Saturday, January 3, 2009

What do you think about destiny?

Destiny refers to a predetermined course of events. It may be conceived as a predeterminate future, whether in general or of an individual. It is a concept based on the belief that there is a fixed natural order to the universe.

Maybe you enjoy reading your horoscope - the notion that somehow the positions of the stars and planets might have an influence on how the week ahead will pan out for you. The idea that the future might somehow predictable is a very interesting one. In fact, until the quantum revolution, scientists were confident that this was indeed possible in principle, suggesting that even if we could not predict them, all future events were nevertheless somehow preordained and detined to take place.

Issac Newton believed that every particle in the Universe should obey simple laws of motion subjects to well-defined forces. This mechanistic view - one that was still shared universally by scientists and philosophers more than two centuries later - states that no matter how complex the workings of nature are, everything should be ultimately reducible to interactions between the fundamental building blocks of matter. A natural process such as a stormy sea or the weather, may look random and unpredictable, but this is just a consequence of its complexity and the huge number of atoms involved.

The success of Newton's law and other physical theories led to the idea of scientific determinism, which was first expressed at the beginning of the nineteenth century by Marquis de Laplace. Laplace suggested that if we knew the positions and velocities of all the particles in the universe at one time, the laws of physics should allow us to predict what the state of the universe would be at any other time in the past or in the future.

At first sight, determinism would also seem to be threatened by the uncertainty principle, which says that we cannot measure accurately both the position and the velocity of a particle at the same time. The more accurately  we measure the position the less accurately we can determine the velocity and vice versa.

Of course in practice such determinism is impossible for all but the simplest systems. We are well aware that forecast cannot predict tomorrow's weather with complete confidence.

Finally, we are also aware of the two slits experiment, when a tiny particle like a photon or electron is shot through two slits it creates an interference pattern where the brightest part of the screen, believe it or not, is the centre where we would not expect many particle to be able to reach!. It seams that the particle have somehow conspired to behave in a way similar to a wave. If we put a detector in place that records which slit each particle passes through, the interference pattern disappears.

Now, I will share my personal opinion. Scientists do not believe in astrology because it is not consistent with other theories that have been tested by experiment. I personally do believe in astrology and specially in the Chinese astrology but I have my own interpretation. I think that life is not deterministic nor relative, it is probabilistic. We create our own reality or destiny by taking decisions every second or minutes around a large number of probabilities. Let me give you an example: you are on a road with 45 miles per hour speed limit and you are driving at 50 miles per hour, so you know that you have a probability to get a ticket and if you drive at 60 m/h you will have more probability to get a ticket and so on ... in summary your actions define your destiny or reality, at the end, you decide to gamble not the stars.

Going back to astrology and quantum physics, I think that you have multiple options in your live but once the astrologer look at it, they collapse in one view (as the particle in the two slit experiment), so they are telling you one side of the story and it is up to you to follow or change it.

The bottom line is that you are the only one who create your own reality or destiny based on the selection you do every second of your life amount a large number of opportunities.

Friday, January 2, 2009

Photoelectric effect

Albert Einstein was awarded the 1921 physics Nobel Prize for his explanation of the photoelectric effect - not for the Relativity Theory as many people think, he never was awarded for it !!!!.
According to Einstein, each electron is knocked out when it is hit by a single photon (1) of light, the energy of which depends on its frequency - each electron absorb one and only one photon. He argued that the reason we do not normally see the particle like nature of light is due to the large number of photons involved, just as we do not see individual pixels of ink on a printed image.

a) The dependence of the ejected electron's energy on the light's frequency rather than its intensity is a direct consequence of Planck's equation relating the energy of light to its frequency.

b) The second feature arises because the threshold for production of the electrons only occurs when the photon energy is sufficient to release an electron. Increasing the intensity of the light just means more photons. It means that the key is the frecuency - the light color. A good number of blue or violet light can knock out some electrons but a billow of red or orange photons can not knock out any electron - very low frecuency, see Radiation section.

c) Finally, the process is instantaneous because the electrons do not haveto accumulate their energy from a wave that is spread out in space. Instead, each photon delivers all its energy to an electron in a single collision. If this energy is above the necessary threshold the electron will escape.

(1) In physics, the photon is an elementary particle, the quantum of the electromagnetic field and thus the basic unit of light and all other forms of electromagnectic radiation.