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🔗 United States 🔗 Military history 🔗 Disaster management 🔗 Military history/North American military history 🔗 Military history/United States military history 🔗 Terrorism 🔗 New York City 🔗 Military history/World War I 🔗 New Jersey 🔗 Public Art 🔗 New Jersey/Hudson County

The Black Tom explosion was an act of sabotage by German agents to destroy U.S.-made munitions that were to be supplied to the Allies in World War I. The explosions, which occurred on July 30, 1916, in the New York Harbor, killed four people and destroyed some $20,000,000 worth of military goods. This incident, which happened prior to U.S. entry into World War I, also damaged the Statue of Liberty. It was one of the largest artificial non-nuclear explosions to have ever occurred.

🔗 Spaceflight 🔗 Physics 🔗 Rocketry

The Tsiolkovsky rocket equation, classical rocket equation, or ideal rocket equation is a mathematical equation that describes the motion of vehicles that follow the basic principle of a rocket: a device that can apply acceleration to itself using thrust by expelling part of its mass with high velocity can thereby move due to the conservation of momentum.

${\displaystyle \Delta v=v_{\text{e}}\ln {\frac {m_{0}}{m_{f}}}=I_{\text{sp}}g_{0}\ln {\frac {m_{0}}{m_{f}}}}$

where:

${\displaystyle \Delta v\ }$ is delta-v – the maximum change of velocity of the vehicle (with no external forces acting).

${\displaystyle m_{0}}$ is the initial total mass, including propellant, also known as wet mass.

${\displaystyle m_{f}}$ is the final total mass without propellant, also known as dry mass.

${\displaystyle v_{\text{e}}=I_{\text{sp}}g_{0}}$ is the effective exhaust velocity, where:

${\displaystyle I_{\text{sp}}}$ is the specific impulse in dimension of time.

${\displaystyle g_{0}}$ is standard gravity.

${\displaystyle \ln }$ is the natural logarithm function.

🔗 Norse history and culture 🔗 Ancient Germanic studies

The sequence alu (ᚨᛚᚢ) is found in numerous Elder Futhark runic inscriptions of Germanic Iron Age Scandinavia (and more rarely in early Anglo-Saxon England) between the 3rd and the 8th century. The word usually appears either alone (such as on the Elgesem runestone) or as part of an apparent formula (such as on the Lindholm "amulet" (DR 261) from Scania, Sweden). The symbols represent the runes Ansuz, Laguz, and Uruz. The origin and meaning of the word are matters of dispute, though a general agreement exists among scholars that the word represents an instance of historical runic magic or is a metaphor (or metonym) for it. It is the most common of the early runic charm words.

The word disappears from runic inscriptions shortly after Migration Period, even before the Christianization of Scandinavia. It may have lived on beyond this period with an increasing association with ale, appearing in stanzas 7 and 19 of the Old Norse poem Sigrdrífumál, compiled in the 13th century Poetic Edda, where knowledge of invocative "ale runes" (Old Norse ölrúnar) is imparted by the Valkyrie Sigrdrífa. Theories have been suggested that the unique term ealuscerwen (possibly "pouring away of alu"), used to describe grief or terror in the epic poem Beowulf, recorded around the 9th to 11th century, may be directly related.

🔗 Time

The Shortt–Synchronome free pendulum clock was a complex precision electromechanical pendulum clock invented in 1921 by British railway engineer William Hamilton Shortt in collaboration with horologist Frank Hope-Jones, and manufactured by the Synchronome Co., Ltd. of London, UK. They were the most accurate pendulum clocks ever commercially produced, and became the highest standard for timekeeping between the 1920s and the 1940s, after which mechanical clocks were superseded by quartz time standards. They were used worldwide in astronomical observatories, naval observatories, in scientific research, and as a primary standard for national time dissemination services. The Shortt was the first clock to be a more accurate timekeeper than the Earth itself; it was used in 1926 to detect tiny seasonal changes in the Earth's rotation rate. Shortt clocks achieved accuracy of around a second per year, although a recent measurement indicated they were even more accurate. About 100 were produced between 1922 and 1956.

Shortt clocks kept time with two pendulums, a master pendulum swinging in a vacuum tank and a slave pendulum in a separate clock, which was synchronized to the master by an electric circuit and electromagnets. The slave pendulum was attached to the timekeeping mechanisms of the clock, leaving the master pendulum virtually free of external disturbances.

🔗 Spaceflight 🔗 Physics 🔗 Rocketry

Direct Fusion Drive (DFD) is a conceptual low radioactivity, nuclear-fusion rocket engine designed to produce both thrust and electric power for interplanetary spacecraft. The concept is based on the Princeton field-reversed configuration reactor invented in 2002 by Samuel A. Cohen, and is being modeled and experimentally tested at Princeton Plasma Physics Laboratory, a US Department of Energy facility, and modeled and evaluated by Princeton Satellite Systems. As of 2018, the concept has moved on to Phase II to further advance the design.

🔗 Environment 🔗 London 🔗 History of Science

Fumifugium, or, The inconveniencie of the aer and smoak of London dissipated together with some remedies humbly proposed by J.E. esq. to His Sacred Majestie, and to the Parliament now assembled is a pamphlet published in London, 1661 (see 1661 in literature), by John Evelyn. It is one of the earliest known works on air pollution and is broken down into three parts which explain the problem, a proposed solution, and a way of improvement upon the air in London. The letter was specifically addressed to King Charles II of England and discussed problems with the capital's air pollution dating back to medieval times. Evelyn refers to Greek philosophers, who once believed that air was the principle of the earth and primary substance of the soul up until the time that air pollution began to cause ill health.

Evelyn was appointed to the newly formed Royal Society, and both Society and pamphlet are celebrated in the 1663 "Ballad of Gresham College". Stanza 23 (given here in modern English) describes how Evelyn

[...] shows that 'tis the sea-coal smoke

That always London does environ,
Which does our lungs and spirits choke,
Our hanging spoil, and rust our iron.
Let none at Fumifuge be scoffing

Who heard at Church our Sunday's coughing.

The sea-coal to which Evelyn referred was appropriately named because it came by sea from Newcastle. When burned, it gave off a terrible smell because of high amounts of sulfur in its composition. When burned the sea coal released sulfur dioxide, carbon dioxide, nitric oxide, soot, and particulates of organic matter into the atmosphere. The pamphlet suggests that burning wood, particularly aromatic woods, will be less harmful to the lungs and recommends relocating some of London's more polluting industries outside the capital, in particular lime-burning and brewing.

🔗 Meteorology 🔗 Paranormal

New England's Dark Day occurred on May 19, 1780, when an unusual darkening of the day sky was observed over the New England states and parts of Canada. The primary cause of the event is believed to have been a combination of smoke from forest fires, a thick fog, and cloud cover. The darkness was so complete that candles were required from noon on. It did not disperse until the middle of the next night.

🔗 Biography 🔗 Canada 🔗 Athletics 🔗 Running 🔗 Biography/sports and games

Terrance Stanley Fox (July 28, 1958 – June 28, 1981) was a Canadian athlete, humanitarian, and cancer research activist. In 1980, with one leg having been amputated due to cancer, he embarked on an east to west cross-Canada run to raise money and awareness for cancer research. Although the spread of his cancer eventually forced him to end his quest after 143 days and 5,373 kilometres (3,339 mi), and ultimately cost him his life, his efforts resulted in a lasting, worldwide legacy. The annual Terry Fox Run, first held in 1981, has grown to involve millions of participants in over 60 countries and is now the world's largest one-day fundraiser for cancer research; over C$750 million has been raised in his name, as of January 2018.

Fox was a distance runner and basketball player for his Port Coquitlam high school, now named after him, and Simon Fraser University. His right leg was amputated in 1977 after he was diagnosed with osteosarcoma, though he continued to run using an artificial leg. He also played wheelchair basketball in Vancouver, winning three national championships.

In 1980, he began the Marathon of Hope, a cross-country run to raise money for cancer research. He hoped to raise one dollar from each of Canada's 24 million people. He began with little fanfare from St John's, Newfoundland and Labrador, in April and ran the equivalent of a full marathon every day. Fox had become a national star by the time he reached Ontario; he made numerous public appearances with businessmen, athletes, and politicians in his efforts to raise money. He was forced to end his run outside Thunder Bay when the cancer spread to his lungs. His hopes of overcoming the disease and completing his marathon ended when he died nine months later.

In addition to being the youngest person ever named a Companion of the Order of Canada, Fox won the 1980 Lou Marsh Award as the nation's top sportsman and was named Canada's Newsmaker of the Year in both 1980 and 1981. Considered a national hero, he has had many buildings, statues, roads, and parks named in his honour across the country.

🔗 Video games 🔗 Role-playing games 🔗 Department of Fun

One theory that explains the addictive nature of Wikipedia and its tendency to produce Wikipediholics is that Wikipedia is a massively multiplayer online role-playing game (MMORPG). The following article explains how Wikipedia shares many characteristics with MMORPGs.

Wikipedia is a sequel to the game Nupedia, an encyclopedia-themed MMORPG in a hack and slash and "article roaming" style. It was released for the World Wide Web by the Wikimedia Foundation, and was developed by the community.

🔗 Visual arts 🔗 Textile Arts

Carpets of Middle-Eastern origin, either from Anatolia, Persia, Armenia, Azerbaijan, the Levant, the Mamluk state of Egypt or Northern Africa, were used as decorative features in Western European paintings from the 14th century onwards. More depictions of Oriental carpets in Renaissance painting survive than actual carpets contemporary with these paintings. Few Middle-Eastern carpets produced before the 17th century remain, though the number of these known has increased in recent decades. Therefore, comparative art-historical research has from its onset in the late 19th century relied on carpets represented in datable European paintings.