Physics

Quantum Physics Structure of Matter Uncertainty Principle Faster than Light



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"What are little girls made of?"

The traditional answer found in the nursery rhyme is "sugar and spice and all things nice". In other words little girls are made of bits and pieces of things, as are little boys although apparently not such nice things. When we take the next step and ask what such things are made of we enter the realm of physics and elementary particles, of molecules and atoms and the like. In fact atoms used to be considered the smallest indivisible particles of matter, of all things, living and non living. With dramatic and sometimes terrifying consequences we have discovered that it is possible to split atoms and produce even smaller particles such as protons, neutrons, electrons plus a myriad other tiny particles and huge quantities of energy. Further than this, it would seem that even protons and neutrons could possibly be split into theoretical particles called quarks, the ultimate bits of matter. Quarks, so named from a passage in the book Finnegan's Wake', are thought to exist only in two dimensions and have weird names like up' and down' and charm' and strange'. If this isn't strange enough, some quantum physicists question whether matter is really made up particles at all. A highly respected physicist from Berkeley, Henry Stapp, suggests that matter often behaves as though it consists of bits of knowledge rather than rocklike' particles.

It all sounds a bit more like science fiction than science fact. How is it possible for elementary particles to behave like bits of knowledge? In an experiment conducted over the Swiss telephone exchange two paired electrons were separated and sent in different directions at close to the speed of light. It was found that an action performed on one member of the pair, comparable to flipping a coin, was instantly translated to the other member of the pair. It was as if the electrons had instant knowledge of each other. This surprising result defies the idea put forward by Einstein that nothing can travel faster than the speed of light. In a similar quite famous experiment into the duality of light, sometimes behaving as particles sometimes as waves, it was found that paired photons, light particles; appear to share instantaneous knowledge of each other even should they be separated by galactic distances. Such are the happenings in the world of quantum physics.

Quantum physics is the science of the very small, so small in fact that no one has ever actually seen' the individual particles themselves and their existence has to be inferred from their reactions with one another, such as may be seen when they pass through a cloud chamber or a very thin section of gold foil. In this subatomic universe the rules surrounding classical physics appear to break down and the kind of scientific measurements we can perform on moving objects like cars, aircraft and rockets become impossible. We are traditionally used to dealing in two or three dimensions when specifying exact locations: latitude and longitude will find the location of most capital cities on the globe. Above the surface of the earth we need three measurements to pinpoint the position of an aircraft or rocket. To be exact we really need a fourth dimension, time, so that we can say when the aircraft or rocket was in any particular position before it moved on. The direction and speed of the aircraft or rocket will provide us with information about its momentum and will allow us to calculate where it will be in any fixed period of time. However in the universe of the very small it becomes impossible to know both the exact position and momentum of sub atomic particles like electrons. The more we know about the position of an electron, the less we know about its momentum and vice versa. It is only possible to state the probability of an electron being in one particular position. This lead Einstein to initially refute the findings of quantum physics declaring that, "God didn't play dice with the universe".

According to the nursery rhyme little boys are made of "slugs and snails and puppy dog tails". Just when we thought that this was no more than a rather amusing use of literary license, it turns out that reality is even stranger than fiction.

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