The Speed of Light (and Gravity?)

Within Relativity Theory, if there is anything unintuitive it is the fact that in the entire Universe, it is the speed of light (and gravity?) alone that is absolute or fixed, not something like space being absolute or time being absolute. It’s unintuitive in that all the other not-light bits and pieces that are in motion can be added or subtracted. The lone exception to that universal rule that velocities can be mathematically combined is the speed of light (and gravity?).

Repeat for emphasis: the anomaly here is that in any other scenario, anything that is not-light and in motion, velocities can be added and subtracted. Repeat again: with that one speed of light exception, velocities may be added or subtracted. If you are on a treadmill that’s moving left at 5 MPH, and you’re on it walking to the right at 5 MPH, to an external observer you are waking yet standing still. You’re much more likely to hit a home run if the wind is blowing towards the outfield fences; planes fly faster with a tailwind than with a headwind; you swim in the river faster going with the flow than against the current. If you are in a train that is moving at say 100 km/hour and you throw a ball at 10 km/hour in the direction at which the train is moving, to an observer outside the train, your ball is traveling at 110 km/hour. If you throw the ball towards the rear of the train, an outside observer will measure the ball as moving at 90 km/hour. If on the other hand, you shine a flashlight in the train, an outside observer will see the velocity of the resulting light beam moving at the speed of light – not the speed of light PLUS the velocity of the train, or the speed of light MINUS the velocity of the train, but at the speed of light! That’s nuts, but it’s scientifically nuts and been proven again and again in any experiment you care to devise. I have no issue with experimentally verified results. That doesn’t mean I don’t have issues with the anomaly.

The velocity of light is a constant to an external observer no matter what. Why that should be no one knows, but it is so. However, my take on this can of worms, which as a consequence requires somewhat counter-intuitively that both time and length have to be flexible, is one should always be a bit suspect when it comes to the lone ranger, the lone ranger being the exception to the rule*. I don’t tend to like exceptions to the rule. There’s something weird afoot here. Mother Nature is trying to tell us something we haven’t figured out yet.

All that said, the speed of light isn’t really a constant if you take into consideration the differing mediums that light can travel through. However, the speed of light is probably also a constant within whatever other medium it happens to be in. The speed of light in air at STP (standard temperature and pressure) is less than the speed of light in the relative vacuum of outer space; even less traveling through pure water and less again traveling through clear glass. One would presume that just as the speed of light in space is constant for observers regardless if they are traveling in a high velocity spaceship or as an astronaut ‘stationary’ on the International Space Station, the speed of light in water sould be a constant for the crew in a submarine that’s underway thus in motion or a diver standing on the seabed.  

That makes me sort of wonder, theoretically, if you could get an underwater submarine to go faster than the speed of light in water (or an aircraft to outpace the speed of light in air), though in either case that would be less than the speed of light in a vacuum, could you then claim, albeit with qualifiers (in water; in air), that you actually traveled faster than the speed of light, if only for the bragging rights? 

Apart from light (photons), presumably gravity, or gravity-waves, also propagate at the speed of light and thus a gravity-wave would have a constant speed regardless of any frame of reference for any observer. But I also presume that necessitates finding the hypothetical graviton particle (to mirror the photon) and that, for the moment, resides in the unknown basket.

That brings up yet another puzzlement. Is gravity just geometry as per General Relativity or is gravity a force transmitted by a force particle, the theoretical graviton, and thus more akin to electromagnetism’s photons (infinite extension; obeys the inverse square relationship) apart from lacking EM’s negative counterpoint – in the case of gravity, that’s antigravity.

Speaking of gravity (gravitons) and light (photons), if gravity can have an effect on light (i.e. – the gravitational lens), then it should be a two-way street and light should be able to have an observable affect on gravity, but I can’t recall ever reading about that aspect of the relationship. 

As per the speed of light being medium dependent; one speed in a vacuum, another in water, well that makes for an interesting question when considering gravity. If a gravity-wave is approaching Earth, will it have one constant velocity in the vacuum of space for all observers, then a differing velocity as it passes through our atmosphere, then another value as it passes through the ocean and yet others as it hits the various density layers inside the planet?    

As is often the case, there tends to be more questions than answers!

*Not that the differing rules for the speed of light vis-à-vis other not-light velocities is the only exception to the rule in modern physics. Quantum tunneling is one of those exceptions to the rule of causality. With respect to the standard model of cosmology and the Big Bang, first there was nothing; then there was something. That means the Big Bang event created both matter and energy out of less than thin air. That’s also a free lunch and one of those exceptions to the rule of physical law usually expressed as the conservation of matter and energy. All these exceptions to the norm suggest that some of the final chapters in modern physics haven’t yet been written.



Time To Question Time: Part Two

Time is the most mysterious concept that you are likely to think about. You know exactly what time is, unless you actually have to explain it and then things bog down. If you admit that time is pure puzzlement, well you’re not alone as the nature of time has been endlessly debated by thinkers, good, bad and average, ever since humans had the ability to think. Okay, I’m a thinker, so here are my thoughts in Q & A form about time.  

Continued from yesterday’s blog…

Q. Is time travel to the future possible?

A. Time travel to the future is easy – you’re doing it right now at the rate of one second per second – boring – or when you fall asleep (or pass out drunk), next thing you know you are in the future, ahead by several hours. You’ve skipped or jumped over some interval of time. That’s what one usually means by travel to the future. It is jumping over some significant interval of time without having to experience or live through it, like say going from 2013 to 2015 and avoiding 2014 entirely. Of course when you arrive in the ‘future’, be it the following morning or by skipping 2014, it’s no longer the future but the present – the ‘now’. It’s actually impossible to be in or to exist in the future, it’s only possible to head towards the future, which you do anyway at the rate of one minute per minute. 

I guess you could construct a philosophical argument that relative to your point of view of yesterday, if you say skipped a day and landed in tomorrow, you are now in the future, but such convolutions don’t get us very far since the you that existed yesterday no longer has any existence or meaning either today or tomorrow or post tomorrow. In fact, the person you call “you” that existed one second ago has now come and gone and passed away into history. The only you that has any reality is the person you call “you” that exists right now.

Apart from your normal modes of time travel into the future, you can accelerate the process. There’s also Einstein’s Relativity twin paradox whereby relative to an outside observer, time, as in rate of change, slows down for someone who is travelling at velocities that are approaching some goodly fraction of the speed of light. So, a twin who heads off at a rapid rate of knots and boldly goes, when returning to meet and greet her stay-at-home twin, will find that though twins they might be, their ages are now different. The stay-at-home twin has aged more quickly, or the boldly going twin has aged more slowly depending on your ‘relativity’ point of view, which isn’t really a paradox, rather the consequences of what happens when you travel at a very rapid rate of knots relative to someone who doesn’t.

However, the same philosophy or argument from those several paragraphs above applies in that you, in this case the you that’s the boldly going twin, is never in the future, only in the now or existing in what passes for the present (along with your stay-at-home twin). That applies even if that present is tens of thousands of years after you were born, which is possible (and thus your stay-at-home twin has long since died and returned to dust). No matter which way you slice and dice things, you only have reality in the present that you find yourself in. 

Q. And what do you conclude about the viability of time travel to the future from the above?

A. Ultimately, to my way of thinking, time travel, even to the future (by skipping over periods of time), is impossible since again time is a concept and not a thing, like a road or a river you have to travel continuously on, up and down on. If time is just a concept, then time travel is illogical.

Q. Is there any other likely impediment to time travel?

A. Yes there is. When you visualise standard time travel stories or films to the past or to the future, your time machine or device keeps you firmly attached to the same set of terrestrial coordinates from which you started, so if you say start in New York City (2013) and go plus or minus say 200 years either to the future (2213) or to the past (1813), you’ll end up in the New York City of that time. That’s bonkers! In that 200 years, either way, Planet Earth on which New York City is attached, but you are not, has moved. Planet Earth is attached to the Sun (gravitationally) and the Sun is in orbit around the Milky Way Galaxy, which itself is moving in space, so when you materialize 200 years in the past or future, the odds are extremely likely that you will materialize into the depths of outer space! Even if you ignore all that, the Earth will not make an exact number of solar orbits and axis revolutions over 200 years to bring you back into exact alignment with the terrestrial coordinates you started out from. So, you just might materialize smack dab in the middle of the Atlantic Ocean. Oops! What one really needs is a time and space machine like the Doctor’s TARDIS where you can also set spatial coordinates. 

Q. Have all billionaires been time travellers to the past?

A. Maybe! It’s easy to imagine looking up say all the long shot horses who won their races in say over one particular year. Now travel back in time to that year and start placing reasonable bets on each ‘long shot’ (that proved a sure thing), make a super-bundle of loot, and hop back to your own era; your own present day and start living the good life. Of course there are many, many variations on this go-back-in-time and get-rich-quick schemes.

Q. We spend our entire lives in the “now” moment, and eternal “now”, yet each “now” moment lasts way less than a nanosecond before the “now” you vanishes into the limbo-land of the past only to be replaced by the future you that was just a theoretical probability that now becomes reality, for just a nanosecond before that you too slips away into the unreachable past. That’s confusing!

A. There’s no real mystery here. There are many examples from daily life of the difference between the continuum and the part of the continuum.

You’re driving along the road in your car. Your car is the continuum since you’re always in your car for the duration (that eternal “now”); the specific section of road you are travelling over is your nanosecond “now” which changes from nanosecond to nanosecond.

You’re swimming with the current in a river. The surrounding water is your eternal “now”; the section of riverbed you’re passing over is your nanosecond “now”. Or, you can reverse the scenario. If you swim exactly against the speed of the river current or flow, the part of the riverbed you are stationary over is now your eternal “now”, while the patch of water around you is ever changing and thus becomes your nanosecond “now”.

If you walk across the stage with the spotlight on you, the light is your eternal “now” but your place on the stage is constantly shifting – your nanosecond “now”.

If you lie in bed all day (and night), the bed is your eternal “now”, but the ticking of the clock, even if only via the changing position of the sun (in the day) and the stars (in the night), or that change from sunrise to sunrise, is your nanosecond “now”.

Note that all of the examples involve motion. Motion is change and change is what the concept of time is all about.  

Q. Does God exist within time or outside of time?

A. There is no God (or gods) so the question is immaterial, irrelevant and has no bearing on the proceedings. But if there is a God(s) they would exist inside of time since to exist is to undergo change and time is nothing but a measure of change. 

Q. When do I exist?

A. Now, and only now. The “you” that existed an hour, even a minute ago is no longer. That past you, actually all those entities you called you (plural) that existed in the past have been consigned to the history books. The “you” that (probably) will exist an hour or even a minute from now, actually all those entities you will call you (plural) that will exist in the future do not yet have reality of any substance.

Q. So again, what is time?

A. One heck of a metaphysical mess!

Time To Question Time: Part One

Time is the most mysterious concept that you are likely to think about. You know exactly what time is, unless you actually have to explain it and then things bog down. If you admit that time is pure puzzlement, well you’re not alone as the nature of time has been endlessly debated by thinkers, good, bad and average, ever since humans had the ability to think. Okay, I’m a thinker, so here are my thoughts in Q & A form about time.  

Are you confused about time? If so, join the crowd. I’m part of that crowd, and I’m confused, but I’ll try to work through my befuddlement via this hypothetical question and answer session which hopefully will enlighten me and you too. 

Q. What is time?

A. Time is a concept, like Wednesday is a concept.

Q. A concept of what?

A. Change. Without change the concept of time is meaningless.

Q. What properties does time have?

A. Time has no properties, just like Wednesday has no properties. Time has no structure or substance; no mass or energy, no colour or spin or charge, it has no associated field, and it exerts no force and has no fundamental particles associated with it. 

Q. Does time have a beginning? Will time ever end?

A. No. Time is eternal. An eternal time removes those nasty philosophical questions of what came before; what comes after?

Q. Can time be created?

A. The concept of time can be created, but only by the mind blessed with some degree of sophistication, but that does not give substance and structure to time itself, any more than the JFK concept of ‘landing a man on the Moon and returning him safely to Earth before the end of the decade’ in and of itself made it so. The concept of a lunar landing is not a real lunar landing. Time itself cannot be created like a soufflé since there are no ingredients that collectively comprise time.

Q. Can time be destroyed?

A. Since time cannot be created, time cannot be destroyed. While that is similar to existing conservation laws, there is no conservation law in existence for time like there is for matter and energy since, unlike matter and energy, time cannot be altered from one form to another, since time is not a thing.

Q. Was the Big Bang event 13.7 billion years ago the start of time?

A. No. Since time cannot be created, the Big Bang banged in existing time which means there was a before the Big Bang. Something had to cause the Big Bang (a change) and that something could only have been an earlier event which happened in already existing time, since an event, a change, defines what time is.

Q. Where does time exist?

A. The concept of time exists only where change exists, and change only exists within that ongoing, yet ever paper-thin slice that we can the “now”. Change neither exists anymore in the past nor does it exist yet in the future.

Q. Are time’s related terms also concepts?

A. Absolutely. None of the following can be placed on the lab’s slab; none of the following are ‘things’, just mental concepts and conventions: past, present, and future; when, now and then; before and after; second, minute, hour, day, week, month, seasons, year, decade, century, millennia, and eon; any of the named days of the week; any of the names of the seasons; any digit that represents a year (i.e. – 2013); any date; yesterday, today and tomorrow; birthday, anniversary and holiday; weekend and weekday; noon and midnight.  A clock or calendar or metronome can be put on the lab’s slab, but a clock, etc. isn’t time, just like a thermometer isn’t temperature, and a Geiger counter isn’t radioactivity.

Q. Is time travel to the past possible?

A. Yes and no.

Einstein’s concepts of General and Special Relativity allow for time travel to the past (and the future), the usual scenario is via a rapidly rotating massive object that can twist space-time around in a loop where the starting point that joins up with itself to form the loop, like a snake swallowing its tail, isn’t any longer at the same point in time. However, the flaw I find with all of that is that this requires space and time, or space-time, to be a thing, which IMHO it is not. Space-time is a concept without substance and structure because both space and time are concepts without substance and structure. Be that as it may.  

The basic argument against going back in time is the creation of a paradox, something along the lines of killing your mother when she was a young girl thus preventing your very existence which means you couldn’t have gone back in time and murdered your mother, etc. Hells, bells, why not just do the suicide properly and go back in time a few months and kill your own self! But any trip back in time will create conditions back then that did not originally exist, and however minor, not only will they become an established part of history, but have that butterfly or ripple effect on down the line – chaos theory. If those new conditions, thanks to your time travelling presence, did not originally exist and now they do, that’s also a paradox as something cannot be and yet be at the same time, and that contradiction extends on down the line as history unfolds differently.

Further, you MUST go back in time (no free will in the matter) to ever create and ensure the conditions that came to pass back when, new conditions that you initially caused – only you never initially caused them since there’s an infinitely recycling causality loop here. You went back in time which caused a certain set of conditions which become a part of established history which means at some point in your life you are required to go back in time to create that certain set of conditions which become a part of established history, all to be endlessly repeated for all eternity. Presumably you couldn’t even commit suicide before you travelled back in time and thus break the cycle.

Of course if the past were somehow changed, then presumably you’d never know it since all records, including those of your memory, would be altered accordingly. But things would be messy if millions of people each travelled back in time and altered this, that and the next thing. History textbooks and other records would be rewritten and altered to conform to all those alterations every second. Then too, what if someone went back in time and altered history to the extent that mankind went extinct as a result – that’s the ultimate going back in time and killing your mother as a young girl!

Here’s a novel concept. Say it is the 10^th of the month. Go back in time to the 1^st of the month and meet and greet yourself. The both of you now wait until the 10^th of the month and then go back in time to the 2^nd of the month where you both can now meet and greet and join up with the other two of you that existed then. Then the four of you wait until the 10^th of the month and the four of you travel back in time to say the 3^rd of the month where the four of you link up with the four of you that existed on the 3^rd. The eight of you now wait until the 10^th of the month and then travel back in time to the 4^th of the month where you group together as a crowd of sixteen. Wait until the 10^th of the month and the sixteen of you travel back to the 5^th and join up with the other sixteen to form a mob of thirty-two, and so on and so on. Starting with just you, you could create an entire army of you!

Q. Where’s the paradox in creating an army just out of you?

A. The paradox here is that you are getting something for nothing, in this case extra copies of you. Where in fact does the extra matter and energy come from that creates that you army?

Q. Anything else?

A. Another reason time travel to the past is suss is that we don’t see any time travellers from our future paying us a visit. Though Einstein’s Special and General Relativity allows time travel to the past, and although the laws of physics are time invariant (they are valid from past to future and future to past), no visitors. Either our descendents don’t have any interest in us, or perhaps there aren’t any – descendents that is – if we go extinct or go back to the Dark Ages sooner rather than later. Or, perhaps time travel just isn’t possible after all or is in the too hard basket.

Q. You lie! What about the Second Law of Thermodynamics?

A. Ah yes, what about the Second Law of Thermodynamics which is held responsible for time’s arrow or the arrow of time (i.e. – things proceed from past (which you remember) to future (which you don’t remember). But the Second Law of Thermodynamics is misnamed since the second ‘law’ isn’t really a ‘law’, just a statement of probability, albeit extremely high probability. When things happen in a statistically probable way (eggs break or scramble; eggs don’t un-break or unscramble) that’s the arrow of time that we perceive. Put in a more thermodynamic context, a boiled egg cools off and heats up the kitchen until both are at the same temperature; the kitchen doesn’t cool down and transfer that energy to the raw egg and cook it.

Q. Anything else?

A. Yes, another postulate has it that one cannot travel further back in time than the time the time machine was constructed. So if our descendents come up with a first ever time machine in the year 2113, they couldn’t come visit us in 2013, though those living in the year 2213 could go back to 2113 (but no farther back).

The way out of that is what about an advanced extraterrestrial civilization’s time machine, say built in 2013 BCE, or over 4000 years ago. Say, what about those pesky UFOs? Instead of ET coming here from out there in their and our present, they come here from there in our present but from their future! The only problem with that is that UFO events and flaps are not clustered around what we would call historically important events, like say the Trinity A-Bomb test in 1945 or the launch of Apollo 11 in 1969 or the sinking of RMS Titanic in 1912. Of course, that they are conspicuous by their absence, well that just maybe our parochialism coming to the fore. Time travelling aliens may have a differing agenda. 

Aliens aside, you could easily imagine a time travelling Travel Agency existing several hundred years from now conducting guided tours to important historical events of their (and our) past, say tours in groups of one hundred per. After several thousand such tours, say to the battle of the Alamo or to Custer’s last stand at the Little Big Horn, things would be getting a mite crowded since each tour has to show up at the same place and date!

Q. And what do you conclude about the viability of time travel to the past from the above?

A. Ultimately, to my way of thinking, time travel, at least to the past, is impossible since time is a concept and not a thing, like a road or a river you can travel up and down on. You can travel in a car, but not in the concept of an automobile.

To be continued…

Scientists’ Doublespeak: Part Two

Even the very best of scientists can exhibit some sort of scientific sleight-of-hand and bamboozle their lay audience with absurdities. Actually, this approach often is just taking a lazy way out. Explaining things in sufficient detail, to avoid the absurdities, would either be too involved or take up too much text. At least I hope that’s the case. If some scientists actually believe what they write, then something is rotten in academia.

Continued from yesterday’s blog…

Dark Energy: Something from Nothing: This is really an extension of both the above and below in that apparently space is constantly being created as you read this and that explains why the Universe is expanding: more on that below. But the bit of creation that keeps on keeping on is with respect to Dark Energy which actually provides the oomph that drives bits of space further apart thus making available more volume to have additional space be created in. Since Dark Energy is a property of space, it all becomes very circular. Dark Energy creates more space and more space creates more Dark Energy and it’s all a sort of positive never ending feedback mechanism. It’s also something from nothing and you cannot create energy out of nothing. Wouldn’t it be great if the energy you use – gasoline, electricity, etc. – was available for free since you could create an endless supply of it out of nothing? Dark Energy is a free lunch – that’s an extraordinary claim!

Cosmology and the Expansion of Space: We are all aware, at least since the early 20^th Century, that our Universe is expanding in volume. That’s the result of a rather messy trilogy of oomph events. The initial Big Bang explosion; a secondary extremely sudden and short-lived burst of ‘inflation’ that transpired almost immediately after the Big Bang; and finally a mysterious force called Dark Energy (named but not explained) that keeps shoving the already expanding Universe to ever greater and greater velocities. In other words, our Universe is not only expanding but the expansion rate is accelerating. Okay, that’s pretty much based on observational evidence. But that still leaves two scenarios. Following on from the above “keep it simple, stupid” rule, the obvious scenario is that all of the stuff of the Universe is expanding through existing and pre-existing space and time. However, standard model cosmologists, in keeping with their “something from nothing” rule, suggest that space itself is expanding; space itself is constantly being created (out of nothing), and thus space itself is causing the stuff of the Universe to spread farther and farther apart, the bits and pieces being dragged apart kicking and screaming somehow glued to their particular patch of space like dots painted or glued on the surface of a balloon that’s being inflated. Again, no cookbook is on offer that gives a recipe for expanding space or how you too at home can expand your space or create more space in which to store your knick-knacks. That space is currently being created out of nothing – that’s an extraordinary claim!

The Atomic Structure of Space-Time (Planck scales: lengths, volumes, etc.): By the very act of suggesting that space and time or space-time has a structure, one is suggesting that space and time are things, and like all things, at extremely tiny scales are subject to the laws, principles and relationships of quantum physics. In other words, space and time (like matter and energy) come in quanta – indivisible discrete units. It is proposed that these fundamental units of space and time or space-time are Planck units which they suggest are the shortest possible length (hence area hence volume) you can have; and a Planck length of time is the shortest measure of time that can exist. Now you will certainly find reference to these Planck units in the scientific literature. That’s not in question. What is in question is the interpretation. It is my understanding that Planck units are the smallest units possible where one can discuss meaningful events or happenings. There comes a time where a volume is too small for any meaningful physics to happen therein. There comes a point where a length of time is too brief for any meaningful event to happen within that time frame. That doesn’t mean that one can’t further divide a Planck unit into smaller and smaller segments unto infinity. It just isn’t meaningful to deal with such smaller units since nothing of significance can happen within them. So, space and time are not things. They can be subdivided indefinitely until the cows come home. There just is however a threshold value below which it’s not overly meaningful to discuss happenings there. If something meaningful is an elephant, it’s not meaningful to talk about an elephant inside a shoebox, though clearly shoebox volumes exist. If it takes a baseball one second to reach home plate from the pitcher’s mound, and it takes the batter say one-tenth of a second to react, then it is not meaningful for any discussion of that scenario to focus on billionths of a second time frames, though a billionth of a second is a legit division of time. That space and time can be constructed or formed out of discrete space or time quanta units – that’s an extraordinary claim!

Black Holes: Crossing the Event Horizon: For some inexplicable reason, I’ve noted several times some scientific author suggest that an external observer (call him Clive) will note that someone (call her Jane) about to crossover a Black Hole’s event horizon, will not only be travelling slower and slower by Clive’s clock as Jane approaches that event horizon, but in fact at contact with the event horizon, again as recorded by Clive, time will have stopped for Jane. In other words, Clive will never witness Jane’s crossover from outside the Black Hole to inside the Black Hole. Jane will appear to be frozen in time at the event horizon, yet as far as Jane is concerned, everything is normal in terms of time flowing at one second per second.

Now that’s a major paradox. Jane can’t be crossing the event horizon at one second per second while at the same time being frozen in time at the time of crossing according to Clive – the external observer. Of course the paradox is bullshit. To an external observer, Clive, time only comes to a screeching halt for someone like Jane, external to them, if they witness Jane travelling at the speed of light. That’s a physical impossibility. There’s no reason to believe that someone like Jane can be crossing the event horizon at light speed. There’s no absolute requirement that Jane is in fact crossing the event horizon at the speed of light. So, in actual reality, our observer Clive will see someone, anyone, including Jane, cross the event horizon, albeit at a slower rate than Jane herself, because Jane is travelling and doing the event horizon cross-over at less than light speed. That time stands still at the Black Hole’s event horizon – that’s an extraordinary claim!

Conclusions: Scientists are extremely fond of invoking the mantra that “extraordinary claims require extraordinary evidence”. Unfortunately, I’m damned if I find any evidence, far less any extraordinary evidence, for the above statements or alleged truisms. The only way I know of that could give you something for nothing, or disregard causality with reckless abandon, would be if we were all products of a virtual reality, just existing in a software-generated simulated universe where anything goes. But that too is an extraordinary claim!

Reality: Really Real, Pseudo-Real, or Unreal? Part Five

Reality – It’s all relative; it’s reversible; it’s symmetric; it’s personal; it kicks back when you kick it; it’s conceptual; it’s theoretical; it’s actual; it’s abstract; it’s bio-friendly; it’s unforgiving; it’s emotional; and ultimately the reality of life, the Universe and everything resides in your mind.

Continued from yesterday’s blog…

Relative Reality:

The same reality can be quite different from the perspective of two different observers. But does it really matter?

Does it really matter if when you witness a sunrise whether or not it’s because the Sun goes around the Earth or because the Earth rotates while going around the Sun?

Does it really matter if you’re driving along while it’s raining vertically yet you see the raindrops hitting the windshield at an angle? Or, while driving, you see the posts go past the car, yet of course it’s the car driving past the posts.

Does it really matter if you’re flying in a plane as assume that the plane is suspended in the air and it’s the Earth’s rotation that’s bringing your destination to you?

Does it really matter if two cars are approaching each other at a combined velocity of 100 km/hour whether car one is standing still and car two is going at 100 km/hour; car one is traveling at 30 km/hour and car two is traveling at 70 km/hour; both cars are each moving along at 50 km/hour? Does it really matter if you’re in line between the two cars and thus have difficulty judging their relative velocities?

Well, ‘yes” it really does matter if you believe there is such a thing as universal or absolute truth. The Earth rotates and goes around the Sun; the raindrops really are on a vertical path downwards and would theoretically intersect the centre of the Earth; the plane is really flying and not suspended in midair; and both cars are moving at 50 km/hour.

Well ‘no’, it really doesn’t matter as long as you get to see the sun rise; you don’t get wet regardless whether or not the rain is falling straight down or at an angle; you reach your destination; and you’re not in either of the two cars on their collision course! The Universe certainly isn’t losing any sleep over this, and I bet neither will you!

But Einstein and the other relativists who followed in his footsteps care deeply about such matters because they do illustrate the principle that there are no God-given (or Nature-given) absolute frames of reference. Different strokes for different folks can produce identical results, or different results, depending..

That second observer, the different folk, complicates things. You on the ground assume the Sun goes around the Earth; the observer in space clearly sees the Earth rotating and orbiting the Sun. You see the rain hitting the windshield at an angle while the observer standing on the roadside clearly sees the rain falling vertically (and gets wet for his trouble). That second observer on the ground clearly sees the plane flying through the air and the hell with what you, the passenger, observe. That second observer from a distant hilltop has a side view sees and easily sees both cars in motion, both at 50 km/hour.

So, what about we hypothesize two identical twins (well it would be odd to have three identical twins!), born on the same day, say, just to be evil, on the sixth of June, 2006! They both die at the exact same time, say a century later. Trouble is, one has moved to the east coast; one has lived on the west coast. The east coaster dies local time at 1 am 6 June 2106. The west coaster dies at the same moment, but west coast local time is 11 pm 5 June 2106. Thus, when reunited and buried side-by-side, one has a headstone that reads b.2006-d.2106, age 100 years; the other’s headstone reads b.2006-d.2106, age 99 years! It would now seem to be a case of relative reality trumping absolute truth!

Does evening and night come before the dawning day, or does the dawning day before evening and night? Does winter follow summer, or does summer follow winter? You may think that Wednesday comes before Thursday, but Thursday the 3^rd comes before Wednesday the 9^th!

One final example, you’re standing on a railway platform, your partner is on the train. Now as the train passes by the platform, your better half drops from say chest height a rubber ball. You, on the platform see the pathway of the dropped but bouncing back up ball as a V. Your partner sees the ball go straight down and straight up. Is there an absolute truth here? Does it cosmically matter?

Relative reality is part and parcel of our overall reality.

To be continued…

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…