Questions tagged [terminology]

Questions regarding specific terms, names, or naming conventions.

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3
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1answer
67 views

Sorting out Julian Day, Julian Date, Julian Day number, Julian Day Calendar, and Julian Day Table

In this answer I mention day number which is 1 on the first day of each calendar year (January 1) and increments to 365 or 366 on December 31 of that year. There was an edit proposed, which included ...
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1answer
118 views

Word for blue ring around the Earth

From certain positions in outer space the Earth will appear to have a blue ring around it when the viewer is in the shadow of the Earth and sunlight is passing through the atmosphere. Here is a ...
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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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What is the name of meteoroids which hit Moon, Mars, or pretty much anything that isn’t the Earth?

A meteorite according to the Oxford English Dictionary is A piece of rock or metal that has fallen to the earth's surface from outer space as a meteor. But, meteors impact other planets. Are they ...
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Are there recommendations to use “Hubble-Lemaître constant” instead of “Hubble constant”?

The IAU recommends renaming the Hubble law as the Hubble-Lemaître law, as discussed at its General Assembly in 2018 (see this press release and the links therein). I have now stumbled upon an ...
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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 (the heck) is a Super Worm Equinox Moon?

Google News feed shows me the following. What does the term "Super Worm Equinox Moon" mean and has it ever been used before this 2019 clickbait instance?
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Terminology for empty space at the edge of the observable universe?

Is there a name for a point at the edge of the observable universe at which there is no visible matter, that appears completely dark? I'm thinking something like "empty space", but that could equally ...
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What's the reason that we have a different number of days each month?

It always was interesting for me to understand the answer for the question: What's the reason that we have a different number of days each month? If the month is fixed on the time that the moon ...
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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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1answer
48 views

Does astronomical observing “count” as remote sensing?

I have long considered astronomical observing as a form of remote sensing, though quite different than typical remote sensing in that many objects observed are not resolved. I am wondering, though, ...
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Logarithmic scale for large distances?

I understand this is an icky subject, but I recently got interested in units for large distances for applications in cosmology and what not (after hearing about the redefinition of the kilo and kelvin)...
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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 exactly are the “ν6 secular Sun-Jupiter-Saturn” and the “1:4 Sun-Jupiter” resonances?

In the recent Acta Astronautica article The edge of space: Revisiting the Karman Line, Harvard-Smithsonian Center for Astrophysics astronomer, Space SE contributor and "inverse namesake" of asteroid (...
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Do astronomers have an established, systematic way for saying what does or doesn't orbit what? (e.g. “Mars orbits Earth”)

A recent comment An object far enough away can certainly orbit the Moon and the Earth (and the Sun) -- Mars, for instance does this. An object in the Earth-Moon L2 is also orbiting both the Earth ...
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How does an eclipse differ from an occultation?

A comment in response to this question suggests that an eclipse differs from an occultation in that the former casts a shadow while the latter doesn't. This isn't particularly satisfactory since ...
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Are asteroid complexes and types the same?

Very novice astronomer here. I keep seeing terms like "S-Complex" thrown around when talking about asteroids, but no matter how much Googling I do I can't figure out what that exactly means (every ...
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86 views

Terminology of Orbits

A hopefully simple terminology question: When you have an object that orbits another object in space, what do you call the object being orbited in relation to the object orbiting? For instance, you ...
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1answer
590 views

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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86 views

WMAP beam profile

What do people mean by the "beam" profile/model pertaining to WMAP? Search results are all rather packed with jargon. Is there a pictorial /layman explanation of it and how does it affect the data?
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Finding the number of stars n light-years from the sun

The nearby stars seem homogenously spaced out enough to give a general "stellar density." Does there exist some kind of mathematical expression that can determine the number of stars n light-years ...
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1answer
176 views

Is there a term for a horizontal moon crescent

I seen the other day the moon lit directly below or towards my horizon perfectly. My question, is there a term for when a moon's crescent is aligned with the viewer's horizon?
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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 is “superficial gravity”

I have seen the term superficial gravity used and it seems to be equivalent to surface gravity seen, e.g., here http://arxiv.org/pdf/1701.02295 Is there any difference between superficial and ...
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Usage of $\sim$, $\approx$, $\simeq$, and $\cong$ in observational astronomy?

My understanding is $\sim$ generally means "on the order of magnitude of" e.g. $T \sim 10^5$ K $\approx$ is obviously "approximately equal to" so for example one might write $d \approx 400$ pc rather ...
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So, what exactly is an 'ultra-cool' dwarf star?

The TRAPPIST-1 system is around an ultra-cool dwarf star. I went looking for more information on that kind of star, and found very little. The Wikipedia article on it lengthened from a minimal stub to ...
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Do astronomers generally agree that the distinction between comets and astroids is not so clear?

edit: I just saw this tweet and find it incredibly relevant :) begin question: First see this answer and then consider if there are known, or likely to be identified cases of solar system bodies that ...
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How close must a full moon be to become a supermoon?

According to this answer there is a scale of super moons depending on how close the full moon(henceforth anti-sol) is to perigee. So how close to anti-sol does the moon's perigee need to be to be ...
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If an earthquake happens on Mars, is it still an earthquake?

Or are seismic phenomenon named differently when they happen on other celestial bodies? If so, what are they called?
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What is left of a universe where no matter and energy exist and is there a term for this?

In the final energy state of the universe, there exists a hypothesis that all matter will have fallen into black holes and neutron stars. If, through Hawking radiation, after all matter is consumed ...
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Terminology: planet plus atmosphere vs planet and atmosphere as separate things

When discussing a rocky planet, is there any terminology to distinguish that you're talking about the whole thing, including the atmosphere, veruses that you're talking about the ocean + crust + ...
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What's the terminology of a meteor “ditch” when impact happens at an angle?

When a meteor hit the surface of a planet, it creates an impact crater. When an meteor hit the surface of a planet at an angle, like it usually happens in the movies, what do you call the long "ditch" ...
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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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1answer
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Term for the period between planet alignments?

Is there an established astronomical term for the period of time between alignments of pairs of planets? For example, Mars, Earth, and the Sun roughly align ever 780 Earth days. In my writing, I've ...
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Why do astronomers not use past tense when discussing observations of the universe [closed]

Describing a galaxy 70 million light years away, I consider it incorrect to state for example "it has an active black-hole at its center". It did 70 million years ago, who knows what is out there now. ...
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1answer
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What does the filter name I+z' mean

On the TRAPPIST telescope, the filter wheels are described to have a filter with the following description: NIR Luminance I+z' (>700nm) After a bit of googling, I wasn't able to find what the ...
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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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Is it possible for the year to have 11 full moons (i.e. the opposite of a blue moon)

A blue moon is so called for when we have 13 full moons in a year. https://en.wikipedia.org/wiki/Blue_moon Is it possible to have 11 fun moons in a year? (Maybe if we included calendar changes, for ...
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Direction Names Within a Galaxy

Are there commonly used names for objective directions within a spiral galaxy? Central and peripheral describe objective directions, because the observer's frame of reference doesn't affect whether ...
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Is a planetary system star's referred to as their sun?

It's my understanding that the Sun (uppercase) is used to refer to our sun/star, because it is The Sun. Latin name is Sol, hence the Solar System. Even the tag (lowercase sun) on this post has the ...
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Term for altitude of the sun?

The sun travels in an arc across the sky. Where I live, during the summer the arc rises higher, but in the winter the arc is lower. Once might speak of highest altitude or elevation the sun reaches ...
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What's the proper terminology for nebula clouds?

I'm writing a research paper over outer space (yeah, yeah, broad topic) and I'm wondering what the proper terminology for nebula clouds is. This is an excerpt from my paper showing how I'm going to ...
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Terminology: Is there a name for the points on the surfaces of tidally locked parent/satellite bodies that always face each other?

This is purely a question about terminology, one that has eluded my googling efforts. When a satellite and its parent body are tidally locked to each other, there is (in an ideal case) a single ...
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Are meteors and meteorites considered “Small Solar System Bodies”?

The difference between meteorites, meteors, and meteoroids is one of altitude relative to a celestial surface: in space, it's a meteoroid; in the atmosphere, it's a meteor; and on the surface, it's a ...
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Questions about terminology used for Mars and its moons

I am having difficulty with some terminology: sub-Martian hemisphere of Deimos ... what place on Deimos does it refer to? leading/trailing apex of Phobos ... what place are those? Apex ... in general ...
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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 ...
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765 views

Is there a difference between the terms 'elliptical' and 'elongated' for galaxies?

While studying the Solar System, I found that some galaxies are either elliptical or elongated. What's the difference?
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What is the term for astronomical objects outside the solar system that are smaller than dwarf planets?

Asteroids and comets only seem to refer to masses within the solar system, and it seems unclear whether planetesimal does.
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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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Time period in which a planet rotates

I notice that Wikipedia give two contradictory terms for the time period in which a planet rotates in relation to an infinitely-distant object. In one place this is called a "sidereal day" and in ...