Is it possible in principle to measure the exact position of a stationary atom?

Answer 1

In harmony with answer four....'Position' is utilitarian value that may not require quantitive concepts. Like another respondant said, a position needs a relation to at least one other position, but for you it may not, for your puposes, need a measurement. It depends on what you're working on, and in working on anything that thing must be known to you relative to your position.

I understand 'stationary' as to mean 'not moving position relative to at least one other position'. Is that possible for 'atom'? Judging from normally equipped sensory perception it is stationary enough at times to succeed, depending on the material state (gas, liguid/fluid, solid) requirments for the project proposed.

Is it possible to detect single atoms. The best small thing detection I know of is the sight of a protein molecule in electromicroscopy. It was a very, very large protein.

Answer 2

No, for two reasons:

1. There is no such thing as exact position ... just relative. An exact position would require a frame of reference. We have no central point to measure from in our universe, just a relative point.

2. Quantum Mechanics proves that even complex stuctures such as atoms do not exist at a particular location until observed. They actually exist everywhere in the universe to a certain degree and only show up where we find them when their probability curve collapses from observation. It's strange, but completely proven beyond any question of a doubt.

However, the other answer about "Heisenberg's Uncertainty Principle" is incorrect. That principle states you cannot detect both the momentum and location of something because observing one affects the other. You can however approximate one to almost certainty through math. The reason why you cannot determine it through a relative marker such as something moving the same speed a fixed distance is because the non-communitive operatators in the calculations.

Answer 3

If you know the exact velocity of the atom (0 in your case, relative to you), you cannot know the exact position with absolute certainty.

For example, if you know the exact velocity of the atom, 0, and you use an electron microscope to obtain its position you have just bombarded the atom with electrons that interact with the atom and thus give you an 'image.' This interaction that yeilds an image has changed the velocity of the atom (because the electron hit it right?), making it no longer 0, and/or the position of the atom moving it to a different place than it was before.

Therefore, you can only know the exact position and velocity of an atom where it 'was,' never where it 'is' with absolute certainty.

Answer 4

Not only can people measure their position, they can choose where the put them, then take a fancy Picture. In 1990 IBM wrote their name in Xenon atoms. Here is a website with the picture. The story is about 1/3 of the way down the page.

Can Proximal Probes Move Atoms With Complete Precision?
http://www.foresight.org/UTF/Unbound_LBW/chapt_4.html

The Heisenberg Uncertainty Principle is only for subatomic particles (electrons, quarks). That's quantum physics. We are talking about atoms so they are not subatomic

Answer 5

Yes. However the more accurate your measure the more the velocity of the atom will change.

Answer 6

You can detect where it WAS. The act of detecting alters its position.

Look up "Heisenberg's Uncertainty Principle".

Answer 7

Theoretically yes, but then the heisenberg uncertainty principle states that its momentum could be anything.