suicidal voyager survives her voyage (curses, foiled again) and gets to play tourist. What will she see or will she see anything at all? Well, yes, she will – see that is. The event horizon is like a one-way mirror. Light can pass through the event horizon into the interior of the Black Hole, but light cannot pass from the interior of the Black Hole through the event horizon to be witnessed by an outside observer. Okay, let there be light, and there was light. Light is energy, so there’s energy inside a Black Hole. It’s also been shown that a Black Hole has entropy, or in other words a temperature. That too is energy. 

There’s matter (mass) inside a Black Hole – obviously, since there’s gravity. Now the big unknown is what kind of matter is that matter? We don’t know. Outside of a Black Hole matter exists in four states – solid, liquid, gas and plasma. The transition from one state of matter to another is called a phase change, as in ice to water to steam. One speculation is that the matter inside a Black Hole undergoes a phase change to something even more solid and denser than, well a dense solid.

We sort of observe this in a Neutron Star, a star extremely massive with extreme gravity, but just short of enough gravity to form an event horizon and turn into a Black Hole. Why is it called a Neutron Star? Well, the gravity is so great that the bits and pieces of the atom, electrons, neutrons and protons are squashed together into one big glob. The positive protons fuse with the negative electrons – these electric charges thus cancelling out – to make neutrons, hence join with the already neutral neutrons, so everything forms into just one huge glob of neutron soup, or a Neutron Star. Rapidly spinning Neutron Stars are also known as Pulsars.

Now if atoms lose all sense of identity, there is no atomic structure, no isotopes, no molecules, no elements, no compounds, no electrons and no protons, then I’d have to define that as a phase transition, but one we don’t witness on Earth. Given the even more extreme gravity inside a Black Hole, would that same phase transition to a neutron soup hold sway, or might there be another beyond that found in Neutron Stars? 

Neutrons are not fundamental particles. A glob of neutron soup is ultimately a glob of quark soup, as quark trios comprise the identity we call a neutron. Neutrons are actually composite particles. However, as quarks are fundamental particles, it’s unlikely they can be crushed or fused together. Electrons too are fundamental, but it is well known – to particle physicists at least – that an isolated neutron will in fairly quick-smart order decay to a proton, an electron and an antineutrino. Reactions are reversible so it is straightforward to create a neutron if the ingredients are brought together with sufficient energy.

Since a Neutron Star is just one coin short of a Black Hole dollar, the inside of a Black Hole could well be akin to a Neutron Star, only slightly more massive. One thing is certain IMHO, the interior will not be matter crushed down to the infinitely small (i.e. – zero volume); the interior will not be infinitely dense.

What lies at the heart of a Black Hole? The traditional answer is a ‘singularity’ – a point of (near) infinite density and (close to) zero volume, matter crushed down to the final, ultimate limit – or maybe not.

Start with a hunk of matter. Keep on keeping on adding more and more and more matter (mass) to it. Your original hunk grows larger, ever denser; its gravity swells in proportion. Finally it’s just a fraction away from achieving Black Hole status – meaning its gravity is so strong not even light can escape from its grasp. It’s that Neutron Star entity.

So you are a thimbleful of salt away from crossing the not-quite-yet a Black Hole to an actual Black Hole boundary. You can (barely) still see your now super-sized hunk of Neutron Star stuff. Now toss in that final thimbleful of stuff onto the hunk. No light now reaches you – you’ve crossed the threshold or boundary and have got a Black Hole. But do you doubt that lurking on the other side of the not-quite-yet a Black Hole to an actual Black Hole boundary, though unseen, you still have that super-sized hunk of stuff, not a singularity, but a really real solid 3-D hunk of stuff? Or, in other words, if the escape velocity of your hunk is 185,999 miles per second, no Black Hole and no singularity, but if it climbs to 186,001 miles per second you have a Black Hole and your hunk morphs into a singularity? A two mile a second difference makes that much difference? I don’t think so.

The other issue though is this really going to be a one-way trip for our boldly going voyager, dead or alive? One of the 64,000 $64,000 questions: Can you pour stuff down a Black Hole indefinitely, or does the Black Hole have a finite capacity and ultimately or eventually will have to spew stuff out the ‘other side’ (i.e. – producing a White Hole) as you keep pouring in more and more and more? I’d wager the conservation relationships and principles of physics and chemistry hold sway here. What goes in ultimately comes out. That doesn’t mean there’s not a temporary holding vessel. Or, in more human terms, you fill what’s empty; you empty what’s full, but in-between those two there’s storage in the stomach and the intestines; the lungs and the bladder.

Let’s adopt that point of view that what goes in, ultimately has to come out.

And so, our intrepid voyager might well exit elsewhere, maybe even elsewhen. The exit could be deemed the opposite of a Black Hole, or a White Hole; the passageway from Black Hole entrance to White Hole exit is that staple of sci-fi, albeit based in the realm of theoretical physics, the Wormhole. That the exit could be elsewhen is based on the theoretical ‘fact’ that a wormhole could be manipulated in such a manner as to allow for time travel. If that’s too far out for you, then a Wormhole elsewhere shouldn’t be. The apt analogy is with an apple. Mr. Worm can crawl around the outside of the apple to get from one side to the other, or Mr. Worm could take a shortcut and worm his way through the apple to get to the other side, or elsewhere.

Now the question arises, is there any observational evidence that White Holes and associated exits exist? Astronomers and cosmologists would argue in the negative, but I’m not convinced. What would be the signature of a White Hole? Well, it would be roughly stellar-sized, not planetary or galactic. It would be vomiting out one heck of a lot of stuff including lots of energy. Does the cosmos contain such beasties? Obvious candidates are quasars – quasi-stellar objects. Quasars are roughly stellar in size, but violently emitting the froth and bubble of nearly an entire galaxy worth of stuff and energy. The other high-energy astrophysical anomaly is gamma ray bursts. They occur way out back of beyond, in the outer fringes of the cosmos, which is all to the good for if a gamma ray burst happened in our stellar neck of the woods, the results would be akin to Kentucky Fried Humans! Still, we don’t know enough squat about them to be able to predict exactly where and when one will happen. So, astronomers who are into studying these cosmic critters are akin to sleeping fireman who never knows when they will be rudely awakened to respond to that rare five-alarm event.

So, in short, we have Black Holes that are your ultimate in garbage disposals; Quasars and gamma ray bursts that are your ultimate in, IMHO, recycling that garbage back into useful cosmic stuff – matter and energy. In other words, they are the exit to the Black Hole’s entrance. 

No matter. Either our boldly going voyager has snuffed it going into a Black Hole; is forever trapped in a Black Hole; or has been turned into a Kentucky Fried Human and vomited back out again via a White Hole quasar or gamma ray burst to become as one with the cosmos. We all started out as starstuff – and so shall we (or what’s left of our remains) all ultimately return to become starstuff again a millennia of millennia from now. 

Singularities: The Heart of Black Holes and the Big Bang

Singularities are fascinating objects and places, yet entirely ‘inaccessible’ in the sense that you can’t actually go there on vacation and send back a postcard, or travel to one on a government grant as a scientific expedition and report back via a peer-reviewed article in a technical scientific journal about the local environment, geography, inhabitants, etc. In a sense singularities are like Heaven in terms of accessibility. You have to rely on intuition or theory or second-hand observations as to what’s what and who’s who.  

Okay, for those readers I’ve already befuddled, I’d better tell you exactly what a singularity is! You’ve all heard of the phrase ‘Black Hole’ and not the one in Calcutta either! I refer to astronomical or cosmic Black Holes. Black Holes are ‘black’ because they have packed inside them so much stuff, so much mass, and hence so much gravity that not even particles of electromagnetic energy (photons) can escape their gravitational clutches. If photons, and that includes visible light photons, are jailed, can not pass go, can not collect $200, then they might as well as, as far as your perception of them is concerned, not exist. If what you don’t see exists, that existence is of no matter (well lots of matter actually). Translated, Black Holes are black because visible light can’t get from them to your eyeball! The absence of light is well, blackness.

So, is a Black Hole just a big lump of stuff, albeit stuff you can’t see? Well, ‘yes’ and ‘no’.  First off, we can ‘see’ Black Holes indirectly because of their gravitational influence on stellar objects we can see. I mean if you see a star whirling around something you can’t see, then the logical interpretation is that the star you can see is in orbit around something you can’t see – i.e. a Black Hole. Well ‘no’, you can’t ‘see’ a Black Hole because light from the Black Hole can’t get away from the crush of that Black Hole’s gravity.

What’s all this got to do with singularities? Well, the stuff composing a Black Hole, all that stuff that clumps together and is the centre of the massive all-encompassing gravity that prohibits the photons to escape the house (Hole) that Jack built is the Black Hole’s singularity. An analogy: The extent of the Black Hole is the extent of the Earth’s outer atmosphere; the singularity is the solid Earth proper. So think of a nebulous outer edge with a solid core of stuff in the middle. The stuff in the middle generates the intense gravity; the nebulous outer edge marks the boundary between gravity below the threshold of light escaping and light not escaping. That boundary is referred to as the ‘event horizon’; the stuff in the middle is the singularity.

Now the idea of a singularity doesn’t stop with the idea behind an astronomical Black Hole. No, a singularity is any concentration of stuff or mass that has such a massive amount of gravity as to prevent photons from leaving the gravitational well or prison so created. What’s the ultimate Black Hole – the Mother of all Black Holes? Well, if bits of our Universe can clump together to form astronomical Black Holes, then our entire Universe, when clumped together and in a relativity tiny state, would have been the Mother of all Black Holes and hence the Mother of all singularities. When was our Universe in such a state? Well, in the beginning!

Our Universe is expanding. That’s verified by direct cosmological observation. Every cluster of galaxies has such astronomically bad ‘body odour’ that every other cluster of galaxies is moving out of the vicinity quick-smart! Well actually you can’t have ‘body odour’ in space, so that’s not the real reason. The real reason is that in the beginning or once upon a time, there was some sort of explosive oomph event that started the expansion process. We call that the ‘Big Bang’ event. At the time of the Big Bang event, our entire Universe had a close encounter with, well, our entire Universe. Our entire Universe was roughly all in the same space at the same time. Translated, if you run the film of an expanding Universe backwards, you eventually get the entire contents of our Universe on collectively very intimate terms. Such a massive collection of stuff, matter, mass, hence gravity, all of the stuffs, matter or mass that the Universe possesses, well let’s just say you’d have the Mother of all singularities – in the Big Bang beginning; or anyway once upon a Big Bang time at least .  

Well surely one didn’t have this Mother of all singularities just sitting around for eons then for no apparent reason go ‘poof’ and thus have an explosive oomph moment which kick-started things off as far as our Universe is concerned. The intense gravity of the Mother of all singularities probably would have muted any oomph to begin with; the birth of our Universe stalled at the onset.

But, let’s throw some momentum into the mix. What’s the opposite of a Big Bang? It’s a Big Crunch! So let’s propose that we have this other universe which, the bits and pieces thereof, under all those mutual gravitational attractions, is slowly, ever so slowly, but ever so surely, coming together. And as it comes together, the contracting velocity gets faster, and faster, and faster. Eventually, you have this massive collection of stuff rushing together to meet at a single point in space and in time at a fantastic velocity. There is such momentum present that the contracting Big Crunch universe just can’t stop on a dime any more than an automobile going a hundred miles an hour can stop with inside of a foot of having the brakes applied. The Big Crunch at the omega point obviously forms the Mother of all Black Holes and singularities, but the sheer momentum of that contracting universe just tears the fabric of things (space and time) apart, and like a glove turning inside-out, the contraction passes through the omega point, spewing its gets out, becoming an alpha point, which is our Big Bang event and the start of our new expanding Universe.

Okay, so we have two sources that have singularities – singularities at the centre of astronomical Black Holes, and the Mother of all singularities residing inside the Mother of all Black Holes, the one that existed at the Big Bang beginning of the Universe.

We of course can’t see a singularity directly (unless you’re willing to take a one-way trip down a Black Hole, but even if you survived that and landed safely on the singularity, you couldn’t ever broadcast back your findings – that speed of light restriction that by definition a Black Hole imparts regarding sending stuff out). So, we have to rely 100% on what theoretical equations predict a singularity to be. Unfortunately, those equations, when pushed to the sorts of mass and gravitational extremes that a singularity would represent, well you get nonsense answers. Translated, if taken at face value, the equations note that the intense gravity crushes the stuff that itself is responsible for that gravity down to a point of zero dimensions and hence infinite density.

The essential problem behind this nonsense is that gravity is represented by Einstein’s Theory of General Relativity which is a classical physics smooth continuum phenomenon. That is, you can have this gravitational value, and that gravitational value, and every possible value in-between. However, tiny objects, which is what a singularity is postulated to be, is in the realm of the quantum, which is a non-continuum phenomena. Think of a staircase. You can be on this step, or the next step, but there is no step in-between the two. That is, you can have this value, or that value, but only certain other values in-between. It’s also like money – you can have a five dollar bill, and a ten dollar bill, but not a six and a third dollar bill, or an eight and three-quarters dollar bill, or even a seven or a nine dollar bill. Money and staircases are non-continuum quantum-like; money and staircases are not a smooth continuum like gravity is.  

So, to adequately come to terms with the really real properties of singularities, you need a theory of quantum gravity. Alas, despite the best efforts of thousands of theoretical physicists over many, many decades, no quantum gravity theory to be had. There’s no quantum gravity dice.

So, let’s abandon that theoretical track and go back to common sense predictions.

Either Black Hole singularities, or the Big Bang singularity, are infinitely dense and have zero volume, or they do not. If they do not (and the alternative defies common sense and is IMHO ridiculous), then singularities have a finite volume and can grow in size as more stuff is added on. You have an original tiny singularity with extremely high, but not infinite density. You keep piling stuff onto it. For a while, the density keeps on increasing, but since it can’t become infinite, there will be a point reached where further increases cease. As more and more stuff continues to be piled on, the only other option is that the size of the singularity must grow. The volume increases, and increases and increases. The upshot is that singularities can reach a size where quantum effects become negligible. Or, in other words, singularities can grow to where they aren’t quantum objects anymore, and while theories of quantum gravity might be still be useful in explaining their properties, it’s probably no longer essential. Singularities have entered the realm of classical physics.

One property of singularities I find interesting is that the stuff that eventually forms the singularity isn’t the same sort of stuff that went down the Black Hole’s throat in the first place. There’s been a phase transition of one kind of stuff to another kind of stuff. You’re quite familiar with phase transitions in your day-to-day life. There’s nothing mysterious about the concept. The most common example is steam or water vapour condensing to liquid water condensing or freezing to ice; ice melting to liquid water hence boiling or evaporating into steam or water vapour.  Apart from your division into solid, liquid and gas, there’s also plasma. Now the sort of matter that composes a singularity is probably something else yet again, a phase transition that only extreme gravity can achieve. That such a new state of matter exists is predicted by the following: If you have an ordinary matter star, and if it should happen to collide with an antimatter star, what you get is one hell of a big Ka-Boom; the annihilation of matter/antimatter into pure energy.  However, say your matter star implodes into a Black Hole with singularity. And say your antimatter star implodes into a Black Hole with singularity. Now have these two Black Holes collide. No Ka-Boom results, just a larger Black Hole! 

Cosmic Fun: Random Ramblings in Modern Cosmology: The Condensing Universe

The following ideas are primarily mine alone, the good, the bad and the ugly, albeit based on and influenced by reading multi volumes of tomes in modern cosmology. However, I’m also quite sure that numerous others have quite independently thought somewhat similar, if not exact, thoughts as well. Therefore, I’ll take no credit for being right, if I don’t get blamed for being wrong!

THE CONDENSING UNIVERSE

The complexity of the Universe is highly temperature dependent.

In the beginning (the Big Bang), the Universe was very hot and very dense. From that moment on, the Universe has expanded, become ever cooler. What happens in general when things become cooler? Well, on can say that complexity increases as things become cooler. Steam isn’t very complex, but cool it down to a liquid (a phase transition) and you’d have to conclude that water is a more complex physical substance than steam. Cool water down through another phase transition and complexity increases again – ice crystals are certainly more complex than drops of water.  In general, if you apply heat to something, inherent complexity decreases. For example, a human body at room temperature is much more complex than that same body post cremation! A rock is chemically more complex than the sun. A magnet loses its magnetism when heated. And so on.

If all you had were steam (water vapour), and you cooled things down, what would condense out would be liquid water: 100% water. If however you have your usual atmospheric mix of gases and cooled things down, you’d condense out the different components at different temperatures. Water might condense out first, the carbon dioxide, and then say oxygen or nitrogen, and probably lastly, hydrogen. What was a uniform chemical mixture has separated into the discrete chemicals that previously were all mixed up together.

Appling the above rules of thumb to the young Universe and I conclude that the Universe has gone from a simple uniform mixture of very hot stuff in the beginning (a ylem – to use George Gamow’s term for the ‘primordial substance from which all matter is formed’), stuff which then condensed out as unique entities (from the ylem-like-plasma to the various particles and forces, hence nucleosynthesis and matter, etc.) as the Universe expanded and cooled, and hence increased in complexity – atoms to molecules to stars and galaxies and planets and life. In other words, I suggest that the ‘in the beginning’ Universe was more akin to our atmosphere (a mixture) rather than just a 100% uniform stuff (like just water vapour).  This makes a sort of sense in particular if our Big Bang was somebody else’s Big Crunch. However, this seems to run against the grain of current thinking which (unless I’ve really misunderstood things) which suggests that ‘in the beginning’ the energy (temperature) was great enough that all the particles/forces were unified. However, I fail to see how a unified stuff (this ylem-like-plasma) could cool and ultimately condense out to produce un-unified stuffs! I’ve probably celebrated pass-over somewhere along the line in that the accepted concept (uniform stuff) has passed over my head!