Heisenbergs uncertainty principle?

Question

As I understand it it means that nothing really exists unless a person is looking at it, all the atoms that make up any object could be at any point in the universe and come together when someone looks at it.
http://news.bbc.co.uk/1/hi/sci/tech/6914175.stm

Iv just tested this. I closed my eyes and touched a wall. Not looking at it and neither was anyone else because it was an inside wall, so therefore it should not be there. Of course it was.

Am I missing something here? Things dont just not exist if us humans dont look at them.
I must have got this wrong, could someone explain it please. In laymens terms please.

Answer 1

Heisenberg's principle is applicable mainly for atomic scale phenomena. For example, electrons move around nucleus at a very high speed (compared to their size) and their positions at given time can not be verified.

Heisenberg postulated that since electrons orbit around at fast speed, their orbits can not be visually verified, but can be deducted using formula for approximate or average position. He added that just because we can not visually verify the position, it does not mean that electrons do not exist.

He provided an example from our daily life. He stated that if an object is attached to one of the propellers of an aeroplane and if the propellers moves at fast speed, we can not see the object at any given time, but we can approximately deduct its orbit.

His theory was an useful tool to understand state of atoms at his time, when powerful microscopes were not developed. For the last years, a new tool called channeling-tunneling microscope is developed, by which we can see individual atoms and molecules.

Answer 2

First of all, don't get your science from your everyday News agencies because half the time they don't know what they are talking about. The Uncertainty Principle states that you can not measure accurately a particle's position and momentum at the same time. So the article is plain wrong about it

What the article did describe is the Schrodinger Equation that states that a particle has all possible states at the same time unless a measurement is made, then all those possible states collapse into one. It does not mean that the particle dose not exist. It just means we don't know which state the particle is in. We can only apply probabilities.

This is most famously shown by the situation known as Schrodigner's cat. Put a cat in a box with two switches inside. One release a poison gas. One release food. Without opening the box, you don't know which switch the cat has chosen. Therefore the Shcrodinger Equation, or the wave function, of the cat states that the cat is both alive and dead at the same time. As soon as somebody opens the box then the two states collapse into one (the cat is either alive or dead)

Now as to your experiment, Quantum Mechanics, which both the uncertainty principle and the Schrodinger equation are part of, only applies to the realm of the very small, subatomic particles to be exact. However, in your case, imagine you closed your eyes and shut your ears such that no input from the outside world can reach you (no touching either). Do you still have confident that the wall is there? How do you know if somebody did not knock down the wall or that the wall has been transport to a different place via quantum mechanic effects when you were isolated from all outside stimuli? Without you mankind a measurement, the wall can be anywhere and in all possible states. You act of observing with your eyes or ears or touch collapses all those states into one state where the wall is there in the same place that you remembered it being before your senses were cut off from the outside world

Answer 3

There is more space between the atoms comprising the wall than the space taken up by the atoms comprising the wall. In other words, the seemingly solid wall is actually made of more nothing than something. There exists the possibility that you COULD move your hand through the wall, regardless of whether or not you were watching. The probability is so astronomically small that it will likely never happen, but it can.

The Heisenberg Uncertainty Principle really only applies at the molecular level, where an atom can exist in several states at the same time, predicting the next state is uncertain.

Answer 4

To formulate the idea that heisenbergs alludes to which was what he called the undeterminency principle,(not uncertainty),it is necessary to know the reason why things move and what is the cause of motion.
If an astronaut throws a ball in space to another space ship and the velocity of the ball was to be measured,it would have to be done as follows;
First the distance of travel from the starting point of motion has to be measured ,and the time it took to get to that point.
Since time is non linear it is impossible to measure time instantaneously.Because as soon as you take one measurement the ball aready has moved one more knotch in time. We cannot stop time.
However we can measure between two end point both time and distance.The ratio of the distance travelled to the time traveled at the end of the destination is called velocity.
However the velocity measured is only an average velocity.
This is so because we cannot take instantaneous measurement without affecting time. So what happens in between is just a guess (probability). this is Heisenberg's uncertainty principle in a nut shell.
Things that exist are existing whether there is an observer or not.
And not every thing in the Universe is visible to an observer. However humans have a gift of perception and we can feel by touching and hearing in addition to seen. So what we cannot see can be felt if it exists. A blind person has a greater space perception than a non blind person.

Answer 5

I think that article is misrepresenting how the principle works ... in order to promote the TV show. That's too bad because BBC Science is usually very good.

The Heisenberg uncertainty principle operates at *very* small scales. Scales much much smaller than an atom.

It has limited application at the level of hands and walls.

But I also think the article is misrepresenting how the principle works at the small level:
>"all the atoms that make up any object could be at any point in the universe and come together when someone looks at it. "

Not all points in the universe are equally likely. Also, it's not atoms, but things smaller than atoms (like electrons).

Specifically, the exact location of an individual electron is indeed impossible to predict ... it is located somewhere in a "cloud" of a certain shape around the nucleus of an atom ... some locations in the cloud are more likely than others, but the probability of finding that electron outside that cloud falls off to zero ... so it is not "at any point in the universe".

So in one sense it is correct ... the specific configurations of the wall (the relative positions of their individual electrons, which determines the space occupied by these atoms) is unknown and unknowable in advance. Heisenberg says that by making an observation, we "collapse" the probability functions to a certain state ... the closer you look, the more it collapses.

When you close your eyes and touch the wall, you are still making an "observation" (eyesight is not the only sense by which we perceive objects). But Heisenberg (as I understand it) does NOT say that the wall "ceases to exist" when you aren't seeing or touching it. Only that it's precise subatomic configuration is impossible (even in theory) to predict ahead of time.

Answer 6

If you really want an answer, hang-on!
The Heisenberg uncertainty principal implies that if you now the exact momentum of a particle you cannot know its exact position.
If you consider that in Einstein / Miller physics, time equals distance then any particle cannot exist, at one time. Each particle did exist in the past and the same particle will exist in the future. The past particle affects the future (self) particle through time as it would a different particle at the same time through distance. But when you get to stopping time, the past particle become infinitely close to future particle. The repulsive forces become infinitely great and the two particles (past and future) cannot co-exist at the same point in time and space.
Therefore, all particles must be in motion, and all particles do not exist.
Furthermore, this suggests that time is continuous and not framed as some people have suggested.
This, also, explains why there must be so much empty space in the atom.
I like to think of time like recording tape passing from reel (the future) over the head (the present) onto the other reel (the past). In this model, the head must be infinitely thin.

Answer 7

By touching it it exists. You touching the wall is actually an electromagnetic interaction between the electrons in your fingers and the electrons in the wall. It's basically seeing with your fingers.
Also the theory doesn't state that something doesn't exist without being seen, it says that a wavefunction doesn't collapse until it interacts with something.
Lastly, it's usually not very easy to analyze a large object with quantum mechanics, it's probably not that simple because of the large amount of objects interacting. Technically the wall is interacting with itself as well as many other things.

Answer 8

Very good answers from most but I think I should add this. The principal not only states that we cannot measure with arbitrary precision two dependant properties of particals but that the particals themselves do not have arbitrarily precise knowledge of those properties.

Answer 9

It essentially means that you cannot specifically say where the particle is or how exactly it is

Answer 10

This might help:

http://www.thebigview.com/spacetime/uncertainty.html