BitTorrent is a peer-to-peer program, first developed in mid-2001 by Bram Cohen and BitTorrent, Inc., to use for uploading and downloading files under the BitTorrent protocol. In the protocol, a "Tracker" hosts information about any active computers which are trying to share data. Trackers are used to find other active computers, but do not store or share file data. Using the .torrent files, BitTorrent users can "Leech" (download) the files. Once a "Leecher" gets 100% of the file(s), they become a "Seeder" and helps "Seed" (upload) the files to other Leechers.
BitTorrent was the first client written for the protocol. Before version 6.0, BitTorrent was written in Python, and was free software. The source code for versions up to and including 3.4.2 were distributed under the MIT license and versions 4.x and 5.x were released under the BitTorrent Open Source License, a modified version of the Jabber Open Source License. Since version 6.0, BitTorrent is a rebranded version of µTorrent. As a result, its source is closed.
The BitTorrent protocol now has many clients, for example :
List of BitTorrent clients
A BitTorrent client is a program that downloads files using the BitTorrent protocol.
The first client, known as BitTorrent, was created by Bram Cohen in the summer of 2002. Most of the other clients are based in part on BitTorrent. Programs that use BitTorrent protocol are:
Bali Nine
The Bali Nine is the name of the nine Australian citizens arrested and convicted for drug trafficking on April 17, 2005, in Denpasar, Bali, Indonesia. The group tried to smuggle 8.3 kg of heroin valued at about 4 million AUD from Indonesia to Australia.
Members of the group are: Andrew Chan, Si Yi Chen, Michael Czugaj, Renae Lawrence, Tach Duc Thanh Nguyen, Matthew Norman, Scott Rush, Martin Stephens and Myuran Sukumaran. All of them are between ages 18 and 28 at the time of their arrests.
After the trial, two of the Bali Nine received death sentences, and the others got 20 years or life sentences. Renae Lawrence finished serving her 20-year sentence in Kerobokan Prison together with Schapelle Corby. Andrew Chan and Myuran Sukumaran were executed by firing squad on 29 April 2015.
Eunuch
A eunuch is a castrated man. His genitals have been removed. This can be cutting off the testicles or removing the penis and the testicles.
Over the millennia since, eunuchs had a lot of different functions in different cultures such as domestics, treble singers, religious specialists, government officials, military commanders, and guardians of women or harem servants. When eunuchs ran a harem, a monarch could be sure he was the one who fathered his wives' children since real eunuchs were always infertile.
In Byzantine art, angels and eunuchs were often shown in a similar light and manner.
Antares Telescope
The ANTARES Experiment is a telescope that is built at the bottom of the Mediterranean Sea. But it is not a normal telescope that uses light to see distant objects. Instead, it uses neutrinos, very small and light particles that can fly through the earth. The name comes from Astronomy with a Neutrino Telescope and Abyss environmental RESearch project. There is also a star called Antares.
It uses 900 light sensors attached to 12 strings that float in the sea to detect neutrinos. The strings are held onto the sea floor by an anchor and straight up by a buoy floating in the sea. Although the neutrinos are invisible, they can create a different particle, a muon, in water. The muon then gives off light by the Cherenkov effect because it travels faster than light in water.
The sensors are so sensitive that they need only very little light and can even detect single photons. This is necessary because the muons produce only very little light.
The detector is located in the Mediterranean, about 40 kilometres off Toulon in southern France. There the sea is 2500 metres deep. It is built by a group of physicists from 12 European countries. Currently, 10 strings are running. The last two strings will be installed in May 2008.
It is the largest neutrino detector in the Northern hemisphere. Two similar detectors are located in the ice of the South Pole (AMANDA and IceCube).
Cherenkov radiation
Cherenkov radiation, also known as Vavilov–Cherenkov radiation (; Russian: Черенков) is a type of electromagnetic radiation produced by charged particles when they pass through an optically transparent medium at a speed which is greater than the speed of light in that medium. (It doesn't violate special relativity because the refractive index slows down the speed of light in a medium. So, the particle doesn't have to travel at the speed of light in a vacuum.) It is named after Pavel Alekseyevich Čerenkov, who discovered this phenomenon in 1934 under the supervision of Sergey Vavilov. Igor Tamm and Ilya Frank developed a theory on this effect in 1937. Pavel Čerenkov, Igor Tamm and Ilya Frank shared the 1958 Nobel Prize in physics because of their contribution in cherenkov radiation.
According to special relativity, a particle cannot move faster than the speed of light in a vacuum. However, when light travels in a transparent medium (such as water or glass), it moves more slowly than it would in a vacuum. This means that particles can actually move faster than the speed of light in certain mediums. When a particle with an electric charge moves faster than light in a medium which can be polarized, it causes the medium to send out photons (light particles) and thereby loses energy. The photons that are sent out can be measured, as they are simple light.
The formation of Cherenkov radiation is analogous to the bow wave caused by a power boat traveling faster than the speed of water waves or to the shock wave (sonic boom) produced by an airplane traveling faster than the speed of sound in air.
When an aircraft passes through the air, it creates a series of pressure waves in front of the aircraft and behind it. These waves travel at the speed of sound and, as the speed of the object increases, the waves get compressed as they cannot get out of each other's way quickly enough. When the aircraft gets the velocity of sound wave, the pressure waves get merge into a single shock wave. As the velocity keeps increasing, the single shock wave extends mostly to the rear and extends from the craft in a restricted widening cone. We hear this as sonic boom. Similarly, a bow wave forms when something moves through a fluid at a speed greater than the speed of a wave moving across the fluid. The mechanism of Cherenkov radiation is same but it occurs for light waves.
When a charged particle moves inside a polarizable medium, it excites some the ellectrons of that medium. As the excited ellectrons return to their ground state, they emits electromagnetic radiation. According to the Huygens principle, the emitted waves move out spherically at the phase velocity of that medium. If the particle moves faster than the speed of light in that medium, the emitted waves add up and at an angle with respect to the particle direction a radiation is emitted which is known as Cherenkov radiation.
Because nothing can move faster than light in a vacuum, there is no Cherenkov light in a vacuum. However, if we say that light in water moves only with 75% of its speed in vacuum, particles with very high energy are now able to move faster than light (through water) and create Cherenkov light.
The reason Cherenkov light often appears blue is because its effect is proportional to the frequency, in that the higher the frequency, the higher the effect of the radiation. Because higher frequency light equates to shorter wavelengths, and blue light has one of the shortest wavelengths of visible light, Cherenkov light is usually blue.
In the first image, a charged particle (red) moves at a speed of formula_1 where
Ratio between the speed of the particle and the speed of light is
In this medium, the velocity of light is (n is the refractive index)