Dear Al,
By now you have had a chance to digest my last letter and there are two alternative outcomes:
Did you do it all within a week as I asked? My guess is that you did and that shows real courage. That’s what the time limit was about, a kind of test, because it would be easy to wait and wait and never do anything. I promise you Al – there will be no more tests. What’s coming next is far too serious for that.
You’re probably terrified. That’s OK. I think I would be too. Be scared: it’ll keep you alert and if you’re alert you won’t make a mistake, and if you make no mistakes then all will be fine.
People have always dreamt, Al, of travelling in time – either into the future or the past. Sometimes both. (Do you remember the play we went to see when you were younger – A Christmas Carol by Charles Dickens? Scrooge is shown Christmases in the past and the future. I think it scared you a bit!)
Recently, we have imagined grand machines that would do the job for us – often, vast spaceships that would zoom through the centuries faster than the speed of light.
And here, Al, lies the problem.
For nothing can travel faster than light. No matter how much energy you have, from whatever source – existing, or yet-to-be-discovered – physically moving faster than a beam of light cannot happen. If it could, then it would mean that all the laws of physics that we know, and have tested for centuries, are wrong.
And we know they are not.
It would mean that Einstein’s theories are wrong and so far, good ol’ Albert has had the last laugh on pretty much everyone who has tried to outsmart him. Sure, there are gaps in our knowledge, but every time we make a new discovery and fill in one of the gaps, it shows us that Einstein was right.
The Higgs Boson? I’ll bet that’s discovered soon. Plenty of people are looking for it, because Einsteinian theory requires it.
The theory of Cosmic Inflation? That’ll be proved soon too, I reckon. It’s another thing that Einstein predicted.
(Now, I don’t really know what a Higgs Boson is, but I know it has been found. And Cosmic Inflation was in the news too so that’s probably what that is. Yay, Einstein!)
“The speed of light,” Einstein said, “is the Universal Speed Limit.”
Einstein suspected that the way we think of time as moving in a line – from one minute to the next, one year following another – may not be the only way to look at it. That in fact everything might be happening simultaneously and that our sense of time is only relative – that is, in our heads. Remember his line about putting your hand on a hot stove?
What we perceive as the progression of events – one thing following another – could merely be the growth of an infinite number of dimensions all happening at the same time, and the key to moving between them might be found, not in a source of super-energy that could propel us faster than the speed of light, but in a mathematical formula.
I know, it’s hard to get our heads round. We are goldfish, remember!
I put the letter down and sigh. I’m not sure I’ve understood a single word and the frustrating thing is that I know my dad’s trying to explain it really simply.
Do you remember learning multiplication in primary school, and instead of saying “what’s five times four?” the teacher would say something like, “there are five dogs, and they each have four legs – how many legs are there altogether?” so you wouldn’t get freaked out by the maths-ness of it all? Well, I can tell that’s what my dad’s doing, but I still don’t get it.
I rub my eyes and read on.
Perhaps that’s as much as you need to understand. You’ll get the rest when you turn on the laptop on the desk.
That, in case you hadn’t guessed, is the time machine.
It wasn’t always there, Al. I was not getting up in the night and sneaking away to a secret underground laboratory. Most of the work I did was in front of a computer screen, in my room at home, while our family life was going on around us.
Calculations, coding, more calculations …
Only when I knew I had the right formula did I open up the bunker and install the required apparatus, when you and Mum were out visiting Aunty Ellie.
Which means that everything is ready for you to travel back to when I was a boy, and save my life. That might sound odd but it will make sense soon.
Now it’s down to you, Al. Go to the time machine laptop and switch it on.
Further instructions will appear.
See you in 1984!
Your loving Dad X