MN Physicists and Philosophers, I have some questions about time travel.

[Slubberdegullion]

Watched Donnie Darko for the first time yesterday, which led to conversation with DH about the possibilities of time travel and alternate universes, which led to wakeful period at 3am with head full of questions.

Anyone here care to have a stab at answering (in a simplistic manner, I did not do very well at A-level physics) some of my questions?

Aw, I got Referral Denied on that link, Lapin.

Can I imagine it's a still from 'The Man with Two Brains?'

Would it?

A mythical martian - in order to travel in any way would need some context of speed in order to travel, surely? Speed is defined by distance travelled over time.

Try this one, Desi

Yes, but that would be distance travelled over our concept of time. Not necessarily of the martians' .

We have to give it up. I doubt there is one person of the 6 billion people on this planet who can think in the fourth dimension. It is the Holy Grail. Einstein made some progress scientifically, and H G Wells made some progress creatively, but as human beings, we are as yet totally incapable of understanding the concept of time travel.

And the reason we can't is that we can't stop thinking in the third dimension.

To put some historical perspective on this, the ancient Greeks referred to the sea as being the colour of wine (red). At first, it was thought to be creative license, but there is now much evidence to support the theory that three thousand years ago (plus), people did not see the range of colours we see today.

Maybe in three thousand years, some people will grasp the fourth dimension.

!!

Respect, wabbit. I don't know how you do that!

I freeze time (a la Nicholson Baker's "Fermata" but without the porn ) and fiddle with graphics, then restart time and post! Easy!

I thought I went a bit 'off' there, for a second!

I love this thread. It's almost as much fun as the Mumsnet Grammar Minutia

And when is the MGM officially meeting?

I don't know, but I must bump the thread, I just finished George MacDonald Fraser's "The Reavers" which was, er, odd, but had some corking words in it!

Well, you're a tad busy at the moment.

It will come to fruition. There are quite a few MNers totally into the idea. A few of them are lurkers, I think. Brillo

Quick hijack: the Reavers is an excellent book. I recommend it to all my friends and they refuse to read it . Worth it for the appendix on the Border families alone (Irvines: bunch of liars; Douglases: bunch of weirdos etc.)

but isn't it the Border Reivers?

Ah, it's not the same book, Effie. The Reavers as opposed to The Reivers. GMF likes to muck around with spelling. It's a comic medieval fantasy, not a serious historic discourse

in which case READ THIS
www.amazon.co.uk/Steel-Bonnets-Anglo-Scottish-Border-Reivers/dp/0002727463/ref=sr_1_1/202-2731489-67 49459?ie=UTF8&s=books&qid=1193747190&sr=8-1

(it is a historical review but not serious AT ALL)

Oh, so they are both by him! I shall purchase it forthwith. I absolutely adore the Flashman books. I was reading an article the other day about a load of Cavalry officers (it was in Tatler ) and they all named Flashman as their favourite books - he was a coward, a cad and a bounder!

glad this is still going about how the thread has got round to the flashman books (DH a big fan).

So I have been thinking about what Desi said about the 4th dimension and had some ponderances about that.

Desi, are you trying to say that time travel through physical means (ie building a space ship with 'Holtzman' space folding/warp engines (another lobbed in sci-fi ref.), or flying into/past a black hole is just not going to cut the mustard, because we can only explore/invent within the means of our own scientific understanding, and that is limited to the dimensions that we can actually experience.

If we could understand the 4th dimension (is this the flying above the time line business, seeing all of 'time' simultaneously) then movement in any direction of time would be possible?

But how can we be in the 4th dimension and remain human? if you are outside of time then how can you have any er matter (for a better word)? Would you not be a god ?(doubt that is the right word either)

But a two dimensional point can exist in 3 dimensional space, so a 3d humanoid should be able to exist in a 4d space/continuum/thingy. In fact, do we not exist in 4d anyway, as time is present? I think what Desi means is that we are oblivious, and anyone who develops the ability to detect/conceptualise 4d would - what? transcend? explode?

The most troubling thing about Donnie Darko is that Jake Gyllenhaal plays a 16 year old boy and in real life he was about 22 when he filmed it, thus giving rise to the theory of whether or not it's right to think that he's really quite fit

Ditto with Daniel Radcliffe in the last Harry Potter film.

yes, sorry. Of course we exist within the 4th dimension. But if we were somehow able to stop being under the control of time (ie living in the present), and be able to 'soar above it' then we would paradoxically be able to time travel, and yet also cease to be.

I feel an increase in pressure in my sinuses just trying to find the right words.

Damn Donnie Darko and his clever mind boggling film.

lol Mrs Archie, if only I could lie awake at 3am and think about whether it is right to fancy a fictitious 16 year old, who is not 16.

Slubber ... yes, I think that's what I'm trying to suggest. That with only three dimensional faculties, it is impossible for even extraordinarily gifted people to work out or connect to the fourth dimension.

I think the answer probably lies in geometry, but as geometry is itself three-dimensional, it obviously can't 'cut the mustard' at the moment.

And as Lapin suggests, if a person were to discover this dimension, it would be impossible for them to exist in a 3-dimensional world. I don't mean in any physical sense ... they'd just be too darned weird to get through the day !

So Desi, in your opinion, do you think if time travel is ever going to be achieved it will be through further understanding/philosophising about the nature of time, rather than building something that can just go very, very fast, or scooting into a black hole without being squished into nothingness?

We're going to need to evolve giant 4d transcending brains rather than develop warp engines?

Hmm, but are we biologically predispositioned to experience the world in a linear way through time? I mean, as far as I understand it our brain works laterally as well as linearly (that's not a word, is it?). Eg with memory we don;t link one concept with one word or event, but create web of links that include past events, present experiences and future predictions. So if I think 'apple' I might think about the first apple I ate, the fact that I have an apple on my desk and my plans to eat it in the next half hour (or raid the biscuits, cross reference to cakes...). So I think our brains could cope with being outside time. Does that make sense?