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🔗 Physics 🔗 Geology

A fossil natural nuclear fission reactor is a uranium deposit where self-sustaining nuclear chain reactions have occurred. This can be examined by analysis of isotope ratios. The conditions under which a natural nuclear reactor could exist had been predicted in 1956 by Paul Kazuo Kuroda. The phenomenon was discovered in 1972 in Oklo, Gabon by French physicist Francis Perrin under conditions very similar to what was predicted.

Oklo is the only known location for this in the world and consists of 16 sites at which self-sustaining nuclear fission reactions are thought to have taken place approximately 1.7 billion years ago, and ran for a few hundred thousand years, averaging probably less than 100 kW of thermal power during that time.

🔗 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.

🔗 Spaceflight 🔗 Physics

A Van Allen radiation belt is a zone of energetic charged particles, most of which originate from the solar wind, that are captured by and held around a planet by that planet's magnetic field. Earth has two such belts and sometimes others may be temporarily created. The discovery of the belts is credited to James Van Allen, and as a result, Earth's belts are known as the Van Allen belts. Earth's two main belts extend from an altitude of about 640 to 58,000 km (400 to 36,040 mi) above the surface in which region radiation levels vary. Most of the particles that form the belts are thought to come from solar wind and other particles by cosmic rays. By trapping the solar wind, the magnetic field deflects those energetic particles and protects the atmosphere from destruction.

The belts are located in the inner region of Earth's magnetosphere. The belts trap energetic electrons and protons. Other nuclei, such as alpha particles, are less prevalent. The belts endanger satellites, which must have their sensitive components protected with adequate shielding if they spend significant time near that zone. In 2013, NASA reported that the Van Allen Probes had discovered a transient, third radiation belt, which was observed for four weeks until it was destroyed by a powerful, interplanetary shock wave from the Sun.

🔗 China 🔗 Writing systems

Since the second half of the 20th century, inscriptions have been found on pottery in a variety of locations in China, such as Banpo near Xi'an, as well as on bone and bone marrows at Hualouzi, Chang'an County near Xi'an. These simple, often geometric, marks have been frequently compared to some of the earliest known Chinese characters appearing on the oracle bones, and some have taken them to mean that the history of Chinese writing extends back over six millennia. However, only isolated instances of these symbols have been found, and they show no indication of representing speech or of the non-pictorial processes that a writing system requires.

🔗 Apple Inc. 🔗 Computing

The term bozo bit has been used in two contexts. Initially a weak copy protection system in the 1980s Apple classic Mac OS, the term "flipping the bozo bit" was later reused to describe a decision to ignore a person's input. It is a whimsical term, possibly derived from the classic children's comedy character, Bozo the Clown.

🔗 Psychology 🔗 Cognitive science

Functional fixedness is a cognitive bias that limits a person to use an object only in the way it is traditionally used. The concept of functional fixedness originated in Gestalt psychology, a movement in psychology that emphasizes holistic processing. Karl Duncker defined functional fixedness as being a "mental block against using an object in a new way that is required to solve a problem". This "block" limits the ability of an individual to use components given to them to complete a task, as they cannot move past the original purpose of those components. For example, if someone needs a paperweight, but they only have a hammer, they may not see how the hammer can be used as a paperweight. Functional fixedness is this inability to see a hammer's use as anything other than for pounding nails; the person couldn't think to use the hammer in a way other than in its conventional function.

When tested, 5-year-old children show no signs of functional fixedness. It has been argued that this is because at age 5, any goal to be achieved with an object is equivalent to any other goal. However, by age 7, children have acquired the tendency to treat the originally intended purpose of an object as special.

🔗 United States 🔗 Environment 🔗 Marketing & Advertising 🔗 United States/Texas 🔗 Road transport 🔗 U.S. Roads 🔗 U.S. Roads/Texas

Don't Mess with Texas is a slogan for a campaign aimed at reducing littering on Texas roadways by the Texas Department of Transportation. The phrase "Don't Mess with Texas" is prominently shown on road signs on major highways, television, radio and in print advertisements. The campaign is credited with reducing litter on Texas highways roughly 72% between 1987 and 1990. The campaign's target market was 18- to 35-year-old males, which was statistically shown to be the most likely to litter. While the slogan was not originally intended to become a statewide cultural phenomenon, it did.

Beyond its immediate role in reducing litter, the slogan has been popularly appropriated by Texans. The phrase has become "an identity statement, a declaration of Texas swagger". Though the origin of the slogan is not well known outside of Texas, it appears on countless items of tourist souvenirs. Since the phrase is a federally registered trademark, the department has tried at times to enforce its trademark rights with cease and desist letters, but has had very limited success. The slogan is the title of the book, Don’t Mess With Texas: The Story Behind the Legend.

"Don't Mess with Texas" has been awarded a plaque on the Madison Avenue Walk of Fame and a place in the Advertising Hall of Fame, a distinction given to only two slogans annually.

"Don't Mess with Texas" is also the official motto of the Virginia-class submarine USS Texas.

In 2011 the result of a public vote for the best "Don't Mess with Texas" ad over the last 25 was revealed, the winner was one created by the Commemorative Air Force (then called the Confederate Air Force). The ad involved the CAF's Boeing B-17 "Sentimental Journey" pursuing and retaliating against a truck from which trash was thrown.

🔗 Computer science 🔗 Philosophy 🔗 Philosophy/Logic 🔗 Philosophy/Philosophy of science 🔗 Philosophy/Philosophy of mind

Moravec's paradox is the observation by artificial intelligence and robotics researchers that, contrary to traditional assumptions, reasoning (which is high-level in humans) requires very little computation, but sensorimotor skills (comparatively low-level in humans) require enormous computational resources. The principle was articulated by Hans Moravec, Rodney Brooks, Marvin Minsky and others in the 1980s. As Moravec writes, "it is comparatively easy to make computers exhibit adult level performance on intelligence tests or playing checkers, and difficult or impossible to give them the skills of a one-year-old when it comes to perception and mobility".

Similarly, Minsky emphasized that the most difficult human skills to reverse engineer are those that are unconscious. "In general, we're least aware of what our minds do best", he wrote, and added "we're more aware of simple processes that don't work well than of complex ones that work flawlessly".

🔗 Religion 🔗 Skepticism 🔗 Bible 🔗 Islam 🔗 Judaism 🔗 Iraq 🔗 Turkey 🔗 Mythology

Searches for Noah's Ark have been reported since antiquity, as ancient scholars sought to affirm the historicity of the Genesis flood narrative by citing accounts of relics recovered from the Ark.^: 43–47 With the emergence of biblical archaeology in the 19th century, the potential of a formal search attracted interest in alleged discoveries and hoaxes. By the 1940s, expeditions were being organized to follow up on these apparent leads.^: 8–9 This modern search movement has been informally called "arkeology".

In 2020, the young Earth creationist group the Institute for Creation Research acknowledged that, despite many expeditions, Noah's Ark had not been found and is unlikely to be found. Many of the supposed findings and methods used in the search are regarded as pseudoscience and pseudoarchaeology by geologists and archaeologists.^{: 581–582 : 72–75}

🔗 Antarctica 🔗 Transport

The Antarctic Snow Cruiser was a vehicle designed from 1937 to 1939 under the direction of Thomas Poulter, intended to facilitate transport in Antarctica during the United States Antarctic Service Expedition (1939–41). The Snow Cruiser was also known as "The Penguin," "Penguin 1" or "Turtle" in some published material.

Poulter had been second in command of Byrd's Second Antarctic Expedition, launched in 1934. From his time in the Antarctic, Poulter had devised several innovative features. However, the massive Snow Cruiser generally failed to operate as hoped under the difficult conditions, and was eventually abandoned in Antarctica. Rediscovered under a deep layer of snow in 1958, it later disappeared again due to shifting ice conditions.