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🔗 Spaceflight 🔗 Astronomy

J002E3 is the designation given to an object in space discovered on September 3, 2002, by amateur astronomer Bill Yeung. Initially thought to be an asteroid, it has since been tentatively identified as the S-IVB third stage of the Apollo 12 Saturn V rocket (designated S-IVB-507), based on spectrographic evidence consistent with the titanium dioxide in the paint used on the rockets. The stage was intended to be injected into a permanent heliocentric orbit in November 1969, but is now believed instead to have gone into an unstable high Earth orbit which left Earth's proximity in 1971 and again in June 2003, with an approximately 40-year cycle between heliocentric and geocentric orbit.

🔗 Technology 🔗 Energy

In pipeline transportation, pigging is the practice of using devices known as pigs or scrapers to perform various maintenance operations. This is done without stopping the flow of the product in the pipeline. These devices are known as pigs because they scrape or clean just like a normal pig.

These operations include but are not limited to cleaning and inspecting the pipeline. This is accomplished by inserting the pig into a "pig launcher" (or "launching station") — an oversized section in the pipeline, reducing to the normal diameter. The launching station is then closed and the pressure-driven flow of the product in the pipeline is used to push the pig along down the pipe until it reaches the receiving trap — the "pig catcher" (or "receiving station").

🔗 Physics 🔗 Meteorology 🔗 Chemistry 🔗 Geology 🔗 Limnology and Oceanography 🔗 Materials

Ice is water frozen into a solid state. Depending on the presence of impurities such as particles of soil or bubbles of air, it can appear transparent or a more or less opaque bluish-white color.

In the Solar System, ice is abundant and occurs naturally from as close to the Sun as Mercury to as far away as the Oort cloud objects. Beyond the Solar System, it occurs as interstellar ice. It is abundant on Earth's surface – particularly in the polar regions and above the snow line – and, as a common form of precipitation and deposition, plays a key role in Earth's water cycle and climate. It falls as snowflakes and hail or occurs as frost, icicles or ice spikes.

Ice molecules can exhibit eighteen or more different phases (packing geometries) that depend on temperature and pressure. When water is cooled rapidly (quenching), up to three different types of amorphous ice can form depending on the history of its pressure and temperature. When cooled slowly correlated proton tunneling occurs below −253.15 °C (20 K, −423.67 °F) giving rise to macroscopic quantum phenomena. Virtually all the ice on Earth's surface and in its atmosphere is of a hexagonal crystalline structure denoted as ice I_h (spoken as "ice one h") with minute traces of cubic ice denoted as ice I_c. The most common phase transition to ice I_h occurs when liquid water is cooled below 0 °C (273.15 K, 32 °F) at standard atmospheric pressure. It may also be deposited directly by water vapor, as happens in the formation of frost. The transition from ice to water is melting and from ice directly to water vapor is sublimation.

Ice is used in a variety of ways, including cooling, winter sports and ice sculpture.

🔗 Internet 🔗 Computing 🔗 Cryptography 🔗 Numismatics 🔗 Numismatics/Cryptocurrency 🔗 Computing/Computer Security

SHA-3 (Secure Hash Algorithm 3) is the latest member of the Secure Hash Algorithm family of standards, released by NIST on August 5, 2015. Although part of the same series of standards, SHA-3 is internally different from the MD5-like structure of SHA-1 and SHA-2.

SHA-3 is a subset of the broader cryptographic primitive family Keccak (), designed by Guido Bertoni, Joan Daemen, Michaël Peeters, and Gilles Van Assche, building upon RadioGatún. Keccak's authors have proposed additional uses for the function, not (yet) standardized by NIST, including a stream cipher, an authenticated encryption system, a "tree" hashing scheme for faster hashing on certain architectures, and AEAD ciphers Keyak and Ketje.

Keccak is based on a novel approach called sponge construction. Sponge construction is based on a wide random function or random permutation, and allows inputting ("absorbing" in sponge terminology) any amount of data, and outputting ("squeezing") any amount of data, while acting as a pseudorandom function with regard to all previous inputs. This leads to great flexibility.

NIST does not currently plan to withdraw SHA-2 or remove it from the revised Secure Hash Standard. The purpose of SHA-3 is that it can be directly substituted for SHA-2 in current applications if necessary, and to significantly improve the robustness of NIST's overall hash algorithm toolkit.

The creators of the Keccak algorithms and the SHA-3 functions suggest using the faster function KangarooTwelve with adjusted parameters and a new tree hashing mode without extra overhead for small message sizes.

🔗 Maps 🔗 Turkey 🔗 Paranormal

The Piri Reis map is a world map compiled in 1513 by the Ottoman admiral and cartographer Piri Reis (pronounced [piːˈɾiː ɾeis]). Approximately one third of the map survives; it shows the western coasts of Europe and North Africa and the coast of Brazil with reasonable accuracy. Various Atlantic islands, including the Azores and Canary Islands, are depicted, as is the mythical island of Antillia and possibly Japan.

The map's historical importance lies in its demonstration of the extent of global exploration of the New World by approximately 1510, and in its claim to have used a map of Christopher Columbus, otherwise lost, as a source. Piri also stated that he had used ten Arab sources and four Indian maps sourced from the Portuguese. More recently, the map has been the focus of claims for the pre-modern exploration of the Antarctic coast.

The Piri Reis map is in the Library of the Topkapı Palace in Istanbul, Turkey, but is not usually on display to the public.

🔗 Military history 🔗 Military history/Military science, technology, and theory 🔗 Military history/World War I 🔗 Military history/German military history 🔗 Birds 🔗 Photography 🔗 Photography/History of photography 🔗 Military history/European military history

Pigeon photography is an aerial photography technique invented in 1907 by the German apothecary Julius Neubronner, who also used pigeons to deliver medications. A homing pigeon was fitted with an aluminium breast harness to which a lightweight time-delayed miniature camera could be attached. Neubronner's German patent application was initially rejected, but was granted in December 1908 after he produced authenticated photographs taken by his pigeons. He publicized the technique at the 1909 Dresden International Photographic Exhibition, and sold some images as postcards at the Frankfurt International Aviation Exhibition and at the 1910 and 1911 Paris Air Shows.

Initially, the military potential of pigeon photography for aerial reconnaissance appeared interesting. Battlefield tests in World War I provided encouraging results, but the ancillary technology of mobile dovecotes for messenger pigeons had the greatest impact. Owing to the rapid perfection of aviation during the war, military interest in pigeon photography faded and Neubronner abandoned his experiments. The idea was briefly resurrected in the 1930s by a Swiss clockmaker, and reportedly also by the German and French militaries. Although war pigeons were deployed extensively during World War II, it is unclear to what extent, if any, birds were involved in aerial reconnaissance. The United States Central Intelligence Agency (CIA) later developed a battery-powered camera designed for espionage pigeon photography; details of its use remain classified.

The construction of sufficiently small and light cameras with a timer mechanism, and the training and handling of the birds to carry the necessary loads, presented major challenges, as did the limited control over the pigeons' position, orientation and speed when the photographs were being taken. In 2004, the British Broadcasting Corporation (BBC) used miniature television cameras attached to falcons and goshawks to obtain live footage, and today some researchers, enthusiasts and artists similarly deploy crittercams with various species of animals.

🔗 Systems 🔗 Politics 🔗 Socialism 🔗 Sociology 🔗 Globalization

World-systems theory (also known as world-systems analysis or the world-systems perspective) is a multidisciplinary, macro-scale approach to world history and social change which emphasizes the world-system (and not nation states) as the primary (but not exclusive) unit of social analysis.

"World-system" refers to the inter-regional and transnational division of labor, which divides the world into core countries, semi-periphery countries, and the periphery countries. Core countries focus on higher skill, capital-intensive production, and the rest of the world focuses on low-skill, labor-intensive production and extraction of raw materials. This constantly reinforces the dominance of the core countries. Nonetheless, the system has dynamic characteristics, in part as a result of revolutions in transport technology, and individual states can gain or lose their core (semi-periphery, periphery) status over time. This structure is unified by the division of labour. It is a world-economy rooted in a capitalist economy. For a time, certain countries become the world hegemon; during the last few centuries, as the world-system has extended geographically and intensified economically, this status has passed from the Netherlands, to the United Kingdom and (most recently) to the United States.

World-systems theory has been examined by many political theorists and sociologists to explain the reasons for the rise and fall of nations, income inequality, social unrest, and imperialism.

The photophone is a telecommunications device that allows transmission of speech on a beam of light. It was invented jointly by Alexander Graham Bell and his assistant Charles Sumner Tainter on February 19, 1880, at Bell's laboratory at 1325 L Street in Washington, D.C. Both were later to become full associates in the Volta Laboratory Association, created and financed by Bell.

On June 3, 1880, Bell's assistant transmitted a wireless voice telephone message from the roof of the Franklin School to the window of Bell's laboratory, some 213 meters (about 700 ft.) away.

Bell believed the photophone was his most important invention. Of the 18 patents granted in Bell's name alone, and the 12 he shared with his collaborators, four were for the photophone, which Bell referred to as his "greatest achievement", telling a reporter shortly before his death that the photophone was "the greatest invention [I have] ever made, greater than the telephone".

The photophone was a precursor to the fiber-optic communication systems that achieved worldwide popular usage starting in the 1980s. The master patent for the photophone (U.S. Patent 235,199 Apparatus for Signalling and Communicating, called Photophone) was issued in December 1880, many decades before its principles came to have practical applications.

🔗 Military history 🔗 Military history/North American military history 🔗 Military history/United States military history 🔗 Military history/Military science, technology, and theory 🔗 Military history/Intelligence 🔗 Military history/Cold War 🔗 Military history/Australia, New Zealand and South Pacific military history 🔗 Military history/Canadian military history 🔗 Military history/European military history 🔗 Military history/British military history

The Five Eyes (FVEY) is an anglophone intelligence alliance comprising Australia, Canada, New Zealand, the United Kingdom and the United States. These countries are parties to the multilateral UKUSA Agreement, a treaty for joint cooperation in signals intelligence.

The origins of the FVEY can be traced back to the post–World War II period, when the Atlantic Charter was issued by the Allies to lay out their goals for a post-war world. During the course of the Cold War, the ECHELON surveillance system was initially developed by the FVEY to monitor the communications of the former Soviet Union and the Eastern Bloc, although it is now used to monitor billions of private communications worldwide.

In the late 1990s, the existence of ECHELON was disclosed to the public, triggering a major debate in the European Parliament and, to a lesser extent, the United States Congress. As part of efforts in the ongoing War on Terror since 2001, the FVEY further expanded their surveillance capabilities, with much emphasis placed on monitoring the World Wide Web. The former NSA contractor Edward Snowden described the Five Eyes as a "supra-national intelligence organisation that does not answer to the known laws of its own countries". Documents leaked by Snowden in 2013 revealed that the FVEY has been spying on one another's citizens and sharing the collected information with each other in order to circumvent restrictive domestic regulations on surveillance of citizens.

In spite of continued controversy over its methods, the Five Eyes relationship remains one of the most comprehensive known espionage alliances in history.

Since processed intelligence is gathered from multiple sources, the intelligence shared is not restricted to signals intelligence (SIGINT) and often involves defence intelligence as well as human intelligence (HUMINT) and geospatial intelligence (GEOINT). The following table provides an overview of most of the FVEY agencies involved in such forms of data sharing.

🔗 Computing 🔗 Computer science 🔗 Cryptography 🔗 Cryptography/Computer science

Diffie–Hellman key exchange is a method of securely exchanging cryptographic keys over a public channel and was one of the first public-key protocols as conceived by Ralph Merkle and named after Whitfield Diffie and Martin Hellman. DH is one of the earliest practical examples of public key exchange implemented within the field of cryptography.

Traditionally, secure encrypted communication between two parties required that they first exchange keys by some secure physical means, such as paper key lists transported by a trusted courier. The Diffie–Hellman key exchange method allows two parties that have no prior knowledge of each other to jointly establish a shared secret key over an insecure channel. This key can then be used to encrypt subsequent communications using a symmetric key cipher.

Diffie–Hellman is used to secure a variety of Internet services. However, research published in October 2015 suggests that the parameters in use for many DH Internet applications at that time are not strong enough to prevent compromise by very well-funded attackers, such as the security services of large governments.

The scheme was published by Whitfield Diffie and Martin Hellman in 1976, but in 1997 it was revealed that James H. Ellis, Clifford Cocks, and Malcolm J. Williamson of GCHQ, the British signals intelligence agency, had previously shown in 1969 how public-key cryptography could be achieved.

Although Diffie–Hellman key agreement itself is a non-authenticated key-agreement protocol, it provides the basis for a variety of authenticated protocols, and is used to provide forward secrecy in Transport Layer Security's ephemeral modes (referred to as EDH or DHE depending on the cipher suite).

The method was followed shortly afterwards by RSA, an implementation of public-key cryptography using asymmetric algorithms.

Expired U.S. Patent 4,200,770 from 1977 describes the now public-domain algorithm. It credits Hellman, Diffie, and Merkle as inventors.