Peta (prefix)
Encyclopedia
Peta- is a prefix
in the metric system
denoting 1015 or . For example:
1 petametre = 1015 metre
s
1 petasecond = 1015 second
s
Adopted in 1975, it was derived from the Greek
πέντε, meaning "five", because of the five in 10005, for which it stands. The peta- prefix is similar to the penta- prefix (for "five"), but without the letter n. This omission is modelled on the way the similar tera- prefix (actually from Greek τέρας = 'monster') for 10004 seems to omit a letter from the tetra- prefix (for "four").
Examples:
In computer science
peta- can sometimes mean (10245 or 250), instead of , especially when used to prefix the byte
, giving a petabyte
. To resolve this ambiguity, the term pebibyte
has been suggested to mean 250 byte
s.
SI prefix
The International System of Units specifies a set of unit prefixes known as SI prefixes or metric prefixes. An SI prefix is a name that precedes a basic unit of measure to indicate a decadic multiple or fraction of the unit. Each prefix has a unique symbol that is prepended to the unit symbol...
in the metric system
Metric system
The metric system is an international decimalised system of measurement. France was first to adopt a metric system, in 1799, and a metric system is now the official system of measurement, used in almost every country in the world...
denoting 1015 or . For example:
1 petametre = 1015 metre
Metre
The metre , symbol m, is the base unit of length in the International System of Units . Originally intended to be one ten-millionth of the distance from the Earth's equator to the North Pole , its definition has been periodically refined to reflect growing knowledge of metrology...
s
1 petasecond = 1015 second
Second
The second is a unit of measurement of time, and is the International System of Units base unit of time. It may be measured using a clock....
s
Adopted in 1975, it was derived from the Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
πέντε, meaning "five", because of the five in 10005, for which it stands. The peta- prefix is similar to the penta- prefix (for "five"), but without the letter n. This omission is modelled on the way the similar tera- prefix (actually from Greek τέρας = 'monster') for 10004 seems to omit a letter from the tetra- prefix (for "four").
Examples:
- the mass–energy equivalence is 89.9 PJ/kg
- 1 light-yearLight-yearA light-year, also light year or lightyear is a unit of length, equal to just under 10 trillion kilometres...
= 9.461 Pm
In computer science
Computer science
Computer science or computing science is the study of the theoretical foundations of information and computation and of practical techniques for their implementation and application in computer systems...
peta- can sometimes mean (10245 or 250), instead of , especially when used to prefix the byte
Byte
The byte is a unit of digital information in computing and telecommunications that most commonly consists of eight bits. Historically, a byte was the number of bits used to encode a single character of text in a computer and for this reason it is the basic addressable element in many computer...
, giving a petabyte
Petabyte
A petabyte is a unit of information equal to one quadrillion bytes, or 1000 terabytes. The unit symbol for the petabyte is PB...
. To resolve this ambiguity, the term pebibyte
Pebibyte
The pebibyte is a standards-based binary multiple of the byte, a unit of digital information storage. The pebibyte unit symbol is PiB....
has been suggested to mean 250 byte
Byte
The byte is a unit of digital information in computing and telecommunications that most commonly consists of eight bits. Historically, a byte was the number of bits used to encode a single character of text in a computer and for this reason it is the basic addressable element in many computer...
s.