An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

1) An act or fact of infecting; state of being infected.
2) An infecting agency or influence.
3) An infectious disease.
4) Computers: The presence of a virus in, or its introduction into, a computer system.

Verbal noun of → infect.

The conjunction of an inferior planet with the Sun when the planet is between the Sun and the Earth. → superior conjunction.

→ inferior; → conjunction.

The meridian transit of a star between the celestial pole and the north point of the horizon. Same as → lower culmination. → superior culmination.

→ inferior; → culmination.

A → statistical population consisting of individuals or items which either possesses the infinite property through some limiting process or is non-enumerable. For example, the population of all → real numbers between 0 and 1 and the population of all → integers are examples of infinite population. In case of random sampling with replacement, any population is always infinite.

→ infinite; → population.

1) General: The act of inflating; the state of being inflated.
2) Cosmology: A brief exponential expansion of the Universe postulated to have occurred 10^-35 seconds after the → Big Bang, in response to the separation of the → strong interaction from the → electroweak interaction. This idea aims at explaining the → flatness problem, the → horizon problem, and the → magnetic monopole problem. See also → inflaton field.

Verbal noun of → inflate.

A class of → Big Bang models of the Universe that include a finite period of accelerated expansion in their early histories. Such an event would have released enormous energy, stored until then in the vacuum of space-time. The horizon of the Universe expanded, temporarily, much faster than the speed of light. → inflaton field.

Inflationary, adj. of → inflation; → model.

The hypothetical → particle that mediates the hypothetical → inflaton field.

From inflat-, from → inflaton field, + particle suffix → -on.

A hypothetical → scalar field that provides a theoretical basis for → inflation in the early → Big Bang history of the → Universe. The inflaton field would fill space with the same energy at every point. In general, the scalar field can vary with time and space, though to a first approximation everywhere in the Universe will have the same value at any time. The field has a particle associated with it, called → inflaton, just as the → electromagnetic field is associated with the → photon. The inflaton field is characterized also by a → negative pressure that would yield a tremendous → repulsive gravity during a brief lapse of time. In the earliest moments of the Universe, space is uniformly filled with an inflaton field, whose value places it higher up on its → potential energy curve. The inflaton's → potential energy would drop in a tiny fraction of a second, on the order of 10^-35 seconds. And yet, during that brief instant, space would expand by a colossal factor, of at least 10³⁰.

→ inflaton; → field.

A change in the form of a word to indicate a change in such grammatical features as tense, person, gender, case, number, voice, or mood. A general term for → declension and → conjugation.

Verbal noun of → inflect.

A point on a → curve at which the → tangent changes direction, from rotating in one sense to rotating in the opposite sense.

→ inflection; → point.

Of, relating to, or characterized by the use of → inflection, e.g. → inflectional affix.

→ inflection + → -al.

An → inflection that is added at the end of a root word. In English there are eight inflectional affixes, which are all suffixes. They always follow derivational suffixes and do not change the category of a word.

→ inflectional + → affix.

1) Knowledge gained through study, communication, research, instruction, etc.
2) Knowledge communicated or received concerning a particular fact or circumstance; news.
3) The act or fact of informing.
4) A sequence of signals that conveys a message to a receiver. Information does not exist on its own. It is contained within something and is coded. The notion of information involves → uncertainty and → randomness; hence the necessity for calling on → probability theory and → statistics.
See also: → information content, → information entropy, → information flow, → information paradox, → information science, → information technology, → information theory, → infosphere, → quantum information, → entropy.

Verbal noun of → inform.

The → negative of the → logarithm of the → probability that a particular → message or → symbol will be emitted by a → source.

→ information; → content.

The measure of information, which is usually expressed by the average number of bits needed for storage or communication. In other words, the degree to which the values of a → random variable X are dispersed. If the → probability density function of X is P(x), the entropy is defined by: H(X) = -Σ P(x) log P(x). Also called → Shannon entropy.

→ information; → entropy.

The flow of data into a system or to the end users.

→ information; → flow.

A paradox raised in 1976 by S. Hawking (1942-2018) whose analysis of the thermodynamic properties of → black holes led him to the prediction that black holes are not in fact black, but radiate due to quantum effects. This implied that, due to the → Hawking radiation, a black hole would eventually evaporate away, leaving nothing. This deduction presented a problem for → quantum mechanics, which maintains that information can never be lost. This topic is a matter of intense debate. Many solutions have been proposed, but all of them have serious drawbacks. In order to analyze better these solutions one needs a quantum gravity theory, which does not exist at the moment. In brief, either the idea of → quantum unitarity must be given up, or a mechanism should be found by which information is not lost after it falls into a black hole.

→ information; → paradox.

Same as → informatics.

→ information; → science.

The science and activity of receiving, storing, processing, and transmitting information by using → computers.

→ information; → technology.

The mathematical theory that defines, quantifies, and analyzes the concept of → information. It involves → probability theory in → transmission of → messages when the → bits of information are subject to various distortions. Its goal is to enable as much information as possible to be reliably stored on a medium, retrieved, or communicated.
See also:
→ information content, → information entropy, → information flow, → information paradox, → information science, → information theory, → quantum information, → entropy.

→ information; → theory.