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

The distance to a remote galaxy based on its redshift assuming that the redshift is caused by the → Doppler effect and reflects the general expansion of the Universe.

→ cosmological; → distance .

→ cosmological; → epoch.

A mathematical description of the Universe, based on observation, which tries to explain its current aspect, and to describe its evolution during time.

→ cosmological; → model.

The → hypothesis that on → large scales the → Universe is → isotropic and → homogeneous, that is, it appears the same at all places and, from any one place, looks the same in all directions. See also → perfect cosmological principle.

Introduced by E.A. Milne in 1933; → cosmological; → principle.

The → redshift of a remote object (galaxy, quasar, supenova) due to the expansion of the Universe.

→ cosmological; → redshift.

The science of the origin, structure, and evolution of the Universe including the origin of galaxies, the chemical elements, and matter.

Cosmology, from → cosmo- + → -logy.

Keyhânšenâsi, from keyhân, → cosmos, + šenâsi, → -logy.

The science of forms, properties, and structure of crystals.

→ crystal; → -graphy; → -logy.

The → Universe at the → redshift z = 0.

→ current; → cosmological; → epoch.

→ common logarithm.

→ decimal; → logarithm.

The branch of → botany dealing with trees and shrubs. Dendrology studies the distinguishing characteristics of tree species for the purpose of identification and classification into orders and other natural groups.

From dendro- a combining form meaning "tree," from Gk. dendron "tree," related to Pers. dâr, → tree, + → -logy.

A chemical compound produced in laboratory experiments to simulate real → interstellar dust grains and thus study them.

→ dust; → analogue.

A catalog of fields along the → ecliptic observed by the → K2 mission. The catalog is hosted at the → Mikulski Archive for Space Telescopes (MAST).

→ ecliptic; → plane; → input; → catalogue.

1) The scientific discipline that is concerned with the relationships between living organisms and their past, present, and future environments.
2) The study of the damaging effects of modern civilisation on the environment, with the aim of prevention or reversal through conservation.

→ eco- + → -logy.

A branch of philosophy that investigates the possibility, origins, nature, methods, and limits of human knowledge.

From Gk. episteme "knowledge," from Ionic Gk. epistasthai "to understand," literally "overstand," from → epi- "over, near" + histasthai "to stand;" cognate with Pers. istâdan "to stand," → standard; PIE base *sta- "to stand."

From šenaxt, → knowledge, + -šenâsi, → -logy.

The study of specific cultures (ethnic groups) in their different aspects (anthropological, social, cultural, etc.) to establish similarities and disparities between them.

→ ethno-; → logy.

The study of the origins and history of the form and meaning of → words.

M.E., from L. etymologia, from Gk. etymologia, from etymon "true sense" (neuter of etymos) + logos, → -logy.

Riše-šenâsi, from rišé "root" (dialectal Tabari rexa; Kurd. regez, riše), from Mid.Pers. rêšak "root," maybe ultimately related to PIE *u(e)rad-, although the Skt. offshoot is absent (Gk. rhiza "root;" L. radix, radius "staff;" O.H.G. wurz "plant, herb;" Ger. Wurz; O.E. rot; E. root) + -šenâsi, → -logy.

The study of life beyond the Earth's atmosphere, as on other planets; also → astrobiology.

→ exo-; → biology.

The part of → astrophysics that searches and studies → extrasolar planets.

→ exoplanet; → -logy.

A system of → formal logic that is an extension of → propositional logic. It is also known as → first-order predicate calculus and → predicate logic. FOL eliminates deficiencies of propositional logic by: representing → objects (their properties, relations and statements about them), introducing → variables, and introducing → quantifiers.

→ first; → order; → predicate; → logic.

The traditional or → classical logic in which the → validity or → invalidity of a conclusion is deduced from two or more statements (→ premises). Based on Aristotle's (384-322 BC) theory of → syllogism, systematized in his book "Organon," its focus is not on what is stated (the content) but on the structure (form) of the → argument and the validity of the inference drawn from the premises of the argument; if the premises are true then the logical consequence must also be true. Formal logic is → bivalent, that is it recognizes only two → truth values: → true and → false. The basic principles of formal logic are: 1) → principle of identity, 2) → principle of excluded middle, and 3) → principle of non-contradiction. See also → symbolic logic, → fuzzy logic.

→ formal; → logic.