talkmagic.co.uk

Does anyone know a thing or two about "higher physics"?

One of his tricks he describes uses: the shortest distances between two points is a straight line" as a theme for an effect. He also mentions that this is not true in advanced physics. Can anyone help me with what "is" the shortest distance between two points.

Thanks,
Ian

I think this is the thing about folding. That is the most basic description.

If you get a piece of paper, draw dot on either side, about an inch from the edge, what is the quickest route? Drawing a straight line? Nope.

Pick up the paper and fold it in half and the dots will touch.


Something like that anyway

My time!

Righty... my degree was in Physics with Satellite Tech, and my particular interests were in Special and General Relativity.

(I'm also slllllightly inebriated, so bear with me)

Right. Simply put.


The shortest distance on a 2D plane (e.g flat piece of paper) is a straight line.

Since we can only perceive three dimensions, but we know there are at least four (time is the basic fourth, string theory and other postulate significantly more, ten or fourteen are common figures at the moment) then we experience at least on less dimension than we can perceive.

-- Incidentally, read "Flatland", it's all about this, and is awesome --

Okies, special relativity allow the four dimensions of space and time to be compressed into a flat sheet - if you travel from Bristol to London, or from the Earth to the Moon, you will be travelling a certain amount of distance, in a certain amount of time. Which can be represented in a 2D graph.

If that 2D graph was actually a sheet of paper, we get towards General relativity, conceptually at least.

In general relativity, that 2D sheet of paper, which represents all three dimensions and time, can be warped and twisted by gravitational input - commonly represented as, say, the earth causing the space/time around it to bend, like a marble sinking into a rubber sheet.

Since the people who live on this rubber sheet (i.e. us) can only perceive the rubber sheet - we cannot see that it is actually bent.

Imagine for simplicity a well. Possibly, since this is a magic forum, a Black Art well.

Point A is on one side of the well, Point B is directly opposite.

A straight line between A and B would run into the well, all the way down the well, up the other side and towards B. Clearly this is not the shortest route - the shortest would be to run around the outside of the well.

Now consider that the people who can see point's A and B (i.e us. in 3/4/whatever dimensional space/time) cannot see the well we have no way of comprehending it's existence, other than mathematics.

General Relativity will tell us that the shortest route between two points is actually an "Geodesic", which can be, but is not necessarily, a straight line. Actually it's a straight line on a curved surface.

Huzzah.

If none of that makes sense, I'm truely sorry Ian, it's a Friday night and I should be asleep.

Hopefully that didn't read as complete c*** (not the best).

Yeah, what he said.

Woo!

Too many pints later and the old brain is still ticking over.

Moose.

My wife used to dabble in non-euclidean geometry at university (now there's a conversation stopper right there!!) and sometimes she'd try and make my head hurt by trying to explain such matters....

Get a sheet of paper and draw a dot at the top and one at the bottom. Draw a line between them and you've got the shortest distance right?? Wrong.. Bend the paper over until the dots meet - that 's the shortest distance. Space is curved....

Or I could get in a plane tomorrow and fly in a straight line due west until I reached Canada or wherever.... Except that if you looked at my plane and the world side on you'd see I was flying in an arc.... So a line can be straight and curved at the same time...

So what does that mean....? No idea.... Do I care...? Not a jot... Goodnight!!

I thought it was that. Thanks for the replies...

Fabulous stuff. I also enjoy reading projective geometry,which shows up in some really cool magical iconography....

A slight aside here, but can I ask how many physicists we actually have on the board? I have an MPhys in physics with astrophysics, and I know I've seen several others around, I just thought it might be interesting!

Does a physical chemist count?

Dominic Rougier wrote:My time!

Righty... my degree was in Physics with Satellite Tech, and my particular interests were in Special and General Relativity.

(I'm also slllllightly inebriated, so bear with me)

Any conversation that starts like that has got me on board! that's brilliant!

Also, I'll chime in and say I have a degree in Mathematics
not that i put it to any use!

Serendipity wrote:Does a physical chemist count?

Moles

Think I found it here somewhere, but this may explain.....
http://myselfdevelopment.net/index.php/ ... dimension/

G