accretion

en-noun

accretion (countable and uncountable, plural accretions)

PIE word
 *h₂éd
Learned borrowing from Latin accrētiō (“increase, increment”) + English -ion (suffix forming nouns denoting actions or processes, or their results). Accrētiō is derived from accrēscō (“to grow, increase”) + -tiō (suffix forming nouns denoting actions or processes, or their results); and accrēscō is from ac- (a variant of ad-, prefix meaning ‘to’, or having an intensifying effect) + crēscō (“to grow; to increase”) (ultimately from Proto-Indo-European *ḱer- (“to cause to grow; to grow; to nourish”)).
Doublet of accrue, crescent, and increase.

af

-tiō<pos:suffix forming nouns denoting actions or processes, or their results>

ac-<pos:a variant of <i class="Latn mention" lang="la">ad-</i>, prefix meaning ‘to’, or having an intensifying effect>

прираст

(gradual) increase by an external addition of matter; an instance of this

срастване

process of separate particles aggregating or coalescing together; thing formed in this manner — see also concretion

на́леп

something gradually added to or growing on a thing externally

This theory, known as pebble accretion, is reshaping how scientists think about the early solar system. […] "In many ways, pebble accretion is the most efficient way of adding mass to a body," says Lambrechts.

2018 April 26, Alexandra Witze, “Earth may have been Formed by a Bunch of Tiny Space Pebbles”, in The Atlantic, Washington, D.C.: The Atlantic Monthly Group, →ISSN, →OCLC, archived from the original on 2023-01-28:

(uncountable) The process of separate particles aggregating or coalescing together; concretion; (countable) a thing formed in this manner.

(astrophysics) The formation of planets, stars, and other celestial bodies by the aggregating of matter drawn together by gravity; also, the growth of a celestial body through this process.

تنامي

formation of celestial bodies by the aggregating of matter drawn together by gravity; growth of a celestial body through this process


event horizon

[əˈvɛɾ̃ həˈɹaɪ.zən]

(astrophysics) The gravitational sphere of a black hole within which the escape velocity is greater than the speed of light.

waarnemingshorison

gravitational sphere within which light cannot escape

(astrophysics) The furthest distance in the past of the universe from which light signals from an event can reach an observer at later times.


secular

en-adj

secular (comparative more secular, superlative most secular)

more secular (comparative)
most secular (superlative)
sæcular (alternative)

monastic

antonym(s) of “not bound by monastic vows”

From Middle English seculer, from Old French seculer, from Latin saeculāris (“of the age”), from saeculum.

Laplace (1749–1827) "saved the world" by using probability theory to estimate the parameters accurately enough to show that the drift of Jupiter was not secular after all; the observations at hand had covered only a fraction of a cycle of an oscillation with a period of about 880 years.

2003, E. T. Jaynes, Probability Theory: The Logic of Science, Cambridge University Press, pages 234–235:

(astrophysics, geology) Relating to long-term non-periodic irregularities, especially in planetary motion or magnetic field.

sekulaarinen

astrophysics: of or pertaining to long-term non-periodic irregularities


accretion disk

accretion disks (plural)
accretion disc (alternative)

(astrophysics) A structure formed by matter falling into a gravitational source such as a galaxy, black hole, or protostar.


periapsis

en-noun

periapsis (plural periapsides or periapsises or periapses)

periapsides (plural)
periapsises (plural)
periapses (plural)

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1983, Richard O. Fimmel, Laurence Colin, Eric Burgess, Pioneer Venus, NASA SP-461, page 109,
Figure 5-19. Sun-Venus-Orbiter geometry illustrates how the periapsis moves around the planet during the Venusian sidereal year to sample day and night hemispheres. Because the planet rotates in a retrograde direction, it takes more than one Venusian sidereal year for periapsis to move over all longitudes of the planet (as explained in text).

We don't always want to burn near periapsis. Suppose we want to change the height at periapsis. The most efficient place to change the radius of periapsis is at apoapsis. Consider applying #92;Deltav at some other point in the orbit. In this case both periapsis and apoapsis will change. If we apply the #92;Deltav tangentially at apoapsis, all of the #92;Deltav will go into changing periapsis, and vice versa.

2001, D. A. Vallado, Fundamentals of Astrodynamics and Applications, Springer, page 325:

2004, R. S. Saunders, et al., Mars Odyssey Mission, C. T. Russell (editor), 2001 Mars Odyssey, Kluwer Academic Publishers, page 34,
The main aerobraking phase began once the point of the spacecraft's periapsis had been lowered to within 110 km above the Martian surface.

(astronomy, astrophysics) The point of a body's (elliptical) orbit in a 2-body gravitational system such that the distance between the two bodies (measured from their respective centres of mass) is at its minimum.


dark matter

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dark matter
en:Fritz Zwicky
en:Vera Rubin

Calque of German Dunkle Materie, from dunkel (“dark”) and Materie (“matter”). Coined by Swiss astronomer Fritz Zwicky in German in 1933, to account for the apparent mass needed to account for galaxy clusters, where the mass of luminous matter did not add up to enough of a gravitational effect, inferring nonluminous matter must exist to account for the missing mass. The term gained new popularity due to the missing mass found in galaxies to account for galaxy rotation curves discovered by Vera Rubin in research published in English in the 1970s.

The evidence for dark matter in galaxies started to accumulate in the mid-1970s. By the following decade it became clear that essentially all galaxies, including our own Milky Way, are surrounded by extensive halos of dark matter.

2001, Susan M. Fitzpatrick, John T. Brue, Carving Our Destiny: Scientific Research Faces a New Millennium:

On large scales like that of clusters of galaxies, gravitational lensing indicates that the dark matter is smoothly distributed, on the average.

2004, L. Bergström, A. Goobar, “Particle Astrophysics and the Dark Sector of the Universe”, in John W. Mason, editor, Astrophysics Update, pages 124–125:

(astronomy, astrophysics, loosely) Matter which cannot be detected by its radiation but whose presence is inferred from gravitational effects.

donker materie

particles of matter that cannot be detected by their radiation


dynamo

A shortening of dynamo-electric machine. The element dynamo- is ultimately from Ancient Greek δύναμις (dúnamis, “power”).

uder

(astrophysics) The mechanism by which a celestial body, such as the Earth or a star, generates a magnetic field.


recombination

(astrophysics) The process by which the plasma of electrons and protons produced after the Big Bang condensed into hydrogen, or the epoch in which this process occurred.


siren

sirens (plural)
sirenes (plural)
sirene (alternative archaic dated)

From Middle English siren, from Old French sereine and Latin Sīrēn, Sīrēna, from Ancient Greek Σειρήν (Seirḗn). The mammalian sense was first attested in French in Dominique Bouhours, Les entretiens d'Ariste et d'Eugène, in 1671. The aquatic salamander sense was originally introduced by Linnaeus in 1766, for a genus of his reptiles. Doublet of serin.

2017, B.P. Abbott, “A gravitational-wave standard siren measurement of the Hubble constant”, in (Please provide the book title or journal name):

(astronomy, astrophysics) An astrophysical event that can be used for calculating cosmic distances.


axis of evil

2002 State of the Union Address
George W. Bush
axis of evil

Coined by American political commentator David Frum in 2002 and first used publicly by President George W. Bush in the 2002 State of the Union Address. Possibly from a historical analogy to the German-Italian-Japanese axis. Extended to astrophysics by Portuguese scientist João Magueijo in 2005.

coin

cosmic microwave background
cosmic microwave background

(astrophysics, cosmology) An anomaly in the temperature of the cosmic microwave background as the result of a preferential axis which may have shaped the development of the universe.


gravitate

en-verb

gravitate (third-person singular simple present gravitates, present participle gravitating, simple past and past participle gravitated)

gravitates (present singular third-person)
gravitating (participle present)
gravitated (participle past)
gravitated (past)

/ˈɡɹævɪteɪt/

Back-formation from gravitation. Or borrowed from New Latin gravito, gravitatus.

Theſe, who have nature's ſteps with care purſued,
That matter is with active force endued,
That all its parts magnetic power exert,
And to each other gravitate, aſſert.

1712, Sir Richard Blackmore, Creation; a philosophical poem in seven books, book II:

(intransitive, astrophysics) To move under the force of gravity.


escape velocity

en-noun

escape velocity (plural escape velocities)

The gravitational force exerted by a planet determines its surface gravity and escape velocity.

1996, Thomas Arny, Explorations: An Introduction to Astronomy, McGraw-Hill Science, page 74:

(astrophysics) The minimum speed needed to escape the gravitational field of a planet or other body.


Van Allen belt

Van Allen radiation belt
Van Allen radiation belt#English

(astrophysics) Synonym of Van Allen radiation belt.


MAD

MAD (countable and uncountable, plural MADs)

magnetically-arrested disc
magnetically-arrested disc#English

(astrophysics) Acronym of magnetically-arrested disc, a type of black hole accretion disc).


Trojan

Trojans (plural)
Troyan (alternative dated)
Troian (alternative dated)

/ˈtɹəʊd͡ʒən/

/ˈtɹoʊd͡ʒən/

From old forms Troyan, Troian, Middle English Troiā̆n, from Old English Trōiān, from Latin Troiānus, from Troia (“Troy”) + -ānus, from Ancient Greek Τροίᾱ (Troíā).

(astrophysics) An object residing at a Trojan point.

Trójan

astronomical object residing at a Trojan point


Trojan

/ˈtɹəʊd͡ʒən/

/ˈtɹoʊd͡ʒən/

Troyan (alternative dated)
Troian (alternative dated)

(astrophysics) Of, or relating to, a Trojan point.


extrasolar

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A four-inch telescope was once used to find an extrasolar planet.

Of course, no one has any idea whether the extrasolar life is anything more than a few trillion microbes.

1993, Octavia E. Butler, Parable of the Sower, HEADLINE PUBLISHING GROUP (2019), page 78:

(astrophysics) of or originating in a system other than Earth's, the solar system.

extra-solaire

originating in a solar system other than ours


Lagrangian

/læˈɡɹɑ̃ʒi.ən/

(astrophysics) Of or relating to a Lagrange point.


Lagrangian

/læˈɡɹɑ̃ʒi.ən/

(astrophysics) An object residing in a Lagrange point.

Lagrangian point
Lagrangian point#English

(astrophysics) Ellipsis of Lagrangian point, a Lagrange point.


s-process

(nuclear physics, astrophysics) the relatively slow nucleosynthesis process, in giant stars, in which neutron capture synthesizes elements up to atomic mass number 210 (at which point alpha decay becomes a deterrent to further building).


r-process

(nuclear physics, astrophysics) The relatively rapid nucleosynthesis process, in supernovae, in which a large neutron flux allows rapid neutron capture and synthesis of elements up to the transuranic elements.


CNO cycle

carbon-nitrogen-oxygen cycle
carbon-nitrogen-oxygen cycle#English

(physics, astrophysics) Synonym of carbon-nitrogen-oxygen cycle.


space reddening

space reddening (plural space reddenings)

(astronomy, astrophysics) The reddening of the light from distant stars because of selective absorption and scattering by interstellar dust


snow line

snow lines (plural)
snow-line (alternative)

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Chris Ormel, an astronomer at the University of Amsterdam, and his colleagues recently calculated that protoplanets began to form at the snow line around the star, then grew quickly by accreting pebbles.

2018 April 26, Alexandra Witze, “Earth May Have Been Formed by a Bunch of Tiny Space Pebbles”, in The Atlantic:

(astrophysics) The inner limit where volatile molecules can remain frozen in the zone around a star.

(astrophysics, specifically) The limit for water remaining solid instead of evaporating away under solar radiation.


dark energy

Coined by American cosmologist Michael Turner in 1998, in reference to the earlier term dark matter.

coin

Even Albert Einstein, who first proposed it as the Cosmological Constant in his 1916 General Theory of Relativity, doubted dark energy existed. He called it his "greatest blunder". Now, after a five-year survey of nearly 240,000 galaxies reflecting eight billion years of cosmic history, a team of astrophysicists has shown the elusive force exists. The data were obtained using the Anglo-Australian Telescope, and 26 scientists contributed to the so-called WiggleZ Dark Energy Survey.

2011 May 20, “After study of 240,000 galaxies, dark energy comes to light”, in The Australian:

cosmological constant
cosmological constant

(astronomy, astrophysics) A hypothetical form of energy thought to be spread uniformly throughout space (and time) and to have anti-gravitational properties: it represents a possible mechanism for the cosmological constant, and thus is one of the possible explanations for the current accelerating rate of expansion of the universe; and it is estimated to account for about 74% of the mass-energy of the universe.

donker energie

hypothetical form of energy which, it is supposed, is spread uniformly throughout space and time and has anti-gravitational properties


big bang

Millions of big bangs may be happening as we speak.

(astrophysics) An explosion giving rise to a universe.


domain wall

The simplest soliton is the domain wall with co-dimension one, and the next simplest is the vortex with co-dimension two, whereas the co-dimension three (four) soliton is called monopole (instanton).

2006, M. Eto et al., “Solitons in Supersymmetric Gauge Theories”, in Particles, Strings and Cosmology, →ISBN, page 266:

(astrophysics) A two-dimensional singularity hypothesized in string theory.


warp bubble

Coined in 1994 by Mexican physicist Miguel Alcubierre.

(astrophysics, science fiction) A detached region of spacetime which is theoretically capable of moving faster than the speed of light.


X factor

X factors (plural)
x-factor (alternative)
x factor (alternative)

(astrophysics) The proportionality constant which converts CO emission line brightness to molecular hydrogen mass.


dex

2004, Cartledge et al 2004, The Homogeneity of Interstellar Oxygen in the Galactic Disk, Abstract, The Astrophysical Journal, Volume 613, Issue 2, pp. 1037-1048,
The data points for low-<nH> paths are scattered more widely than those for denser sight lines, because O/H ratios for such paths shorter than 800 pc are generally about 0.10 dex lower than the values for longer ones.

(physics and astrophysics) An order or factor of ten.


GW

gravitational wave
gravitational wave#English

(astronomy, astrophysics, physics) Initialism of gravitational wave.


(astrophysics) Abbreviation of Lagrange point 1, located between the larger and smaller objects along a line connecting the two.


(astrophysics) Abbreviation of Lagrange point 2, located beyond the smaller object on a line passing through the centers of the smaller and larger objects.


cosmographer

/kɒzˈmɒɡɹəfə/

From cosmography + -er, corresponding to cosmo- + -grapher.

(astrophysics) A scientist specializing in understanding and describing the nature of the universe.


astroparticle

(astrophysics) A subatomic particle of cosmic origin


spaghettification

/spəˌɡɛtɪfɪˈkeɪʃən/

/spəˌɡɛtəfəˈkeɪʃən/

From spaghetti + -ification (suffix meaning ‘the process of becoming’ forming nouns), alluding to the appearance of a strand of spaghetti.

suffix

Spaghettification was due to gravity intensifying, metre by metre, in the approach to a black hole.

1977, Nigel Calder, “Starcrusher”, in The Key to the Universe: A Report on the New Physics, New York, N.Y.: Viking Press, →ISBN, page 143:

But in the approach to a black hole the effect is far stronger: the astronaut’s body is stretched out on a gravitational rack. Before he comes near the event horizon, his body will be pulled out beyond the limits that flesh and blood can stand and he will suffer the excruciating death of ‘spaghettification’ long before he is in any position to unravel the secrets of the black hole. The strength of the spaghettification effect (usually known more prosaically as ‘tidal stretch’ for it is related to the way the Moon raises tides on Earth) depends on the mass of the rack-inducing black hole.

1981, Nigel Henbest, “Black Holes”, in Mysteries of the Universe, New York, N.Y.: Van Nostrand Reinhold Company, →ISBN, page 140, column 1:

‘Spaghettification. Let me guess,’ said Rimmer. ‘I can see only two options: one – due to the bizarre effects of the intense gravitational pull, and because we’re entering a region of time and space where the laws of physics no longer apply, we all of us inexplicably develop an irresistible urge to consume vast amounts of a certain wheat-based Italian noodle conventionally served with Parmesan cheese; or two – we, the crew, get turned into spaghetti. I have a feeling we can eliminate option one.’

1990, Grant Naylor [pseudonym; Rob Grant; Doug Naylor], chapter 5, in Better Than Life, London: Viking, →ISBN, part 3 (Garbage World), page 153:

I am convinced, by arguments given by [John Archibald] Wheeler in 1957, that the end point of spaghettification—the singularity itself—is governed by a union, or marriage, of the laws of quantum mechanics and those of spacetime warpage. This must be so, since the warpage spaghettifies space on scales so extremely microscopic that they are profoundly influenced by the uncertainty principle.

2002, Kip S[tephen] Thorne, “Spacetime Warps and the Quantum World: Speculations about the Future”, in Stephen W[illiam] Hawking et al., The Future of Spacetime, New York, N.Y.: W[illiam] W[arder] Norton & Company, →ISBN, page 136:

The so-called Cauchy singularity discovered by [Roger] Penrose and his colleagues turns out to be a weak singularity, according to a classification introduced by Frank Tipler: there are no unbounded tidal forces. It is not, therefore, the kind of singularity that spells inevitable spaghettification.

2005, Michael Lockwood, “Closed Timelike Curves: Science Fact or Science Fiction?”, in The Labyrinth of Time: Introducing the Universe, Oxford, Oxfordshire: Oxford University Press, →ISBN, page 141:

During this violent spaghettification process, long, thin strands of material that make up the star collapse into the intense gravity of a black hole – which basically swallows it up like stellar spaghetti. The event releases a bright burst of energy that can be detected by astronomers.

2020 October 15, Sophie Lewis, “Star dies by ‘spaghettification’ as it’s consumed by supermassive black hole”, in CBS News, archived from the original on 2021-02-14:

(astrophysics) The gravitational stretching of objects into long, thin shapes, usually near a black hole.

スパゲッティ化現象

スパゲッティかげんしょう


spaghettified

en-adj

spaghettified (comparative more spaghettified, superlative most spaghettified)

more spaghettified (comparative)
most spaghettified (superlative)

(astrophysics) Having undergone spaghettification.


apocentric

(astrophysics) Of or pertaining to the apocenter, the point in an orbit which is furthest from the orbited body


apsidally

en-adv

apsidally (comparative more apsidally, superlative most apsidally)

more apsidally (comparative)
most apsidally (superlative)

The planet's orbit is aspidally aligned with the dust disk.

(astrophysics) With regard to or in relation to an apsis, the point at which an orbiting object is at its minimum or maximum distance from the orbited object


nonbaryonic

nonbaryonic dark matter

(astrophysics, nuclear physics) Not containing or consisting of baryons


asteroseismology

From aster- (“star”) + -o- + seismology (“study of Earth's vibrations (ie. earthquakes)”).
Ultimately from Ancient Greek ἀστήρ (astḗr, “celestial body”) + σεισμός (seismós, “earthquake”) + -λογία (-logía, “study of”)

der

astroseismology (alternative)
asterseismology (alternative)

(astrophysics) The study of oscillations in stars.


twilight zone

Because such a zone (in the literal sense of the term) is twilit; see twilight § Etymology.

(astronomy, astrophysics) A moving line that divides the daylit side and the dark night side of a planetary body.


magnetoid

A young black hole formed in the center of galaxy can develop into the cocooned black hole or, as extreme possibility, into a magnetoid with a black hole inside.

1981, Victor J. Stenger, Dumand-80, page 194:

(astrophysics) a supermassive rotating highly magnetized star at the center of a compact galactic nucleus.


reionization

(astrophysics) The process by which the plasma of electrons and protons is produced after the Big Bang, when stars and galaxies ionized neutral hydrogen, or the era in which this occurs.


antistar

(astrophysics) A conjectured type of star formed from antimatter.

αντιάστρο

a conjectured type of star formed from antimatter


antigalaxy

(astrophysics) A conjectured type of galaxy formed from antimatter.

antigaláxia

a conjectured type of galaxy formed from antimatter


CBR

cosmic background radiation
cosmic background radiation#English

(astrophysics) Initialism of cosmic background radiation.


nonrotating

(engineering, astrophysics) That does not rotate.


GWB

gravitational wave background
gravitational wave background#English

(uncountable, astronomy, cosmology, astrophysics) Abbreviation of gravitational wave background.


nongalactic

(astronomy, astrophysics) Far from galaxies; not interacting with galaxies.


(astrophysics) Abbreviation of Lagrange point 3, located 180 degrees away from the smaller object and slightly outside the smaller object's orbit around the larger object.


(astrophysics) Abbreviation of Lagrange point 4, located 60 degrees ahead of the smaller object along its orbit around the larger object.


Lagrange point

Lagrange points (plural)
Lagrangian point (alternative)

Named after Joseph Louis Lagrange, who discovered the points L₄ and L₅, building on earlier work by Leonhard Euler, and in 1772 published an essay on the three-body problem.

Mathematically, the Lagrange points represent solutions to a restricted form of the three body problem in which the mass of one object is assumed negligible compared to that of the two principal bodies—as, for example, an artificial satellite and the Earth–Moon system.

Lagrange points are significant for lunar development in that raw materials, such as near-Earth objects (NEOs) can be safely stored at L-4 and L-5 prior to mining and processing.

2008, David Schrunk, Burton Sharpe, Bonnie L. Cooper, Madhu Thangavelu, The Moon: Resources, Future Development and Settlement, Springer, Praxis Publishing, page 57:

The $1.27-billion (1 billion euros) SOHO satellite was launched in 1995 and is flying a joint mission between NASA and the European Space Agency (ESA). It watches solar activity from an orbit about the Lagrange Point 1, a gravitationally stable spot between Earth and the sun that is about 932,000 miles (1.5 million kilometers) from our planet.

2013 July 28, Megan Gannon, “Spacecraft Sees Giant 'Hole' In the Sun”, in news.yahoo.com, retrieved 2013-07-29:

For science several of the Lagrange points are important. The question of access to Lagrange points or GSO slots emerges as these become congested.

2016, Francis Lyall, Paul B. Larsen, Space Law, Taylor & Francis (Routledge), page 247:

(astrophysics, orbital mechanics) A point in an orbital configuration of a two-body system where a small object affected only by gravity can theoretically be stationary relative to the two larger objects.


(astrophysics) Abbreviation of Lagrange point 5, located 60 degrees behind the smaller object along its orbit around the larger object.


Clarke orbit

From Arthur C. Clarke, who first proposed placing communications satellites in such an orbit.

(astrophysics) stationary orbit (an orbit around any body)


Trojan point

point troyen

(astrophysics) any L4 and L5 Lagrange points

(astrophysics) the L4 and L5 Lagrange points of the Sun-Jupiter orbital configuration

point troyen

(astrophysics) by extension, any L4 and L5 Lagrange points


Trojan asteroid

en-noun

Trojan asteroid (plural Trojan asteroids)

Derived from the names of the first three Trojan asteroids found (Achilles, Patroclus, Hektor)

(astrophysics) an asteroid occupying the Trojan points of the Sun-Jupiter system

(astrophysics) by extension, any asteroid occupying a Trojan point


Trojan moon

(astrophysics) A pseudo-moon that occupies a Trojan point of a system.


Trojan planet

(astrophysics) a planet that occupies a Trojan point of a star system


Lagrangian point

Lagrangian point (plural Lagrangian points)

(astrophysics) Alternative form of Lagrange point.


antiworld

But possibly there is an antiworld in which, in addition to matter, time is also negative. […] In such an antiworld man would grow younger with time and a broken glass would come together from its fragments.

It follows that somewhere antiworlds consisting of antiparticles are bound to wander. No traces of these antiworlds have as yet been found.

1982, Rudolʹf Konstantinovich Balandin, Vladimir Vernadsky:

There could be whole antiworlds and antipeople made out of antiparticles. However, if you meet your antiself, don't shake hands!

1988, Stephen Hawking, A Brief History of Time: From the Big Bang to Black Holes, page 75:

(astrophysics) A hypothetical world constructed from antimatter.

antimundo

a hypothetical world constructed from antimatter


gravity assist

gravity assists (plural)
gravitational assist (alternative)
gravity-assist (alternative)

/ˈɡɹævɪti əˈsɪst/

After going into orbit around Jupiter with a gravity assist from the volcanic moon Io, Galileo will spend 22 months studying the planet.

1989 October 10, Warren E. Leary, “Galileo's Itinerary”, in New York Times, retrieved 2011-09-04:

Cassini is supposed to swing by Earth in 1999 for a gravity assist that would sling it out toward Saturn.

1997 September 22, Dick Thompson, Michael D. Lemonick, “Nukes in Space”, in Time:

MESSENGER successfully flew by Mercury yesterday, gaining a critical gravity assist that will enable it to enter orbit about Mercury in 2011.

2009 Oct. 2, "MESSENGER Gains Critical Gravity Assist For Mercury Orbital Observations," spacedaily.com (retrieved 4 Sep. 2011)

(astrophysics) The favorable alteration of the speed and trajectory of a spacecraft as a result of its passing near to a celestial body.

painovoimalinko

the favorable alteration of the speed and trajectory of a spacecraft as a result of its passing near to a celestial body


naked singularity

naked singularity (plural naked singularities)

gravitational singularity
gravitational singularity

(astrophysics) An as yet theoretical gravitational singularity with no event horizon, making it observable, unlike a black hole whose event horizon prevents light from reaching an observer situated outside the event horizon.

naga osobliwość

a gravitational singularity with no event horizon


FDM

fuzzy dark matter
fuzzy dark matter#English

(particle physics, quantum mechanics, astrophysics, cosmology) Abbreviation of fuzzy dark matter.


antisun

antisun (countable and uncountable, plural antisuns)

(astrophysics, countable) A hypothetical sun composed of antimatter.


antiplanet

(astrophysics) A hypothetical planet composed of antimatter.

antiplaneta

a hypothetical planet composed of antimatter


antiuniverse

(astrophysics, cosmology) A conjectured universe formed from antimatter.

antiuniverso

a conjectured universe formed from antimatter


dark flow

dark flow (countable and uncountable, plural dark flows)

From dark (“hidden”) + flow. From the motion of galaxy clusters due to a hidden influence, possibly from beyond the horizon of the observable universe.

(astrophysics) A possible non-random component of the peculiar velocity of galaxy clusters.


frost line

frost lines (plural)
frostline (alternative)

In our Solar System the frost line lies between Mars and Jupiter at about five astronomical units from the Sun.

(astrophysics) In a solar system, the distance from the protosun beyond which hydrogen-containing gas compounds freeze.


BAL

BAL (countable and uncountable, plural BALs)

broad absorption line
broad absorption line#English

broad absorption line trough
broad absorption line trough#English

(astrophysics) Initialism of broad absorption line or broad absorption line trough.


MECO

magnetospheric eternally collapsing object#English

(astrophysics) Acronym of magnetospheric eternally collapsing object.


coronal hole

(astrophysics) A region in the corona of a star where magnetic field lines extend out into space, allowing solar wind to escape.


pseudostreamer

LL-Q1860 (eng)-Flame, not lame-pseudostreamer.wav

From pseudo- + streamer (“a loop-like structure in the corona of a star”).

prefix

(astrophysics) A bright loop-like structure in the corona of a star, similar to a helmet streamer, but connecting coronal holes of the same magnetic polarity.


helmet streamer

en-noun

helmet streamer (plural helmet streamers)

(astrophysics) A bright loop-like discharge of stellar matter in the corona of a star, connecting coronal holes of opposite magnetic polarity.


dark sector

From dark + sector. From being named after dark matter and dark energy, and being portion (sector) of a whole (universe).

(astrophysics, cosmology, astronomy, physics) The unknown portion of the Universe outside standard physics, including dark matter and dark energy.

The fraction of the universe that is dark matter and dark energy.


accelerating universe

accelerating universe (plural accelerating universes)

(astronomy, astrophysics) A theory that describes and seeks to explain the seemingly increasing rate of the expansion of the universe.


Schwarzschild density

Named after German physicist and astronomer Karl Schwarzschild (1873–1916).

named-after

(astrophysics) The minimum density a black hole can have: c²/(2G) or 6.734×10²⁶ kg/m (kilograms per meter).


antihorizon

White holes must therefore be surrounded by the opposite of an event horizon, something known as an antihorizon, which would allow one-way traffic out and never in. Unfortunately, antihorizons are very unstable and get converted to normal horizons in a matter of seconds after forming.

2002, Jim Al-Khalili, Black Holes, Wormholes and Time Machines, page 199:

The Kruskal diagram of the Schwarzschild geometry showed it to possess not only a normal horizon but also an antihorizon, beyond which there was, supposedly, another Universe.

2009, Jon Schiller, 21st Century Cosmology, page 54:

To distant observers the light appears, due to gravitational time dilation, to slow down as it approaches the antihorizon.

2010, Enrico Rodrigo, The Physics of Stargates:

(astrophysics) The opposite of an event horizon, allowing escape but not entry.


nuclear pasta

From the resemblance of its phases to various types of pasta.

Watanabe, Gentaro, Iida, Kei, Sato, Katsuhiko (2000 August 7) “Thermodynamic properties of nuclear "pasta" in neutron star crusts”, in Nuclear Physics A, volume 676, numbers 1-4, →DOI, pages 455–473

The elastic properties of neutron star crusts are relevant for a variety of currently observable or near-future electromagnetic and gravitational wave phenomena. These phenomena may depend on the elastic properties of nuclear pasta found in the inner crust.

2018 September 24, M. E. Caplan, A. S. Schneider, C. J. Horowitz, “Elasticity of Nuclear Pasta”, in Physical Review Letters, volume 121, number 13, →DOI, retrieved 2021-08-26, page 132701:

The inner crust [of a neutron star] is where the nuclear pasta phase, a novel state of matter having nucleons arranged in a variety of complex shapes, is expected to appear. In the innermost layers near the crust/core boundary, because of the large effect of the Coulomb lattice energy, cylindrical and planar geometries can occur, both as nuclei and as bubbles. These phases are collectively named nuclear pasta (by analogy to the shape of spaghetti, macaroni and lasagna).

2013, José A. Pons, Daniele Viganò, Nanda Rea, “Too much "pasta" for pulsars to spin down”, in Nature Physics, volume 9, number 7, →Bibcode, →DOI, [arxiv.org arXiv] 1304.6546, pages 431–434:

(astrophysics) A type of degenerate matter found within the crusts of neutron stars, where the competition between nuclear attraction and Coulomb repulsion forces of similar magnitude allows for the formation of a variety of complex structures assembled from neutrons and protons.


Planck star

The entire matter of the sun condensed into the space of an atom: a Planck star should be constituted by this extreme state of matter.

2015, Carlo Rovelli, translated by Simon Carnell and Erica Segre, Seven Brief Lessons on Physics, Penguin, published 2016, page 44:

(astrophysics) A hypothetical astronomical object whose energy is around the Planck density (5.155 × 10⁹⁶ kg/m³).


YORP effect

From the first letters of the surnames Yarkovsky, O'Keefe, Radzievskii and Paddack + effect. Coined in 2000 by American geophysicist David Perry Rubincam.

(astrophysics) The effect of solar radiation on an asymmetric asteroid or other small body whereby its rate of rotation increases, potentially leading to the object's eventual disintegration.


spaghettify

en-verb

spaghettify (third-person singular simple present spaghettifies, present participle spaghettifying, simple past and past participle spaghettified)

spaghettifies (present singular third-person)
spaghettifying (participle present)
spaghettified (participle past)
spaghettified (past)

Back-formation from spaghettification, equivalent to spaghetti + -fy.

If, for example, a black hole eats enough to triple its mass, then it will have grown three times as wide. For this reason, black holes in the universe can be almost any size, but not all of them will spaghettify you before you cross the event horizon.

2007, Neil deGrasse Tyson, Death by Black Hole:

First, the intense gravitational forces around a black hole may 'spaghettify' space travellers before they even reach the event horizon, and second, the theory may be fully confirmed only if someone were prepared to test it.

2013, David Wilkinson, Science, Religion, and the Search for Extraterrestrial Intelligence:

(astrophysics) To stretch an object into a long thin shape under the influence of a very strong gravitational field gradient, such as found near a black hole.


dark light

Blend of dark matter + light. From being a force found in the dark sector that acts on dark matter, analog to light in the "light sector" (the part of the universe that is not part of the dark sector) that acts on "light matter" (ordinary matter that interacts electromagnetically, thus visibly).

(astrophysics, cosmology, astronomy, physics) A hypothetical force of nature that acts on dark matter to allow dark matter to interact with itself.


infaller

The relative boost I talked about is again between an early infaller which could be part of the matter and a late infaller.

2016, Roger Blandford, David Gross, Alexander Sevrin, Astrophysics and Cosmology: Proceedings of the 26th Solvay Conference on Physics:

(astrophysics) A particle that falls behind the event horizon, for example into a black hole.


Hubble flow

From Hubble (“Edwin Hubble”) + flow. From the flowing/movement of galaxies in the Universe under the influence of Hubble expansion.

(astrophysics, cosmology) The motion of galaxies due to the expansion of the universe


synestia

For any rotating planetary body, there is a thermal limit beyond which the rotational velocity at the equator intersects the Keplerian orbital velocity. Beyond this corotation limit (CoRoL), a hot planetary body forms a structure, which we name a synestia, with a corotating inner region connected to a disk-like outer region.

2017 May 23, SJ Lock, ST Stewart, “The structure of terrestrial bodies: Impact heating, corotation limits, and synestias”, in Journal of Geophysical Research:

For a brief time during its infancy, Earth was a hot, doughnut-shaped blob called a synestia. […] A synestia has an exterior region marked by clouds of molten rock and dust, all at a scorching 2000°C or hotter.

2017 June 3, Shannon Hall, “Early Earth was a molten doughnut”, in New Scientist, volume 234, number 3128, page 10:

The investigation also examined the geochemical consequences of lunar formation resulting from the high-energy collision of proto-planets that created a huge, vaporized, doughnut-shaped object called a synestia.

2019 April 24, G. Jeffrey Taylor, “Volatile Elements Test Models for the Origin of the Moon”, in Planetary Science Research Discoveries:

(astrophysics) A donut-shaped body of vaporized and molten rock formed from the collision of two planet-sized objects.


Schwarzschild's method

Named after German-American astrophysicist Martin Schwarzschild (1912–1997).

named-after

This is because in Schwarzschild's method we seek to match the distribution of matter only in configuration space but we ignore the velocity distribution which is an outcome of the method for any particular solution w#95;o.

2008, Daniel Benest, Topics in Gravitational Dynamics:

(astrophysics, astronomy) A method to develop triaxial equilibrium kinematic models of actual galaxies (without knowledge of the motions of the component elements of the actual galaxies) using a grid and assigning masses and orbits, simulating gravitational evolution with the resulting estimated distributions, to compare with the actual galaxy, until a model results in similarity with the actual galaxy.

Schwarzschild model

a model built by using the Schwarzschild's method


Schwarzschild model

en-noun

Schwarzschild model (plural Schwarzschild models)

From Schwarzschild + model, from being a model developed using Schwarzschild's method.

Schwarzschild's method
Schwarzschild's method

(astrophysics, astronomy) A triaxial equilibrium kinematic model of an actual galaxy built using Schwarzschild's method.


A&A

1. Aoki, W., Tsuji, T., and Ohnaka, K. A&A, 333, L19, 1998.
2. Aoki, W., Tsuji, T., and Ohnaka, K. A&A, 350, 945, 1999.
[…]
4. Bachiller, R., Forveille, T., Huggins, P. J., and Cox, P. A&A, 324, 1123, 1997.

2004, Harm J. Habing, Hans Olofsson, editors, Asymptotic Giant Branch Stars, Springer, →ISBN, page &pg=PA402&dq=%22A%26A%22 402:

Astronomy and Astrophysics
w:Astronomy and Astrophysics

(astronomy, astrophysics) Initialism of Astronomy and Astrophysics: a scientific journal founded in 1969, covering theoretical, observational, and instrumental astronomy and astrophysics.


CGB

(uncountable, astronomy, cosmology, astrophysics) Abbreviation of cosmic gravitational-wave background.


radiopanspermia

(astrophysics) The propagation of life through space by way of scattering via radiation pressure of stars, or being launched into space from the source habitats via electrical and magnetic currents in the exospheres of those habitable worlds.


phantom energy

Star Wars: Episode I – The Phantom Menace

Coined by physicist Robert R. Caldwell in 1998, in reference to the Star Wars movie The Phantom Menace, in his paper "A Phantom Menace? Cosmological consequences of a dark energy component with super-negative equation of state" referring to the "phantom energy menace" that would lead to the Big Rip.

(cosmology, astrophysics, astronomy, physics) A category of dark energy, where dark energy is not fixed in amount nor in density, and continuously increases over time.

Big Rip

destruction of the Universe caused by ever increasing dark energy (ie. phantom energy)

cosmological constant

a category of dark energy, where dark energy is constant in density


boson star

From boson + star (“celestial body”).
From being an astronomical object composed of mostly bosons, not a star or stellar remnant in the usual sense.

(astrophysics) A theoretical type of heavenly body composed of a form of boson that is self-repelling, what should be highly dense and bend spacetime in a manner approaching that of a black hole.

dark matter star

theoretical bosons that would compose a boson star are dark matter candidates

dark matter

boson stars are candidate dark matter particles

axion star

axion are a theoretical boson that may conform to the requirements needed for bosonic components of a boson star


rotation curve

(astrophysics) for a galaxy, a plot of the orbital velocity of objects with respect to the center of the galaxy, as a function of the distance between the two

rotationskurve

a plot of the orbital velocity of solar systems with respect to the center of its galaxy, as a function of the distance between the two


ISCO

innermost stable circular orbit
innermost stable circular orbit#English

(astrophysics) Acronym of innermost stable circular orbit.


MBH

MBHs (plural)
μBH (alternative)
mBH (alternative)
μBH (alternative)
mBH (alternative)
mBH (alternative)

micro black hole
micro black hole#English

(astrophysics) Abbreviation of micro black hole.

(astrophysics) Abbreviation of mini black hole.


M/L ratio

M/L ratio (countable and uncountable, plural M/L ratios)

mass-to-light ratio
mass-to-light ratio#English

(astrophysics) Initialism of mass-to-light ratio.


light sector

Blend of light + dark sector. From not being part of the dark sector.

(astrophysics, cosmology, astronomy, physics) The known universe; the part of the universe that is not part of the dark sector; the segment of the universe that is explained by the known laws of physics, and whose components (particles) are predicted by it. The portion of the universe that is not dark matter nor dark energy.

The fraction of the universe that interacts with electromagnetism (ie. light).


libration point

libration point (plural libration points)

(astrophysics) Synonym of Lagrange point.


Planck relic

(physics, cosmology, astronomy, astrophysics, quantum mechanics, relativity theory) A black hole with an event horizon on the order of a Planck length (~ 10⁻³⁵ metres), and a mass on the order of a Planck mass (~ 20 micrograms).

quantum mechanics; relativity theory; quantum mechanics; relativity theory


circumtriple

(astrophysics) orbiting around three stars or other centers.


dredge-up

(astrophysics) A temporary episode of deep convection in an evolved star, which brings fusion products to the surface of the star and allows them to be detected in the star's spectrum.


SANE

(astrophysics) Ellipsis of SANE disc, a type of black hole accretion disc.


SANE

(astrophysics) Acronym of standard and normal evolution.


Hayashi limit

Named after Japanese astrophysicist Chushiro Hayashi (25 Jul 1920–28 Feb 2010).

When a star is fully within hydrostatic equilibrium—a condition where the inward force of gravity is matched by the outward pressure of the gas—the star can not exceed the radius defined by the Hayashi limit.^([Wikipedia])

However, the approximate locations of the Hayashi limits point to remarkably low masses for the three T Tauri stars investigated here. It should be noted, that the Hayashi limits are valid only for stars in hydrostatic equilibrium.

1977, Rudolf Kippenhahn, Walter Strohmeyer, The Interaction of Variable Stars with Their Environment, Remeis-Sternwarte, page 69:

Since the Hayashi limit approaches close to the main sequence at about 1 M⊙, the 'Hertzsprung gap' between the terminal main sequence and the Hayashi limit is much less marked than at high masses.

2006, Peter Eggleton, Evolutionary Processes in Binary and Multiple Stars, Cambridge University Press, page 75:

The latest-type RSGs^([Red Supergiants]) in the Magellanic Clouds are cooler than the current evolutionary tracks allow, occupying the region to the right of the Hayashi limit where stars are no longer in hydrostatic equilibrium.

2009, Donald Gerard Luttermoser, Beverly Joy Smith, Robert E. Stencel, editors, The Biggest, Baddest, Coolest Stars: Proceedings of a Workshop, Astronomical Society of the Pacific, page 33:

(astrophysics) A theoretical maximum radius of a star of given mass; the radius at which the inward force of gravity exactly balances the outward pressure of the gas of the star.

limite de Hayashi

theoretical upper limit of the radius of a hydrostatically stable star


GRMHD

(astrophysics) Abbreviation of general-relativistic magnetohydrodynamic.


SRMHD

(astrophysics) Abbreviation of special-relativistic magnetohydrodynamic.


GRRMHD

general relativistic
general relativistic#English

(astrophysics) Abbreviation of general relativistic radiative magnetohydrodynamic.


RMHD

(astrophysics) Abbreviation of relativistic magnetohydrodynamic.

(astrophysics) Abbreviation of radiative magnetohydrodynamic.


Population III

Proposed as a category of stars of even poorer metallicity than Population II.

In other words, we have not yet discovered a true Population III star; revealing these elusive, early stars is one of the main science goals of the soon-to-be-launched James Webb Space Telescope.

2019 October 26, Ethan Siegel, “Ask Ethan: How Many Generations Of Stars Formed Before Our Sun?”, in Forbes, archived from the original on 2020-11-12:

Thus, the earliest stars – known as Population III – were likely composed of just hydrogen and helium.

2022 November 9, Brandon Vigliarolo, “This ancient quasar may be the remains of the first-gen star that started us all”, in The Register, archived from the original on 2022-12-13:

Emerging from the primordial hydrogen and helium gas that pervaded the early universe, Population III stars would lack heavier elements, allowing them to reach humongous sizes—hundreds of times bulkier than our sun.

2022 December 6, Jonathan O'Callaghan, “Astronomers Grapple with JWST’s Discovery of Early Galaxies”, in Scientific American, archived from the original on 2022-12-09:

(astrophysics, usually attributively) A hypothetical population or group of stars which may have existed in the early history of the Universe, characterized by being extremely massive and hot and having an extremely low metallicity.


Population II

Proposed by astronomer Walter Baade in 1944.

While the thick disk is largely composed of Population II stars, they found it contains two stellar populations.

2019 December 11, Brian Koberlein, “The Stars In Our Galaxy Are More Varied Than We Thought”, in Forbes, archived from the original on 2022-09-15:

Those heavy elements were created by fusion within Population II stars that exploded as supernovas and seeded them into interstellar clouds.

2021 May 21, Tom Metcalfe, “An ancient star casts new light on the birth of the universe”, in NBC News, archived from the original on 2022-07-06:

The brightness of these galaxies could be attributed to such stars, which would be much hotter and brighter than subsequent Population II stars and Population I stars, such as our sun, both of which fill our modern-day universe.

(astrophysics, usually attributively) A population or group of stars formed early in the history of the Universe, characterized by having a low metallicity.


Population I

We generally place stars into one of three populations based on their metallicity. Population I stars like the Sun are metal heavy. They are younger stars and tend to be found in the spiral arms of the Milky Way.

Most stars, such as the sun, are third-generation "Population I" stars that contain relatively heavy elements such as iron, nickel, carbon and oxygen.

(astrophysics, usually attributively) A population or group of stars formed relatively late in the history of the Universe, characterized by having a high metallicity.


frozen star

frozen+star
* (stellar black hole, black hole alternative): From relativity predicting the passage of time slowing to a stop as the star collapses through its event horizon, "freezing" time and the star.
* (Population 0 star): From the existence of frozen volatiles, such as water ice, existing in the atmosphere and on the surface of such a star

sense

(astrophysics) Synonym of stellar black hole.


frozar

From froze + -ar. From being a star frozen in time.

(astrophysics) Synonym of frozen star (“black hole alternative”) An astrophysical star stilled to a stop by gravitational relativistic time dilation effects, during its final collapse at the end of its fusion lifetime


HEDLA

HEDLA still has limits; not all astrophysical phenomena can be studied in the laboratory.

2023 January 3, Adam Frank, “The Universe Is More in Our Hands Than Ever Before”, in The Atlantic:

(astrophysics) Acronym of high-energy density laboratory astrophysics.


technetium star

en-noun

technetium star (plural technetium stars)

(astrophysics) A star in which technetium has been detected. Technetium is too short-lived to occur primordially in the star, if the star is about 4.5 billion years old (the estimated age of the Earth), so the star must be producing technetium.


Poynting-Robertson drag

To study the observability of the martian dust belts in this paper, we employed our dynamical code that numerically integrates orbit-averaged equations of motion of a circummartian particle in Lagrange elements derived by Krivov et al. (1996)[…], which we recently generalized to accommodate the Poynting–Robertson drag (Makuch et al., 2005).

2006 August, Alexander V. Krivov, Artem G. Feofilov, Valeri V. Dikarev, “Search for the putative dust belts of Mars: The late 2007 opportunity”, in Planetary and Space Science, volume 54, numbers 9–10, →DOI, page 873:

Poynting-Robertson effect
Poynting-Robertson effect#English

(astrophysics) Synonym of Poynting-Robertson effect.


Poynting-Robertson effect

the Poynting-Robertson effect (canonical)

Named after English physicist John Henry Poynting (1852–1914) and American mathematician Howard P. Robertson (1903–1961).

(astrophysics) A process by which solar radiation causes a dust grain orbiting a star to lose angular momentum relative to its orbit around the star.


strange quark star

strange quark star (plural strange quark stars)

(astrophysics) Alternative form of strange star.


quark matter

(astrophysics) A hypothetical phase of matter made up of quarks that are so tightly packed (due to high surrounding pressure) that they do not chunk into baryons.


Jeans escape

Jeans escape (countable and uncountable, plural Jeans escapes)

Named after English physicist Sir James Jeans (1877–1946), who is credited with calculating the rate of such atmospheric escape.

2014, Eugene F. Milone, William J. F. Wilson, Solar System Astrophysics, Springer, 2nd Edition, page 413,
As will be seem in Sects. 11.7.2.3 and 11.7.3.2, Jeans escape of H atoms from Venus is negligible compared to other, nonthermal mechanisms, whereas Jeans escape dominates the loss of H from Mars. On both planets, Jeans escape of O, O₂ and CO₂ is negligible.

where a≡m/2k_BT, n is the number density of particles and v is the magnitude of the velocity.

2017, Kevin Heng, Exoplanetary Atmospheres, Princeton University Press, page 213, The simplest model of Jeans escape [112], a mechanism named after the Englishman James H. Jeans, assumes that the constituent particles of the atmosphere may be described by a Maxwell-Boltzmann distribution, f_M=(a/π)ne, (13.6)

2021, Mark H. Thiemens, Mang Lin, 2: Discoveries of Mass Independent Isotope Effects in the Solar System, Ilya N. Bindeman, Andreas Pack (editors), Reviews in Mineralogy and Geochemistry, Volume 86: Triple Oxygen Isotope Geochemistry, Mineralogical Society of America, page 70,
The hydrogen is lost from the system by diffusion and Jeans escapes.

(planetology, astrophysics) A type of atmospheric escape in which a light gas atom or molecule (typically a helium atom or hydrogen molecule) gains sufficient momentum through collision with other molecules to escape the atmosphere (and gravitational pull) of a planet.


extremal black hole

extremal black hole (plural extremal black holes)

(astrophysics, cosmology) A black hole with the minimum possible mass that is compatible with its charge and angular momentum.


Henyey track

pre-main-sequence star
pre-main-sequence star

Hertzsprung–Russell diagram
Hertzsprung–Russell diagram

(astrophysics) A path taken by pre-main-sequence stars with masses greater than 0.5 solar masses in the Hertzsprung–Russell diagram after the end of the Hayashi track.


Hayashi track

(astrophysics) A luminosity–temperature relationship obeyed by infant stars of less than 3 M☉ in the pre-main-sequence phase (PMS phase) of stellar evolution.


pre-main-sequence star

pre-main-sequence star (plural pre-main-sequence stars)

(astrophysics) A star in the stage when it has not yet reached the main sequence.


infant star

Perhaps thy sight is wandering far Throughout the kindled sky, In tracing every infant star Amid the lights on high,

1849, M. A. H., “The Dying Child”, in Echoes of Infant Voices, page 86:

Emitted radiation and a stellar wind flow from the infant star.

2006, Gregory L. Matloff, Deep Space Probes: To the Outer Solar System and Beyond, page 15:

In one discovery, Spitzer's infrared eyes have peered into the place where planets are born—the center of a dusty disc surrounding an infant star—and sped the icy ingredients of planets and comets.

2008, Paul Hutchins, The Secret Doorway: Beyond Imagination, page 61:

(astronomy, astrophysics) A newly formed star; a star that has just begun to sustain a fusion reaction.


LCDM

“L.C.D.M. is being put through its paces by precision tests coming at it from every direction,” Dr. Turner said.

2024 April 4, Dennis Overbye, quoting Michael Turner, “A Tantalizing ‘Hint’ That Astronomers Got Dark Energy All Wrong”, in Thew New York Times:

lambda cold dark matter (model)
w:Lambda-CDM model

(astrophysics) Short for lambda cold dark matter (model)


one-way light time

one-way light time (countable and uncountable, plural one-way light times)

(astronomy, astrophysics) The amount of time required for light or a radio signal to travel between the Earth and a celestial body.


Forbush effect

Named after American physicist Scott Forbush.

coronal mass ejection
coronal mass ejection

(astrophysics) A rapid decrease in the observed galactic cosmic ray intensity following a coronal mass ejection.


spacetime metric

spacetime metric (plural spacetime metrics)

(astrophysics) Any method used to measure the geometry of the universe.


Yarkovsky effect

Named after Polish-Russian civil engineer Ivan Yarkovsky.

(astrophysics) A force acting on a rotating body in space caused by the anisotropic emission of thermal photons, which carry momentum.


eternal black hole

eternal black hole (plural eternal black holes)

(astrophysics, cosmology) A theoretical idealization of a usually stationary black hole that has existed forever, rather than being formed from the collapse of some matter.


stellar black hole

stellar black hole (plural stellar black holes)

gravitational collapse
gravitational collapse

(astrophysics, cosmology) A black hole formed by the gravitational collapse of a star.


intermediate mass black hole

intermediate mass black hole (plural intermediate mass black holes)

(astrophysics, cosmology) A class of a black hole with a mass in the range of 102–105 solar masses.


micro black hole

micro black hole (plural micro black holes)

(astrophysics, cosmology) A hypothetical tiny black hole, of less than one solar mass, for which quantum mechanical effects play an important role.


BZ black hole

An initialism of Roger Blandford and Roman Znajek, theoretical astrophysicists.

The 'Blandford-Znajek' (BZ) black hole magnetospheric power extraction process was one of the first (1977) analytic attempts to define a general relativistic theory for axisymmetric, stationary, ideal-MHD, BH magnetospheres.

2002, Chang-Hwan Lee, Hŏn-yŏng Chang (editors), Current High-energy Emission Around Black Holes, page 36:

(astrophysics, cosmology) A rotating black hole that extracts energy from its rotation and magnetic fields to emit a jet of particles and radiation.


atmospheric escape

atmospheric escape (countable and uncountable, plural atmospheric escapes)

(astrophysics) The loss of planetary atmospheric gases to outer space.


triple-alpha process

triple-alpha process (plural triple-alpha processes)

triple-alpha processes (plural)
triple-α process (alternative)

(physics, astrophysics) A set of fusion reactions by which stars are thought to convert helium to carbon.

réaction triple alpha

group of nuclear reactions thought to occur in stars


absolute horizon

absolute horizon (plural absolute horizons)

(astrophysics) A boundary in spacetime, defined with respect to the external universe, inside which events cannot affect] an external observer.


apparent horizon

apparent horizon (plural apparent horizons)

(astrophysics) A surface that is the boundary between lightrays that are directed outwards and moving outwards and those directed outward but moving inward.


isolated horizon

isolated horizon (plural isolated horizons)

(astrophysics) In the context of black holes, a null hypersurface (a surface where light rays travel) that is in equilibrium with its surrounding environment.