How was a simple merchant connected to the beginning and end of the American Civil War? Detailed answer

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How was a simple merchant connected to the beginning and end of the American Civil War? Detailed answer

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How was a simple merchant connected to the beginning and end of the American Civil War?

The first episode of hostilities in the US Civil War took place on July 21, 1861 in the state of Virginia, on the farm of the wholesaler Wilmer McLean - the northerners fired artillery at the house where the headquarters of the Confederate Army General Beauregard was located. Two years later, McLean moved his family 200 km to the south, and on April 9, 1865, the military knocked on his new house and asked him to use it as a place for signing the act of surrender of the southerners in the person of General Lee to the commander of the northerners, Ulysses Grant. This gave McLean reason to claim that the Civil War began in his backyard and ended in his living room.

Authors: Jimmy Wales, Larry Sanger

Random interesting fact from the Great Encyclopedia:

What is a black hole?

Black holes, so named in 1967 by American astrophysicist John Wheeler, are nothing more than the result of the gravitational collapse of stars whose mass is more than 2,5 times that of the Sun. In this case, the internal pressure of the star is not able to stop its gravitational collapse. A star rapidly compressed by gravitational forces shrinks to the size of a Schwarzschild sphere, after which no signals from the surface of the star can go outside.

According to general relativity, an observer at a great distance from a collapsed star will never know what is happening inside the Schwarzschild sphere. He will not even see the moment when the surface of the star crosses the Schwarzschild sphere: due to the relativistic time dilation, the star for the observer will approach the gravitational radius for an infinitely long time and "freeze" at sizes close to the gravitational radius.

The size of a black hole, or rather, the radius of the Schwarzschild sphere, is proportional to its mass. For a black hole with a mass of about 10 solar masses, the radius of the Schwarzschild sphere is approximately 30 kilometers.

Astrophysics does not impose any restrictions on the size of a star, and therefore a black hole can be arbitrarily large. If, for example, it has a mass of about 10 million solar (it arose due to the merger of hundreds of thousands, or even millions of relatively small stars), its radius will be about 300 million kilometers, that is, twice the earth's orbit.

Apparently, it is precisely such black holes that are found in the centers of galaxies. In any case, astronomers today count about 50 galaxies, in the center of which, judging by indirect evidence, there are black holes with a mass of about a billion solar masses. In our Galaxy, too, apparently, there is a black hole - its mass is estimated at about 2,4 million solar.

The theory suggests that, along with such supergiants, black mini-holes with a mass of about 100 million tons (the mass of an asteroid with a diameter of only about 200 meters) and a radius comparable to the size of an atomic nucleus should have arisen. They could appear in the first moments of the existence of the Universe as a manifestation of a very strong inhomogeneity of space-time with a colossal energy density.

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To increase the volume of transmitted data, communication systems are beginning to conquer the millimeter wave band, in particular, the band around 60 GHz, which does not require frequency licensing to operate. He is open. Today, the 60 GHz 802.11ad standard is used to transmit data over very short distances (up to 10 meters, but in practice - almost close). For example, it turned out to be very relevant for headsets with immersion in virtual reality. A new 60 GHz 802.11ay standard is being prepared, which will expand the communication range from 10 to 300 meters. Also, the 60 GHz band can be used in 5G cellular networks to organize local subnets.

Phased antenna arrays (PAR) have been and remain one of the important components of millimeter-wave transceivers. The PAR can be used to control the antenna lobes, providing the maximum data rate over multiple channels with the best efficiency. In combination with RF power amplifiers, this is a rather expensive element of the transceiver system, which can be made cheaper with the help of unified reference modules. Pharrowtech, a business unit spun off from Imec as part of the institute's commercial incubator, has developed exactly such a module for distribution through OEM channels.

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