virus: Re : TT and meaning of life

Hakeeb A. Nandalal (
Sat, 09 Nov 1996 04:59:33 +0000

Tadeusz Niwinski wrote :-

> ..........
> (1) Physics. The Uncertainty Principle does not say atoms are unpredictable.
> It is the interference of the observer which effects atoms. At the atomic
> level we are not able to measure things to well because we use the same
> things (eg. photons) in order to observe. The observer's interference is
> making things seem "unpredictable". In fact everything works according to
> the same rules, but our observation is part of the picture. The degree to
> which we can measure things is limited. It does not make the world
> unpredictable.
> ..........

I'm no physicists but from what I've read of The Heisenberg Uncertainty Principle, it has less to do with the
limits of physical measurement and more to do with mathematics. Heisenberg showed mathematically that it was
impossible to know both position and momentum precisely at the same time.

Some nerd wrote this :-

Heisenberg Uncertainty Principle
An odd aspect of Quantum Mechanics is contained in the Heisenberg
Uncertainty Principle (HUP). The HUP can be stated in different ways, let me
first talk in terms of momentum and position.

If there is a particle, such as an electron, moving through space, I can
characterize its motion by telling you where it is (its position) and what
its velocity is (more precisely, its momentum). Now, let me say something
strange about what happens when I try to measure its position and momentum.

* Classically, i.e., in our macroscopic world, I can measure these two
quantities to infinite precision (more or less). There is really no
question where something is and what its momentum is.

* In the Quantum Mechanical world, the idea that we can measure things
exactly breaks down. Let me state this notion more precisely. Suppose a
particle has momemtum p and a position x. In a Quantum Mechanical
world, I would not be able to measure p and x precisely. There is an
uncertainty associated with each measurement, e.g., there is some dp
and dx, which I can never get rid of even in a perfect experiment!!!.
This is due to the fact that whenever I make a measurement, I must
disturb the system. (In order for me to know something is there, I must
bump into it.) The size of the uncertainties are not independent, they
are related by

o dp x dx > h / (2 x pi) = Planck's constant / ( 2 x pi )

The preceding is a statement of The Heisenberg Uncertainty Principle.
So, for example, if I measure x exactly, the uncertainty in p, dp, must
be infinite in order to keep the product constant.

This uncertainty leads to many strange things. For example, in a
Quantum Mechanical world, I cannot predict where a particle will be
with 100 % certainty. I can only speak in terms of probabilities. For
example, I can say that an atom will be at some location with a 99 %
probability, but there will be a 1 % probability it will be somewhere
else (in fact, there will be a small but finite probabilty that it will
be found across the Universe). This is strange.

We do not know if this indeterminism is actually the way the Universe
works because the theory of Quantum Mechanics is probably incomplete.
That is, we do not know if the Universe actually behaves in a
probabilistic manner (there are many possible paths a particle can
follow and the observed path is chosen probabilistically) or if the
Universe is deterministic in the sense that I can predict the path a
particle will follow with 100 % certainty.

A consequence of the Qunatum Mechanical nature of the world, is that
particles can appear in places where they have no right to be (from an
ordinary, common sense [classical] point of view)!

This notion has interesting consequences for nuclear fusion in stars.

Thank Homo Deus for nerds.


Hakeeb A. Nandalal
"Nothing unreal exists"