Direction - A fundamental property?

[CoolATIGuy]

Just curious...I've been reading about 3 fundamental properties (Length, Mass, and Time), and was wondering about direction...what is that? It's definitely not Time nor Mass, but it's not quite Length. Are there more fundamental properties?

 

Sorry if this is too basic; gotta start somwhere.

 

 

CoolATIGuy

[5614]

what is it about Length, Mass, and Time that make them fundemental?

 

direction is fundemental in a 3D shape and if you are talking about movement, but to a 2D shape, direction isnt really important.

[CoolATIGuy]

what is it about Length, Mass, and Time that make them fundemental?

 

Maybe that's what I need clarified...what *does* make them fundemental/what does that imply/what does that mean?

 

direction is fundemental in a 3D shape and if you are talking about movement, but to a 2D shape, direction isnt really important.

 

If you are referring to a "shape" as an object, direction *is* still important to a 2 Dimension shape, isn't it? It can go any direction in a 3d environment, and still has 2 directions in a 2D environment...

 

If you are referring to a "shape" as an environment, direction *is still important to a 2 Dimension environment, isn't it? Objects inside can still go 2 directions...

 

 

CoolATIGuy

[swansont]

Direction depends on your coordinate system. As far as one can tell the basic nature of space is isotropic - there is no preferred direction.

[CoolATIGuy]

Direction depends on your coordinate system. As far as one can tell the basic nature of space is isotropic - there is no preferred direction.

 

Correct, but distance is the same...we, as humans, just chose set lengths to determine distances. So wouldn't direction be the same?

 

 

CoolATIGuy

[swansont]

Correct' date=' but distance is the same...we, as humans, just chose set lengths to determine distances. So wouldn't direction be the same?

[/quote']

No.

 

Two observers facing each other in the same inertial system will agree on the length of an object, but won't agree on whether the object is pointing left or right.

 

The fact that we define a certain length to be a meter doesn't have an effect on the actual size of an object.

[Martin]

Just curious...I've been reading about 3 fundamental properties (Length' date=' Mass, and Time), and was wondering about direction...what is that? It's definitely not Time nor Mass, but it's not quite Length. Are there more fundamental properties?

 

Sorry if this is too basic; gotta start somwhere.

 

 

CoolATIGuy[/quote']

 

Your title was "Direction--A fundamental property?"

 

But it sounds to me as if you are wondering about "What is a fundamental property?" "what makes some type of physical quantity more fundamental?" And similar to what you ask in yr post "Are there other fundamental properties besides mass, length, time?"

 

It sounds like you are trying to think of other fundamental physical quantities besides those three---and you picked direction out of the hat to ask about, was it another fundamental quantity.

 

I cant answer yr question but I can throw out some possbilities

 

1. what about temperature? is it fundamental like mass or is it more a delicate sophisticated construct made from other ideas? it seems very fundamental to me personally but that is just my opinion

 

2. what about electric charge? Isnt that pretty fundamental? the charge on the electron, the charge on the proton.

 

if charge is not fundamental then what are you going to build the idea out of (can you build charge out of mass, length, time?)

 

3. what about energy and momentum? well....maybe they are more effete derivative ideas that have to be based on firmer notions....or?

 

4. what about FORCE? do you really think that force is not primitive just because you can define it in terms of mass and acceleration, that is you can algebraically concoct a measure of force in terms of mass and distance and time? do we take force as a root fundamental idea or as a derived idea.

 

5. the einstein equation of General Rel. connects spacetime curvature in a region with the density of energy in that region. I think nobody knows how to make that equation any simpler than it is. you cannot write it in terms of mass or force or petty stuff like that, if you want it to be simple you have to write it in terms of curvature and energy-concentration. whoa! weird!

does that mean that bizarre ideas like curvature and the concentratedness of energy might be really essential? this way lies madness.

 

No ATI. Mass and Length and Time are the only fundamental types of physical quantity and that is why the Metric System is based on the Kilogram, the Meter, and the Second Get a glass of water and go back to bed.

[CoolATIGuy]

Mass and Length and Time are the only fundamental types of physical quantity

 

So just what are temperature, electric charge, etc.? And putting it that way sounds like a modified version of what was believed along time ago, that everything was either wind, fire, earth, or water, doesn't it?

 

 

CoolATIGuy

[Martin]

So just what are temperature' date=' electric charge, etc.? And putting it that way sounds like a modified version of what was believed along time ago, that everything was either wind, fire, earth, or water, doesn't it?

 

 

CoolATIGuy[/quote']

 

I was kidding you about mass, length, time, being the only fundamental types of physical quantity.

 

they are some but not all.

 

I dont happen to know the whole list, and i think it changes as people keep tinkering with the central theories of physics and cosmology.

 

yes identifying any short list of types of quantity as basic DOES sound very much like how the Greek philosophers used to talk. You are right.

 

But is that necessarily bad? Just because the earth-air-fire-water model turned out to have serious limitations as an explanation does that mean that humans should not keep on looking?

 

You have to decide for yourself how you feel about this human quest---people are still doing it and they will probably keep on for the foreseeable----and each of us can say if he thinks it is foolish or not.

Theoretical physics---in particular what is called the Standard Model---which has around 26 separate parameters that go into it---is an ageold effort to discover a finite set of essences

 

(fields, particles, interactions, spacetime, earth, air, fire,... )

[CoolATIGuy]

Get a glass of water and go back to bed.

 

ugh...maybe I should get that glass of water. *smack* I can't believe I, czar of sarcasm, didn't look past the end of my nose. Anywho, I'm getting a clearer picture...thanks!

 

 

CoolATIGuy