Random Articles
Have a deep view into what people are curious about.
🔗 False Vacuum
In quantum field theory, a false vacuum is a hypothetical vacuum that is relatively stable, but not in the most stable state possible. In this condition it is called metastable. It may last for a very long time in this state, but could eventually decay to the more stable one, an event known as false vacuum decay. The most common suggestion of how such a decay might happen in our universe is called bubble nucleation – if a small region of the universe by chance reached a more stable vacuum, this "bubble" (also called "bounce") would spread.
A false vacuum exists at a local minimum of energy and is therefore not completely stable, in contrast to a true vacuum, which exists at a global minimum and is stable.
🔗 List of common misconceptions
This is a list of common misconceptions. Each entry is formatted as a correction; the misconceptions themselves are implied rather than stated. These entries are meant to be concise, but more detail can be found in the main subject articles.
Discussed on
- "List of Common Misconceptions" | 2022-07-13 | 21 Upvotes 8 Comments
- "List of Common Misconceptions" | 2020-05-22 | 52 Upvotes 15 Comments
- "List of common misconceptions" | 2018-06-14 | 94 Upvotes 26 Comments
- "List of Common Misconceptions" | 2010-06-27 | 169 Upvotes 53 Comments
🔗 List of Creepypastas
Creepypastas are horror-related legends or images that have been copied and pasted around the Internet. These Internet entries are often brief, user-generated, paranormal stories intended to scare, frighten, or discomfort readers. The term "Creepypasta" originates from Copypasta, made from the words "copy" and "paste".
Discussed on
- "List of Creepypastas" | 2022-08-29 | 190 Upvotes 124 Comments
🔗 Young's Lattice
In mathematics, Young's lattice is a partially ordered set and a lattice that is formed by all integer partitions. It is named after Alfred Young, who, in a series of papers On quantitative substitutional analysis, developed representation theory of the symmetric group. In Young's theory, the objects now called Young diagrams and the partial order on them played a key, even decisive, role. Young's lattice prominently figures in algebraic combinatorics, forming the simplest example of a differential poset in the sense of Stanley (1988). It is also closely connected with the crystal bases for affine Lie algebras.
Discussed on
- "Young's Lattice" | 2021-12-07 | 42 Upvotes 15 Comments
🔗 Wikipedia deletes entry on PBWiki, the biggest hosted competitor with 550,000 wikis
PBworks (formerly PBwiki) is a commercial real-time collaborative editing (RTCE) system created by David Weekly, with Ramit Sethi and Nathan Schmidt, who joined shortly thereafter as co-founders. Based in San Mateo, California, United States, the company operates on a freemium basis, offering basic features free of charge and more advanced features for a fee.
PBworks' investors include Mohr Davidow Ventures and the Seraph Group, as well as angel investors Ron Conway and Chris Yeh.
Discussed on
- "Wikipedia deletes entry on PBWiki, the biggest hosted competitor with 550,000 wikis" | 2008-09-18 | 15 Upvotes 16 Comments
🔗 Chants of Sennaar
Chants of Sennaar is a 2023 adventure video game developed by Rundisc and published by Focus Entertainment. Players solve puzzles and minigames to translate fictional languages.
Discussed on
- "Chants of Sennaar" | 2023-12-26 | 10 Upvotes 1 Comments
🔗 One red paperclip
One red paperclip is a website created by Canadian blogger Kyle MacDonald, who bartered his way from a single red paperclip to a house in a series of fourteen online trades over the course of a year. MacDonald was inspired by the childhood game Bigger, Better. His site received a considerable amount of notice for tracking the transactions. "A lot of people have been asking how I've stirred up so much publicity around the project, and my simple answer is: 'I have no idea'", he told the BBC.
Discussed on
- "One red paperclip" | 2020-12-25 | 93 Upvotes 41 Comments
- "One red paperclip" | 2018-04-19 | 14 Upvotes 4 Comments
🔗 Levenshtein Distance
In information theory, linguistics and computer science, the Levenshtein distance is a string metric for measuring the difference between two sequences. Informally, the Levenshtein distance between two words is the minimum number of single-character edits (insertions, deletions or substitutions) required to change one word into the other. It is named after the Soviet mathematician Vladimir Levenshtein, who considered this distance in 1965.
Levenshtein distance may also be referred to as edit distance, although that term may also denote a larger family of distance metrics known collectively as edit distance. It is closely related to pairwise string alignments.
Discussed on
- "Levenshtein Distance" | 2019-08-22 | 215 Upvotes 126 Comments
🔗 Lincolnshire Poacher (numbers station)
The Lincolnshire Poacher was a British powerful shortwave numbers station that transmitted from Cyprus from the mid-1970s to June 2008. The station gained its commonly known name as it uses bars from the English folk song "The Lincolnshire Poacher" as an interval signal. The radio station was believed to be operated by the British Secret Intelligence Service and emanated from the island of Cyprus. Amateur direction finding linked it with the Royal Air Force base at Akrotiri, Cyprus, where several curtain antennas had been identified as being its transmitter. It consisted of an electronically synthesised English-accented female voice reading groups of five numbers: e.g. '0-2-5-8-8'. The final number in each group was spoken at a higher pitch. It is likely that the station was used to communicate to undercover agents operating in other countries, to be decoded using a one-time pad.
An Asian numbers station of identical format is believed to have been broadcast from Australia, and nicknamed "Cherry Ripe". It uses several bars from the English folk song of the same name as its interval signal. Cherry Ripe continued to be on-air until December 2009.
Discussed on
- "Lincolnshire Poacher (numbers station)" | 2016-04-06 | 17 Upvotes 1 Comments
🔗 Von Neumann Universal Constructor
John von Neumann's universal constructor is a self-replicating machine in a cellular automata (CA) environment. It was designed in the 1940s, without the use of a computer. The fundamental details of the machine were published in von Neumann's book Theory of Self-Reproducing Automata, completed in 1966 by Arthur W. Burks after von Neumann's death.
Von Neumann's goal was to specify an abstract machine which, when run, would replicate itself. In his design, the machine consists of three parts: a 'blueprint' for itself, a mechanism that can read any blueprint and construct the machine (sans blueprint) specified by that blueprint, and a 'copy machine' that can make copies of any blueprint. After the mechanism has been used to construct the machine specified by the blueprint, the copy machine is used to create a copy of that blueprint, and this copy is placed into the new machine, resulting in a working replication of the original machine. Some machines will do this backwards, copying the blueprint and then building a machine.
To define his machine in more detail, von Neumann invented the concept of a cellular automaton. The one he used consists of a two-dimensional grid of cells, each of which can be in one of 29 states at any point in time. At each timestep, each cell updates its state depending on the states of the surrounding cells at the prior timestep. The rules governing these updates are identical for all cells.
The universal constructor is a certain pattern of cell states in this cellular automaton. It contains one line of cells that serve as a 'tape', encoding a sequence of instructions that serve as a 'blueprint' for the machine. The machine reads these instructions one by one and performs the corresponding actions. The instructions direct the machine to use its 'construction arm' to build a copy of the machine, without tape, at some other location in the cell grid. The tape can't contain instructions to build an equally long tape, just as a container can't contain a container of the same size. Therefore, the machine contains a separate 'copy machine' which reads the tape and places a copy into the newly constructed machine. The resulting new machine and tape is identical to the old one, and it proceeds to replicate again.
Discussed on
- "Von Neumann Universal Constructor" | 2020-03-30 | 90 Upvotes 29 Comments