Thursday, 16 April 2009

How to corpse a physicist :)

So, here I am, last day before I go back home tonight, the other half is still sleeping, and I've woken up. Go figure (we're both on similar shifts, now, thank wotsit) :)

Anyhow, last night (read: in the early hours of this morning), we'd been watching a Dr. Who DVD, and then discussed Time Travel in general.

This got us into a typical discussion regarding the "Grandfather Paradox".

I better also point out that my partner holds a degree in Physics, and is part way through studying for a Masters in it as well. "Good bleedin' luck", says I, since (1) I never passed physics at school, and (2) it gives me a headache!

Anyhow, as I understand it, the "Grandfather Paradox" goes something like this: Assume that time travel is possible for a moment. A man travels back in time and kills his grandfather before his grandfather has even met his future wife (the time travellers grandmother).

This therefore results in one of the time traveller's parents never having been conceived and born, and thus also results in the time traveller never having been conceived and born.

Simple logic then dictates that the time traveller could not have travelled back in time to kill his grandfather, which then shows that his grandfather was never killed, and that his parents existed, that the time traveller was born, and that the time traveller went back and killed his grandfather, at which time most folks would be sporting one killer headache from trying to sort out the contradictions in logic and so on. Kinda makes your head want to explode, doesn't it? :)

It's a form of "logical paradox" that has come to signify the immense problems around the concept of certain interactions within the idea of time travel.

The grandfather paradox has, I should add, been used by some to point out that rearwards time travel (that is, travelling back in time) is impossible. However, a number of alternative methods to avoid the paradox have been suggested over the years (sic), for instance the "Many Branches" theory that has it that the time traveller would end up in a parallel timeline, while the timeline in which the traveller was actually born in branches off, remaining "real and independent" but blocked off at the point of the grandfathers death... I know... it's making my head ache just trying to describe it here... Anyhow, the field of science that covers this is called "Quantum Physics".

Anyway, there we are, with us arguing - I mean energetically discussing - left right and centre, the holes one could drive a bus through with these ideas, when out of the blue, it emerges from my partner that high-end maths, or the study of probabilities, is at the core of Quantum Physics.

It's at this point that I realise that I'm on a sticky wicket, to say the least, as I recognise the signs that my partner is about to either baffle me with bull droppings, or blind me with science.

So quick as a flash, I come out with:

"So, then, smartypants, what's the probability that Quantum Physics is wrong?"

Cue one bug eyed face, slack of jaw, and "b... b... wha-" and then I got a teddy bear (not, thankfully, Schrödinger's cat!) lobbed at me at close to the speed of light, with both of us laughing our backsides off...

And so, for a good two or so minutes, we sat there laughing until my partner, who was alternatively laughing like a drain, or giving me "That Look", sat bolt upright with eyes like saucers, and said:

"You know you just destroyed an entire branch of high-end physics, don't you?"

Um... oops?

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