Spacetime diagrams

[geordief]

Specifically these Minkowski diagrams.

 

It has taken me a (long) time to realise that these are actually"correct" models of "reality". (I thought they looked too "childish" to be for real) but I have since come to understand that they are fully predictive (am I right now?)

 

Anyway I have a specific question about them.

 

Are there any circumstances when these diagrams do not "work" (within the theory of Special Relativity) ?

 

In other words is their applicability fully co-extensive with that theory?

 

 

[Mordred]

They work with a good degree of accuracy within the limits of SR. Which is usually the observer at rest. If the observer is also inertial one can apply calibration corrections.

 

see here.

 

 

 

http://www.google.ca/url?sa=t&source=web&cd=12&rct=j&q=minkowski%20space%20time%20diagram&ved=0ahUKEwiYuNLFgKjLAhWDLmMKHa-yC4gQFgg-MAs&url=http%3A%2F%2Farxiv.org%2Fpdf%2Fphysics%2F0703002&usg=AFQjCNG05MLRMRIA2O4Ruuzujq8vQfL7NQ

Edited March 4, 2016 by Mordred

[ydoaPs]

You have to be careful in interpreting them, though. The spatial distance and temporal distance don't combine in a pythagorean way. The square of the spacetime distance is the difference of the square of the temporal distance and the spatial distance. So, in the diagram, you can't always judge a line by the length on the paper.

[geordief]

thanks ,yes I have learned a bit about that minus sign.

 

That is great .Knowing that these diagrams are completely compatible with SR should provide me with an alternative approach to that theory -which could be useful for slow learners

[ydoaPs]

thanks ,yes I have learned a bit about that minus sign.

 

That is great .Knowing that these diagrams are completely compatible with SR should provide me with an alternative approach to that theory -which could be useful for slow learners

Tim Maudlin has a good overview of SR and GR (and some philosophical issues therein) devoloped using just the diagrams.

 

Here's the book on Amazon.

[geordief]

Tim Maudlin has a good overview of SR and GR (and some philosophical issues therein) devoloped using just the diagrams.

 

Here's the book on Amazon.

Thanks for that. Looks like a good present for myself.

[ajb]

Knowing that these diagrams are completely compatible with SR should provide me with an alternative approach to that theory -which could be useful for slow learners

These diagrams describe in a graphical way the causal structure of Minkowski space-time, no more and no less. You will not be able to reduce everything to simply looking at these diagrams, for example when looking at relativistic collisions.

[geordief]

These diagrams describe in a graphical way the causal structure of Minkowski space-time, no more and no less. You will not be able to reduce everything to simply looking at these diagrams, for example when looking at relativistic collisions.

Are relativistic (or any ) collisions covered by SR?(that is not the domain of GR -or do they overlap to an extent?)

By the way ,do you happen to know in a historical way if these spacetime diagrams result from the arrival of film making technology?

They seem ,in my mind to dovetail almost perfectly with that technology: the way you can stack celluloid frames one on top of each other to show how an object moves through space and time in an objectively measurable way.

Was the development of these diagrams (and their geometry) facilitated by this new way of looking at things?

I apologize if it has taken me so long to work out the bleeding obvious:-)

EDIT:apparently 1889 was the year of the "first true motion picture" ( or something that could be so called)

Edited March 6, 2016 by geordief

[Mordred]

I doubt it, butif your interested in a historical reprint of SR.

 

http://www.gutenberg.org/files/30155/30155-pdf.pdf: "Relativity: The Special and General Theory" by Albert Einstein

 

Its a rather good read

[geordief]

I doubt it, butif your interested in a historical reprint of SR.

 

http://www.gutenberg.org/files/30155/30155-pdf.pdf: "Relativity: The Special and General Theory" by Albert Einstein

 

 

Its a rather good read

You are quite right. It is right up my street even though I anticipate struggling badly with it(I have already read bits of it on the computer) . It would probably complement the other book that ydoaPs suggested.

 

I rarely read books but when I do they are much more pleasurable (and hopefully effective) than looking at a computer screen.

Edited March 6, 2016 by geordief

[ajb]

Are relativistic (or any ) collisions covered by SR?(that is not the domain of GR -or do they overlap to an extent?)

I was thinking of just in special relativity. In general relativity we can always locally (i.e., in a small enough region of space-time) ignore gravity, so for particle collisions we probably don't need to worry too much about gravity, at least locally.

 

By the way ,do you happen to know in a historical way if these spacetime diagrams result from the arrival of film making technology?

I doubt there is a connection.

 

 

Was the development of these diagrams (and their geometry) facilitated by this new way of looking at things?

I doubt it. People have been drawing all sorts of diagrams to describe physics for a very long time.