what makes a 'dimension' to the scientific community?

ok, now to all of you smart pants, this may sound utterly stupid, for that i do apologize, unfortunately the extent of my scientific knowledge only goes about as far as star trek and star gate lol. Good news though, im trying to learn

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just bought Brian Greenes fabric of the cosmos and im halfway through, though its a tad clogged with simpsons metaphors and references.... anywho on to the clarification of my question.

What confuses me so to speak is that a dimension is defined as "a measurable extent of a particular kind, such as length, breadth, depth, or height"

Why isnt gravity classed as a universal dimension? why isn't temperature/heat? i mean these are both things that everything in the universe has right? whether in the positive or negative.... so why aren't they also classed as dimensions alongside 'time and space'??

Thanks in advance all

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Dimensions can be used to locate a specific point in space time. If I wanted to meet with you and using the earth coordinate system, I would need to specify a latitude (x) a longitude (y) a height (z) and a time (t).
Those are dimensions because that is all that is needed for defining a point in space-time. The other things you mentioned would not help to locate a point.

Welcome to the forum.

 

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thanks for the welcome

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I understand what you're saying i think and i get that on earth no, they wouldnt be useful dimensions unless you were looking for a super-dooper fat guy and about thousand electric blankets, but on a universal scale. in a similar manner to X, Y, Z and T, which you might use to find something within a grid of time-space, so to speak, wouldn't Gravity and Heat be a separate dimension outside that grid? or atleast tied into the 'space' section of it, because gravity effects all of the above and not the other way around right?

and heat well, i dunno, heat can be quite an effective means of locating things.... just ask those U.S. attack drones.... it may not be so effective from the surface of the earth, but again on a universal scale if 'Heat' isnt listed as a quantifiable method for defining a point in space.... why is light? they're again, sort of entangled, but entirely different right? you can have heat(or lack there of) without light, but not light without heat..... if i was asked to locate the hottest and coldest points within our solar system using only heat detection, i could do that. i mean this is all supposition but... both gravity and heat, seem to me to be dimensions in and of their own still... so maybe i need someone to clarify, clearly. and then call my an idiot. lol

 

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No, they cannot be used to define a point in space-time.

Gravity and temperature are important but they cannot be used to define a point in space-time.

No heat would be useless to define a point in space. I will meet you at 92.7 Fahrenheit would not be very useful would it?

Huh? Light isn't.

The sun is not a point in space it is hurtling through space as it orbits the center of the milky way. I can use real dimensions x,y,z & t to specify the location of the sun at a specific point in time however.

 

In GR they're 4 dimensions used to model gravitational phenomenon. Three space dimensions and one unidirectional time dimension. They're other theoretical models of gravity that use more dimensions to model gravitational phenomenon. Such as String Theory or Kaluza Klein in five dimensions. In physics temperature and heat are scalars and do describe specific phenomenon at a specific place on the manifold you're doing physics on.
http://www.excelatphysics.com/scalar-vs-vector-quantities.html
The gravitational field, g field, is a vector quantity which is infinite in extent but we measure g at a specific place on the manifold. IE

g=M/r^2

 

oky doky, i get it, just to clarify i didnt actually mean the sun was a stationary point in the solar system (I'm not that silly

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) i just said that i could theoretically locate the hottest and coldest points within, it goes to show that were i to locate the warmest point within the solar system at the moment though, since that is the selected grid, the hottest point would be located wherever the path of the sun happened to intercede.... so i dont know what youre getting at with that... i mean the coldest point would naturally be where ever pluto's orbit happened to have it's dark side sitting at the time of this theoretical scan anyway... lol so any 'hot' or 'cold' point is rendered sort of moot by the X, Y, Z, T grid because of this constant universal motion which you bring up. all bodies are in motion through out the constantly expanding universe right? so X, Y, Z, T works well on a small scale, but not on the whole, for mapping out bodies and areas within the solar system its fine, but on a larger scale, Gravity and temperature must also come into play as physical dimensions? i mean.... it just seems so narrow of a definition, latitude, longitude, height, time. ok fine thats nice for picking a spot to have a meeting in beijing or to bomb a warring nation, but the universe is constantly expanding and these dimensions are constantly shifting as a result right? albeit in a significantly slower rate than we will have any foreseeable problems with, but theoretically, on a cosmic scale, across galaxies rather than solar systems, when charting billions of clusters of suns and such, wouldnt gravity and temperature have a higher significance than height or circumference in locating the milky way amongst all the other billions of galaxies? wouldnt that qualify them as being worthy of classed as dimensions even by the standards of co-ordinate navigation? its hard to argue with "Second star to the right and straight on till morning" so to speak....

Now, maybe what i'm refering to is the physical dimensions. so i suppose my question has changed but.. it also hasnt... and yes i know this is sort of just circling the drain lol but what i was getting at overall was that aren't gravity and heat, or lack of, in association with the X, Y, Z, & T a sort of 'physical dimension' relative to any particular mass in question. since they are according to the definition of a dimension both a measurable extent of a particular variety, i.e. mass and temperature?

i mean i could give you my X, Y, Z & T right now or of where i will be tomorrow at lunch, but that wouldn't help you locate me, just this general area of the planet i reside in, i could give you the X, Y, Z and T, you would also need my "physical dimensions", such as mass & general level of heat output, etc... does that make sense??

again i really appreciate the help and so sorry for the super long post... just trying to wrap my head around this lol

 

Gravity = mass by revolutions square?

 

r is the distance.

 

How could gravity and temperature possible be a dimension? I tried..

No, that would give me your exact location. You could specify the location down to angstroms and picoseconds.

No, not really. How would the gravity or temperature get you any closer a to point specified by x, y, z & t?

 

Hello JuliaG

I'm no expert, so have a chuckle on this...

In one sense you could say gravity is a 'warping' of the grid squares that you have set up to represent the dimension of space/distance.

Picture your grid squares, each made of little iron rods, and covering all the surface of a flat marble tabletop. Then at various places under this surface are blow torches heating the marble, after a time in spots some of the iron rods above will expend and upset your nice neat squares.

Remembering that those rods already represent your dimension for space or distance, all you have done by introducing gravity( blow torch) is upset or warped your existing dimension, so to speak.
Blow torch = mass and energy.

Then, on the other hand...another chuckle...
If you say as some do, you already have gravity being called a dimension, in the sense that, space and time is just another name for the gravitational field of the universe. Some places it's flat, no mass and energy present and in other places it's warped because of the presence of mass and energy.

One thing to remember in this model of space and time, is although this 'warpage' of space is real, how you experience it depends on your motion and position relative to it.
That is, the distant observer of a black hole will never 'see' an infaller reach the event horizon, whereas the infaller in his frame does and can cross the horizon too.

Welcome.

 

r is the radius. I wrote g down in geometric units. That's where you change all units to a distance. So we can make M one solar mass which is 1477 meter. Let's make the radius 10M or 14,770 meter. So

g=1477m/14,770m^2 = .o0000677m-1

To convert this to conventional units you factor c^2 (.00000677m-1) = 9E16m^2/s^2(.00000677m-1) = 6.093E11m/s^2. g at the surface of earth is 9.81m/s^2. Jaba the Hut to E11. LOL.

 

JuliaG I think what you're reaching for is "degrees of freedom" to describe a system. A degree of freedom, such as charge, temperature, etc, can be considered a dimension of the phase space but not specifically in the (more limited) temporal-spatial sense.

 

A dictionary-like definition for some words & concepts is often inadequate.

For such concepts, using a word or phrase in various contexts results in better understanding. For dimension, consider the following (not a quote: I like the quote format)

Some seeming counter intuitive results can be obtained by mathematical analysis. Consider a unit square, a unit cube, & various unit hyper-cubes.

 

A dimension refers to a geometrical physical metric such as length that is treated in Euclid's plane geometry, although such metrics may not be limited to a plane, nor even a mutually orthogonal (at right angles) or rectilinear coordinate system. Any physical length may also be referenced in terms of light travel time, which is preferred by scientific calibration standards laboratories like NIST, because the speed of light is known to be an invariant quantity in all inertial reference frames, whereas the length of a strip of metal or wood is not.

I can't read anything by Brian Greene, other than 'The Last Mimsy', which is fiction, and was a decent movie. I can't watch his PBS NOVA science episodes because he does such a poor job of presenting basic science. If you can find a popular book on the same subject by a different author that appeals to you, I would encourage you to read that instead.

 

IMO, a dimension is no more than a "inherent measurable condition" of (in) spacetime.

In physics,
1 point is not a dimensional (measurable) condition

2 points create a condition of a line (measurable 1 dimension)
3 points create a condition of a plane (measurable 2 dimension)
4 points create a condition of a volume (measurable 3 dimension)

In metaphysics,
Time is a condition wherein chronological change has taken place (measurable 4 dimension)



edit: wow, I just posted the link, without the "media" brackets.

 

Most here are restricting dimension to a location. The OP asked about temperature which, as I mentioned before, is also a dimension in the more general usage of the term (like charge, mass, color or any other degree of freedom)

 

Could we say that temperature is a result of physical conditions in spacetime?

I am a little hesitant to call temperature a "dimension" of spacetime, but see it more as an expression (result) of physical change in dimensional space. I do understand your thinking, but then, could we not also say that "energy" is a dimension or that "dynamical change" itself is a dimension of spacetime?

p.s. I love your avatar; "I think, therefore I am".
https://en.wikipedia.org/wiki/Cogito_ergo_sum

 

Perhaps the nuance is that you said a dimension "of spacetime". Here is a quote from wiki on Degrees of Freedom:

 

Yes, perhaps our difference is just semantic.
I mentioned temperature as a result of change in spacetime, where change is a result of freedoms afforded by permissive conditions. I interpreted these permissive conditions as the inherent dimensions of spacetime.

My thinking is influenced by the Bohmian hierarchical dimensional ordering of spacetime, but again this may be just a semantic nuance.

 

Why isnt gravity classed as a universal dimension? why isn't temperature/heat? i mean these are both things that everything in the universe has right? whether in the positive or negative.... so why aren't they also classed as dimensions alongside 'time and space'??

Hold that thought this will get more interesting than you know...