Archive for the ‘Physics’ Category

Sir Edward V Appleton (1892-1965) British,


Appleton was an English physicist and Nobel prize winner (1947) who discovered the ionosphere.

In 1924 Appleton began research into the strength of the radio signals received at Cambridge from the BBC station in London. He soon discovered that the strength of the signal was constant during the day but varied during the night, rising and falling in an almost regular manner. He suggested that, at night, the Cambridge apparatus was receiving not one but two waves, one travelling directly and the other being reflected by the atmosphere. The existence of a reflecting layer had first been suggested around forty years earlier by Balfour Stewart. In 1902 Oliver Heaviside and A.E. Kennelly had independently postulated the theory of a conducting layer of the atmosphere: the Kennelly-Heaviside Layer. Following their lead Appleton began a series of experiments, which proved the existence of that layer in the upper atmosphere now called the ionosphere. Moreover, by a slight change of wavelength it was possible to measure the time taken by the waves to travel to the upper atmosphere and back. The position of the reflecting layer was thus identified and its height (60 miles above ground) determined. The method used was what is now called “frequency-modulation radar”. The ionosphere was thus the first “object” detected by radiolocation, and this led to a great development of radio research and to a military invention of the greatest importance in World War II


Further experiments which led to the possibility of round-the-world broadcasting were carried out and in 1926 he discovered a further atmospheric layer 150 miles above ground, higher than the Heaviside Layer and electrically stronger. This layer, named the Appleton Layer after him, reflects short waves round the earth. Three years later Appleton made an expedition to Northern Norway for radio research, studying the Aurora Borealis and in 1931 he published the results of further research on determining the height of reflecting layers of the ionosphere, including the use of a transmitter that sent out “spurts” of radio energy, and the photography of the received echo-signals by cathode ray oscillography.(Ack: Nobelprize.org, BBC.Co.UK-history)

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What are we? Science was young when the ancient Greeks put forward a set of classical elements: from water, air, fire and earth; the Chinese believed in water, fire, earth, metal and wood. Still it was young and naiive. In this age of Large Hadron Collider in Geneva the Physicists would put down matter as made of twelve fundamental particles – quarks and leptons. These have no substructure and cannot be broken down into smaller particles. Quarks and leptons interact via four forces to make the universe we know today.

How these particles work to make matter.

The nucleus and the electrons are attracted to each other, exchanging photons. The force between the nucleus and electrons is the electromagnetic force.

Many atoms constitute objects in our everyday life as well as much bigger components of the universe such as stars and galaxies. The force dominating this level of macroscopic phenomena is gravity.

In an atomic nucleus a proton is made up of two up quarks and one down quark, and a neutron is composed of one up quark and two down quarks. The force that binds three quarks in a proton or a neutron is called the strong force and this force is due to exchanges of gluons. Having said this let us examine force mediator that facilitates exchanges. There are four such mediators the “gluon”, “photon”, “graviton” and “weak bosons”.

An atomic nucleus constitutes an atom together with electrons orbiting around it. The relation between the nucleus and electrons resembles the one between the sun and planets in the solar system.

In the centre of stars, huge energy is generated by nuclear fusion being mediated by weak bosons. This energy makes the universe bright. In nuclear fusion, a down quark is changed to an up quark by the weak force. Stars are luminous because the fundamental building blocks are changing their types and providing energy.

Quarks like to hang in groups

Although most physicists believe that quarks are the fundamental building blocks which make up the universe, no one has observed an isolated quark on its own. This is due to the nature of the strong force.

Like a nucleus and an electron that attract each other due to their electrical charges, quarks are combined together by their color charges.

Many atoms constitute objects in our everyday life as well as much bigger components of the universe such as stars and galaxies. The force dominating this level of macroscopic phenomena is gravity, intermediated by gravitons.

Experiments in 1968 provided the evidence for the quark model. The quark model actually explains the existence of more than 100 particles, all known as “hadrons” (as in Large Hadron Collider) and made up of different combinations of quarks. For example the proton is made of three quarks. If protons are hit hard enough, the strong force can be overcome and the proton smashed apart. With the LHC recently updated is powerful and the scientists are ready to look deeper into the world of quarks.

The Large Hadron Collider, famous for finding the Higgs boson, has now revealed another new and rather unusual particle. Pentaquarks are incredibly difficult to see; they are very rare and very unstable. This means that if it is possible to stick five quarks together, they won’t stay together for very long. The team on the LHCb experiment made their discovery by looking in detail at other exotic hadrons produced in the collisions and they way these break apart. All hadrons seem to be made up of combinations of either two or three quarks, whereas pentaquarks as the name suggests are made up of five quarks.

Why is this important?

The discovery answers a decades-old question in particle physics and highlights another part of the mission of the LHC. Discoveries of new fundamental particles such as the Higgs boson tell us something completely new about the universe. But discoveries like pentaquarks give us a more complete understanding of the rich possibilities that lie in the universe we already know.

By developing this understanding, we may get some hints about how the universe developed after the Big Bang and how we’ve ended up with protons and neutrons instead of pentaquarks making up everyday matter.(Ack: the Conversation,Feb15 of 2013,2015- Takashi Kobota/Gavin Hesketh)

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All stable matter in the universe is made from lightest particles that signify these belong to the first generation; any heavier particles quickly decay to the next most stable level. When matter is made up to delineate forms that we can name and cherish say, a baby, remember it is made up at its fundamental level by particles and these are ‘condemned’ to decay. Growing from cradle to grave is not a curse but nature’s decree of changes.

Consider energy is neither created nor destroyed. So energy is passed around recycling which in human terms we may say we age and move from infancy to maturity leaving room for another generation of babies to take our place. There is a great democracy in this change: baby born with a silver spoon must make for a baby with a wooden spoon stuck into its mouth.

When we see the nature in its myriad colours we may understand that there are also quarks and leptons involved. Quarks come in three different colors which however when mixed create only colourless objects. For those who rely on their senses to make sense of the world, another world which has no colour, form or shape but equally admissible also exists. You may use your reason if you will or deny its existence. It matters little. Faith rules this realm given the hint that we can empirically know as existent at fundamental level.


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The Standard Model

Everything in the universe is found to be made from a few basic building blocks called fundamental particles, governed by four fundamental forces. Our best understanding of how these particles and three of the forces are related to each other is encapsulated in the Standard Model of particle physics.

These particles occur in two basic types called quarks and leptons. Each group consists of six particles, which are related in pairs, or “generations”. The lightest and most stable particles make up the first generation, whereas the heavier and less stable particles belong to the second and third generations. All stable matter in the universe is made from particles that belong to the first generation; any heavier particles quickly decay to the next most stable level.

There are four fundamental forces at work in the universe: the strong force, the weak force, the electromagnetic force, and the gravitational force. They work over different ranges and have different strengths. Gravity is the weakest but it has an infinite range. The electromagnetic force also has infinite range but it is many times stronger than gravity. The weak and strong forces are effective only over a very short range and dominate only at the level of subatomic particles. Despite its name, the weak force is much stronger than gravity but it is indeed the weakest of the other three.

The words of Jesus comes to mind, ‘The last shall be first. (Mt.19:30,Isa 33:23.) The lame shall take the prey. Weakness on a moral plane is humility. Principles of the Sermon on the Mount can be explained in its material make-up of matter.

(ack: home.web.cern.ch)


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