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Hydrogen line

Index Hydrogen line

The hydrogen line, 21-centimeter line or H I line refers to the electromagnetic radiation spectral line that is created by a change in the energy state of neutral hydrogen atoms. [1]

80 relations: Academic publishing, American Journal of Physics, Azimuthal quantum number, Big Bang, Chronology of the universe, Cosmic dust, Dark Ages Radio Explorer, Doppler effect, Edward Mills Purcell, Electric charge, Electromagnetic radiation, Electromagnetic spectrum, Electron, Electronvolt, Focal point (game theory), Forbidden mechanism, Frequency, Galactic Center, Galaxy, Galaxy rotation curve, Georgia State University, Giuseppe Cocconi, Gravitational constant, Ground state, H I region, H-alpha, Harmonic, Harvard University, Hendrik C. van de Hulst, Hydrogen, Hydrogen atom, Hydrogen maser, Hydrogen spectral series, Hyperfine structure, HyperPhysics, Intensity mapping, Ionosphere, Irrational number, Jan Oort, L band, Light, Matter power spectrum, Microwave, Milky Way, Opacity (optics), Oxford University Press, Philip Morrison, Photon, Photon energy, Physical cosmology, ..., Pi, Pioneer 10, Pioneer 11, Pioneer plaque, Planck constant, Planck–Einstein relation, Principal quantum number, Proportionality (mathematics), Proton, Pulsar, Quantum, Radio astronomy, Radio spectrum, Radio wave, Recombination (cosmology), Redshift, Reionization, Rydberg formula, Search for extraterrestrial intelligence, Solar System, Spacecraft, Spectral line, Spin (physics), Synchrotron radiation, Turn (geometry), Ultra high frequency, Vacuum, Velocity, Voyager 1, Voyager 2. Expand index (30 more) »

Academic publishing

Academic publishing is the subfield of publishing which distributes academic research and scholarship.

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American Journal of Physics

The American Journal of Physics is a monthly, peer-reviewed scientific journal published by the American Association of Physics Teachers and the American Institute of Physics.

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Azimuthal quantum number

The azimuthal quantum number is a quantum number for an atomic orbital that determines its orbital angular momentum and describes the shape of the orbital.

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Big Bang

The Big Bang theory is the prevailing cosmological model for the universe from the earliest known periods through its subsequent large-scale evolution.

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Chronology of the universe

The chronology of the universe describes the history and future of the universe according to Big Bang cosmology.

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Cosmic dust

Cosmic dust, also called extraterrestrial dust or space dust, is dust which exists in outer space, as well as all over planet Earth.

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Dark Ages Radio Explorer

The Dark Ages Radio Explorer (DARE) mission is a proposed concept lunar orbiter intended to identify redshifted emanations from primeval hydrogen atoms just as the first stars began to emit light.

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Doppler effect

The Doppler effect (or the Doppler shift) is the change in frequency or wavelength of a wave in relation to observer who is moving relative to the wave source.

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Edward Mills Purcell

Edward Mills Purcell (August 30, 1912 – March 7, 1997) was an American physicist who shared the 1952 Nobel Prize for Physics for his independent discovery (published 1946) of nuclear magnetic resonance in liquids and in solids.

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Electric charge

Electric charge is the physical property of matter that causes it to experience a force when placed in an electromagnetic field.

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Electromagnetic radiation

In physics, electromagnetic radiation (EM radiation or EMR) refers to the waves (or their quanta, photons) of the electromagnetic field, propagating (radiating) through space-time, carrying electromagnetic radiant energy.

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Electromagnetic spectrum

The electromagnetic spectrum is the range of frequencies (the spectrum) of electromagnetic radiation and their respective wavelengths and photon energies.

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Electron

The electron is a subatomic particle, symbol or, whose electric charge is negative one elementary charge.

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Electronvolt

In physics, the electronvolt (symbol eV, also written electron-volt and electron volt) is a unit of energy equal to approximately joules (symbol J).

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Focal point (game theory)

In game theory, a focal point (also called Schelling point) is a solution that people will tend to use in the absence of communication, because it seems natural, special, or relevant to them.

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Forbidden mechanism

In spectroscopy, a forbidden mechanism (forbidden transition or forbidden line) is a spectral line associated with absorption or emission of light by atomic nuclei, atoms, or molecules which undergo a transition that is not allowed by a particular selection rule but is allowed if the approximation associated with that rule is not made.

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Frequency

Frequency is the number of occurrences of a repeating event per unit of time.

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Galactic Center

The Galactic Center is the rotational center of the Milky Way.

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Galaxy

A galaxy is a gravitationally bound system of stars, stellar remnants, interstellar gas, dust, and dark matter.

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Galaxy rotation curve

The rotation curve of a disc galaxy (also called a velocity curve) is a plot of the orbital speeds of visible stars or gas in that galaxy versus their radial distance from that galaxy's centre.

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Georgia State University

Georgia State University (commonly referred to as Georgia State, State, or GSU) is a public research university in downtown Atlanta, Georgia, United States.

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Giuseppe Cocconi

Giuseppe Cocconi (1914–2008) was an Italian physicist who was director of the Proton Synchrotron at CERN in Geneva.

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Gravitational constant

The gravitational constant (also known as the "universal gravitational constant", the "Newtonian constant of gravitation", or the "Cavendish gravitational constant"), denoted by the letter, 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 general theory of relativity.

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Ground state

The ground state of a quantum mechanical system is its lowest-energy state; the energy of the ground state is known as the zero-point energy of the system.

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H I region

An HI region or H I region (read H one) is a cloud in the interstellar medium composed of neutral atomic hydrogen (HI), in addition to the local abundance of helium and other elements.

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H-alpha

H-alpha (Hα) is a specific deep-red visible spectral line in the Balmer series with a wavelength of 656.28 nm in air; it occurs when a hydrogen electron falls from its third to second lowest energy level.

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Harmonic

A harmonic is any member of the harmonic series, a divergent infinite series.

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Harvard University

Harvard University is a private Ivy League research university in Cambridge, Massachusetts.

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Hendrik C. van de Hulst

Hendrik Christoffel "Henk" van de Hulst (19 November 1918 – 31 July 2000) was a Dutch astronomer and mathematician.

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Hydrogen

Hydrogen is a chemical element with symbol H and atomic number 1.

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Hydrogen atom

A hydrogen atom is an atom of the chemical element hydrogen.

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Hydrogen maser

A hydrogen maser, also known as hydrogen frequency standard, is a specific type of maser that uses the intrinsic properties of the hydrogen atom to serve as a precision frequency reference.

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Hydrogen spectral series

The emission spectrum of atomic hydrogen is divided into a number of spectral series, with wavelengths given by the Rydberg formula.

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Hyperfine structure

In atomic physics, hyperfine structure refers to small shifts and splittings in the energy levels of atoms, molecules and ions, due to interaction between the state of the nucleus and the state of the electron clouds.

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HyperPhysics

HyperPhysics is an educational website about physics topics.

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Intensity mapping

In cosmology, intensity mapping is an observational technique for surveying the large-scale structure of the universe by using the integrated radio emission from unresolved gas clouds.

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Ionosphere

The ionosphere is the ionized part of Earth's upper atmosphere, from about to altitude, a region that includes the thermosphere and parts of the mesosphere and exosphere.

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Irrational number

In mathematics, the irrational numbers are all the real numbers which are not rational numbers, the latter being the numbers constructed from ratios (or fractions) of integers.

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Jan Oort

Jan Hendrik Oort (or; 28 April 1900 – 5 November 1992) was a Dutch astronomer who made significant contributions to the understanding of the Milky Way and who was a pioneer in the field of radio astronomy.

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L band

The L band is the Institute of Electrical and Electronics Engineers (IEEE) designation for the range of frequencies in the radio spectrum from 1 to 2 gigahertz (GHz).

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Light

Light is electromagnetic radiation within a certain portion of the electromagnetic spectrum.

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Matter power spectrum

The matter power spectrum describes the density contrast of the universe (the difference between the local density and the mean density) as a function of scale.

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Microwave

Microwaves are a form of electromagnetic radiation with wavelengths ranging from one meter to one millimeter; with frequencies between and.

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Milky Way

The Milky Way is the galaxy that contains our Solar System.

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Opacity (optics)

Opacity is the measure of impenetrability to electromagnetic or other kinds of radiation, especially visible light.

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Oxford University Press

Oxford University Press (OUP) is the largest university press in the world, and the second oldest after Cambridge University Press.

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Philip Morrison

Philip Morrison (November 7, 1915 – April 22, 2005) was a professor of physics at the Massachusetts Institute of Technology (MIT).

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Photon

The photon is a type of elementary particle, the quantum of the electromagnetic field including electromagnetic radiation such as light, and the force carrier for the electromagnetic force (even when static via virtual particles).

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Photon energy

Photon energy is the energy carried by a single photon.

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Physical cosmology

Physical cosmology is the study of the largest-scale structures and dynamics of the Universe and is concerned with fundamental questions about its origin, structure, evolution, and ultimate fate.

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Pi

The number is a mathematical constant.

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Pioneer 10

Pioneer 10 (originally designated Pioneer F) is an American space probe, launched in 1972 and weighing, that completed the first mission to the planet Jupiter.

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Pioneer 11

Pioneer 11 (also known as Pioneer G) is a robotic space probe launched by NASA on April 6, 1973 to study the asteroid belt, the environment around Jupiter and Saturn, solar wind and cosmic rays.

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Pioneer plaque

The Pioneer plaques are a pair of gold-anodized aluminium plaques which were placed on board the 1972 Pioneer 10 and 1973 Pioneer 11 spacecraft, featuring a pictorial message, in case either Pioneer 10 or 11 is intercepted by extraterrestrial life.

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Planck constant

The Planck constant (denoted, also called Planck's constant) is a physical constant that is the quantum of action, central in quantum mechanics.

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Planck–Einstein relation

The Planck–Einstein relationFrench & Taylor (1978), pp.

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Principal quantum number

In quantum mechanics, the principal quantum number (symbolized n) is one of four quantum numbers which are assigned to all electrons in an atom to describe that electron's state.

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Proportionality (mathematics)

In mathematics, two variables are proportional if there is always a constant ratio between them.

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Proton

| magnetic_moment.

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Pulsar

A pulsar (from pulse and -ar as in quasar) is a highly magnetized rotating neutron star or white dwarf that emits a beam of electromagnetic radiation.

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Quantum

In physics, a quantum (plural: quanta) is the minimum amount of any physical entity (physical property) involved in an interaction.

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Radio astronomy

Radio astronomy is a subfield of astronomy that studies celestial objects at radio frequencies.

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Radio spectrum

The radio spectrum is the part of the electromagnetic spectrum with frequencies from 3 Hz to 3 000 GHz (3 THz).

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Radio wave

Radio waves are a type of electromagnetic radiation with wavelengths in the electromagnetic spectrum longer than infrared light.

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Recombination (cosmology)

In cosmology, recombination refers to the epoch at which charged electrons and protons first became bound to form electrically neutral hydrogen atoms.

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Redshift

In physics, redshift happens when light or other electromagnetic radiation from an object is increased in wavelength, or shifted to the red end of the spectrum.

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Reionization

In the field of Big Bang theory, and cosmology, reionization is the process that caused the matter in the universe to reionize after the lapse of the "dark ages".

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Rydberg formula

The Rydberg formula is used in atomic physics to describe the wavelengths of spectral lines of many chemical elements.

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Search for extraterrestrial intelligence

The search for extraterrestrial intelligence (SETI) is a collective term for scientific searches for intelligent extraterrestrial life, for example, monitoring electromagnetic radiation for signs of transmissions from civilizations on other planets.

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Solar System

The Solar SystemCapitalization of the name varies.

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Spacecraft

A spacecraft is a vehicle or machine designed to fly in outer space.

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Spectral line

A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies.

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Spin (physics)

In quantum mechanics and particle physics, spin is an intrinsic form of angular momentum carried by elementary particles, composite particles (hadrons), and atomic nuclei.

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Synchrotron radiation

Synchrotron radiation (also known as magnetobremsstrahlung radiation) is the electromagnetic radiation emitted when charged particles are accelerated radially, i.e., when they are subject to an acceleration perpendicular to their velocity.

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Turn (geometry)

A turn is a unit of plane angle measurement equal to 2pi radians, 360 degrees or 400 gradians.

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Ultra high frequency

Ultra high frequency (UHF) is the ITU designation for radio frequencies in the range between 300 megahertz (MHz) and 3 gigahertz (GHz), also known as the decimetre band as the wavelengths range from one meter to one decimeter.

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Vacuum

Vacuum is space devoid of matter.

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Velocity

The velocity of an object is the rate of change of its position with respect to a frame of reference, and is a function of time.

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Voyager 1

Voyager 1 is a space probe launched by NASA on September 5, 1977.

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Voyager 2

Voyager 2 is a space probe launched by NASA on August 20, 1977, to study the outer planets.

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Redirects here:

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References

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

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