h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Oh well it was on horizon last night.. erm, its saturday morning her now, so it must have been on thurday evening, in the uk, horizon did a quick intro sorta thingy to m theory, via super string and super gravity theories, via wave particle duality ect

So M theory isn't just superstring theory? I kind of assumed it was, dealing with 10-dimensional strings and all that.

M theory is based on superstring theory... basically, for ages and ages the superstring theorists were convinced that there were 10 dimensions and 10 dimensions only... but then they tried to work out what superstring theory had to say about the blackhole and got confused - they would check the theory over, and they discoverd another superstring theory, and they carried on thinking, and eventually they realised that there were 5 seperate superstring theories, all similar, but nonetheless different.... and each one relied on 10 dimensions and one universe, but couldnt explain the singularity at t=0 at start of big bang....

then there was some guy called Duff or something, I cant remember exactly...

and he was adamant all along that there were 11 dimensions, and he was turned into physisist paria and ingored by all serious thinkers, and he kept on saying 11 dimensions I tell you, 11.

So meanwhile the superstringers were getting pretty desperate - they had 5 theories instead on one, and then one of them had a zany idea, and he talked talked about it at some presentation, then met up with two other physicists who had been there, and on the way to the thearte they had an hours brainstorming session on the train, as you do....

mmmm, Duff beer...

So M-theory does explain event 0? If so I'm impressed.

basically the 10th dimension had been assumed to be a pretty tranquil and very very thin place, which had our universe sat in it diong not very much. Then this zanyilly ideaed bloke came along and suggested that maybe the universe was actually a wave inside the 10th dimension, and that it was vibrating like any other wave type thing.

After that all you needed to do is have another wave in this 10 th dimension, and as they are both moving in this exceedingly narrow (I think 10 to the power of -40 or something meters wide) they might collide, and the collision would be what sparked off the big bang....

It seems odd to suggest that these strings existed before the big bang. I wonder where they came from.

I know superstring theory involves vibrating strings, which are very narrow in all but 4 dimensions, so this isn't that different, probably.

computer just crashed half way thourgh my next rather long posting, will start again

I lost my train of thought now...

Oh yes: if you have more than one wave, then there is no reason why you shouldnt have many of them, and if they collide once, then they can collide again.

Now, in order for a wave to move in this terrible narrow dimension, it kinda needs more degrees of freedom, or in other words, an extra dimension...
so all the superstringers went back to their 5 theories, and added 11th dimension, and make rather funny discovery:...

The five different 10D theories were all actually the same single 11D theory, but kind of seen turned 90 degrees away fro oneanother, so that when viewed in just 10D they all looked completely different (it might help to think about how a cube and a long cuboid can look totally different when drawn in 2D from the side but appear identical in 2D from the front, but dont think about it too hard )

Now, the intersting bit in all of the above ( you may not have spotted it ) is where I mentioned how if two waves (actually they are called membranes, and its probably best to think of these waves in the 10th dimension as waves in a bed sheet which is billowing in the wind. The bed sheet can be a variety of shapes and sizes, with normal flat sheets, flat sheets joined along two edges to make cylinder, and spherical sheets all possible. For membranes, read sheets)

so if two ripples/waves in two different membranes collide once, what is to stop them colliding again?

Okay, this is sort of making sense.

By the way, is researcher 189981 you or someone else?

Answer: nothing. There could be colliosions between membranes all the time, big bangs kickstarting universes all over the latter dimensions, ie parallel universes - possibly infinite numbers of them.

parallel universes are quite useful things to have around for physicists, as it is possible that they can help explain the relative weakness of gravity: any small fridge magnet can pick a paperclip off a table, yet the gravity which is holding paperclip on table in the first place is caused by the really massive Earth. SO how come the ickle magnet has stronger force?

the completely mad suggestion is is that maybe the force of gravity is actually a strong force in a parallel universe with completely different set of physical laws maybe, which is "leaking" out of that universe into ours, hece the relative weakness.

So much I dont understand, so many amazing concepts to think about, and all from one tv program courtesy of the bbc. fantastic.

sorry if I started boring anyone by the way, but it was kind of like a revision excercise for me - I wanted to get all that off my chest to work out how much of it I had remembered, and which bits made any sense to me at all, even if I failed rather miserably to write it all down coherently.

woops: more like physics at phive now

So where did the membranes come from? Were they created by some GNAB GIB at the start of the first dimension? I suspect not even dead clever people will ever know.

to Amy btw

Hmm, I'm not sure I see the need for parallel universes to explain gravity (at least in general, it may well make sense in M-theory), since once we work out what causes gravity, we will probably find out why it's relatively weak.

researcher 198891 is someone else - they are online, but last I checked (ie before you got me all excited about M theory ) they hadnt made any postings or anything, so I was unable to pay them a visit and congratulate them on their palindrome at their space, so i thought I would try messaging them from across the whos online box

There's something there now, though he or she seems to have accomplished little enough whilst online.

Are we assuming it is a non newbie?
In which case there are 19 people logged on at the moment, 2 of them are us, one of them is Mr palindrome hirself, leaving 16 potential researchers who might have spotted U189980 loggen on earlier and seen their chance - actually, I think it might well be U189980, but who knows?

hmm

I suspect the use of smileys indicates someone already familiar with the site. and could be from any internet-savvy type, but and all them are fairly specific to h2g2. I'm not quite sure how you'd predict which number you'll get, unless you happen to be looking at the New Researchers page and just notice that one more than the last newbie's number looks quite cool.