Trains and a unifying theory. Not of, but for, us

France’s TGV – Train à Grande Vitesse or high-speed train – certainly lives up to its name, but at 320km/h or it’s still about three billion times slower than the speed of light.  But as it’s faster and greener than driving and waaaaay greener than flying we’ll forgive it, I think.  In November last year Sam and I took the TGV – because of the incredible Ecopassenger website – as our preferred mode of transportation to Belgium for Christmas, and watched a documentary about Einstein on the way.  Hence the speed of light stuff.  Technology, huh?


In his 1905 paper, Einstein used a thought experiment to explore his ideas of time and simultaneity.   (As an aside, to anyone who thinks that unnecessarily complicated writing makes you sound smarter, read this paper!  Its point is understandable even if you’re not keen on the maths, and it was written by one of the smartest people in recent history.)  This first idea became the Special Theory of Relativity.  A decade later, he included gravity, and posed his General Theory of Relativity.  There are loads of resources out there explaining these, and I’ll leave it to you to discover more if you’re so inclined (this is a good intro though).

(It’s safe to skip the geeky bits if you need to, there’s another note lower down for where to start again!)

Imagine two people, one – in red – standing on a train platform, and another – in green – on the TGV.  Suddenly, two bolts of lightning strike the earth.  These strikes are exactly the same distance from the green train on each side, and they’re also exactly the same distance from the red spot on the platform.  Because light travels as a wave, if we started a film reel from the instant of the lightening strikes, this is what we’d see:

  • At the instant of the strikes, neither red or green can see it as the light wave hasn’t travelled to their position yet.
  • A little – a very little – while later, the red point can see both the strikes at the very same time, as the light wave has travelled the same distance from each strike to the red point.  But the green train is moving – towards one strike point and away from the other – so the green train sees the right strike first and the left one later, as the light wave on the left has to travel further to catch up to the train.

According to who you ask, the strikes happen at the same time, or one after another.  Einstein’s conclusion was that the speed at which you travel must affect time itself.  But … what does that even mean?  How can time not be the same everywhere?  How is it that gravity affects time?  (that was another thought experiment which came later).  Einstein was a pretty smart guy, and I’m really not in a position to disagree, but I’ve found a way of thinking about his theory that makes more sense to me (and disclaim all responsibility for its physical accuracy).

A simplified analogy of a simplified thought experiment.  Imagine two ducks sitting on a pond.  I throw two rocks into the pond, which hit the water at the same (according to my eyes) time.  Daffy was sitting exactly halfway between the two splashes, so the ripples of the rocks reach him at the same time.  Daffy’s conclusion?  The two rocks were thrown simultaneously.  But Daisy saw that I was about to chuck rocks at her, and started swimming as fast as she could towards the edge of the pond.  Even though it happened that she was exactly halfway between the splashes, the fact that she’s moving means that she will encounter the ripples of one before she encounters the ripples of the other.  Her conclusion?  The two rocks were not simultaneous.  Both of the conclusions depend on perception: the manner of measurement or observation affects what is found to be true.  

There have been several (real-life as well as thought-based) experiments done to test Einstein’s theories of special and general relativity: the difference in time as measured by an atomic clock at sea-level and a second one up a mountain or in space; the rate of aging of astronauts, and more.  But any and all experiments, whether by analogy or not, depend on measurement or observation of some kind.  

I measured my living room this week in January and found it to be 6.2m wide.  The only reason I say “6.2m” is because I have a tape measure.  But all I can really be sure of is that my living room had, at the instant of measurement, the same width as the 6.2m point on my tape measure.  Whether or not it’s actually 6.2m depends on the quality of my tape measure, the quality of my measurement, and other things like temperature and CDF (corner dustiness factor).  If I have a job interview at 3pm the only reason I can hope that I arrived on time is because the little hand points to 3 and the big hand to 12 on my particular watch.  If my watch is slow, then I am late.  My conclusions depend on my measurements.

Even in Einstein’s thought experiment (reproduced above a la Daffy and Daisy) the measurement is the two people’s perception of the light which reaches their eyes (or ripple reaching duck’s bottom).  And any form of experiment or investigation involves a measurement medium: the tape measure, my watch, my eyes, (a duck’s bottom).  Let’s make this (more) ridiculous to make a point.  Suppose I want to measure my living room, but this time I don’t have a tape measure.  Because I live in Switzerland and there’s quite a lot of it about, I decide to line up blocks of cheese across the floor and count them.  It is 60 blocks of cheese wide.  It’s winter now.  I decide to measure it again in the summertime, and now it’s only 58 blocks of cheese wide because in summer the cheese slumps a bit into wider blocks so it takes fewer to fill the space.  My measurement tool has been affected by its situation; it is not absolute, it is not constant.  Of course, this is the very reason why standards – the metre standard, the kilogram, etc – were kept in very carefully controlled environments (or recently approved to be soon replaced with something else entirely).

In all these situations we must include the effects of the measurement tool on the outcome: that atomic processes go slower in space; that the way our eyes perceive light is as a wave of finite speed; that the metabolic processes of astronauts are affected by their speed and gravity, acting in different directions.

We could take account of the changes to all of these processes and tools: I could define a “summer block of cheese” or “winter block of cheese” to have certain dimensions at certain temperatures, and adjust for my current season.  I could extrapolate from the rate of the atomic clock at sea level to the one up the mountain and come up with adjustments and correction factors and special cases for all of them.  We could, we used to, but the point of Einstein’s theories are that we don’t have to.  Not if we are prepared to see that our most fundamental observational quantity – time – is not absolute, but is affected by those things too.  The discovery that metabolic rates, atomic decay rates, any kind of clock, and any other kind of rate you can think of, all need adjustment by the same amount, makes it so much easier to adjust our current measurement standard – time itself – instead of separately considering each one as a special, deviant case.

(Not a geek? Start reading again here …)

While watching the documentary about fast-moving trains on this particular fast-moving train, something else occurred to me.  Despite the apparent simplicity of Einstein’s theories, they provided something unifying.  Not quite the total unification he was going for, but still, they brought together all of the situations previously needing adjustments and fudge-factors and corrections, and turned them all into something better.  Something more useful, but, more importantly, something more wholly representative, more true.  Instead of defining a usual or standard condition (eg: my lounge, sunny, 24.9C) and going to all the trouble of adjusting other measurements and observations relative to my assumed standard (usually grumpily because it makes the maths more complicated), Einstein’s theory threw the singular usual out the window and welcomed instead the plural, the spectrum, the continuum, the range.  The various situations which were not the perfect day in early summer are not exceptions: they are simply Other.  There is none more valid, or more fundamental, or more inconvenient than any other.

And now I come to us.  You and me.  People, folks, humanity, all of us.  After all, we have a standard human, a holotype or lectotype, against which all others are compared (for humans that’s Carl Linnaeus).  Before I googled “human holotype” – and then trawled through the long discussions about how the misconception (further perpetuated by Qi) that it was another guy called Edward Drinker Cope – did I know about this standard?

Nope.  Not a clue.

So I’ve lived my life so far without any appreciation for what a normal person really is.  Unbelievable! or because he’s Swedish, otrolig!  How have I survived?  Let’s face it, of all of us not many – if any – compare ourselves to an old male Swedish botanist from the 18th century; instead we each use our own definition of normal.  Is that such a bad thing?  Yes, and no.

Let’s start with the no: our own individual definitions of normal is a fab idea.  After all, isn’t that going to be my point?  That there’s no single standard?  That we can choose our own?  Nope, not this time.  The trouble is that choosing our own standard isn’t going to help us.  After all, we (well, me, and perhaps the majority of people reading this too) didn’t know that there was a formal standard until reading this, so we’ve been making up our own versions of normal for years and years anyway.  This is nothing new, it’s the status quo.  And yet, the world is poisoned by self-image issues, by self-esteem problems, by anorexia, bulimia, eating disorders related to misguided body perceptions, from aiming for Barbie, and on and on and on.  Setting our own standards hasn’t worked for us so far: this option is the status quo.

But what’s the alternative?

A collective average?  A mean?  A median?  A mode?  Before you scratch your heads and feel guilty that your high-school stats isn’t quite as polished as it once was, here’s an example.  My friend’s favourite food is fried chicken, my partner’s favourite food is cheese, my favourite food is chocolate.  The only way to make everyone happy is to cook chocolatey cheesy chicken*.  Solomon knew you can’t keep two women happy with half a baby each.  Venus is not Earth’s closest neighbour – on average.  Even if it were possible to calculate a set of average measurements and describe an average person, that would still be one set of measurements, and probably no-one could be them.  What is, for example, an average gender?  Average, and all the other stats terms, are simply nonsense here (cue collective sighs of relief).

*I wrote this to be absurd, but apparently I didn’t try hard enough …

So what do we do now?  Define lots of different normals – categories, boxes, stereotypes – in the hope that we’ll all fit conveniently into one of them somehow?  But we’ve been there, and done that – rather inconsistently.  In California people identifying as Hispanic or Latino number more than those who do not, yet are still refered to as a minority group.  Do we bow to a dictatorial standard set by someone else which will now rule our lives?  Yeah, nah, bro, I think that one’s out too.  This is all Life Before Einstein.  Lots of measurements, lots of adjustment and correction and fudging and, let’s be honest, lots of grumpy people fighting with each other for no real reason.

I’m suggesting something much, much simpler.  Life After Einstein.  To realise, and acknowledge, and well-and-truly get our tiny, insecure, narcissistic and judgemental brains around the idea that there is no such thing as normal.  There is no standard.  There are no allowances and adjustments to be made.  Just as time itself is not a constant, neither are we.

And I reckon it’s about time (see what I did there?) we knew it.









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