Lost & Found

A Blog dedicated to History

Sunday, May 25, 2008

The Heisenberg uncertainty principle

In quantum physics, the Heisenberg uncertainty principle is the statement that locating a particle in a small region of space makes the momentum of the particle uncertain; and conversely, that measuring the momentum of a particle precisely makes the position uncertain.

In quantum mechanics, the position and momentum of particles do not have precise values, but have a probability distribution. There are no states in which a particle has both a definite position and a definite momentum. The narrower the probability distribution is in position, the wider it is in momentum.

Physically, the uncertainty principle requires that when the position of an atom is measured with a photon, the reflected photon will change the momentum of the atom by an uncertain amount inversely proportional to the accuracy of the position measurement. The amount of uncertainty can never be reduced below the limit set by the principle, regardless of the experimental setup.

Thursday, May 8, 2008

Erich Hartmann

The highest scoring ace of all time was the great German Luftwaffe expert Erich Hartmann with 352 aerial kills. Flying Bf 109s (Me-109s) against the overmatched Soviet MiGs and Yaks for almost three years, he accumulated his unrivalled score. Hartmann claimed, that of all his accomplishments, he was proudest of the fact that he never lost a wingman.

He is also reputed to have said. "Get close .. when he fills the entire windscreen ... then you can't possibly miss."

Hartmann was born in 1922, in Weissach, Wurttemberg. At age 19 (1941), he joined the Luftwaffe and was posted to Jagdgeschwader 52 (JG 52) on the Eastern Front in October, 1942. He scored his first kill in November, and only achieved his second three months later. In the first half of 1943, he worked out some of the tactics which would prove so successful later on. If he was attacked from behind, he would send his wingman down low and out in front. Then he would get behind the enemy and fire a short, quick accurate burst, waiting "until the enemy aircraft filled the windscreen." He would normally content himself with one victory; he was willing to wait for another day. His natural talents began to tell: excellent eyesight, lightning reflexes, an aggressive spirit, and an ability to stay cool while in combat

Tuesday, May 6, 2008

Lothar von Richthofen

Forever fated to be known as the Red Baron's younger brother, Lothar von Richthofen was a great ace in his own right, downing forty Allied planes.

Lothar was injured in a dogfight with a B.E.2a on May 13. He was subsequently awarded the Pour le MĂ©rite, whihc he received while in the Hamburg military hospital. In his 1917 autobiography, Manfred von Richthofen described Lothar's fight and injury:

I had not yet passed eight days of my leave when I received the telegram: "Lothar is wounded but not mortally." That was all. Inquiries showed that he had been very rash. He flew against the enemy, together with Allmenröder. Beneath him and a good distance on the other side of the front, he saw in the air a lonely Englishman crawling about. He was one of those hostile infantry fliers who make themselves particularly disagreeable to our troops. We molest them a great deal. Whether they really achieve anything in crawling along the ground is very problematical.

My brother was at an altitude of about six thousand feet, while the Englishman was at about three thousand feet. He quietly approached the Englishman, prepared to plunge and in a few seconds was upon him. The Englishman thought he would avoid a duel and he disappeared likewise by a plunge. My brother, without hesitation, plunged after. He didn't care at all whether he was on one side of the front or the other. He was animated by a single thought: I must down that fellow. That is, of course, the correct way of managing things. Now and then I myself have acted that way. However, if my brother does not have at least one success on every flight he gets tired of the whole thing.

Only a little above the ground my brother obtained a favorable position against the English flier and could shoot into his shop windows. The Englishman fell. There was nothing more to be done.

After such a struggle, especially at a low altitude, in the course of which one has so often been twisting and turning, and circling to the right and to the left, the average mortal has no longer the slightest notion of his position. On that day it happened that the air was somewhat misty. The weather was particularly unfavorable. My brother quickly took his bearings and discovered only then that he was a long distance behind the front. He was behind the ridge of Vimy. The top of that hill is about three hundred feet higher than the country around. My brother, so the observers on the ground reported, had disappeared behind the Vimy height.

It is not a particularly pleasant feeling to fly home over enemy country. One is shot at and cannot shoot back. It is true, however, that a hit is rare.

My brother [Lothar] approached the line. At a low altitude one can hear every shot that is fired, and firing sounds then very much like the noise made by chestnuts which are being roasted. Suddenly, he felt that he had been hit. That was queer to him. My brother is one of those men who cannot see their own blood. If somebody else was bleeding it would not impress him very greatly, but the sight of his own blood upsets him. He felt his blood running down his right leg in a warm stream. At the same time, he noticed a pain in his hip. Below the shooting continued. It followed that he was still over hostile ground. At last the firing gradually ceased. He had crossed the front. Now he must be nimble for his strength was rapidly ebbing away. He saw a wood and next to the wood a meadow. Straight for the meadow he flew and mechanically, almost unconsciously, he switched off the engine. At the same moment he lost consciousness.

My brother was in a single-seater. No one could help him. It is a miracle that he came to the ground, for no flying machine lands or starts automatically. There is a rumor that they have at Cologne an old Taube which will start by itself as soon as the pilot takes his seat, which makes the regulation curve and which lands again after exactly five minutes. Many men pretend to have seen that miraculous machine. I have not seen it. But still I am convinced that the tale is true. Now, my brother was not in such a miraculous automatic machine. Nevertheless he had not hurt himself in landing. He recovered consciousness only in hospital, and was sent to Douai.

Werner Heisenberg

Werner Karl Heisenberg (December 5, 1901 – February 1, 1976) was a celebrated German physicist and Nobel laureate, one of the founders of quantum mechanics and acknowledged to be one of the most important physicists of the twentieth century. Heisenberg was the head of the German nuclear energy project under the Nazi regime, though the nature of this project, and his work in this capacity, has been heavily debated. He is most well-known for discovering one of the central principles of modern physics, the Heisenberg uncertainty principle, and for the development of quantum mechanics, for which he was awarded the Nobel Prize in Physics in 1932.

In addition to the development of quantum mechanics, Heisenberg made many other notable contributions to physics. He discovered isospin, co-discovered and heavily developed the Kolmogorov theory of turbulent scaling, and introduced S-matrix theory.