Does 'exact' actually exist?

Ok so I know psychology well but I am for lack of a better term stupid when it comes to physical sciences.

As a hobby I read books regarding physics, cosmology and astronomy. I can handle most theoretical stuff well but man there is some things that I cannot get my mind around. So if anyone knowledgeable in physics and math and such I would love an answer to the following question

I promise this isn't a trap or a method to make anyone look stupid. I truly am interested in this discussion

I will do my best to succinct and clear

Does the concept of precise actually exist?

Here is what I am getting at. Say I have a pencil and I want to measure it. I do so with a ruler and it measures out to be approximately 5 inches long (these numbers are arbitrary so bear with me)

So my quandary is, can you ever have exact measurements or do we not truly know the dimensions or objects? Could it be that we can always make better machines to measure and will find out the pencil isn't 1 inch and is indeed 1 inch plus some ridiculously small fraction? And when we find that will another new machine find an even more precise measurement?

Is there ever a limit to how deeply and precisely we can measure?

Thanks in advance to all who reply

I am really lost on this subject

a reply to: KyoZero

Maybe this will help

www.ndt-ed.org...

a reply to: Justacasualobserver

Yeah I mean I realize I could have easily looked it up but I won't deny that it still confuses me at times.

Thanks for the link, I will give it a good solid read

a reply to: KyoZero

KyoZero

Theoretically speaking there is, the Plank Length.

From the source:

Simple dimensional analysis shows that the measurement of the position of physical objects with precision to the Planck length is problematic. Indeed, we will discuss the following thought experiment. Suppose we want to determine the position of an object using electromagnetic radiation, i.e., photons. The greater the energy of photons, the shorter their wavelength and the more accurate the measurement. If the photon has enough energy to measure objects the size of the Planck length, it would collapse into a black hole and the measurement would be impossible. Thus, the Planck length sets the fundamental limits on the accuracy of length measurement.

Generally speaking though, determining absolute dimension or spatial location is governed by how much money and time you have. For example, in determining the area of a circle 22/7 can be used as Pi. 22/7 is a very low order of accuracy, Pi as 3.1415926536 however is more appropriate for millimetric calculations on say a planetary scale.

The higher the order of accuracy required, the more time it takes to determine and subsequently the more money it costs to achieve.

Hope this helps a little.

Kind Regards
Myselfaswell

You know, when I was in jr. high and high school, I remember arguing with people that exact didn't really exist.

(OK, so I was a little weird in my school years. I'm all better, now.)

Mandelbrot opens his famous text on fractals by retelling the coastlline paradox.

the measurement problem lies at the heart of the most difficult and profound questions in modern physics.... a good one to ponder.

Come to think of it... all matter vibrate so there is really no one measurement. Everything fluctuates.

Just something to ponder on

Yes exactness exists.

There can always ever be somethingness and nothingness. Nothingness is pure nothingness. And somethingness is the non nothingness that exists.

Something cannot come from nothing. Something cannot be created or destroyed. So there is a finite amount of something that has existed, exists, and will always exist.

Now the reason I believe, and think it is very true that exactness exists, is because if you go from both sides and narrow down you will eventually 'pigeon hole' an exactitude.

For your pencil example, if you have measuring tools on either side of the pencil, that incrementally decrease their distance to one another (two lines (thin lines) closing in on one another and towards the ends of the pencil), and at the same time, linked up, a device which starts in the middle (can there be an exact middle!?!?!, yes I think so, but this question could be more obviously thought in the terms of a circle, and then thinking about the nature of points and dimension, because there must be an exact center of a circle, because a circle is infinite points an equal distance from a common center (ya know, trace the points and its an arc, and circle) and so one by one using the smallest possible increments of advancement eventually the two measuring system will be at a point where if they were to increment any further they would be 'passed their objective', which for the one would be to stop right as the ends touch air/space, and the other right as the air/space touches the ends.

Physics is all about this problem but in the direction of objects, and composition, is an apple an exact apple object...well its really these molecules which are parts, which are really these atoms which have parts, which really have fundamental particles, and its not known entirely what the true fundamental nature of that primal energy is, how it exists, fields, particles, waves, but I suppose the thought that that stuff is quantized lends credence to the thought that there exists exactness to all things.

originally posted by: Justacasualobserver
a reply to: KyoZero

Maybe this will help

www.ndt-ed.org...

That's a start, but it really doesn't get into the Heisenberg uncertainty principle, which defines the limits of measuring a particle's position and momentum simultaneously:

In quantum mechanics, the uncertainty principle is any of a variety of mathematical inequalities asserting a fundamental limit to the precision with which certain pairs of physical properties of a particle known as complementary variables, such as position x and momentum p, can be known simultaneously. For instance, in 1927, Werner Heisenberg stated that the more precisely the position of some particle is determined, the less precisely its momentum can be known, and vice versa...

Thus, the uncertainty principle actually states a fundamental property of quantum systems, and is not a statement about the observational success of current technology.

So no measuring technology is expected to overcome this obstacle to exactness.

Now can anything ever be exact? Not measurements according to that, but what about definitions? The answer is yes, definitions can be exact. Take for example the definition of one second:

en.wikipedia.org...

Under the International System of Units (via the International Committee for Weights and Measures, or CIPM), since 1967 the second has been defined as the duration of 9192631770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom.

So a second is exactly 9192631770 cycles because that's what we say it is, by definition. But when you see how the definition has changed to incorporate difficulties in measurement, you can see that measuring it is more difficult than defining it:

In 1997 CIPM added that the periods would be defined for a caesium atom at rest, and approaching the theoretical temperature of absolute zero (0 K), and in 1999, it included corrections from ambient radiation.

I like thinking about the perfect pyramid. The tip, infinitely sharp, the best fit you could have to approximate Exact.

If you could imagine yourself the size of a sub-atomic particle, climbing up the side of the pyramid, you could never reach the top.

a reply to: KyoZero

Arbitrageur's post is right on. The idea of the continuum, the real number line where between any two real numbers exists an infinite number of other real numbers, breaks down through the revelations offered by quantum mechanics.

It becomes clear why this must when you think about information, and what can be encoded in a number. Suppose there is a number between 1 and 0, and encoded in its digits, is the entire universe. ( a whole lot of information) So the first gazillion digits are the state of the universe at the first tick of time after the big bang, the second gazillion digits the next tick of time, and so on. So somewhere in this number is encoded everything that ever happens in the universe. If you believe in the continuum, when the chicken crosses the road (moving from position 0 to position 1), it must at some point be at a position where the entire past, present, and future of the universe are encoded in its position. Not only this, but it must cross positions which encode every possible universe as well.

The universe itself rejects this wasteful nonsense, and that rejection takes the form of quantum mechanics. Quantum mechanics tells us that there are limits on how exact things can be. We will never be able to observe the past, present, and future of the entire universe encoded in the position of a particle, because we are simply never that certain. And this is a good thing.

a reply to: Arbitrageur

I thought about the Heisenberg's uncertainty principle but that is about measuring BOTH position and momentum at the same time. If you for example want to observe an electron you would know precisely it's location but you wouldn't know (or are not sure) of it's momentum (or velocity).

Heisenberg sometimes explained the uncertainty principle as a problem of making measurements. His most well-known thought experiment involved photographing an electron. To take the picture, a scientist might bounce a light particle off the electron's surface. That would reveal its position, but it would also impart energy to the electron, causing it to move. Learning about the electron's position would create uncertainty in its velocity; and the act of measurement would produce the uncertainty needed to satisfy the principle.

www.scientificamerican.com...

a reply to: KyoZero

I think that most of the words in the English language, which play into this subject area, are used with the context of the situation in mind. Since it is highly unlikely that anything regarding a pencil will ever need to be measured down to the nearest atomic diameter, precision could be achieved by saying that the pencil is 127mm in length, since to go further would be fruitless in the extreme.

However, when calibrating a particle accelerator, one would not work in such large measures, but begin to focus on the nanometer scale. The definition therefore, of precision, is not as important as the context in which the word is used.

originally posted by: Deaf Alien
a reply to: Arbitrageur

I thought about the Heisenberg's uncertainty principle but....

You thought about it but....and then you post a source that says what I already said? If you were trying to make a point I don't get it.

Let me put it another way, try to measure the length of a pencil. On one end, you've got a point. If you developed super-sharpening technology to get one atom at the tip of the point, you still don't know where the edge of the tip is because it's an electron cloud which is a wave function which means you can't say where the electron is. Even if you say you don't care about the momentum and you just want to find the position, you only found the position at one instant in time, and if the electron is on the pencil side of the nucleus when you measure it, it's not giving you the pencil length anyway because the nucleus is outside it. A millionth of a second later another measurement would show the electron to be outside the nucleus changing your length measurement.

But we can get pretty accurate. One of the engineering triumphs scientists like to boast about are spheres sent into space that are about the size of ping pong balls and spherical within about 40 atoms, so we are able o measure pretty well to even be able to determine that:

Gravity Probe B

At the time, the gyroscopes were the most nearly spherical objects ever made. Two gyroscopes still hold that record, but third place has been taken by the silicon spheres made by the Avogadro project. Approximately the size of ping pong balls, they were perfectly round to within forty atoms (less than 10 nm). If one of these spheres were scaled to the size of the earth, the tallest mountains and deepest ocean trench would measure only 2.4 m (8 ft) high.

I think 40 atoms accuracy is pretty good, but when you get down to individual atoms, you can't even say where the edge of the atom is because of the electron cloud.

a reply to: KyoZero

@ times OP 1 picks up that many things made of atoms are moving (vibrating) in slow slurry like movements that the eyes made of atoms cannot detect due to the eye atoms and the material atoms both moving as atoms do.
It seems as if some of the human brain mechanisms function is to process the moving reality experienced and visualized within this slow slurry like or constant moving 3 dimensional realm and make things appear or seem still (maybe to make the reality projected easier for the experiencing to handle and interact within.
It makes 1 think what does everything really look like objectively from a higher aware perspective.

This is why possibly the measuring of things exactly may always have room for more tuning or is not ever really exact.

(from another perspective or view)
Everything may appear connected in a continuous bonded reality where the computer in front of you is observed but the space between you and the computer from this other perspective does not exist… But within these HUMAN processed boundaries OF AWARNESS & PERCEPTION the brain tells some that there is invisible ethereal like space between you and other existing objects (which may not exist if processed from another type of visual observers perspective).

Further considering this, you and the nearest STAR would be connected or bonded as would you and all surrounding you, following this premise certain physical or metaphysical movements and or thoughts practiced or acted upon may be having an effect on nearby objects (depending on your wave energy level for if asleep you may not acknowledge what is going on even if participating). Add in the conscious mind and its metaphysical properties associated with EM fields etc. and you begin to see how things though distant are still directly corresponding to you or your waves emitted consciously along with your physical electrical movements…

I know it sounds a little strange to consider but its something that has been processing as of recent with 1. So again this may cause the measuring issue.

NAMASTE*******

AP David: On The Laws Of Nature | EU2014 www.youtube.com... descriptive and prescriptive a reply to: KyoZero

Tell ya what, have this argument with a machine shop foreman and he's not going to fire up any machines for your little project.

a reply to: Arbitrageur

Yeah sorry I was bit drunk last night but you are correct. I guess my point was to clarify to the OP is that the Heisenberg's uncertainty principle is about measuring both position and momentum.

a reply to: KyoZero

I say that exact doesn't truly exist.

originally posted by: Asynchrony
a reply to: KyoZero

I say that exact doesn't truly exist.

At least in the real physical sense.