Olbers’ Paradox and Black Holes

Unless you are blind, it’s obvious to the rest of us that there is quite a difference between daytime and night-time. At night, the sky is dark! Why? Well, it’s obviously dark at night because the Sun isn’t shining in our night sky – wrong answer. In fact, if you stop to think about it, the night sky should be as bright as the daytime sky. That it’s not means there’s a paradox, usually referred to as Olbers’ Paradox (after German astronomer Heinrich Wilhelm Olbers). Resolutions have been around for yonks; I introduce another one here. 

Olbers’ Paradox: Why is the night sky dark? In our vast Universe, assuming it is static and infinite in space and time, with an infinite number of stars (or galaxies or some sort of radiating objects) in it, it would seem that no matter in what direction you looked, sooner or later your line of sight would intersect or intercept a star or galaxy or some sort of radiating object. Thus, the night sky should be as close to infinitely bright as makes no odds. Of course you know and I know that’s not the case. 

Perhaps there are massive interstellar clouds of gas and dust which, like window blinds blocking out sunlight, block out the stars, galaxies and related. Trouble is, you can only absorb radiation for just so long before the substance doing the absorption can’t absorb any more before reradiating it. Your window blinds eventually feel the heat and you will too when you touch them. However, there’s one exception to that rule and the point of this revisitation – see below.

The most logical resolution to the paradox is that there’s only a finite number of radiating objects out there and thus our line of sight could extend out to infinity and not intersect or intercept any radiating objects.

Then too, our Universe is expanding and therefore many astronomical objects (distant galaxies mainly) exhibit Doppler Effect red-shifts. This is just the Doppler Effect for an emitter of light that’s receding from us as opposed to the more familiar shift in sound to lower frequencies such as a train blowing its whistle drops in pitch as it passes and recedes away from us: same principle. Anyway, their visible light is red-shifted into the infrared which we can’t see and so therefore our line of sight assumes there’s nothing there. Two problems: firstly that just substitutes heat for light so the sky should be hot; secondly, radiation at shorter wavelengths than visible light, like ultraviolet, should be red-shifted down into the visible range.

Since our Universe is expanding, maybe the light from vastly distant objects hasn’t had time yet to reach our eyeballs and telescopes, so we can’t yet intersect or intercept their light. In fact, over time, because our Universe is expanding, distant cosmic objects are constantly slipping beyond and over our observable horizon, just like a ship at sea sailing away from us disappears over the observable horizon.

The Exception to the Rule: Here’s my new explanation, which is a supplement, not a substitute, in explaining the paradox. It’s a variation on those massive interstellar clouds of gas and dust which block out the stars, galaxies and related. In our Universe there are two kinds of astronomical objects. There are cosmic faucets like stars and anything else that gives off or reflects electromagnetic (EM) waves. That’s the cosmic “In Tray”. Then there are cosmic sinks and drains that absorb electromagnetic waves – Black Holes, the cosmic “Out Tray”.

It would seem to me that over the course of 13.7 billion years, an awful lot of EM (light, IR, UV, radio, microwave, gamma-ray, etc.) photons, not to mention neutrinos and cosmic rays, would have gobbled up and removed from the Universe’s inventory by being sucked into and forever residing in the insides of Black Holes. Since all astronomical observations, hence conclusions about the state of the Universe, rely on the detection of that which is emitted or reflected by cosmic faucets, then it stands to reason that in order to arrive at valid conclusions, what cosmic sinks and drains remove from the Big EM Picture must be taken into account. But is it? I’ve never read any account where the removal of EM photons from the Universe’s inventory has been considered. Maybe I haven’t read widely enough – maybe. 

One example that springs to mind of the possible significance of Black Holes is the minor temperature variations in the cosmic microwave background radiation (CMBR), that leftover heat from the Big Bang event 13.7 billion years ago – perhaps those slightly cooler spots in the CMBR are due to large Black Holes between our measuring devices and the CMBR that is sucking up those CMBR microwaves before they reach our measuring telescope or space probe or high altitude balloon. I seem to recall cosmologist George Gamow back in the 1940’s making a theoretical prediction that the (then undetected) CMBR would be somewhere between 5 to 7 degrees Kelvin, instead of the roughly 2.7 degrees Kelvin that eventuated. Perhaps, the overall cooler CMBR was due to Black Holes sucking up lots of those CMBR photons over all those billions of years.

So another reason why the night sky is dark is because in many cases when you look outwards, you intersect or intercept a Black Hole in your line of sight that’s between you and some sort of cosmic faucet further on.

Can Black Holes Evaporate? Part Two

While there is a constant transfer of matter and radiant electromagnetic energy (photons) between bodies throughout the cosmos, there are sinks, ultimate final resting places where matter/energy can retire to and be removed from the rest of the cosmos. These cosmic sinks are Black Holes. But is that retirement permanent, or can stuff re-enter the cosmic workforce? Can Black Holes evaporate? The theoretical short answer is “yes”; the long answer is “no”.

Continued from yesterday’s blog…

Now what about a Black Hole? Clearly a Black Hole isn’t isolated from the rest of the cosmos and objects therein. If you were just outside the event horizon you’d ‘see’ photons (of all wavelengths) because you’d see stars and galaxies, etc. just like you can locally. Neutrinos would still pass right through you on their way to their doom once passing through the event horizon. The Universe is full of interstellar and intergalactic atoms and molecules and dust and of course lots of larger stuff a Black Hole can snack on. Black Holes will sweep up stuff just like Earth does, only more so since it has more gravity with which to grab hold of stuff with, and also because once caught there’s no escape for the cosmic fish. Unlike Earth, everything that crosses that event horizon, that hits the Black Hole, won’t be reflected back (like photons). Neutrinos that can pass through light-years worth of solid lead without even ‘breathing hard’ will be imprisoned when they try that trick in a Black Hole’s inner sanctum. And of course atoms, molecules, interstellar dust, the big chunks will also get imprisoned. 

But we can imagine an idealized cosmos where all Black Holes have swallowed up all existing radiated particles (photons), all the atoms,  molecules, the dust and all the bigger stuff – all those stars and planets; asteroids and comets; even all that mysterious ‘dark matter’. So you have a cosmos of just Black Holes and the vacuum energy (well maybe a few bits and pieces escaped, but so few to be of no consequence).  Of course there is one further logical extension. Black Holes can swallow other Black Holes. Black Holes can merge to form bigger Black Holes. The final product is that the cosmos consists of one Black Hole – the Mother of all Black Holes – plus the vacuum energy!  So you end up with one Black Hole left standing with nothing left to eat.

Okay, so the only scenario now possible is that this Mother of all Black Holes evaporates via Hawking radiation. It might take trillions upon trillions upon trillions of years, but evaporate it does. Since matter and energy can neither be created nor destroyed, once the Mother of Black Holes has finally gone ‘poof’, the Universe is right back where it started from – full of stuff from photons to fundamental particles which them undergo chemistry to form atoms and molecules and stars and planets and perhaps life – and new Black Holes!

Perhaps this is a new and improved version of a cyclic/oscillating universe! - But then again, maybe not. There’s a fly in that ointment (but I had you going for a while back there!). That “idealized cosmos” was only a ‘what if’ thought experiment.

Firstly, it’s actually very, very unlikely all the Black Holes in the Universe will ever merge together as long as the Universe keeps expanding. Since the galaxies are getting farther and farther away from each other due to that expansion, the collection of Black Holes contained within each galaxy keep getting further and further apart from other clusters of Black Holes contained within other galaxies. It’s like the passengers in one car get more and more remote from the passengers in another car when each car is going at different velocities and heading in different directions.

Now the collection of all Black Holes in any one galaxy could well coalesce into one super Black Hole galaxy. You have a galaxy that instead of containing billions and billions of stars and debris and particles now consists of just one Black Hole – the car only has one occupant. You have a pure Black Hole galaxy, or a galactic sized Black Hole. 

One might end up with a Universe composed of just these pure Black Hole galaxies, all spreading farther and farther apart over time. 

But secondly, there’s another fly in the ointment. All the space that separates these pure Black Hole galaxies from each other isn’t a perfect vacuum, quite apart from the vacuum energy. All the radiating stars and stuff may have been gobbled up within each galaxy, but all of interplanetary space, all of interstellar space, and all of intergalactic space, isn’t pure vacuum. There’s still the ‘it’s everywhere, it’s everywhere’ Cosmic Microwave Background Radiation (CMBR).

So what’s this CMBR?  If you have a massive hot explosion (like the Big Bang event is alleged to have been), and all that heat energy expands and expands, then you’d expect the temperature of the area occupied by that energy to drop, the temperature ever decreasing as the volume that finite amount of energy occupies increases. As the energy expands it gets diluted and thus cools, but can never reach an absolute zero temperature for reasons already noted. And that’s just what we find on a universal scale. There’s a fine microwave energy “hiss” representing a temperature a few degrees above absolute zero that’s absolutely everywhere in the cosmos. That’s the diluted heat energy of the very hot Big Bang – well it has been a long time since the Big Bang event (13.7 billion years worth of time) and that energy is now spread throughout a lot of cosmic volume. That microwave “hiss”, called the CMBR, was predicted way before it was discovered. There’s no doubt that it exists.

Since the CMBR is just photons with very long wavelengths, Black Holes could suck up the CMBR photons as easily as light photons. Removal of CMRB photons, already representing a temperature just slightly about the theoretical minimum – absolute zero – would mean the Universe gets even colder, which it would anyway since the Universe is ever expanding and thus available electromagnetic energy (photons) is ever diluting. Combining the two effects and the Universe is a chilly place indeed and will get even colder.

However, it’s probably not possible for Black Holes collectively to swallow up all of the CMBR since there will come a point of diminishing returns. What happens when the temperature of Black Holes equals the temperature of the Universe at large – the CMBR? The answer is thermal equilibrium like when your hot cup of coffee cools off to room temperature. Input into Black Holes from the CMBR will equal output via Hawking radiation. For every photon emitted via Hawking radiation, a CMBR photon gets sucked in. What does that mean? It means a Black Hole can not evaporate.

What about very tiny (micro) Black Holes that are relatively ‘hot’? Might they go ‘poof’ before thermal equilibrium is achieved? Will the contents of the Black Hole evaporate into the surrounding cosmos before they can equate to the surrounding temperature? The analogy might be like a hot drop of water could evaporate into the cold atmosphere before the liquid water drop can attain the temperature of its surrounding environment.

Even so, I still imagine that in the current matter and radiation dominated Universe, incoming would still exceed outgoing.

Of course if you could take a Black Hole, isolate and shield it from the rest of the cosmos and all that it contains, so all you have is the Black Hole and its internal energy (including the all pervading vacuum energy therein). An isolated Black Hole would be in a setting equivalent to putting it into an absolute zero temperature environment. If that’s the case then outgoing would exceed incoming since there could be no incoming, and therefore that Black Hole would then radiate and slowly evaporate and eventually go ‘poof’. BUT, and there’s always a BUT, I can not envision any scenario where a Black Hole can exist in such a theoretical isolation. So, Professor Hawking is quite correct – in theory. In practice, in the here and now, input exceeds Hawking radiation output, and even in the unimaginably far distant future equilibrium will be established where input equals output. 

Parallel Universes: Part Two

Parallel universes, or alternative universes or mirror universes have had a long run of popularity in science fiction and science fantasy, in both print and visual formats. One need only look at an “Alice in Wonderland” or look no further than the “Star Trek” universe (our Universe in less than obvious disguise) to view the near endless plot variations that such parallel / alternative / mirror universes provide our heroes and heroines. Do they actually exist and do they explain anything?

Continued from yesterday’s blog…

How do they, parallel universe photons say, actually get here? Well, at the quantum level, all manner of virtual particles pop into and out of existence from what’s called the vacuum energy. At the extremely microscopic level, what’s often called the ‘quantum foam’, is a level seething with activity, including the popping into and out of existence of micro wormholes, wormholes that can connect one universe with another, even if only for nanoseconds. But, that’s enough to allow the transfer of micro objects, like photons, and electrons, etc. from one universe to another. It’s like seeing the ocean from space. It looks really smooth and tranquil. However, at rowboat level, there’s this twenty foot wave about to come crashing down on top of you.

As the collection of all universes is the Multiverse, and since the wave-particle duality is at the heart and soul of quantum mechanics, then it follows that perhaps quantum physics is just the physics of the Multiverse!

The double slit experiment can be (and has been) repeated with electrons, and neutrons and protons, etc. Same results! So, therefore, there must be virtual or shadow or ghost electrons and neutrons (or quark trios) and protons (or again quark trios). Now things get interesting! But before I get to that, David Deutsch never speculated above the level of shadow or ghost protons (or other elementary particles) as proof of parallel universes. The following extrapolations are my doing!

If there are virtual / shadow / ghost protons and neutrons, then there are (let’s just call them) ghost nuclei. Add your ghost electrons and you have ghost atoms, hence ghost molecules and on up the chain to… well, ghosts!

Now these parallel universe ghosts aren’t dead people, but people quite alive in said parallel universe. They could appear to us as dead acquaintances or even dead loved ones, but parallel universes aren’t of necessity identical copies of ours (recall the heads, tails and coin-on-edge example). Just because Mum is deceased in our Universe doesn’t mean she’s yet snuffed it in a parallel one.

These virtual or shadow or ghostly images don’t even have to be living things of course. There’s a long history of apparently sane and sober people seeing, quite unexpectedly, spectral images of non-living ‘things’, like a building appearing in a otherwise verified field-of-grass only.

There’s equally a long list of documented transient phenomena, unfortunately unpredictable and unverifiable - UFOs anyone?

Speaking of UFOs (as intelligently piloted vehicles from elsewhere and/or elsewhen), sceptics often will claim ‘it can’t be, therefore it isn’t’, where the ‘can’t be’ usually refers to the impossibility of interstellar spaceflight which would require faster-than-light velocities to make things practical and viable, blah, blah, blah…. Quite apart from the fact that that assessment is total nonsense as I’ve already elaborated on elsewhere, subluminal interstellar travel doesn’t, of necessity, violate any laws of physics, period. End of discussion. However, nobody, including me, says it will be easy, but that’s a different horse of another colour.

Anyway, if there can be some sort of now and again natural interaction between parallel universes, then it follows that an advanced technological race of beings (call them aliens if you will), might be able to artificially manipulate such ‘gateways’ and go exploring – not so much in time and space but as in crossing over from X-universe to a parallel Y-universe, which in distance terms might be as close to zero kilometres as makes no odds.

Cryptozoology is another ripe area potentially explainable in part at least by parallel dimensions. Take Loch Ness and its alleged monster, one of the most baffling of cases in all of cryptozoology. On the one hand, you’ve lots of seemingly credible witnesses with no axe to grind going back over many decades. Are they all lying, exaggerating, and being fooled or just hallucinating?  The odds of that are poor for the collective of all sightings. On the other hand, you have a relatively small and confined area offering little hiding room to a relatively large animal. It’s an area that has been combed many times with all the sophisticated technology we can muster – no animal. However, it doesn’t stretch the imagination to breaking point and beyond to suggest that in some parallel universe(s), plesiosaurs (or equivalent) still exist and that for some reason there is, albeit just a rarely now and again, some sort of harmonic resonance between that world and our world, and presto, a sighting of the elusive Loch Ness Monster.

Perhaps a most likely interaction between parallel universes is evident in our dreams.

We often seemingly invent out of thin air quite unfamiliar people, places, and situations when dreaming, as well as finding ourselves in more familiar surroundings, albeit rarely something exactly parallel down to the Nth detail – at least that’s my experience. It’s maybe 90% familiar territory; never 100%.

If there is some sort of parallel universe interactions, your dreams could be, in a nebulous sort of way, a link with the lifestyle of your counterpart(s), and presumably said counterpart(s) now and again dream slightly unfamiliar scenarios that reflect your actual situations; your world and your lifestyle and relations.

It’s a sort of telepathy perhaps only achievable at the subconscious level when you’re asleep and all those day-to-day routines and constant mental activities can’t overwhelm that incredibly faint signal from a parallel universe(s).  

Now that’s not to say all dreams are parallel universe related, but some might be.

Since the double slit experiment with one photon at a time, produces interference patters 100% of the time, yet things like ghosts, UFOs, the Loch Ness Monster, even dreams, aren’t reproducible on demand, I can only conclude that it’s much easier for micro bits like photons and atoms to crossover from X-universe to Y-universe (our Universe) than it is for macro objects. But, that’s not an uncommon experience within our own world. Bacteria are vastly more common than humans – bacteria are everywhere; humans aren’t. Small things or objects can wriggle through small spaces where larger objects can not fit. It takes exceptional circumstances, an exceptional large gateway or hole between universes for a UFO or a Loch Ness Monster to make its ever so brief and unexpected appearance. So, lots of small holes or ‘gateways’ allowing lots of ghost photons (and presumably other particle types – very, very, few large holes or ‘gateways’, so actual sightings of living ghosts, etc. are very, vary rare.

Now more likely as not, it’s only a relatively few parallel universes that have a real resonance with ours. There could be other universes with physics so different that they are totally out of sight, even if not out of mind.     

Summary: The concept of parallel universes is a sound, yet novel way of explaining one of the (many) deep mysteries contained in the double slit experiment that illustrates the wave-particle duality of matter.  From that, the concept can be extrapolated or expanded to explain possible other, but more macro, anomalous phenomena.

*But with one very, very important caveat. The Copenhagen Interpretation of the quantum requires that Nature makes up Her mind when, and only when an observer or an observer’s measurement is made. Until then all is probability and nothing has reality or actual existence. The Moon has no reality unless someone is observing or measuring it! To me, observers are irrelevant – reality is reality, with or without observers. 

**Deutsch, David; The Fabric of Reality; Penguin Books, London; 1998:

Parallel Universes: Part One

Parallel universes, or alternative universes or mirror universes have had a long run of popularity in science fiction and science fantasy, in both print and visual formats. One need only look at an “Alice in Wonderland” or look no further than the “Star Trek” universe (our Universe in less than obvious disguise) to view the near endless plot variations that such parallel / alternative / mirror universes provide our heroes and heroines. Do they actually exist and do they explain anything?

There are apparently two theoretical counterparts in our real world, or in our physics. Firstly, there’s the idea that from the beginning, there’s an infinite number of parallel universes where all things that can happen, do happen. Our Universe is just one of that infinite set. In five of those universes, you 1) flip a coin – in one, it’s a heads you flip; in another, tails; in the third, the coin stands on edge! Or, in a fourth universe you decide not to flip a coin at all, or in universe #5 you decide to flip something else instead.

The other theoretical set of parallel universes is a set that ever increases, staring with just one. Universes split whenever an either/or choice is forced upon it, such that all results that can happen, happen. In this (our) Universe you decide not to flip a coin – but that decision results in a division, the universe splits and in that split, in the new universe, you do flip a coin. In that universe it comes up heads. But, that universe then splits into two and yet another universe where your flip has tails comes up. There’s also another universe where the coin lands on edge! There’s also a universe that originally splits off where you decide to flip something other than a coin. This is known as the ‘Many Worlds Interpretation’ theory, (which resulted out of a need to explain certain quantum phenomena). With every passing second, more and more universes branch off (actually trillions per second).

I’ve never been a fan of the Many Worlds Interpretation of all things quantum. That is, the universe keeps splitting each time it comes to a fork in the road. The question of where all the matter/energy comes from – created out of nothing apparently – I’ve yet to see addressed in the texts. But, many top notch scientists adopt it – perhaps as the least of all the evils certain quantum phenomena dish up. As to where they fit, all those extra universes, that’s not as much of a problem. A motel with an infinite number of rooms never has to put out a ‘no vacancy’ sign – if you get the analogy. Oh, the Many Worlds Interpretation also means that there’s no such thing as free will. You may think you have free will in deciding to wear your red dress instead of your green dress, but in the Many Worlds Interpretation, you do both – so no free will.

However, I myself go for the Copenhagen Interpretation* – when you come to a fork in the road, one and only one choice is made – the other possible choice(s) are never realized and ultimately never have any reality. But, if you start out from scratch with an infinite number of universes, or at least a vast number, then the issue of ‘where’ all the universes are is irrelevant, and the creation of all the stuff that makes them up is equally irrelevant. In the beginning, it was so!

You can have an infinite number of universes in an infinite amount of space. An analogy – there are an infinite number of whole numbers like 1, 2, 3, 4, 5, 6, etc. There’s also an infinite number of even numbers such as 2, 4, 6, 8, 10, 12, etc. Ditto an infinite number of odd numbers. Yet the infinite set of even numbers, plus the infinite number of odd numbers, equals the infinite set of whole numbers. Infinity + infinity = infinity! Or, if you like, think of your house (volume) with just one molecule (universe) in it. You’d agree there’s room for one hell of a lot more molecules (universes). If your house had infinite volume, then…

I had always assumed, and followed the assumptions of others infinitely more brilliant than I, that such theoretical constructions, such parallel / alternative / mirror universes, was forever beyond our actual reach – works of fiction aside of course. We could construct them as an intellectual exercise, but could never verify and understand the actual existence of these mental or thought experiments. That’s because these universes, if they exist, would not be part of our space-time continuum and thusly we could never interact with them.

But what if that assumption is wrong? What if parallel / alternative / mirror universes not only exist, but can and do interact with ours, and thereby give some additional credence to the adventures of our “Alice in Wonderland” and “Star Trek” characters, not to mention the reputations of those physicists who propose infinite universes or Many Worlds Interpretation theories. 

Micro & Macro Mysteries: Well, those assumptions just might now be put to the test. I’d love to be able to say I thought of this idea, even independently, it’s just that brilliant. Alas, I didn’t, and I’m kicking myself because it’s just so simple and elegant.  The credit for this goes to physicist David Deutsch, and for a fuller and better outline of his proposals, see his book cited below**. 

The basics are as follows and deals with the paradoxical and famous ‘double slit’ experiment with light – an experiment with photons.

If you shine a light (millions of photons worth) at a slit, you’ll get a blob of light on the surface behind the slit. No problems – the photon ‘bullets’ go through the slit and impact on the surface behind.

Now you shine the light (millions of photons) at two slits. Contrary to expectation, you don’t get two blobs of light – one opposite each slit – but a classic wave interference pattern of alternating light and dark areas on the surface behind. So photons aren’t ‘bullets’; light must be a wave.

Thus is demonstrated the classic wave-particle duality or paradox of light. Is light a continuous wave, or is it a collection of individual ‘bullet’ particles?

Instead of firing millions of photons at these slits at a go, redo the experiment by firing off photons one at a time – say one per hour. That can actually be done. If you fire the one per hour photons at a single slit, the picture that emerges over time is your blob of light behind the slit. Photons are behaving as ‘bullet’ particles as before.

Now, fire the photons – one per hour – at the two slits. Clearly, you’d expect two blobs of light to ultimately form on the (say photographically sensitive) surface that is behind each slit. Sometimes the single photon would go through one slit; sometimes the other. Alas, you still get a wave-like interference pattern! How can this be? What’s interfering in real time with the actual photons that you’re shooting off?

The only object capable of interfering with photons, to cause wave-like interference, an alternating light-dark pattern, is other photons. But there are no other photons in the vicinity if they are shot out at one per hour and your photon source is the only photon source!

The inescapable conclusion is that there must be other photons around that can’t be detected (seen). Call these photons virtual photons, or shadow photons or ghost photons. Where do they come from? The answer is from our parallel / alternative / mirror universes. There is therefore a form of weak interaction between universes.

To be continued...