Questions tagged [terminology]
Questions regarding specific terms, names, or naming conventions.
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Do astronomers generally agree that the distinction between comets and asteroids is not so clear?
edit: I just saw this tweet and find it incredibly relevant :)
begin question: See this answer and then consider if there are known or likely solar system bodies that might be identified as both ...
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What are "non-Keplerian" orbits? What are some familiar examples in our solar system, and can some still be closed?
This excellent answer to Forms of stellar orbits around the galactic center invokes the following concepts:
non-Keplerian orbits
closed orbits
I have a fairly good idea what these mean and so might ...
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Is the difference between LIGO & Virgo and their "Advanced" versions really generational, or were these just planned incremental upgrades?
I just learned the term "third generation gravitational wave detector" in answers to What would a kHz gravitational wave detector look like? (mountains on millisecond magnetars) How would it ...
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Hydrogen burning vs Hydrogen fusing
Does the term "Hydrogen burning" mean the same as "Hydrogen fusing" in astronomy? If not, then what is the product of "Hydrogen burning"? Assume the product of "...
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Is there an established distinction between a geyser and a cryovolcano in solar system bodies?
Is there an established distinction between a geyser and a cryovolcano in the context of cold solar-system bodies such as the moons of Jupiter and Saturn, or Kuiper belt objects (e.g. Pluto)?
Both ...
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Is lithium considered a metal in astronomy?
My lecture notes are conflicting on this issue so I seek definitive clarification. In Astronomy, are metals either
A: the elements which form within stars (i.e., not Big Bang nucleosynthesis, where ...
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What is the name of that which exists beyond the Universe?
"The Universe is commonly defined as the totality of existence" but that is more of a philosophical position. Empirically we know (or believe) that it is of finite size some believe it is expanding ...
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What's the name for [the other kind of planet] in a binary star system?
This XKCD what-if talks about rainbows on planets in a binary star system. It points out that there are two types:
circumbinary planets, where the planet orbits far from and around both stars
[the ...
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What exactly are "H30α and He30α images"? (ALMA)
I ran across this paper's title η Carinae: high angular resolution continuum, H30α and He30α ALMA images (arXiv) and see that the body of the paper also mentions "H40α, H30α and H29α".
What ...
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Are the dispersion directions of the prism and the grating in Hubble WFC3 UVIS G280 perpendicular? Can we call this a "grism"? With cross-disparsion?
Prologue
From Into the UV: A precise transmission spectrum of HAT-P-41b using Hubble's WFC3/UVIS G280 grism:
The UVIS grism, however, comes with several quirks that make it difficult to observe with ...
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Is there a term for asteroseismology as applied to giant planets?
Giant planets such as Jupiter have oscillations which enable analyses using the techniques of asteroseismology, for example Gaulme et al. (2011) detected global modes on Jupiter via radial velocity ...
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Difference between "planetary ring" and "circumstellar disk"?
Related: Do/Can Ringed Stars Exist?
Is there any particular difference, in behavior or properties, between a planetary ring system and a circumstellar disk? Or is the only real difference a matter of ...
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What exactly is a Hamiltonian telescope? Is this one?
This comment on the current answer to Why is this telescope so short? How hard is it to make such a fast primary? says
In this forum topic Borisov appears to call it an f/1.5 Hamiltonian.
Wikipedia'...
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How does one go about submitting a name for a newly-discovered lunar crater?
Suppose I discover an uncatalogued crater on the lunar surface, and decide to name it. How would I submit my proposed name to the IAU?
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Origins and most frequently used; perinigricon vs peribothron?
Gizmodo.com's Astronomers Spot Unprecedented Flashes From Our Galaxy's Black Hole mentions Sgr A*'s companion gas cloud G2 and that Wikipedia article uses the term perinigricon, but that mentions ...
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Is the Big Bang a theory or a model?
I ask this because someone mentioned ‘it isn't a theory, it's a model’ in the comments in an old question of mine: Is the expansion of the universe proof of the big bang?
I guess defining terms is ...
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What is a radio "homology telescope" and is the 500m dish in China one?
This question is about design aspects of large radio telescope dishes which allow them to flex under the influence of gravity as they change elevation angle, and still maintain good optical ...
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At what point are orbital resonances no longer "ordered" but "chaotic?"
Orbital resonances are typically in small valued integer ratios, like 2:1, 3:2, or 4:7. However, there are some resonances whose ratios have large reduced values, including the 73:69 Naiad:Thalassa ...
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What does "additive fringing from the (multiplicative) twilights" mean?
The question How can I make the fringing pattern visible in my flat (twilight) images for filter i? includes:
I have a bunch of twilight flats that have been preprocessed (dark, bias, overscan etc.)...
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The defintion of star/planetary/solar system
In many science fiction stories, we hear the term star system that mostly refers to a star and its planets. This is often used interchangeably with the term solar system. But after some research I ...
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"Periapsis" or "Periastron"?
I was taught from Bate Mueller and White, that the proper terms for the closest and furthest points and distances from a body in orbit around another unspecified body are "periapsis" and &...
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Is there a distinction between NEOs and near-Earth asteroids? Is there a difference?
My "real question" is in Space Exploration Meta (neo (near-earth-object) and near-earth-asteroid tags, do we need both?), but I think that astronomers will be able to help understand the situation and ...
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What's the origin and culture of funny astronomical terminology?
I'm not in the industry myself, but as an interested member of the public the terminology of astronomy seems a bit funny. Astronomers who today talk publicly about the interstellar medium say that the ...
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What is "emission measure"?
Many papers mention emission measure, and some of them give the expression of EM, BUT there is no clear definition of EM.
My question is what EM is on earth? Its unit is supposed to be cm-3.
How to ...
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What is the difference between the terms collision and merger? How are they used differently in Astronomy?
We often hear of mergers of two stellar objects but we also sometimes talk about these or much smaller objects like planets or asteroids colliding.
What is the actual differences between Astronomy and ...
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How many solar system objects that can really qualify as a KBO are likely to enter Pluto's Hill sphere each day?
A comment below Which celestial body is able to come closest to Pluto? says that
Technically, many, many small Kuiper belt objects enter Pluto's Hill Sphere (or sphere of influence SOI) every day.
...
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How many constellations in the Zodiac?
The astronomical zodiac contains a bunch of constellations along the ecliptic.
Some sources say there are 13 constellations in the astronomical zodiac. Other sources claim there are 12.
According to ...
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Why do some call the no-hair conjecture the no-hair theorem?
This excellent answer to Why would a black hole's magnetic hair being short-lived not violate the no-hair conjecture, but long-lived hair would? How long is “long-lived”? has got me thinking because ...
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The sun "burns" hydrogen and even has "campfires" on it, but has anyone calculated a rate of actual chemical burning on the Sun?
Answers to Hydrogen burning vs Hydrogen fusing explain that in astrophysics "burning" generally refers to nuclear fusion or at least nuclear reactions1, and information at
Why didn't we ...
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Is it still called an orbital resonance if the ratio is irrational?
Previously, I asked At what point are orbital resonances no longer "ordered" but "chaotic?", and received an answer from @CarlWitthoft:
Perhaps if the calculated fraction had an ...
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Why are helium resonance lines called "resonance lines"?
Examples of the use of the term:
Formation of the helium extreme-UV resonance lines
On the Formation of the Resonance Lines of Helium in the Sun (unpaywalled)
Formation of the helium EUV resonance ...
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When we say a variable star is "fainting" does it mean something more or different than "dimming" or "fading"?
A comment below the question Does the current “fainting” of Betelgeuse show any spectral trends that differ from it's normal variability? suggests that "dimming" would be a better term, but I have a ...
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Terminology question: gas giant vs gas planet
While not exactly the most exciting question, I'm wondering: is there any real, semantic difference between a gas planet and gas giant, or are the two terms used interchangeably by most in popular ...
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What is an "Off Rowland-circle Telescope"? Are there "On Rowland-circle Telescope" as well?
The NASA Goddard news item NASA to Demonstrate New Star-Watching Technology with Thousands of Tiny Shutters says:
The technology, called the Next-Generation Microshutter Array (NGMSA), will fly for ...
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Adjective for things outside our solar system
I know we have "exoplanets" etc. but those are nouns for specific objects outside our solar system.
We have extraterrestrial for objects outside Earth's atmosphere, but I don't know if we have a ...
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What are the differences between astronomy and cosmology?
Are astronomy and cosmology same? If not, what are the differences? And which one is greater in terms of subject area?
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Term for the moment when hydrogen fusion begins in a star
I have read of this process many times, but I don't think I know the term specifically for the moment when hydrogen fusion begins. What is this moment called?
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What are the "lines" in a constellation or asterism called?
Is there a technical term for the "lines" in a constellation or asterism? Alternatively, is there an astronomy related coloquialism or any informal term that refers specifically to these lines, and ...
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Is Sofia a radio telescope proper?
I usually think of SOFIA, the Stratospheric Observatory for Infrared Astronomy as an infrared optical telescope:
SOFIA uses a 2.5 m (8.2 ft) reflector telescope, which has an oversized, 2.7 m (8.9 ft)...
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Are there actual asteroids in the Oort cloud?
This answer to At what annual rate are new exoplanets being recognized? How does it compare to new asteroids? shows that the rate of new asteroid discovery is roughly two orders of magnitude higher ...
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What is the opposite of the vernal point?
The equator and the ecliptic cross at two nodes. One of those nodes is the vernal point. What is the other one called?
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Does the Honey moon have a precession problem?
In Steven Colbert's interview with Neil deGrasse Tyson after about 03:16 the following is explained:
But wait, all the moons - all the full moons of the year have ...
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Does the KBO 2014-MU69 have two numbers and entries in asteroid databases? How did it get promoted to Major Body designation?
In this answer I show that the (now pretty famous) Kuiper Belt Object 2014-MU69 has two entries in JPL's ephemeris generating Horizons site; Major Body ...
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How does one think about optical depth in the context of gravitational microlensing? Is it measured or deduced from observations? Used for planning?
This excellent answer to Which studies prior to 2018 "claimed to find evidence of extragalactic planets in the Andromeda galaxy"? Which instrument was used? introduces the technique of "...
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Is intrastellar commonly used by astronomers to refer to objects within our solar system?
The CNET article Interstellar comet Borisov looks ordinary, making Oumuamua even weirder says:
A paper published Monday in Nature Astronomy lays out the early data on Borisov, which is just the ...
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