Those Black Holes Revisited

I’ve noted in earlier essays that someone crossing over the Event Horizon of a cosmic Black Hole does so from a personal perspective of one second per second – normal time. An outside observer would see that same crossover event as one frozen in time for all eternity. That implies a paradox in that something cannot happen at one second per second and yet take an infinite amount of time to happen. The paradox might be resolvable if it were only the image of the happening frozen in time. Alas, that too has issues. 

I’ve read several times some scientific author suggest that to an external observer, someone (or something) that’s on a bullseye path toward an astronomical Black Hole, well someone will not only be travelling at a time rate slower and slower by the external observer’s clock as they (let’s call that person a pilot) approach the Event Horizon, but in fact at contact with the Event Horizon, the pilot’s time, again as recorded by the external observer, will have stopped. In other words, the external observer will never witness the pilot’s crossover from outside the Black Hole’s Event Horizon to inside the Black Hole’s Event Horizon. The pilot will appear to be frozen in time at the Event Horizon, as witnessed by the external observer for all eternity, yet as far as the pilot is concerned, everything is normal in terms of time flowing at one second per second. The pilot, from the pilot’s perspective, crosses the Event Horizon as easily as driving to the local supermarket.

Now that’s a major paradox. The pilot can’t be crossing the Event Horizon at one second per second, while at the same time being frozen in time while crossing, which is the case according to our external observer. Of course the paradox is bullshit. To an external observer, time only comes to a screeching halt from their point of view for someone external to them if they witness that someone travelling at the speed of light. Firstly, that’s a physical impossibility. There’s no reason to believe that our cosmically Black Hole bound pilot is crossing the Event Horizon at light speed. There’s no absolute requirement that our pilot is crossing the Event Horizon at the speed of light. The pilot in fact might have fired retro-rockets to slow down just prior to crossing the Event Horizon in order to better savour the moment (just like crossing the equator for the first time)! So, in actual reality, our external observer will see the pilot cross the Event Horizon, albeit at a way slower rate than the pilot will because the pilot is travelling, hence doing the Event Horizon cross-over, though at less than the speed of light but still at some subluminal velocity relative to the external observer. Any velocity incurs some slowing of time when viewed by an external observer; the faster the velocity, the greater the slowdown.  IMHO, some ‘experts’ need to go back and redo Physics 101.

Only here’s the expert’s explanation which explains why there is no paradox. 

Space is a thing and mass (hence gravity) can warp space, twist space around its little finger. The most extreme form or amount of gravity is contained within a cosmic Black Hole from which not even light can escape – hence the blackness of the Black Hole. Because space is a thing, the Black Hole or the super ultra intense gravity of a Black Hole can suck in space (as well as matter). Okay, so a Black Hole can gobble up space.

Issues arising #1: IMHO, space is not a thing but a concept. Gravity therefore cannot interact with space. Gravity is a thing; matter is a thing; light is a thing, so interactions between gravity and matter and light (representing energy which is just matter in another form) are not an issue.

Issues arising #2: presumably that means that anything that has gravity (like you) will suck in some amount of space since even the tiniest amount of gravity will warp space to some degree.

Meantime, back to the expert: Space (as a thing), gets sucked towards a cosmic Black Hole at less that the speed of light, but speeds up as space gets closer and closer to the point of no return (the Event Horizon). When space crosses the Event Horizon, it is travelling at the speed of light. Once inside the Event Horizon, space falls down the gravity gurgler at a speed greater than that of light, which is okay since space, albeit a thing doesn’t have any mass. Anything with mass cannot travel at superluminal velocities since anything with mass can’t cross the speed of light boundary from subluminal to become superluminal.

Any physical object crossing the Event Horizon will be giving off and/or reflecting light (or any other form of electromagnetic energy) at the speed of light. But the Event Horizon is that exact boundary between space being sucked in at less than light speed and being sucked in at greater than light speed so light being given off at the Event Horizon is escaping at the same velocity that it is being sucked in. It’s like you running on a treadmill at the exact same velocity but opposite direction to that of the treadmill. To an external observer you are running yet standing still, and would appear so for all eternity.

We have to assume that the material object itself can’t be crossing the Event Horizon at the speed of light (that’s not allowed), nor will it travel at or beyond the speed of light once inside the cosmic Black Hole and dropping down it’s gravity gurgler. Though the material object crosses the Event Horizon at less than light speed, the visual image of that object will travel at light speed, but light at the Event Horizon is like the runner on the treadmill. It’s a balancing act in that the image from the object is escaping from the Black Hole’s Event Horizon outward bound at the exact same rate as it is being sucked into and past the Event Horizon by space itself.

Issues arising #3: IMHO, the Event Horizon must be extremely thin, since the Event Horizon by definition is that boundary where a velocity just a tiny, tiny, tiny (add some more ‘tiny’ here) fraction under the speed of light becomes just a tiny, tiny, tiny (add some more ‘tiny’ here) fraction above the speed of light. Or, the Event Horizon is that boundary that marks the speed of light exactly (and any tiny, tiny, tiny deviation either side is no longer the speed of light). The Event Horizon must in fact be the shortest allowable thickness that’s allowed by quantum physics, which is the Planck Length (which is so small in length, or thickness, not even the most powerful of microscopes could resolve it).

The implications revolve around the fact that any image, like that of our pilot in their spacecraft, is going to be massively larger than the thickness of the Event Horizon. In actual practice our outside observer will more decidedly not see the image frozen at the Event Horizon for all eternity. Part of the image will have to be above the Event Horizon and thus be able to escape away from the Black Hole. Part of the image will be below the Event Horizon and sucked into the cosmic Black Hole never to be seen again. Any remaining image is one Planck Length thick – invisible to the human eye and the most powerful of microscopes. Even that tiny remnant won’t last long due to ever present quantum fluctuations. The Event Horizon has the tiniest of jitters but it’s enough to disrupt the remaining bit of image from remaining for very long. The upshot is that the frozen image of the pilot and the craft as witnessed by the external observer will be fleeting at best.

Issues arising #4: When it comes to those astronomical Black Holes, we are all external observers. If our expert is correct, and images are frozen for all time at the Event Horizon by objects consisting of matter and energy that cross the Event Horizon, then absolutely anything and everything that has crossed over the Event Horizon since the creation of any specific cosmic Black Hole – since the year dot probably – well their images collectively should still be, well, visible. Each individual image would be piled on top of the next one top of the next on top of the next and so on. Somehow I very much doubt that’s the case. It should be bleeding obvious through our astronomical telescopes. And so, I repeat that IMHO, some ‘experts’ need to go back and redo Physics 101.

Time Travel via 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. While there are some serious reasons to suspect that parallel universes do exist, there’s another, albeit more theoretical proof of the parallel universe concept. Time travel is the name of the game!

Continued from yesterday’s blog…

But there’s also a second catch – and here’s where parallel universes enter the picture. To avoid all those time travel paradoxes sci-fi writers love so well, if you travel back in time you also have to travel between parallel universes!

By all means go back to early April 1912 (I’m ignoring Catch #1 for sake of illustration here) and warn the Captain of RMS Titanic of what’s going to shortly happen. Assuming you convince him of the pending disaster (but more likely as not you’ll be thrown straight into the loony bin), and the disaster is avoided, you’ll have saved the ship and passengers and crew in a parallel universe – not in our Universe. Our RMS Titanic sank. People died. That cannot be changed, at least not by anyone from our Universe.

Because parallel universes don’t have to be carbon copies of ours, you might find, of course, that the ship maybe known as HMS Titan, and she’ll be due to strike a mine instead of a iceberg because the First World War started a decade earlier in that universe.

Maybe one could go back and warn parallel dinosaurs that a parallel asteroid was coming – only I doubt they’d listen (unless of course in this parallel universe they had evolved both an intelligence and technology to deal with the issue).

Or, by all means go back to 1912 and meet (and chat up) your now young and future great grandmother (or great grandfather as the case may be). You both fall in love and get married and thus your real great grandparents never meet and therefore one of your grandparents never was born and thus one of your parents never made it into this world and thus neither did you. So how can you exist therefore to have gone back in time and meet your great grandparent? (Note that this is a more humane version of the grandfather paradox where you kill one of your ancestors before they got their reproductive act together). I assume here that by doing so, that is going back in time and meeting your great grandparent, that you’re not actually going to be able to parent or father or produce your own grandparent, hence parent, hence yourself. You’re not your own great grandparent. Not in this Universe.

If you had done the above in our Universe, you’d have a paradox. You have prevented yourself from being conceived and born. You can’t be your own ancestor. There’s no paradox if you went back to a 1912 in a parallel universe. In that universe you indeed prevented your potential future existence in that universe, but not your actual existence which happened in our Universe.

But maybe you didn’t really travel back in time at all (eliminating Catch #1). If there is such a thing as a universal ‘now’, then our 2012 might correspond to another universe’s 1912 (and our 1912 corresponded to their 1812, and so on). Therefore, that you in our Universe in 2012 can perhaps see the living, albeit ghostly, image of someone/something that exists in that other universe’s 1912 (and maybe vice versa).

Now it doesn’t follow that our Universe of 2012 is actually a century older than a parallel universe whose ‘now’ is 1912. Evolution just developed at an ever so slightly slower pace in our parallel universe – that’s all.

There’s apparently yet another catch in all this. If you do time travel to a parallel universe, whether its real time travel, or pseudo and just apparent time travel, once you go, you’re stuck – there’s no coming home again. Of course you might in turn time travel to a third and fourth, etc. parallel universe, but you can’t come back to our Universe again, for that could mean one universe, our Universe, contains two copies of identical bits of matter – matter (in the form of you) has been created out of apparently nothing, in violation of basic conservation laws.  

Why can’t you go home again? You could conceivably return to the time just before you originally left and therefore there would be two identical copies of you existing at the same time and vicinity. Another universe could of course contain more than one copy of you. A universe can lose matter (you) to another parallel universe. A universe therefore can gain matter (you again), but no universe can have more than one copy of identical matter. That doesn’t mean that 50 parallel universes couldn’t lose their own version of you, and all 50 versions of you ends up in say a 51^st universe. There are no exact duplications, so no problems.

There’s also what’s known as information paradoxes within time travel scenarios that are also resolved via parallel universes. Say, for example, that your name is Richard Wagner (I’m sure there are lots of people in our 21^st Century with that name), and you were named after the famous opera composer. And say, like millions of others, you’re a fan of Wagner’s operatic music and productions, and further say you have the ways and means to travel back in time to the 19^th Century and have a desire to meet your famous namesake. And so off you go to meet the young budding opera composer – maybe get his autograph!

Upon arrival in the 19^th Century however you find that there is no such person! Well, being a fast thinker ready to seize the moment, you figure you won’t be missed in the 21^st Century (you’re an only child, an orphan, unemployed and unmarried). So you decide to step in and fill history’s breach and become somebody famous. You know exactly what to do, and so you become THE Richard Wagner. The operas (which you know so well) are duly composed by you and performed and all’s well with established history and the world – or is it?

The question arises, and remains, where did the operas (music, plots, etc.) actually come from? You learned and eventually knew them by heart when living back in the 21^st Century, yet you apparently composed them yourself based on that knowledge in the 19^th Century. Something is screwy somewhere. Original opera music and productions have apparently been written and created without any creativity or intellect involved.

Of course there is no paradox if you invoke a parallel universe. In our Universe there really was a 19^th Century opera composer known as Richard Wagner, and a 21^st Century enthusiast of his music and productions with the same name. The 21^st Century Richard Wagner does travel back in time to a 19^th Century, but a 19^th Century in a universe where the composer Richard Wagner never existed. Our 21^st Century fan of Richard Wagner brought our 19^th Century’s Wagner’s music to a parallel universe where it hadn’t or wouldn’t otherwise have existed. So, no paradox! There was a point of origin or an original intellect and acts of creativity in our Universe and in our 19^th Century.

And by the way, there are dozens of variations on this theme in the literature, especially books that highlight the paradoxes of time travel.

As you see, you can have a lot of fun with proposals that give credibility to parallel universes, which is all the better as these proposals are thoroughly grounded in hard science. Lastly, we need the concept of parallel universes to help keep our beloved sci-fi authors in a profitable job! 

Summary: Because time travel is allowable in relativity physics, to avoid time travel paradoxes, one requires parallel universes to exist.

Time Travel via 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. While there are some serious reasons to suspect that parallel universes do exist, there’s another, albeit more theoretical proof of the parallel universe concept. Time travel is the name of the game!

Why go back in time at all? Just to observe? That’s okay, as long as you look and don’t touch. Just to get rich? Probably! Just to do good deeds? I’d have to advise against that. Travelling to the past from the future, armed with the knowledge of what that future holds, brings a ‘wealth’ of opportunities – accent on the wealth. I mean go back in time and there’s this new company called IBM or Microsoft just starting to sell shares. You’d make a killing! You know in advance about the Global Financial Crisis. Put that to your advantage! Knowledge is power. Maybe all our billionaires are time travellers from the future who came back to make a killing! Sorry for taking such a cynical view. Actually the danger is the ‘butterfly effect’. Go back in time, be a goodie-goodie two shoes and correct something – kill Hitler in 1935 say – and the ripple effect could have so changed the future from which you came from that you might never have existed. Say that soldier in WWII, killed by the Nazis, lived instead because you assassinated Hitler in 1935 and he married your Mum instead of your Dad. You were then never born. Or say you assassinated Hitler in 1935, and someone else took over the leadership, but that someone started up Germany’s nuclear program almost immediately. Thus, Germany had the A-bomb when she started WWII – Germany won! Of course maybe somebody else goes back in time and assassinates you just before you bump off Hitler! Lesson: You do not muck around by changing the past since you can’t predict the rippling effects on down the line. Ray Bradbury’s excellent short story (also filmed) that illustrates this point nicely is “The Sound of Thunder”.

Be that as it may, I can immediately think of four actual, possible or theoretical ways of doing the time warp – again!

The first is your tried and true traditional time travel into the future, and one which you have no control over – we all travel into the future at the speed of one second per second.

Secondly, there’s a possible albeit highly theoretical equivalent for an antimatter you. You’d have a tried and true traditional time travel into the past, again one which you have no control over, and again (presumably) at a rate of one second per second. That’s because of the idea that antimatter is just normal matter, but normal matter going backwards in time at the rate of one second per second. I don’t rate that too highly on the reality scale. 

Thirdly, when you view any object, you’re time travelling back into the past. That’s because it takes a finite amount of time for light to reach you from whatever it is you’re looking at. What you actually see is how it looked that finite amount of time ago. Since you always view what happened in the past, I guess that’s a form of time travel! By the way, even if you directly touch or taste something, it still takes a finite time to travel on up the nerves to the brain and a finite time to register and be processed.

Fourthly, there’s the concept that if you travel and accelerate outwards at a significant percentage of the speed of light, stop, reverse, accelerate and come home again, when you land, you will have aged less than those stay-at-homes, or translated, you’ve travelled into the future a lot quicker than otherwise would have been the case. You and your stay-at-home twin are now both at the same point in time again; it’s just that you have biologically aged far less. That’s the ‘twin paradox’ of relativity physics, but it’s no paradox – it actually happens.

Interestingly, at the micro, hence macro levels, the laws of physics do not forbid other ways and means of time travel, for example using rotating Black Holes, wormholes, etc. While these are theoretically possible, in practice it would be difficult in the extreme, very energy intensive, and certainly way, way beyond our current, or even projected, level of technology, and may indeed remain forever out of our practical experiences and thus remain a parlour game for physics professors. But maybe, just maybe…

However, for starters, there’s a catch – there’s always a catch! Travelling backwards in time is restricted. You can’t travel back in time beyond the point where the time travel device was first constructed. If we should construct such a device in say the year 2050, nobody will be able to visit 2949 or any earlier date. Thus, since no such terrestrial device yet exists, we’re not overrun by tourists from our future. Our descendents can’t reach us. We cannot have time travelling visitors from the future who can tell us our future because they are not from our future, but from the future of an elsewhere – you guessed it, from the future of a parallel universe where a time travelling devise exists.

The reason, as I understand it, that you can’t time travel in your time travelling device before the device itself existed, is that your device isn’t a machine or a device you sit in – it’s a medium. It’s likely to a natural object, even if manipulated – rotating Black Holes or wormholes. A tunnel allows you to go from one side of the mountain to another, but in doing so you don’t take the tunnel with you. A ship travels through the water – it doesn’t take the water along with it. A tennis ball gets hit by the tennis racket; it doesn’t take the racket along with it. Instead, it relies on finding another racket in its new ‘universe’ or ‘time frame’ or court, able to return it home! You probably get the drift. That’s why you can’t go back in time further than the medium itself you used. If your mountain tunnel was built in 2009, you can’t go through and exit it in 2008! But you could go through and exit it in 2010, so you’re not of necessity stuck in the past if you get the analogy. The tunnel allows travel both ways, but just not before it was constructed. Anyway, forget your time travel movies with machines – no machines allowed. Probably the best movie to illustrate the point that the device is a medium and not a machine is “The Final Countdown”.

That of course says nothing about extraterrestrial intelligence(s) time travellers who may have had a working time travel devices eons ago, so we certainly can’t rule out, or preclude such a possibility – there’s those pesky UFOs again!

To be continued...