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๐ Longest-lasting incandescent light bulbs
This is a list of the longest-lasting incandescent light bulbs.
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- "Longest-lasting incandescent light bulbs" | 2023-08-04 | 85 Upvotes 93 Comments
๐ Fleurons in Unicode
A fleuron (;), also known as printers' flower, is a typographic element, or glyph, used either as a punctuation mark or as an ornament for typographic compositions. Fleurons are stylized forms of flowers or leaves; the term derives from the Old French: floron ("flower"). Robert Bringhurst in The Elements of Typographic Style calls the forms "horticultural dingbats". A commonly-encountered fleuron is the โฆ, the floral heart or hedera (ivy leaf). It is also known as an aldus leaf (after Italian Renaissance printer Aldus Manutius).
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- "Fleurons in Unicode" | 2023-10-07 | 74 Upvotes 37 Comments
๐ Endurance Running Hypothesis
The endurance running hypothesis is the hypothesis that the evolution of certain human characteristics can be explained as adaptations to long-distance running. The hypothesis suggests that endurance running played an important role for early hominins in obtaining food. Researchers have proposed that endurance running began as an adaptation for scavenging and later for persistence hunting.
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- "Endurance Running Hypothesis" | 2019-09-17 | 97 Upvotes 52 Comments
๐ The Colditz Glider
The Colditz Cock was a glider built by British prisoners of war for an escape attempt from Oflag IV-C (Colditz Castle) in Germany.
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- "The Colditz Glider" | 2017-07-23 | 47 Upvotes 7 Comments
๐ Lion-Eating Poet in the Stone Den
The Lion-Eating Poet in the Stone Den (Chinese: ๆฝๆฐ้ฃ็ ๅฒ; pinyin: Shฤซ-shรฌ shรญ shฤซ shว) is a short narrative poem written in Classical Chinese that is composed of 92 characters in which every word is pronounced shi ([สษปฬฉ]) when read in present-day Standard Mandarin, with only the tones differing.
The poem was written in the 1930s by the Chinese linguist Yuen Ren Chao as a linguistic demonstration. The poem is coherent and grammatical in Classical Chinese, but the loss of older sound combinations in Chinese over the centuries has greatly increased the number of Chinese homophones, making Classical Chinese difficult to understand in oral speech. In Mandarin, the poem is incomprehensible when read aloud, since only four syllables cover the entire 92 words of the poem. The poem is less incomprehensibleโbut still not very intelligibleโwhen read in other varieties of Chinese such as Cantonese, in which it has 22 different syllables, or Hokkien Chinese, in which it has 15 different syllables.
The poem is an example of a one-syllable article, a form of constrained writing possible in tonal languages such as Mandarin Chinese, where tonal contours expand the range of meaning for a single syllable.
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- "Lion-Eating Poet in the Stone Den" | 2019-04-19 | 49 Upvotes 14 Comments
๐ Fluoroantimonic Acid
Fluoroantimonic acid is a mixture of hydrogen fluoride and antimony pentafluoride, containing various cations and anions (the simplest being H
2F+
and SbFโ
6). This substance is a superacid that can be excess of a quadrillion times stronger than 100% pure sulfuric acid, depending on proportion of its ingredients. It has been shown to protonate even hydrocarbons to afford pentacoordinate carbocations (carbonium ions). Extreme caution needs to be in place when handling fluoroantimonic acid. It is exceptionally corrosive, but can be stored in containers lined with PTFE (Teflon).
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- "Fluoroantimonic Acid" | 2022-01-09 | 10 Upvotes 2 Comments
๐ Oxford Electric Bell
The Oxford Electric Bell or Clarendon Dry Pile is an experimental electric bell that was set up in 1840 and which has run nearly continuously ever since. It was one of the first pieces purchased for a collection of apparatus by clergyman and physicist Robert Walker. It is located in a corridor adjacent to the foyer of the Clarendon Laboratory at the University of Oxford, England, and is still ringing, though inaudibly due to being behind two layers of glass.
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- "Oxford Electric Bell" | 2018-10-06 | 109 Upvotes 12 Comments
- "Oxford Electric Bell" | 2014-06-02 | 106 Upvotes 60 Comments
๐ The โOh-My-God Particleโ
The Oh-My-God particle was the highest-energy cosmic ray detected at the time (15 October 1991) by the Fly's Eye detector in Dugway Proving Ground, Utah, US. Its energy was estimated as (3.2ยฑ0.9)ร1020ย eV, or 51ย J. This is 20 million times more energetic than the highest energy measured in electromagnetic radiation emitted by an extragalactic object and 1020 (100 quintillion) times the photon energy of visible light, equivalent to a 142-gram (5ย oz) baseball travelling at about 26ย m/s (94ย km/h; 58ย mph). Although higher energy cosmic rays have been detected since then, this particle's energy was unexpected, and called into question theories of that era about the origin and propagation of cosmic rays.
Assuming it was a proton, this particle traveled at 99.99999999999999999999951% of the speed of light, its Lorentz factor was 3.2ร1011 and its rapidity was 27.1. At this speed, if a photon were travelling with the particle, it would take over 215,000 years for the photon to gain a 1ย cm lead as seen in Earth's reference frame.
The energy of this particle is some 40 million times that of the highest energy protons that have been produced in any terrestrial particle accelerator. However, only a small fraction of this energy would be available for an interaction with a proton or neutron on Earth, with most of the energy remaining in the form of kinetic energy of the products of the interaction. The effective energy available for such a collision is โ2Emc2, where E is the particle's energy and mc2 is the mass energy of the proton. For the Oh-My-God particle, this gives 7.5ร1014ย eV, roughly 60 times the collision energy of the Large Hadron Collider.
While the particle's energy was higher than anything achieved in terrestrial accelerators, it was still about 40 million times lower than the Planck energy. Particles of such energy would be required in order to explore the Planck scale. A proton with that much energy would travel 1.665ร1015 times closer to the speed of light than the Oh-My-God particle. As viewed from Earth it would take about 3.579ร1020ย years, or 2.59ร1010 times the current age of the universe, for a photon to gain a 1 cm lead over a Planck energy proton as observed in Earth's reference frame.
Since the first observation, at least 72 similar (energy > 5.7ร1019ย eV) events have been recorded, confirming the phenomenon. These ultra-high-energy cosmic ray particles are very rare; the energy of most cosmic ray particles is between 10ย MeV and 10ย GeV. More recent studies using the Telescope Array have suggested a source for the particles within a 20-degree radius "warm spot" in the direction of the constellation Ursa Major.
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- "Oh-My-God Particle" | 2023-10-06 | 69 Upvotes 52 Comments
- "The โOh-My-God Particleโ" | 2018-02-27 | 118 Upvotes 71 Comments
- "Oh-My-God particle" | 2014-05-07 | 165 Upvotes 41 Comments
๐ Cybiko
The Cybiko is a Russian handheld computer introduced in the United States by David Yang's company Cybiko Inc. as a retail test market in New York on April 2000, and rolled out nationwide in May 2000. It is designed for teens, featuring its own two-way radio text messaging system. It had over 430 "official" freeware games and applications. Because of the text messaging system, it features a rubber QWERTY keyboard. An MP3 player add-on with a SmartMedia card slot was made for the unit as well. The company stopped manufacturing the units after two product versions and only a few years on the market. Cybikos can communicate with each other up to a maximum range of 100 metres (300 feet). Several Cybikos can chat with each other in a wireless chatroom. By the end of 2000, the Cybiko Classic sold over 500,000 units.
๐ Kasparov versus the World
Kasparov versus the World was a game of chess played in 1999 over the Internet. Conducting the white pieces, Garry Kasparov faced the rest of the world in consultation, with the World Team moves to be decided by plurality vote. Over 50,000 people from more than 75 countries participated in the game.
The host and promoter of the match was the MSN Gaming Zone, with sponsorship from First USA bank. After 62 moves played over four months, Kasparov won the game. Contrary to expectations, the game produced a mixture of deep tactical and strategic ideas, and although Kasparov won, he admitted that he had never expended as much effort on any other game in his life. He later said, "It is the greatest game in the history of chess. The sheer number of ideas, the complexity, and the contribution it has made to chess make it the most important game ever played."
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- "Kasparov versus the World" | 2018-04-28 | 256 Upvotes 60 Comments
- "In 1999, Kasparov played chess against 50000 people." | 2008-12-10 | 33 Upvotes 25 Comments