Large numbers are numbers significantly larger than those typically used in everyday life (for instance in simple counting or in monetary transactions), appearing frequently in fields such as mathematics, cosmology, cryptography, and statistical mechanics. They are typically large positive integers, or more generally, large positive real numbers, but may also be other numbers in other contexts. Googology is the study of nomenclature and properties of large numbers.
The long and short scales are two of several naming systems for integer powers of ten which use some of the same terms for different magnitudes. Some languages, particularly in East Asia and South Asia, have large number naming systems that are different from both the long and short scales, such as Chinese, Japanese or Korean numerals, and the Indian numbering system. Much of the remainder of the world adopted either the short scale or the long scale for everyday counting powers of ten.
Giga (ˈgɪgə or ˈdʒɪgə) is a unit prefix in the metric system denoting a factor of a short-scale billion or long-scale milliard (109 or 1 000 000 000). It has the symbol G. Giga is derived from the Greek word γίγας (gígas), meaning "giant". The Oxford English Dictionary reports the earliest written use of giga in this sense to be in the Reports of the IUPAC 14th Conférence Internationale de Chimie in 1947: "The following prefixes to abbreviations for the names of units should be used: G giga 109×.
A googol is the large number 10100. In decimal notation, it is written as the digit 1 followed by one hundred zeroes: 10,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000. Its systematic name is 10 duotrigintillion. (The short scale names are standard in the English-speaking world.) The term was coined in 1920 by 9-year-old Milton Sirotta (1911–1981), nephew of U.S. mathematician Edward Kasner.
1,000,000,000 (one billion, short scale; one thousand million or one milliard, one yard, long scale) is the natural number following 999,999,999 and preceding 1,000,000,001. With a number, "billion" can be abbreviated as b, bil or bn. In standard form, it is written as 1 × 109. The metric prefix giga indicates 1,000,000,000 times the base unit. Its symbol is G. One billion years may be called an eon in astronomy or geology. Previously in British English (but not in American English), the word "billion" referred exclusively to a million millions (1,000,000,000,000).
The Zimbabwean dollar (sign: ,orZ to distinguish it from other dollar-denominated currencies) was the name of four official currencies of Zimbabwe from 1980 to 12 April 2009. During this time, it was subject to periods of extreme inflation, followed by a period of hyperinflation. The Zimbabwean dollar was introduced in 1980 to directly replace the Rhodesian dollar (which had been introduced in 1970) at par (1:1), at a similar value to the US dollar. The pengő (ˈpɛŋɡøː; sometimes written as pengo or pengoe in English) was the currency of Hungary between 1 January 1927, when it replaced the korona, and 31 July 1946, when it was replaced by the forint. The pengő was subdivided into 100 fillér. Although the introduction of the pengő was part of a post-World War I stabilisation program, the currency survived for only 20 years and experienced the most serious case of hyperinflation ever recorded.
A year is the orbital period of a planetary body, for example, the Earth, moving in its orbit around the Sun. Due to the Earth's axial tilt, the course of a year sees the passing of the seasons, marked by change in weather, the hours of daylight, and, consequently, vegetation and soil fertility. In temperate and subpolar regions around the planet, four seasons are generally recognized: spring, summer, autumn and winter.
An order of magnitude is an approximation of the logarithm of a value relative to some contextually understood reference value, usually 10, interpreted as the base of the logarithm and the representative of values of magnitude one. Logarithmic distributions are common in nature and considering the order of magnitude of values sampled from such a distribution can be more intuitive. When the reference value is 10, the order of magnitude can be understood as the number of digits in the base-10 representation of the value.
A light-year, alternatively spelled light year, is a unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (9.46e12km), or 5.88 trillion miles (5.88e12mi). As defined by the International Astronomical Union (IAU), a light-year is the distance that light travels in a vacuum in one Julian year (365.25 days). Because it includes the word "year", the term is sometimes misinterpreted as a unit of time.
