Have a deep view into what people are curious about.

🔗 Physics 🔗 Astronomy 🔗 Physics/relativity 🔗 Astronomy/Astronomical objects

In general relativity, a white hole is a hypothetical region of spacetime and singularity that cannot be entered from the outside, although energy-matter, light and information can escape from it. In this sense, it is the reverse of a black hole, which can be entered only from the outside and from which energy-matter, light and information cannot escape. White holes appear in the theory of eternal black holes. In addition to a black hole region in the future, such a solution of the Einstein field equations has a white hole region in its past. This region does not exist for black holes that have formed through gravitational collapse, however, nor are there any observed physical processes through which a white hole could be formed.

Supermassive black holes (SBHs) are theoretically predicted to be at the center of every galaxy and that possibly, a galaxy cannot form without one. Stephen Hawking and others have proposed that these SBHs spawn a supermassive white hole/Big Bang.

🔗 London 🔗 Visual arts

The Ambassadors (1533) is a painting by Hans Holbein the Younger. Also known as Jean de Dinteville and Georges de Selve, it was created in the Tudor period, in the same year Elizabeth I was born. As well as being a double portrait, the painting contains a still life of several meticulously rendered objects, the meaning of which is the cause of much debate. It also incorporates a much-cited example of anamorphosis in painting. It is part of the collection at the National Gallery in London.

🔗 Philosophy 🔗 Philosophy/Philosophical literature 🔗 Books

Simulacra and Simulation (French: Simulacres et Simulation) is a 1981 philosophical treatise by Jean Baudrillard, in which the author seeks to examine the relationships between reality, symbols, and society, in particular the significations and symbolism of culture and media involved in constructing an understanding of shared existence.

Simulacra are copies that depict things that either had no original, or that no longer have an original. Simulation is the imitation of the operation of a real-world process or system over time.

🔗 Biography 🔗 Chemistry 🔗 Florida

Marvin Pipkin (November 18, 1889 – January 7, 1977) was an American chemist. During his time in the United States Army he worked on gas masks. In his civilian life he invented a process for frosting the inside of incandescent light bulbs to cut down on the sharp glare and diffuse the light. He went on to make many other inventions and innovative improvements to the light bulb.

🔗 Polynesia 🔗 Organizations 🔗 Hawaii

The Polynesian Voyaging Society (PVS) is a non-profit research and educational corporation based in Honolulu, Hawaiʻi. PVS was established to research and perpetuate traditional Polynesian voyaging methods. Using replicas of traditional double-hulled canoes, PVS undertakes voyages throughout Polynesia navigating without modern instruments.

🔗 History of Science

A knowledge production mode is a term from the sociology of science which refers to the way (scientific) knowledge is produced. So far, three modes have been conceptualized. Mode 1 production of knowledge is knowledge production motivated by scientific knowledge alone (basic research) which is not primarily concerned by the applicability of its findings. Mode 1 is founded on a conceptualization of science as separated into discrete disciplines (e.g., a biologist does not bother about chemistry). Mode 2 was coined in 1994 in juxtaposition to Mode 1 by Michael Gibbons, Camille Limoges, Helga Nowotny, Simon Schwartzman, Peter Scott and Martin Trow. In Mode 2, multidisciplinary teams are brought together for short periods of time to work on specific problems in the real world for knowledge production (applied research) in the knowledge society. Mode 2 can be explained by the way research funds are distributed among scientists and how scientists focus on obtaining these funds in terms of five basic features: 1) knowledge produced in the context of application; (2) transdisciplinarity; (3) heterogeneity and organizational diversity; (4) social accountability and reflexivity; (5) and quality control. Subsequently, Carayannis and Campbell described a Mode 3 knowledge in 2006.

🔗 Syria

The Hurrian songs are a collection of music inscribed in cuneiform on clay tablets excavated from the ancient Amorite-Canaanite city of Ugarit, a headland in northern Syria, which date to approximately 1400 BCE. One of these tablets, which is nearly complete, contains the Hurrian hymn to Nikkal (also known as the Hurrian cult hymn or A Zaluzi to the Gods, or simply h.6), making it the oldest surviving substantially complete work of notated music in the world. While the composers' names of some of the fragmentary pieces are known, h.6 is an anonymous work.

🔗 Technology 🔗 Computing 🔗 Computing/Computer hardware

Holographic data storage is a potential technology in the area of high-capacity data storage. While magnetic and optical data storage devices rely on individual bits being stored as distinct magnetic or optical changes on the surface of the recording medium, holographic data storage records information throughout the volume of the medium and is capable of recording multiple images in the same area utilizing light at different angles.

Additionally, whereas magnetic and optical data storage records information a bit at a time in a linear fashion, holographic storage is capable of recording and reading millions of bits in parallel, enabling data transfer rates greater than those attained by traditional optical storage.

🔗 United States 🔗 Biography 🔗 Military history 🔗 Military history/North American military history 🔗 Military history/United States military history 🔗 United States/Military history - U.S. military history 🔗 Military history/Military biography 🔗 Biography/military biography 🔗 Military history/World War II 🔗 United States/Vermont

Ronald James Read (October 23, 1921 – June 2, 2014) was an American philanthropist, investor, janitor, and gas station attendant. Read grew up in Dummerston, Vermont, in an impoverished farming household. He walked or hitchhiked 4 mi (6.4 km) daily to his high school and was the first high school graduate in his family. He enlisted in the United States Army during World War II, serving in Italy as a military policeman. Upon an honorable discharge from the military in 1945, Read returned to Brattleboro, Vermont, where he worked as a gas station attendant and mechanic for about 25 years. Read retired for one year and then took a part-time janitor job at J. C. Penney where he worked for 17 years until 1997.

Read died in 2014. He received media coverage in numerous newspapers and magazines after bequeathing US$1.2 million to Brooks Memorial Library and $4.8 million to Brattleboro Memorial Hospital. Read amassed a fortune of almost $8 million by investing in dividend-producing stocks, avoiding the stocks of companies he did not understand such as technology companies, living frugally, and being a buy and hold investor in a diversified portfolio of stocks with a heavy concentration in blue chip companies.

🔗 Ecology

The Lotka–Volterra equations, also known as the Lotka–Volterra predator–prey model, are a pair of first-order nonlinear differential equations, frequently used to describe the dynamics of biological systems in which two species interact, one as a predator and the other as prey. The populations change through time according to the pair of equations: $${\displaystyle {\begin{aligned}{\frac {dx}{dt}}&=\alpha x-\beta xy,\\{\frac {dy}{dt}}&=-\gamma y+\delta xy,\end{aligned}}}$$

where

• the variable x is the population density of prey (for example, the number of rabbits per square kilometre);
• the variable y is the population density of some predator (for example, the number of foxes per square kilometre);
• ${\displaystyle {\tfrac {dy}{dt}}}$ and ${\displaystyle {\tfrac {dx}{dt}}}$ represent the instantaneous growth rates of the two populations;
• t represents time;
• The prey's parameters, α and β, describe, respectively, the maximum prey per capita growth rate, and the effect of the presence of predators on the prey death rate.
• The predator's parameters, γ, δ, respectively describe the predator's per capita death rate, and the effect of the presence of prey on the predator's growth rate.
• All parameters are positive and real.

The solution of the differential equations is deterministic and continuous. This, in turn, implies that the generations of both the predator and prey are continually overlapping.

The Lotka–Volterra system of equations is an example of a Kolmogorov population model (not to be confused with the better known Kolmogorov equations), which is a more general framework that can model the dynamics of ecological systems with predator–prey interactions, competition, disease, and mutualism.