Top 10 best (or worst) terms in astronomy and physics

a dense web of wires and magnets in a circular arrangement
The Compact Muon Solenoid (CMS) pictured here can capture images of particles up to 40 million times per second. (Image credit: xenotar via Getty Images)

Modern astronomy and physics stretch back centuries, so naturally, they've accumulated a lot of interesting names for objects, ideas and phenomena.

And let's face it: Some are downright strange. 

From odd choices for the names of astronomical bodies to hard-to-pronounce physics terms, sometimes the words we use in astronomy and physics can be off-putting or come with problematic historical backgrounds.

Here is a list of my favorite ones. 

Related: Astronomy: Everything you need to know

10. Uranus

A zoomed-in image of Uranus as seen by the James Webb Space Telescope on Feb. 6, 2023. (Image credit: NASA, ESA, CSA, STScI, J. DePasquale (STScI))

In 1781, astronomer William Herschel discovered a new planet beyond the orbit of Saturn. When his friend prompted him to do the astronomical community a favor and suggest a name, he proposed "Georgium Sidus," which is Latin for "George's Star," in honor of King George III, the king of England at the time (and Herschel's financial patron). Another prominent astronomer, Johann Bode, suggested "Uranus," which fit with the mythological theme of the other planetary names. 

Oddly, while the other planets are named after Roman gods, Bode's suggestion of "Uranus" is really the Latin translation of the Greek god, not the name of the Roman god himself. Historians aren't sure if Bode knew this. Regardless, generations of kids have him to thank for countless jokes about Uranus — which, by the way, is pronounced "YOOR'-un-us."

9. Neptune

Voyager 2 snapped this close up shot of a blue windy Neptune back in 1989. (Image credit: NASA/JPL-Caltech)

In 1846, French astronomer Urbain Le Verrier predicted the existence of yet another planet more distant than Uranus. Once it was discovered, the community looked to Le Verrier for a name. At first, he suggested "Neptune" (which was also a contender for what would become Uranus). But he quickly changed his mind and offered the totally modest suggestion of … Leverrier. 

The only organization to support this idea was the Paris Observatory, which retconned history and started calling Uranus "Herschel" as a way to legitimize Le Verrier's bold suggestion. Nobody else in the world cared much for that, so his original suggestion of Neptune stuck. 

Related: Night sky, Aug. 2023: What you can see tonight [maps]

8. Tomhanks

The very same. (Image credit: Apple TV+)

The International Astronomical Union (IAU), headquartered in Paris, maintains sole naming authority for all astronomical objects and features. According to the IAU's guidelines, you must adhere to certain restrictions in naming most deep-sky objects — basically, you have to give any new discovery a boring category number. The exception is asteroids

If you spot a new asteroid, the IAU will generally accept your suggested name. So when University of Arizona astronomer Joseph L. Montani discovered a new asteroid in 1996, he decided to name it after one of his favorite actors, Tom Hanks. Because the IAU mandates that asteroids have only a single name, however, the space rock's official designation is 12818 Tomhanks.

Related: How are stars named? 

7. St. Catherine's Wheel

Messier 99, also known as St. Catherine's Wheel. (Image credit: Adam Block/Mount Lemmon SkyCenter/University of Arizona)

This distant galaxy has the proper designation of Messier 99, after a catalog created in 1774 by French astronomer Charles Messier. But the large spiral galaxy, located in the Virgo Cluster, has a more sinister nickname: St. Catherine's Wheel. 

The galaxy has roughly three times more active star formation than a typical galaxy, so through a telescope, it appears as a fantastic wheel of stars, reminiscent of a torture wheel used to kill St. Catherine, an 18-year-old martyr, in A.D. 305. 

6. The Fetus Nebula

Planetary Nebula, NGC 7008, the Fetus Nebula. (Image credit: Bob and Janice Fera)

This planetary nebula is the remains of a sunlike star; all that's left are wisps of gas and dust blown out by the powerful winds of the dying star. Its formal name is NGC 7008, but based on its appearance, the nebula, which sits about 2,800 light-years away, has a much more anatomical name: The Fetus Nebula. 

5. Syzygy

Skywatcher Thomas Warloe took this photo of annular solar eclipse from Fountain Valley, CA, on May 20, 2012. (Image credit: Thomas Warloe)

If it looks like a cat just walked over someone's keyboard, it's probably an astronomical term. Case in point: syzygy (pronounced SIZ'-a-jee), which comes from the Greek word for "union." This is the astronomical term for when three or more celestial objects find themselves in a straight line. Perhaps the most famous example of a syzygy is a total solar eclipse, when the sun, the moon and Earth all line up. 

4. Gedankenexperiment

An illustration of the Schrödinger's cat thought experiment that presents a cat that is in a superposition of alive and dead states, depending on a random quantum event. (Image credit: Wikimedia Commons/Dhatfield)

 The practice of physics requires an enormous amount of creative brainpower. The epitome of this is the "gedankenexperiment," which is German for "thought experiment." Physicists constantly imagine hypothetical scenarios and use those to think through the logical consequences of a hypothesis, and the practice has become so cemented as a part of physics training that it got its own name. Perhaps the most famous gedankenexperiment is attributed to Albert Einstein, who imagined what it would be like to ride alongside a beam of light. His insights would eventually lead to the theory of special relativity

3. Quarks

3D illustration of an atom and quarks. (Image credit: Shutterstock)

When physicist Murray Gell-Mann cracked the inner workings of the strong nuclear force, he discovered that his theory required three new particles of name. Struggling to find a suitable moniker, he came upon a quote from James Joyce's 1939 novel "Finnegans Wake": "Three quarks for Muster Mark!" The name seemed new and interesting, so Gell-Mann used it for the subatomic particle. Later physicists discovered that there were actually six quarks, but by then, the name had stuck. 

2. Jerk

This visualization of Earth's core shows how turbulent waves (shown in red and blue) twist up the planet's magnetic field lines (orange) into pockets of intense activity. This mysterious phenomenon is called a geomagnetic jerk. (Image credit: Aubert et al./IPGP/CNRS Photo library)

Yeah, this word describes an unsavory person — but it's also a strange term for a particular measurement of movement. If you change your position, you have velocity. If you change your velocity, you have acceleration. And if you change your acceleration, you have jerk. 

The term doesn't come about frequently, because for almost all applications, all we need to care about are velocity and acceleration. But it's there in case you need it. 

1. Hand-waving

Astrophysicist Neil deGrasse Tyson in a 2011 interview. (Image credit: TheBigThink)

If you've ever encountered an argument that seemed to skip a few critical steps, you've seen an example of hand-waving. It's an endearing term in physics, because eventually, everyone does it at one time or another. Not every argument or line of thought is supported by the most rigorous steps, so sometimes, you just have to "wave your hands" and hope for the best. 

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Paul Sutter
Space.com Contributor

Paul M. Sutter is an astrophysicist at SUNY Stony Brook and the Flatiron Institute in New York City. Paul received his PhD in Physics from the University of Illinois at Urbana-Champaign in 2011, and spent three years at the Paris Institute of Astrophysics, followed by a research fellowship in Trieste, Italy, His research focuses on many diverse topics, from the emptiest regions of the universe to the earliest moments of the Big Bang to the hunt for the first stars. As an "Agent to the Stars," Paul has passionately engaged the public in science outreach for several years. He is the host of the popular "Ask a Spaceman!" podcast, author of "Your Place in the Universe" and "How to Die in Space" and he frequently appears on TV — including on The Weather Channel, for which he serves as Official Space Specialist.

  • Unclear Engineer
    I guess that list was interesting, but I am not agreeing that those were the worst choices that astronomers and physicists have made when naming things they discovered.

    My candidates would include:

    "barn" - the unit for measuring the area of an atomic nucleus as seen by an approaching subatomic particle;

    "Hertz" - which used to be called what it really is (cycles per second) got renamed to something that nobody in the public recognizes for what it is and sounds like a unit for car rentals;

    "charm", etc. naming the characteristics of sub-atomic particles with words that seem to have entirely different meanings to normal people. (At least "spin" has some relevance to the measurements used to measure it, although theory indicates that it cannot be actual physical spin.)

    Anybody else have some candidates for the alternative list?
    Reply
  • danR
    "Hertz"
    Yes. Its over-extension is almost imbecilic.
    Reply
  • danR
    "Spin"
    There isn't enough of a classical component (the idea of a bulk-rotation of a mass-with-radial-extension around its center of mass) to the essential attribute in question here to warrant the use 'spin' for sub-atomic particles.

    To learn "spin", one must unlearn its intuitive coupling to "rotation". Dozens of youTube videos attempt this uncoupling; but the main success of each is found more in the effusive fanboi- or shilI- comment praise—you know... the monotonous drumbeat of "wow, I learned more about spin (or tensors, or radioactively doomed/undoomed cats, etc) in 20 minutes than 4 years of undergrad head-scratching!!.."—than in the exposition itself.
    Reply
  • Helio
    Perhaps the most convoluted problem is the Sun designated as a yellow dwarf star. It won’t be yellow for several billion years. The Sun is one of the larger stars, so not a “dwarf“. The dwarf idea was simply to separate out the non-giant stars, which happened when it was discovered that both red and blue stars come in dramatically different sizes, contrary to then stellar evolution theory.

    But if we correct the Sun’s color to white, then how can we call it a white dwarf? . White dwarfs aren’t even stars, but extremely hot (for billions of years). They are so hot, most aren’t white but bluish white. * cough*

    Messy ain’t it.

    This will likely take a long time to fix. But it took about four decades to establish ”Uranus”.
    I think ”singularity” is an inherently problematic word. They possibly don’t exist, but they’re treated as factual.

    I’m ok with restoring “George“ and dumping “Uranus”. It‘s not that Greek, but it’s established that it has a certain ring to it. ;)

    George
    Reply
  • p3orion
    A little off topic, but the WORST term? One the author used himself: "three times more" (refering to star formation in Messier 99, which occurs at triple the rate of typical galaxies.)

    Articles on Space.com are rife with ridiculously imprecise language like this, using constructions like "three times more" when what is really meant is "three times AS MUCH." No, they're NOT the same thing: "three times more" means "300% more," or 400% of whatever is being compared to.

    The only thing worse is when they use something like "six times LESS" (for example "the moon has six times less gravity than Earth", which if read correctly means gravitational acceleration there is negative five G.)

    It's hopeless to try to explain the distinction to TV anchors and advertisers, but when it says "PhD in astrophysics" in your bio, we should be able to expect better.
    Reply
  • skynr13
    I submit the term, 'Planetary Nebula', which doesn't refer to planets at all. It's a region of gas and dust formed from the cast-off outer layers of a collapsed, dying Star.
    Reply
  • jim_robison
    Unclear Engineer said:
    I guess that list was interesting, but I am not agreeing that those were the worst choices that astronomers and physicists have made when naming things they discovered.

    My candidates would include:

    "barn" - the unit for measuring the area of an atomic nucleus as seen by an approaching subatomic particle;

    "Hertz" - which used to be called what it really is (cycles per second) got renamed to something that nobody in the public recognizes for what it is and sounds like a unit for car rentals;

    "charm", etc. naming the characteristics of sub-atomic particles with words that seem to have entirely different meanings to normal people. (At least "spin" has some relevance to the measurements used to measure it, although theory indicates that it cannot be actual physical spin.)

    Anybody else have some candidates for the alternative list?
    I have always thought "black hole" was an unfortunate choice of names. A hole is usually considered empty or sparsely populated, yet the center of a black hole is the most dense object we know of. I nominate "light sucker" as the new name.
    Reply
  • jim_robison
    p3orion said:
    A little off topic, but the WORST term? One the author used himself: "three times more" (refering to star formation in Messier 99, which occurs at triple the rate of typical galaxies.)

    Articles on Space.com are rife with ridiculously imprecise language like this, using constructions like "three times more" when what is really meant is "three times AS MUCH." No, they're NOT the same thing: "three times more" means "300% more," or 400% of whatever is being compared to.

    The only thing worse is when they use something like "six times LESS" (for example "the moon has six times less gravity than Earth", which if read correctly means gravitational acceleration there is negative five G.)

    It's hopeless to try to explain the distinction to TV anchors and advertisers, but when it says "PhD in astrophysics" in your bio, we should be able to expect better.
    I agree with you, 400%, more or less.
    Reply
  • ARTGLICK
    I like the terms physicists employ to rename things so as to catch the public's attention and garner funding.

    My 2nd best favorite was renaming the unified field theory to the "theory of everything", but my all time favorite is referring to the Higg's Boson as the "god particle". Sheesh! Give me a break.
    Reply