Theoretical astronomy, the Glossary

Table of Contents

1. 150 relations: Absorption (electromagnetic radiation), Age of the universe, Algorithm, Almagest, Andromeda Galaxy, Apparent place, Astrochemistry, Astrometry, Astronomical object, Astronomical radio source, Astronomy, Astroparticle physics, Astrophysical X-ray source, Astrophysics, Atomic clock, Barycentric Coordinate Time, Barycentric Dynamical Time, Bedrock, Big Bang, Binary star, Black hole, Calendar, Cambridge University Press, Carbon, Carbon-13, Celestial mechanics, Celestial navigation, Celestial sphere, Cepheid variable, Chemical element, Chemistry, CNO cycle, Compton scattering, Computation, Computational model, Cosmic Background Explorer, Cosmic dust, Cosmic inflation, Cosmic ray, Dark energy, Dark matter, Density, Deuterium, Earth science, Earth's rotation, Electromagnetic spectrum, Electromagnetism, Ephemeris, Escape velocity, Expansion of the universe, ... Expand index (100 more) »

2. Astronomical sub-disciplines

Absorption (electromagnetic radiation)

In physics, absorption of electromagnetic radiation is how matter (typically electrons bound in atoms) takes up a photon's energy — and so transforms electromagnetic energy into internal energy of the absorber (for example, thermal energy).

See Theoretical astronomy and Absorption (electromagnetic radiation)

Age of the universe

In physical cosmology, the age of the universe is the time elapsed since the Big Bang.

See Theoretical astronomy and Age of the universe

Algorithm

In mathematics and computer science, an algorithm is a finite sequence of mathematically rigorous instructions, typically used to solve a class of specific problems or to perform a computation.

See Theoretical astronomy and Algorithm

Almagest

The Almagest is a 2nd-century mathematical and astronomical treatise on the apparent motions of the stars and planetary paths, written by Claudius Ptolemy in Koine Greek.

See Theoretical astronomy and Almagest

Andromeda Galaxy

The Andromeda Galaxy is a barred spiral galaxy and is the nearest major galaxy to the Milky Way.

See Theoretical astronomy and Andromeda Galaxy

Apparent place

The apparent place of an object is its position in space as seen by an observer. Theoretical astronomy and apparent place are astrometry.

See Theoretical astronomy and Apparent place

Astrochemistry

Astrochemistry is the study of the abundance and reactions of molecules in the universe, and their interaction with radiation. Theoretical astronomy and Astrochemistry are astronomical sub-disciplines.

See Theoretical astronomy and Astrochemistry

Astrometry

Astrometry is a branch of astronomy that involves precise measurements of the positions and movements of stars and other celestial bodies. Theoretical astronomy and Astrometry are astronomical sub-disciplines.

See Theoretical astronomy and Astrometry

Astronomical object

An astronomical object, celestial object, stellar object or heavenly body is a naturally occurring physical entity, association, or structure that exists within the observable universe.

See Theoretical astronomy and Astronomical object

Astronomical radio source

An astronomical radio source is an object in outer space that emits strong radio waves.

See Theoretical astronomy and Astronomical radio source

Astronomy

Astronomy is a natural science that studies celestial objects and the phenomena that occur in the cosmos. Theoretical astronomy and Astronomy are space science.

See Theoretical astronomy and Astronomy

Astroparticle physics

Astroparticle physics, also called particle astrophysics, is a branch of particle physics that studies elementary particles of astrophysical origin and their relation to astrophysics and cosmology.

See Theoretical astronomy and Astroparticle physics

Astrophysical X-ray source

Astrophysical X-ray sources are astronomical objects with physical properties which result in the emission of X-rays.

See Theoretical astronomy and Astrophysical X-ray source

Astrophysics

Astrophysics is a science that employs the methods and principles of physics and chemistry in the study of astronomical objects and phenomena. Theoretical astronomy and Astrophysics are astronomical sub-disciplines.

See Theoretical astronomy and Astrophysics

Atomic clock

An atomic clock is a clock that measures time by monitoring the resonant frequency of atoms.

See Theoretical astronomy and Atomic clock

Barycentric Coordinate Time

Barycentric Coordinate Time (TCB, from the French Temps-coordonnée barycentrique) is a coordinate time standard intended to be used as the independent variable of time for all calculations pertaining to orbits of planets, asteroids, comets, and interplanetary spacecraft in the Solar System.

See Theoretical astronomy and Barycentric Coordinate Time

Barycentric Dynamical Time

Barycentric Dynamical Time (TDB, from the French Temps Dynamique Barycentrique) is a relativistic coordinate time scale, intended for astronomical use as a time standard to take account of time dilation when calculating orbits and astronomical ephemerides of planets, asteroids, comets and interplanetary spacecraft in the Solar System.

See Theoretical astronomy and Barycentric Dynamical Time

Bedrock

In geology, bedrock is solid rock that lies under loose material (regolith) within the crust of Earth or another terrestrial planet.

See Theoretical astronomy and Bedrock

Big Bang

The Big Bang is a physical theory that describes how the universe expanded from an initial state of high density and temperature.

See Theoretical astronomy and Big Bang

Binary star

A binary star or binary star system is a system of two stars that are gravitationally bound to and in orbit around each other.

See Theoretical astronomy and Binary star

Black hole

A black hole is a region of spacetime where gravity is so strong that nothing, not even light and other electromagnetic waves, is capable of possessing enough energy to escape it.

See Theoretical astronomy and Black hole

Calendar

A calendar is a system of organizing days.

See Theoretical astronomy and Calendar

Cambridge University Press

Cambridge University Press is the university press of the University of Cambridge.

See Theoretical astronomy and Cambridge University Press

Carbon

Carbon is a chemical element; it has symbol C and atomic number 6.

See Theoretical astronomy and Carbon

Carbon-13

Carbon-13 (13C) is a natural, stable isotope of carbon with a nucleus containing six protons and seven neutrons.

See Theoretical astronomy and Carbon-13

Celestial mechanics

Celestial mechanics is the branch of astronomy that deals with the motions of objects in outer space. Theoretical astronomy and Celestial mechanics are astrometry and astronomical sub-disciplines.

See Theoretical astronomy and Celestial mechanics

Celestial navigation

Celestial navigation, also known as astronavigation, is the practice of position fixing using stars and other celestial bodies that enables a navigator to accurately determine their actual current physical position in space or on the surface of the Earth without relying solely on estimated positional calculations, commonly known as dead reckoning.

See Theoretical astronomy and Celestial navigation

Celestial sphere

In astronomy and navigation, the celestial sphere is an abstract sphere that has an arbitrarily large radius and is concentric to Earth. Theoretical astronomy and celestial sphere are astronomical coordinate systems.

See Theoretical astronomy and Celestial sphere

Cepheid variable

A Cepheid variable is a type of variable star that pulsates radially, varying in both diameter and temperature. Theoretical astronomy and Cepheid variable are astrometry.

See Theoretical astronomy and Cepheid variable

Chemical element

A chemical element is a chemical substance that cannot be broken down into other substances by chemical reactions.

See Theoretical astronomy and Chemical element

Chemistry

Chemistry is the scientific study of the properties and behavior of matter.

See Theoretical astronomy and Chemistry

CNO cycle

The CNO cycle (for carbon–nitrogen–oxygen; sometimes called Bethe–Weizsäcker cycle after Hans Albrecht Bethe and Carl Friedrich von Weizsäcker) is one of the two known sets of fusion reactions by which stars convert hydrogen to helium, the other being the proton–proton chain reaction (p–p cycle), which is more efficient at the Sun's core temperature.

See Theoretical astronomy and CNO cycle

Compton scattering

Compton scattering (or the Compton effect) is the quantum theory of high frequency photons scattering following an interaction with a charged particle, usually an electron. Theoretical astronomy and Compton scattering are observational astronomy.

See Theoretical astronomy and Compton scattering

Computation

A computation is any type of arithmetic or non-arithmetic calculation that is well-defined.

See Theoretical astronomy and Computation

Computational model

A computational model uses computer programs to simulate and study complex systems using an algorithmic or mechanistic approach and is widely used in a diverse range of fields spanning from physics, engineering, chemistry and biology to economics, psychology, cognitive science and computer science.

See Theoretical astronomy and Computational model

Cosmic Background Explorer

The Cosmic Background Explorer (COBE), also referred to as Explorer 66, was a NASA satellite dedicated to cosmology, which operated from 1989 to 1993.

See Theoretical astronomy and Cosmic Background Explorer

Cosmic dust

Cosmic dustalso called extraterrestrial dust, space dust, or star dustis dust that occurs in outer space or has fallen onto Earth.

See Theoretical astronomy and Cosmic dust

Cosmic inflation

In physical cosmology, cosmic inflation, cosmological inflation, or just inflation, is a theory of exponential expansion of space in the early universe.

See Theoretical astronomy and Cosmic inflation

Cosmic ray

Cosmic rays or astroparticles are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light.

See Theoretical astronomy and Cosmic ray

Dark energy

In physical cosmology and astronomy, dark energy is an unknown form of energy that affects the universe on the largest scales.

See Theoretical astronomy and Dark energy

Dark matter

In astronomy, dark matter is a hypothetical form of matter that appears not to interact with light or the electromagnetic field.

See Theoretical astronomy and Dark matter

Density

Density (volumetric mass density or specific mass) is a substance's mass per unit of volume.

See Theoretical astronomy and Density

Deuterium

Deuterium (hydrogen-2, symbol H or D, also known as heavy hydrogen) is one of two stable isotopes of hydrogen (the other is protium, or hydrogen-1).

See Theoretical astronomy and Deuterium

Earth science

Earth science or geoscience includes all fields of natural science related to the planet Earth.

See Theoretical astronomy and Earth science

Earth's rotation

Earth's rotation or Earth's spin is the rotation of planet Earth around its own axis, as well as changes in the orientation of the rotation axis in space.

See Theoretical astronomy and Earth's rotation

Electromagnetic spectrum

The electromagnetic spectrum is the full range of electromagnetic radiation, organized by frequency or wavelength.

See Theoretical astronomy and Electromagnetic spectrum

Electromagnetism

In physics, electromagnetism is an interaction that occurs between particles with electric charge via electromagnetic fields.

See Theoretical astronomy and Electromagnetism

Ephemeris

In astronomy and celestial navigation, an ephemeris (pl. ephemerides) is a book with tables that gives the trajectory of naturally occurring astronomical objects as well as artificial satellites in the sky, i.e., the position (and possibly velocity) over time. Theoretical astronomy and ephemeris are astrometry.

See Theoretical astronomy and Ephemeris

Escape velocity

In celestial mechanics, escape velocity or escape speed is the minimum speed needed for an object to escape from contact with or orbit of a primary body, assuming.

See Theoretical astronomy and Escape velocity

Expansion of the universe

The expansion of the universe is the increase in distance between gravitationally unbound parts of the observable universe with time.

See Theoretical astronomy and Expansion of the universe

Figure of the Earth

In geodesy, the figure of the Earth is the size and shape used to model planet Earth.

See Theoretical astronomy and Figure of the Earth

Flatness problem

The flatness problem (also known as the oldness problem) is a cosmological fine-tuning problem within the Big Bang model of the universe.

See Theoretical astronomy and Flatness problem

Frame of reference

In physics and astronomy, a frame of reference (or reference frame) is an abstract coordinate system whose origin, orientation, and scale are specified by a set of reference points―geometric points whose position is identified both mathematically (with numerical coordinate values) and physically (signaled by conventional markers).

See Theoretical astronomy and Frame of reference

Galaxy formation and evolution

The study of galaxy formation and evolution is concerned with the processes that formed a heterogeneous universe from a homogeneous beginning, the formation of the first galaxies, the way galaxies change over time, and the processes that have generated the variety of structures observed in nearby galaxies.

See Theoretical astronomy and Galaxy formation and evolution

Galaxy groups and clusters

Galaxy groups and clusters are the largest known gravitationally bound objects to have arisen thus far in the process of cosmic structure formation.

See Theoretical astronomy and Galaxy groups and clusters

General relativity

General relativity, also known as the general theory of relativity and Einstein's theory of gravity, is the geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of gravitation in modern physics.

See Theoretical astronomy and General relativity

Geocentric Coordinate Time

Geocentric Coordinate Time (TCG - Temps-coordonnée géocentrique) is a coordinate time standard intended to be used as the independent variable of time for all calculations pertaining to precession, nutation, the Moon, and artificial satellites of the Earth.

See Theoretical astronomy and Geocentric Coordinate Time

Geocentric model

In astronomy, the geocentric model (also known as geocentrism, often exemplified specifically by the Ptolemaic system) is a superseded description of the Universe with Earth at the center. Theoretical astronomy and geocentric model are astronomical coordinate systems.

See Theoretical astronomy and Geocentric model

Geodesy

Geodesy or geodetics is the science of measuring and representing the geometry, gravity, and spatial orientation of the Earth in temporally varying 3D.

See Theoretical astronomy and Geodesy

Geoid

The geoid is the shape that the ocean surface would take under the influence of the gravity of Earth, including gravitational attraction and Earth's rotation, if other influences such as winds and tides were absent.

See Theoretical astronomy and Geoid

Geology

Geology is a branch of natural science concerned with the Earth and other astronomical objects, the rocks of which they are composed, and the processes by which they change over time.

See Theoretical astronomy and Geology

Gravitational collapse

Gravitational collapse is the contraction of an astronomical object due to the influence of its own gravity, which tends to draw matter inward toward the center of gravity.

See Theoretical astronomy and Gravitational collapse

Gravitational constant

The gravitational constant is an empirical physical constant involved in the calculation of gravitational effects in Sir Isaac Newton's law of universal gravitation and in Albert Einstein's theory of general relativity.

See Theoretical astronomy and Gravitational constant

Gravitational wave

Gravitational waves are waves of the intensity of gravity that are generated by the accelerated masses of binary stars and other motions of gravitating masses, and propagate as waves outward from their source at the speed of light.

See Theoretical astronomy and Gravitational wave

Gravity

In physics, gravity is a fundamental interaction which causes mutual attraction between all things that have mass.

See Theoretical astronomy and Gravity

Greenwich Mean Time

Greenwich Mean Time (GMT) is the local mean time at the Royal Observatory in Greenwich, London, counted from midnight.

See Theoretical astronomy and Greenwich Mean Time

Helium

Helium (from lit) is a chemical element; it has symbol He and atomic number 2.

See Theoretical astronomy and Helium

Hubble Space Telescope

The Hubble Space Telescope (often referred to as HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation.

See Theoretical astronomy and Hubble Space Telescope

Hydrogen

Hydrogen is a chemical element; it has symbol H and atomic number 1.

See Theoretical astronomy and Hydrogen

Internal pressure

Internal pressure is a measure of how the internal energy of a system changes when it expands or contracts at constant temperature.

See Theoretical astronomy and Internal pressure

International Astronomical Union

The International Astronomical Union (IAU; Union astronomique internationale, UAI) is an international non-governmental organization (INGO) with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach, education, and development through global cooperation.

See Theoretical astronomy and International Astronomical Union

International Atomic Time

International Atomic Time (abbreviated TAI, from its French name temps atomique international) is a high-precision atomic coordinate time standard based on the notional passage of proper time on Earth's geoid.

See Theoretical astronomy and International Atomic Time

International Celestial Reference System and its realizations

The International Celestial Reference System (ICRS) is the current standard celestial reference system adopted by the International Astronomical Union (IAU). Theoretical astronomy and International Celestial Reference System and its realizations are astrometry and astronomical coordinate systems.

See Theoretical astronomy and International Celestial Reference System and its realizations

International Earth Rotation and Reference Systems Service

The International Earth Rotation and Reference Systems Service (IERS), formerly the International Earth Rotation Service, is the body responsible for maintaining global time and reference frame standards, notably through its Earth Orientation Parameter (EOP) and International Celestial Reference System (ICRS) groups.

See Theoretical astronomy and International Earth Rotation and Reference Systems Service

International System of Units

The International System of Units, internationally known by the abbreviation SI (from French Système international d'unités), is the modern form of the metric system and the world's most widely used system of measurement.

See Theoretical astronomy and International System of Units

Interplanetary spaceflight

Interplanetary spaceflight or interplanetary travel is the crewed or uncrewed travel between stars and planets, usually within a single planetary system.

See Theoretical astronomy and Interplanetary spaceflight

Interstellar medium

The interstellar medium (ISM) is the matter and radiation that exists in the space between the star systems in a galaxy.

See Theoretical astronomy and Interstellar medium

Iron

Iron is a chemical element.

See Theoretical astronomy and Iron

Isotope

Isotopes are distinct nuclear species (or nuclides) of the same chemical element.

See Theoretical astronomy and Isotope

Isotopes of caesium

Caesium (55Cs) has 41 known isotopes, the atomic masses of these isotopes range from 112 to 152.

See Theoretical astronomy and Isotopes of caesium

Isotopes of nitrogen

Natural nitrogen (7N) consists of two stable isotopes: the vast majority (99.6%) of naturally occurring nitrogen is nitrogen-14, with the remainder being nitrogen-15.

See Theoretical astronomy and Isotopes of nitrogen

Jet Propulsion Laboratory

Jet Propulsion Laboratory (JPL) is a Federally Funded Research and Development Center (FFRDC) in La Cañada Flintridge, California, Crescenta Valley, United States.

See Theoretical astronomy and Jet Propulsion Laboratory

Johannes Kepler

Johannes Kepler (27 December 1571 – 15 November 1630) was a German astronomer, mathematician, astrologer, natural philosopher and writer on music.

See Theoretical astronomy and Johannes Kepler

Kepler's laws of planetary motion

In astronomy, Kepler's laws of planetary motion, published by Johannes Kepler between 1609 and 1619, describe the orbits of planets around the Sun.

See Theoretical astronomy and Kepler's laws of planetary motion

Kerogen

Kerogen is solid, insoluble organic matter in sedimentary rocks.

See Theoretical astronomy and Kerogen

Lambda-CDM model

The Lambda-CDM, Lambda cold dark matter, or ΛCDM model is a mathematical model of the Big Bang theory with three major components.

See Theoretical astronomy and Lambda-CDM model

Large Magellanic Cloud

The Large Magellanic Cloud (LMC) is a dwarf galaxy and satellite galaxy of the Milky Way.

See Theoretical astronomy and Large Magellanic Cloud

Lead

Lead is a chemical element; it has symbol Pb (from Latin plumbum) and atomic number 82.

See Theoretical astronomy and Lead

Lithium

Lithium is a chemical element; it has symbol Li and atomic number 3.

See Theoretical astronomy and Lithium

Mass

Mass is an intrinsic property of a body.

See Theoretical astronomy and Mass

Mathematical model

A mathematical model is an abstract description of a concrete system using mathematical concepts and language.

See Theoretical astronomy and Mathematical model

Matter

In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume.

See Theoretical astronomy and Matter

Meteorite

A meteorite is a rock that originated in outer space and has fallen to the surface of a planet or moon.

See Theoretical astronomy and Meteorite

Molecular cloud

A molecular cloud, sometimes called a stellar nursery (if star formation is occurring within), is a type of interstellar cloud, the density and size of which permit absorption nebulae, the formation of molecules (most commonly molecular hydrogen, H2), and the formation of H II regions.

See Theoretical astronomy and Molecular cloud

Monthly Notices of the Royal Astronomical Society

Monthly Notices of the Royal Astronomical Society (MNRAS) is a peer-reviewed scientific journal in astronomy, astrophysics and related fields.

See Theoretical astronomy and Monthly Notices of the Royal Astronomical Society

Moon

The Moon is Earth's only natural satellite.

See Theoretical astronomy and Moon

NASA

The National Aeronautics and Space Administration (NASA) is an independent agency of the U.S. federal government responsible for the civil space program, aeronautics research, and space research.

See Theoretical astronomy and NASA

NASA Deep Space Network

The NASA Deep Space Network (DSN) is a worldwide network of spacecraft communication ground segment facilities, located in the United States (California), Spain (Madrid), and Australia (Canberra), that supports NASA's interplanetary spacecraft missions.

See Theoretical astronomy and NASA Deep Space Network

Natural satellite

A natural satellite is, in the most common usage, an astronomical body that orbits a planet, dwarf planet, or small Solar System body (or sometimes another natural satellite).

See Theoretical astronomy and Natural satellite

Nitrogen

Nitrogen is a chemical element; it has symbol N and atomic number 7.

See Theoretical astronomy and Nitrogen

Nordtvedt effect

In theoretical astrophysics, the Nordtvedt effect refers to the relative motion between the Earth and the Moon that would be observed if the gravitational self-energy of a body contributed differently to its gravitational mass than to its inertial mass.

See Theoretical astronomy and Nordtvedt effect

Nuclear fusion

Nuclear fusion is a reaction in which two or more atomic nuclei, usually deuterium and tritium (hydrogen isotopes), combine to form one or more different atomic nuclei and subatomic particles (neutrons or protons).

See Theoretical astronomy and Nuclear fusion

Nuclear physics

Nuclear physics is the field of physics that studies atomic nuclei and their constituents and interactions, in addition to the study of other forms of nuclear matter.

See Theoretical astronomy and Nuclear physics

Nucleosynthesis

Nucleosynthesis is the process that creates new atomic nuclei from pre-existing nucleons (protons and neutrons) and nuclei.

See Theoretical astronomy and Nucleosynthesis

Numerical analysis

Numerical analysis is the study of algorithms that use numerical approximation (as opposed to symbolic manipulations) for the problems of mathematical analysis (as distinguished from discrete mathematics).

See Theoretical astronomy and Numerical analysis

Observable universe

The observable universe is a ball-shaped region of the universe consisting of all matter that can be observed from Earth or its space-based telescopes and exploratory probes at the present time; the electromagnetic radiation from these objects has had time to reach the Solar System and Earth since the beginning of the cosmological expansion.

See Theoretical astronomy and Observable universe

Observational astronomy

Observational astronomy is a division of astronomy that is concerned with recording data about the observable universe, in contrast with theoretical astronomy, which is mainly concerned with calculating the measurable implications of physical models. Theoretical astronomy and Observational astronomy are astronomical sub-disciplines.

See Theoretical astronomy and Observational astronomy

Orbital mechanics

Orbital mechanics or astrodynamics is the application of ballistics and celestial mechanics to the practical problems concerning the motion of rockets, satellites, and other spacecraft.

See Theoretical astronomy and Orbital mechanics

Oxygen

Oxygen is a chemical element; it has symbol O and atomic number 8.

See Theoretical astronomy and Oxygen

Physical cosmology

Physical cosmology is a branch of cosmology concerned with the study of cosmological models. Theoretical astronomy and Physical cosmology are astronomical sub-disciplines.

See Theoretical astronomy and Physical cosmology

Physics

Physics is the natural science of matter, involving the study of matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force.

See Theoretical astronomy and Physics

Planet

A planet is a large, rounded astronomical body that is generally required to be in orbit around a star, stellar remnant, or brown dwarf, and is not one itself. Theoretical astronomy and planet are observational astronomy.

See Theoretical astronomy and Planet

Polycyclic aromatic hydrocarbon

A polycyclic aromatic hydrocarbon (PAH) is a class of organic compounds that is composed of multiple aromatic rings.

See Theoretical astronomy and Polycyclic aromatic hydrocarbon

Polytrope

In astrophysics, a polytrope refers to a solution of the Lane–Emden equation in which the pressure depends upon the density in the form P.

See Theoretical astronomy and Polytrope

Proper motion

Proper motion is the astrometric measure of the observed changes in the apparent places of stars or other celestial objects in the sky, as seen from the center of mass of the Solar System, compared to the abstract background of the more distant stars. Theoretical astronomy and Proper motion are astrometry and stellar astronomy.

See Theoretical astronomy and Proper motion

Proton

A proton is a stable subatomic particle, symbol, H+, or 1H+ with a positive electric charge of +1 e (elementary charge).

See Theoretical astronomy and Proton

Ptolemy

Claudius Ptolemy (Πτολεμαῖος,; Claudius Ptolemaeus; AD) was an Alexandrian mathematician, astronomer, astrologer, geographer, and music theorist who wrote about a dozen scientific treatises, three of which were important to later Byzantine, Islamic, and Western European science.

See Theoretical astronomy and Ptolemy

Pulsar

A pulsar (from pulsating radio source) is a highly magnetized rotating neutron star that emits beams of electromagnetic radiation out of its magnetic poles.

See Theoretical astronomy and Pulsar

Quantum fluctuation

In quantum physics, a quantum fluctuation (also known as a vacuum state fluctuation or vacuum fluctuation) is the temporary random change in the amount of energy in a point in space, as prescribed by Werner Heisenberg's uncertainty principle.

See Theoretical astronomy and Quantum fluctuation

Radar astronomy

Radar astronomy is a technique of observing nearby astronomical objects by reflecting radio waves or microwaves off target objects and analyzing their reflections. Theoretical astronomy and Radar astronomy are observational astronomy.

See Theoretical astronomy and Radar astronomy

Radio astronomy

Radio astronomy is a subfield of astronomy that studies celestial objects at radio frequencies. Theoretical astronomy and radio astronomy are astronomical imaging, astronomical sub-disciplines and observational astronomy.

See Theoretical astronomy and Radio astronomy

Radio telescope

A radio telescope is a specialized antenna and radio receiver used to detect radio waves from astronomical radio sources in the sky. Theoretical astronomy and radio telescope are astronomical imaging.

See Theoretical astronomy and Radio telescope

Radius

In classical geometry, a radius (radii or radiuses) of a circle or sphere is any of the line segments from its center to its perimeter, and in more modern usage, it is also their length.

See Theoretical astronomy and Radius

Red giant

A red giant is a luminous giant star of low or intermediate mass (roughly 0.3–8 solar masses) in a late phase of stellar evolution.

See Theoretical astronomy and Red giant

Satellite geodesy

Satellite geodesy is geodesy by means of artificial satellites—the measurement of the form and dimensions of Earth, the location of objects on its surface and the figure of the Earth's gravity field by means of artificial satellite techniques.

See Theoretical astronomy and Satellite geodesy

Satellite navigation

A satellite navigation or satnav system is a system that uses satellites to provide autonomous geopositioning.

See Theoretical astronomy and Satellite navigation

Scattering

In physics, scattering is a wide range of physical processes where moving particles or radiation of some form, such as light or sound, are forced to deviate from a straight trajectory by localized non-uniformities (including particles and radiation) in the medium through which they pass.

See Theoretical astronomy and Scattering

Science in the Renaissance

During the Renaissance, great advances occurred in geography, astronomy, chemistry, physics, mathematics, manufacturing, anatomy and engineering.

See Theoretical astronomy and Science in the Renaissance

Sidereal time

Sidereal time ("sidereal" pronounced) is a system of timekeeping used especially by astronomers.

See Theoretical astronomy and Sidereal time

SN 1987A

SN 1987A was a type II supernova in the Large Magellanic Cloud, a dwarf satellite galaxy of the Milky Way.

See Theoretical astronomy and SN 1987A

Solar System

The Solar SystemCapitalization of the name varies. Theoretical astronomy and Solar System are space science.

See Theoretical astronomy and Solar System

Solar time

Solar time is a calculation of the passage of time based on the position of the Sun in the sky.

See Theoretical astronomy and Solar time

Spacecraft

A spacecraft is a vehicle that is designed to fly and operate in outer space.

See Theoretical astronomy and Spacecraft

Spectroscopy

Spectroscopy is the field of study that measures and interprets electromagnetic spectra. Theoretical astronomy and Spectroscopy are observational astronomy.

See Theoretical astronomy and Spectroscopy

Star

A star is a luminous spheroid of plasma held together by self-gravity. Theoretical astronomy and star are stellar astronomy.

See Theoretical astronomy and Star

Star cluster

Star clusters are large groups of stars held together by self-gravitation.

See Theoretical astronomy and Star cluster

Star system

A star system or stellar system is a small number of stars that orbit each other, bound by gravitational attraction.

See Theoretical astronomy and Star system

Stellar dynamics

Stellar dynamics is the branch of astrophysics which describes in a statistical way the collective motions of stars subject to their mutual gravity. Theoretical astronomy and Stellar dynamics are stellar astronomy.

See Theoretical astronomy and Stellar dynamics

Stellar evolution

Stellar evolution is the process by which a star changes over the course of its lifetime and how it can lead to the creation of a new star. Theoretical astronomy and Stellar evolution are stellar astronomy.

See Theoretical astronomy and Stellar evolution

String theory

In physics, string theory is a theoretical framework in which the point-like particles of particle physics are replaced by one-dimensional objects called strings.

See Theoretical astronomy and String theory

Sun

The Sun is the star at the center of the Solar System.

See Theoretical astronomy and Sun

Supernova

A supernova (supernovae or supernovas) is a powerful and luminous explosion of a star.

See Theoretical astronomy and Supernova

Synchrotron radiation

Synchrotron radiation (also known as magnetobremsstrahlung radiation) is the electromagnetic radiation emitted when relativistic charged particles are subject to an acceleration perpendicular to their velocity.

See Theoretical astronomy and Synchrotron radiation

Terrestrial Time

Terrestrial Time (TT) is a modern astronomical time standard defined by the International Astronomical Union, primarily for time-measurements of astronomical observations made from the surface of Earth.

See Theoretical astronomy and Terrestrial Time

Thermal radiation

Thermal radiation is electromagnetic radiation emitted by the thermal motion of particles in matter.

See Theoretical astronomy and Thermal radiation

Time standard

A time standard is a specification for measuring time: either the rate at which time passes or points in time or both.

See Theoretical astronomy and Time standard

Trihydrogen cation

The trihydrogen cation or protonated molecular hydrogen (IUPAC name: hydrogenonium ion) is a cation (positive ion) with formula, consisting of three hydrogen nuclei (protons) sharing two electrons.

See Theoretical astronomy and Trihydrogen cation

Universal Time

Universal Time (UT or UT1) is a time standard based on Earth's rotation.

See Theoretical astronomy and Universal Time

Universe

The universe is all of space and time and their contents.

See Theoretical astronomy and Universe

X-ray astronomy

X-ray astronomy is an observational branch of astronomy which deals with the study of X-ray observation and detection from astronomical objects. Theoretical astronomy and x-ray astronomy are astronomical imaging, astronomical sub-disciplines and observational astronomy.

See Theoretical astronomy and X-ray astronomy

See also

Astronomical sub-disciplines

• Archaeoastronomy
• Astrobiology
• Astrochemistry
• Astrometry
• Astrophysics
• Celestial mechanics
• Cultural astronomy
• Extragalactic astronomy
• Forensic astronomy
• Galactic astronomy
• Gamma-ray astronomy
• Geodetic astronomy
• Gravitational-wave astronomy
• Historical astronomy
• Multi-messenger astronomy
• Neutrino astronomy
• Observational astronomy
• Physical cosmology
• Planetary science
• Radio astronomy
• Stellar astronomy
• Theoretical astronomy
• Ultraviolet astronomy
• X-ray astronomy

References

[1] https://en.wikipedia.org/wiki/Theoretical_astronomy

Also known as Mathematical astronomy, Time in astronomy.

, Figure of the Earth, Flatness problem, Frame of reference, Galaxy formation and evolution, Galaxy groups and clusters, General relativity, Geocentric Coordinate Time, Geocentric model, Geodesy, Geoid, Geology, Gravitational collapse, Gravitational constant, Gravitational wave, Gravity, Greenwich Mean Time, Helium, Hubble Space Telescope, Hydrogen, Internal pressure, International Astronomical Union, International Atomic Time, International Celestial Reference System and its realizations, International Earth Rotation and Reference Systems Service, International System of Units, Interplanetary spaceflight, Interstellar medium, Iron, Isotope, Isotopes of caesium, Isotopes of nitrogen, Jet Propulsion Laboratory, Johannes Kepler, Kepler's laws of planetary motion, Kerogen, Lambda-CDM model, Large Magellanic Cloud, Lead, Lithium, Mass, Mathematical model, Matter, Meteorite, Molecular cloud, Monthly Notices of the Royal Astronomical Society, Moon, NASA, NASA Deep Space Network, Natural satellite, Nitrogen, Nordtvedt effect, Nuclear fusion, Nuclear physics, Nucleosynthesis, Numerical analysis, Observable universe, Observational astronomy, Orbital mechanics, Oxygen, Physical cosmology, Physics, Planet, Polycyclic aromatic hydrocarbon, Polytrope, Proper motion, Proton, Ptolemy, Pulsar, Quantum fluctuation, Radar astronomy, Radio astronomy, Radio telescope, Radius, Red giant, Satellite geodesy, Satellite navigation, Scattering, Science in the Renaissance, Sidereal time, SN 1987A, Solar System, Solar time, Spacecraft, Spectroscopy, Star, Star cluster, Star system, Stellar dynamics, Stellar evolution, String theory, Sun, Supernova, Synchrotron radiation, Terrestrial Time, Thermal radiation, Time standard, Trihydrogen cation, Universal Time, Universe, X-ray astronomy.