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Learn more about "II"
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2 (number)
Evolution of the glyph
Image:Evolution2glyph.png
The glyph we use today in the Western world to represent the number 2 traces its roots back to the Brahmin Indians, who wrote 2 as two horizontal lines (it is still written that way in modern Chinese written language|Chinese and Japanese writing system|Japanese). The Gupta script|Gupta rotated the two lines 45 degrees, making them diagonal, and sometimes also made the top line shorter and made its bottom end curve towards the center of the bottom line. Apparently for speed, the Nagari started making the top line more like a curve and connecting to the bottom line. The Ghubar Arabs made the bottom line completely vertical, and now the glyph looked like a dotless closing question mark. Restoring the bottom line to its original horizontal position, but keeping the top line as a curve that connects to the bottom line leads to our modern glyph.[Georges Ifrah, ''The Universal History of Numbers: From Prehistory to the Invention of the Computer'' transl. David Bellos et al. London: The Harvill Press (1998): 393, Fig. 24.62]
In fonts with text figures, 2 usually has the same height as a lowercase X, for example, Image:Text figures 256.svg.
In science
- The number of polynucleotide strands in a DNA double helix.
- The first Magic number (physics)|magic number.
- The atomic number of helium.
- Group '''2''' in the Periodic table of the elements consists of the alkaline earth metals whose usual valence (chemistry)|valence is +2.
- Period '''2''' in the Periodic table consists of the eight elements lithium through neon.
Astronomy
- Messier object Messier 2|M2, a magnitude 6.5 globular cluster in the constellation Aquarius (constellation)|Aquarius.
- The New General Catalogue object NGC 2, a visual magnitude|magnitude 14.2 spiral galaxy in the constellation Pegasus (constellation)|Pegasus
- The Saros number of the solar eclipse series which began on May 4 2861 BC and ended on June 21 1563 BC . The duration of Saros series 2 was 1298.1 years, and it contained 73 solar eclipses.
- The Saros number of the lunar eclipse series which began on February 21 2541 BC and ended on April 22 1225 BC. The duration of Saros series 2 was 1316.2 years, and it contained 74 lunar eclipses.
- The Roman numeral II stands for bright giant in the stellar classification|Yerkes spectral classification scheme.
- The Roman numeral II (usually) stands for the second-discovered satellite of a planet or minor planet (e.g. Pluto II or (87) Sylvia II Remus)
- A binary star is a Star system|stellar system consisting of two stars Planetary orbit|orbiting around their center of mass.
In technology
- The resin identification code used in recycling to identify high-density polyethylene.
In religion
The number 2 is important in Judaism, with one of the earliest reference being that God ordered Noah to put two of every animal in his ark (see Noah's Ark). Later on, the Ten Commandments were given in the form of two tablets (''Shnei Luchot HaBrit'').
The number also has ceremonial importance, such as the two candles that are traditionally kindled to usher in the Shabbat, recalling the two different ways Shabbat is referred to in the two times the Ten Commandments are recorded in the Torah. These two expressions are known in Hebrew language|Hebrew as שמור וזכור ("guard" and "remember"), as in "Guard the Shabbat day to sanctify it" (Deut. 5:12) and "Remember the Shabbat day to sanctify it" (Ex. 20:8) Two challahs (''lechem mishnah'') are placed on the table for each Shabbat meal and a blessing made over them, to commemorate the double portion of manna which fell in the The Exodus|desert every Friday to cover that day's meals and the Shabbat meals
In Halakha|Jewish law, the testimony of two witnesses are required to verify and validate events, such as Jewish view of marriage|marriage, divorce, and a crime that warrants capital punishment
"Second-Day Yom Tov" (''Yom Tov Sheini Shebegaliyot'') is a rabbinical enactment that mandates a two-day celebration for each of the one-day Jewish holiday|Jewish festivals (i.e., the first and seventh day of Passover, the day of Shavuot, the first day of Sukkot, and the day of Shemini Atzeret) outside the land of Israel
In culture
The most common philosophical dichotomy is perhaps the one of Goodness and value theory|good and evil, but there are many others. See dualism for an overview. In Georg Wilhelm Friedrich Hegel|Hegelian dialectic, the process of synthesis creates two perspectives from one.
Two (二, ''èr'') is a good number in Chinese culture. There is a Chinese saying "good things come in pairs". It is common to use double symbols in product brandnames, e.g. double happiness, double coin, double elephants etc. Guangdong|Cantonese people like the number two because it sounds the same as the word "easy" (易) in Cantonese language|Cantonese.
In Finland, two candles are lit on Independence Day. Putting them on the windowsill invokes the symbolical meaning of division, and thus independence.
In pre-1972 Indonesian language|Indonesian and Malay language|Malay orthography, ''2'' was shorthand for the reduplication that forms plurals: ''orang'' "person", ''orang-orang'' or ''orang2'' "people".
In North American educational systems, the number 2.00 denotes a academic grading in North America|grade-point average of "C," which in some colleges and universities is the minimum required for good academic standing at the undergraduate level.[''For a typical example'', ''see'' the University of Oklahoma grading regulations.]
In Astrology, Taurus (constellation)|Taurus is the second astrological sign|sign of the Zodiac.
In other fields
Groups of two:
- Lists of pairs
- list of twins
- The name of several fictional characters: '''''Number Two'''''.
- The designation of the Trans-Canada Highway in most of the province of New Brunswick.
- U.S. Route 2, two separated highways in the northern tier of the United States, the western segment connecting Everett, Washington to St. Ignace, Michigan and the eastern route connecting Rouses Point, New York to Houlton, Maine.
- The lowest channel of television in the United States, Canada, and Mexico on which television signals are broadcast.
References
Category:Integers|02
nds-nl:2 (getal)
simple:Two
zh-yue:2
Related Images- right
- 2 as a resin identification code, used in recycling.
Sources: StartLearningNow, Wikipedia | Usage license: GNU FDL
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