January 20, 1953 took place the first flight of the Intercontinental strategic jet bomber M-4 (103M). Test “flight” lasted only 10 minutes and ended successfully, with him during the year occurred on 27 flights, and then, after a number of structure modifications, took place on 18 flights. Prototype of the M-4 was equipped with an engine S-3 and could fly at distances up to 9050 km at a speed of 800 km/h.
Museum exhibit M-4 at the airbase Ukrainka
It is interesting that this plane was created parallel to the legendary Tu-95 and distinguished from it by greater speed and bomb load, but a smaller range. M-4 was produced from 1954 to 1956, in 1955, it entered service with the Soviet air force and operated until 1983. In just two years, produced 2 prototype and serial 32. Original M-4 was going to use to deliver the “Tsar Bomba”, but the design did not allow to secure it so that it didn’t interfere with takeoff. In the end, the most powerful bomb created in the Soviet Union was dropped from Tu-95.
20 January 1969, astronomers from the University of Arizona first optical identification of the pulsar PSR B0531+21, located in the crab nebula. The pulsar (in the broad sense) is the source of cosmic radiation coming to Earth in the form of periodic bursts. PSR B0531+21 is a young neutron star, the remnant of the supernova SN1054, which was observed from Earth in 1054. Formally, the discovery of this pulsar took place in late 1968, however, to establish a pulsation in the optical range have been a little later, on 20 January 1969, and corresponding research paper was published on 1 February of the same year.
The crab nebula in conventional colors, the pulsar is in the center
And a year later, an astronomer named Michael Curtis suggested the presence of the pulsar companion of planetary mass to explain the observed variations in time of the radiation of the pulsar. The supposed planet has a mass equal to 0.01 of the mass of Jupiter or 3.3 Earth masses.
Observation of crab nebula and now are actively conducted. Moreover, it is often used as a calibration source in x-ray astronomy due to its high brightness in x-rays and constant density flow.
January 20, 1999 the China News Service announced the introduction of new state restrictions for Internet cafes. This event can be considered the beginning of the “Great Chinese firewall”. Under the new rules owners of Internet cafes and computer clubs should be to exclude access to resources that are marked as “undesirable”.
Top 10 resources that are blocked in modern China
Such strict rules for individual users of the Internet did not exist, because their number was small. But as the growth in the number of subscribers of the global web, the government introduced new restrictions. Now in China you cannot use Facebook, Twitter, it is impossible to go on YouTube and IMDb, even with all these resources replaced with local equivalents.