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🔗 California 🔗 Military history 🔗 Military history/North American military history 🔗 Military history/United States military history 🔗 Military history/World War II 🔗 Paranormal 🔗 California/Southern California

The Battle of Los Angeles, also known as the Great Los Angeles Air Raid, is the name given by contemporary sources to a rumored attack on the mainland United States by Imperial Japan and the subsequent anti-aircraft artillery barrage which took place from late 24 February to early 25 February 1942, over Los Angeles, California. The incident occurred less than three months after the U.S. entered World War II in response to the Imperial Japanese Navy's surprise attack on Pearl Harbor, and one day after the bombardment of Ellwood near Santa Barbara on 23 February. Initially, the target of the aerial barrage was thought to be an attacking force from Japan, but speaking at a press conference shortly afterward, Secretary of the Navy Frank Knox called the purported attack a "false alarm". Newspapers of the time published a number of reports and speculations of a cover-up.

When documenting the incident in 1949, the United States Coast Artillery Association identified a meteorological balloon sent aloft at 1:00 am as having "started all the shooting" and concluded that "once the firing started, imagination created all kinds of targets in the sky and everyone joined in". In 1983, the U.S. Office of Air Force History attributed the event to a case of "war nerves" triggered by a lost weather balloon and exacerbated by stray flares and shell bursts from adjoining batteries.

🔗 Ships

The Voith Schneider propeller (VSP), also known as a cycloidal drive is a specialized marine propulsion system (MPS). It is highly maneuverable, being able to change the direction of its thrust almost instantaneously. It is widely used on tugs and ferries.

🔗 Numbers 🔗 Canada 🔗 Arctic 🔗 Writing systems 🔗 Indigenous peoples of North America 🔗 Canada/Canadian Territories 🔗 Alaska

Kaktovik numerals are a featural positional numeral system created by Alaskan Iñupiat.

Arabic numeral notation, which was designed for a base-10 numeral system, is inadequate for the Inuit languages, which use a base-20 numeral system. Students in Kaktovik, Alaska, invented a base-20 numeral notation in 1994 to rectify this issue, and this system spread among the Alaskan Iñupiat and has been considered in other countries where Inuit languages are spoken.

The image at right shows the digits 0 to 19. Twenty is written as a one and a zero (\ɤ), forty as a two and a zero (Vɤ), four hundred as a one and two zeros (\ɤɤ), eight hundred as a two and two zeros (Vɤɤ), etc.

🔗 Climate change 🔗 Environment 🔗 Antarctica 🔗 Glaciers

The Western Antarctic Ice Sheet (WAIS) is the segment of the continental ice sheet that covers West Antarctica, the portion of Antarctica on the side of the Transantarctic Mountains that lies in the Western Hemisphere. The WAIS is classified as a marine-based ice sheet, meaning that its bed lies well below sea level and its edges flow into floating ice shelves. The WAIS is bounded by the Ross Ice Shelf, the Ronne Ice Shelf, and outlet glaciers that drain into the Amundsen Sea.

🔗 Maps 🔗 Photography

The Boston Camera, also known as Pie Face and officially classified as the K-42 Camera Model, was a prototype airborne photo reconnaissance camera manufactured for the United States Air Force by Boston University in 1951 and tested on the Convair B-36 and the C-97 Stratofreighter. The model carried on the first ERB-36D (44-92088) had a 6,096-millimetre (240.0 in) focal length, which was achieved using a series of lenses and mirrors. The lens had an f/8 stop and used a 1/400 second shutter speed, and could photograph a golf ball from an altitude of 45,000 feet (14,000 m) feet. The camera used 18-by-36-inch (46 by 91 cm) negatives. The camera was installed aboard Boeing C-97A 49-2592 (not an "RC-97" or "EC-97" as often widely quoted) which was used operationally by the 7405th Support Squadron based at Wiesbaden, West Germany between 1952 and 1962. It was given to the Air Force Museum in 1964, along with a contact print of a golf ball on a course.

In the words of CIA historian Dino Brugioni:

The lens was designed in 1947 by Dr. James Baker for installation in a camera designed by the Boston University Optical Research Laboratory. The camera weighed about three tons, and eight hundred pounds of lead shot were required to balance it. Supposedly, it was first installed and test-flown in an RB-36, then installed as a left-looking oblique camera in an RC-97. The first photo Arthur Lundahl and I saw from this project was of New York City. The aircraft was seventy-two miles away, and yet we could see people in Central Park.

The Boston Camera was plagued with problems that caused it to vibrate and produce smearing on the newspaper-sized negative, so that photo interpreters would see several smeared frames along with several clear ones. It is currently displayed at the National Museum of the US Air Force in Dayton, Ohio.

From the display placard:

This camera, manufactured for the US Air Force by Boston University in 1951, is the largest aerial camera ever built. It was installed in an RB-36D in 1954 and tested for about a year. Later it was used in a C-97 aircraft flying along the air corridor through communist East Germany to Berlin, but a 10,000 ft (3,000 m) altitude restriction imposed by the communists made the camera less useful than at a higher altitude. It was also used on reconnaissance missions along the borders of Eastern European nations. The camera made an 18 x 36 inch negative and was so powerful a photo interpreter could detect a golf ball from an altitude of 45,000 feet (14,000 m). Dr. James Baker of Harvard University designed the camera.

Technical Notes:

Shutter Speed: 1/400 sec

Weight: 6,500 lbs (3 metric ton) (camera and aircraft mount)

🔗 Death 🔗 Greece 🔗 Paranormal

The term Drosoulites (Greek: Δροσουλίτες) refers to a long procession of visions, seen by residents around Frangokastello castle in Sfakia region of Crete (Greece). The phenomenon is rumored to be visible every year, on the anniversary of the Battle of Frangokastello or even in early June near a small village in southern Crete.

The visions, as described by witnesses, consist of a group of human-like shadows dressed in black, walking or riding, armed with weapons, moving from the monastery of Agios Charalambos and advancing towards the old fort, Frangokastello, a 14th-century Venetian fortification. Legend has it that this group of people are Greek fighters that died during the Battle of Frangokastello (17 May 1828) and since then they appear as supernatural beings in the area.

The ghost army is led by Hatzimichalis Dalianis, from Delvinaki in Epirus, the chief of the Greek men, 350 of whom were lost, in the battle. The army took refuge in the fort during the Greek War of Independence against the Turks, where they were killed after a seven-day siege.

The local people named them Drosoulites ("dew shadows") due to the time of day that the phenomenon takes place. The phenomenon is observed when the sea is calm and the atmosphere is moist and before the sun rises too high in the sky. It usually lasts about 10 minutes.

The shadows are visible from the valley at a distance of 1000 m. Many have tried to explain the phenomenon scientifically, and at one time it was explained as a mirage from the coast of North Africa, but still there is no accepted consensus. On the other hand, another, occult, interpretation implies the existence of a psychic phenomenon, clairvoyance, seen in some countries like Britain and Germany, also regarding ghost armies. The appearance of the Drosoulites is documented over the ages. In 1890 a transient Turkish army took the images for rebels and fled away. Even during the Second World War, a German patrol is said to have opened fire on the visions.

🔗 Mathematics 🔗 Percussion

To hear the shape of a drum is to infer information about the shape of the drumhead from the sound it makes, i.e., from the list of overtones, via the use of mathematical theory.

"Can One Hear the Shape of a Drum?" is the title of a 1966 article by Mark Kac in the American Mathematical Monthly which made the question famous, though this particular phrasing originates with Lipman Bers. Similar questions can be traced back all the way to Hermann Weyl . For his paper, Kac was given the Lester R. Ford Award in 1967 and the Chauvenet Prize in 1968.

The frequencies at which a drumhead can vibrate depend on its shape. The Helmholtz equation calculates the frequencies if the shape is known. These frequencies are the eigenvalues of the Laplacian in the space. A central question is whether the shape can be predicted if the frequencies are known; for example, whether a circle-shaped triangle can be recognized in this way. Kac admitted he did not know if it was possible for two different shapes to yield the same set of frequencies. The question of whether the frequencies determine the shape was finally answered in the negative in the early 1990s by Gordon, Webb and Wolpert.

🔗 Military history 🔗 Military history/Military science, technology, and theory 🔗 Military history/Weaponry 🔗 Elements 🔗 Military history/Cold War

Red mercury is purportedly a substance of uncertain composition used in the creation of nuclear weapons, as well as other weapons systems. Because of the great secrecy surrounding the development and manufacture of nuclear weapons, there is no proof that red mercury exists. However, all samples of alleged "red mercury" analyzed in the public literature have proven to be well-known, common red substances of no interest to weapons makers.

Red mercury is therefore considered a hoax, perpetrated by con artists who sought to take advantage of gullible buyers on the black market for arms. There have been reports of "red mercury" on the international black markets since 1979, but the hoax seems to have been most common in the early 1990s, with very high asking prices.

🔗 Military history 🔗 Heraldry and vexillology 🔗 Catholicism 🔗 Military history/Crusades 🔗 Military history/Medieval warfare 🔗 Countries 🔗 Former countries 🔗 Military history/National militaries 🔗 Malta 🔗 Orders, decorations, and medals

The Sovereign Military Order of Malta (SMOM), officially the Sovereign Military Hospitaller Order of Saint John of Jerusalem, of Rhodes and of Malta (Italian: Sovrano Militare Ordine Ospedaliero di San Giovanni di Gerusalemme di Rodi e di Malta; Latin: Supremus Militaris Ordo Hospitalarius Sancti Ioannis Hierosolymitani Rhodiensis et Melitensis), commonly known as the Order of Malta, Malta Order or Knights of Malta, is a Catholic lay religious order, traditionally of military, chivalric and noble nature. Though it possesses no territory, the order is a sovereign entity of international law and maintains diplomatic relations with many countries.

SMOM claims continuity with the Knights Hospitaller, a chivalric order that was founded c. 1099 by the Blessed Gerard in the Kingdom of Jerusalem. The order is led by an elected Prince and Grand Master. Its motto is Tuitio fidei et obsequium pauperum ('defence of the faith and assistance to the poor'). The order venerates the Virgin Mary as its patroness, under the title of Our Lady of Philermos. Its modern-day role is largely focused on providing humanitarian assistance and assisting with international humanitarian relations, for which purpose it has had permanent observer status at the United Nations General Assembly since 1994.

🔗 Computing 🔗 Computing/Early computers

The TX-0, for Transistorized Experimental computer zero, but affectionately referred to as tixo (pronounced "tix oh"), was an early fully transistorized computer and contained a then-huge 64K of 18-bit words of magnetic core memory. Construction of the TX-0 began in 1955 and ended in 1956. It was used continually through the 1960s at MIT. The TX-0 incorporated around 3600 Philco high-frequency surface-barrier transistors, the first transistor suitable for high-speed computers. The TX-0 and its direct descendant, the original PDP-1, were platforms for pioneering computer research and the development of what would later be called computer "hacker" culture.