Sciency Words: The Milky Way

Hello, friends!  Welcome back to Sciency Words, a special series here on Planet Pailly where we talk about the definitions and etymologies of science or science-related terms.  Today on Sciency Words, we’re talking about:


A while back, there was a very famous marketing campaign, coupled with a very famous slogan.  Some of you may remember it.  The purpose of this marketing campaign was, obviously, to encourage tourists to visit our galaxy.

According to ancient Greek mythology, the Milky Way was created as a result of a breastfeeding accident.  You see, the demigod Heracles was absurdly strong, even as a baby.  One day, the goddess Hera was breastfeeding baby Heracles.  Because Heracles was so strong, he started suckling too hard, and Hera had to pull him off her breast.  As a result, Heracles spat up all the milk he’d been drinking.  And, once again because Heracles was so absurdly strong, he ended up spewing milk all the way up into the sky.

Thus, the Greeks called all that “milk” in the sky Galaxias Kyklos, or “the Milky Circle.”  The “Way” part came later, thanks to the Romans, who looked at that same wide band of light cutting across the nighttime sky and thought it looked kind of like a road.  Thus, the Romans named it Via Lactea, which can be translated as “Road of Milk” or “Way of Milk.”  Or “Milky Way.”

So that’s how our galaxy came to be known officially as the Milky Way.  Except… is that really the official name?  I tried really hard, but I couldn’t find any statement or document from the International Astronomy Union (I.A.U.) concerning the official name of our galaxy.  The official names of other galaxies?  Sure, there are rules for that.  But our own galaxy?  Nothing.

I suspect the I.A.U.’s stance on this is similar to their stance on the official names for the Earth and the Moon, or the Sun and the Solar System: just keep using whatever names you already use in your native language.

According to Wikipedia, our galaxy is known as the Silver River (China), the Heavenly River (Japan), and the Ganges of the Sky (India).  In large portions of Africa and Central Asia, our galaxy is called the Straw Way or the Straw Thief’s Way.  Several cultures in and around the Arctic Circle call it the Bird’s Path, because it is said that birds follow that pathway of stars during migratory seasons.

Personally, I don’t think the Milky Way looks much like milk.  It’s too shiny.  Too sparkly.  Thanks to light pollution, I’ve only seen the Milky Way a few times in my life.  The first time was while camping in the backwoods of Indiana.  I thought then, and I still think now, that the Milky Way looks like someone spilled diamonds across the sky.

So if I ever got the chance to rename our galaxy (and as a science fiction writer, perhaps I will have that chance at some point), I’d want to name it something diamond-y.  The Diamond Way, or the Diamond River, or something like that.

So what do you think?  Do you like the name Milky Way, or do you prefer a different name like Silver River or Bird’s Path?  Or would you rather make up your own name, if you had the chance?

P.S.: According to the Mars Wrigley’s website, the Milky Way candy bar was NOT named after the galaxy.  As a space nerd, I was deeply disappointed to learn this.  In the future, I will be spending my candy allowance elsewhere.

Sciency Words A to Z: Quijote

Welcome to a special A to Z Challenge edition of Sciency Words!  Sciency Words is an ongoing series here on Planet Pailly about the definitions and etymologies of science or science-related terms.  In today’s post, Q is for:


The International Astronomy Union (I.A.U.) still seems to think they were right about the whole Pluto thing.  However, they also seem to realize that they made a mistake in being so very dismissive of public opinion on the matter, and they’ve been trying to do a better job with public outreach since then.

To that end, in 2014 the I.A.U. announced a partnership with Zooniverse, and they enlisted the general public in the process of assigning official names to exoplanets.  As stated in this I.A.U. press release:

For the first time, in response to the public’s increased interest in being part of discoveries in astronomy, the International Astronomy Union (IAU) is organizing a worldwide contest to give popular names to selected exoplanets along with their host stars.

Now the I.A.U. already had a system in place for naming exoplanets, but that system produced “names” like HD 219134g, or KOI-4427b, or PSR 1257+12c.  There are astronomers who can rattle off this alphanumeric gobbledygook with ease, but I have a tough time with it.  As Doctor Who once said about planets: “I’m terribly old-fashioned. I prefer names.”

But of course letting the general public decide these sorts of things doesn’t always go well.  The I.A.U. did not want something like the Boaty McBoatface scenario to happen to some poor planet.

So the official process was that astronomy clubs and non-profit astronomy organizations (i.e.: people who would take this seriously) got to submit names, and then an I.A.U. committee picked the best options and put those up for a vote.

Quijote—as in Don Quijote (or Don Quixote, as it’s spelled in English) of the famous Spanish novel—was one of the winners.  According to Wikipedia, Quijote was initially thought to have a highly eccentric orbit, but after we learned more about the planet, it turned out its orbit was not as eccentric as it first seemed.  I’m not super familiar with the Don Quijote story, but from what I’ve heard the name seems fitting.

In that same I.A.U. naming contest, Quijote’s star got the name Cervantes, in honor of the author of Don Quijote, and all the other known planets in the system were named after other characters from the book.  As for astrobiological interest in Quijote, the planet does lie within Cervantes’ Goldilocks zone; however, Quijote is a gas giant, so it’s E.S.I. score must be quite low.

Still, it’s conceivable that Quijote might have Earth-like moons. So as we continue our quixotic search for alien life, Quijote might not be a bad place to check.

Next time on Sciency Words A to Z, could it be that we really are alone in the universe?

P.S.: Scattered disk object (225088) 2007 OR10 is currently the largest unnamed object in the Solar System.  If you’d like to vote on what the I.A.U. should name it, click here.

P.P.S.: I cast my vote for “Holle,” the only female name on the ballot, because I think we need more female representation in the cosmos.

Sciency Words: Submoon

Sciency Words: (proper noun) a special series here on Planet Pailly focusing on the definitions and etymologies of science or science-related terms.  Today’s Sciency Word is:


After my recent post about exomoons and trickster moons, a reader commented asking about moons with moons.  Honestly, I couldn’t think of any reason why that wouldn’t be possible, but I felt like it must be an extremely rare thing. Otherwise we probably would’ve found something like that in our own Solar System by now.

And according to this paper entitled “Can Moons Have Moons?” the answer is yes.  Theoretically, under certain circumstances, a moon could have a very, very tiny moon of its own.

It’s important to note, however, that for an object to truly be considered a moon, its orbit must be stable.  For example, there are multiple objects that are in temporary orbit around Jupiter, but since those objects are not expected to stick around for more than a few years, or maybe a few decades at the most, they are not included in the official count of Jupiter’s moons.

In most cases, a small object caught in orbit around a moon will have a very difficult time maintaining that orbit.  The gravitational attraction of the nearby planet will just keep tugging and tugging, stretching the orbital path into a wider and wider ellipse.  It won’t take long before the moon’s gravity can no longer hold the small object it captured.

But according to that “Can Moons Have Moons?” paper, if a moon is relatively large (like our own Moon) and orbits relatively far away from its host planet (also like our own Moon), and if there aren’t a whole lot of other moons around to make gravitational interactions complicated, then yes: that moon could have a moon in a stable orbit.  A very, very tiny moon.  Something asteroid sized.

The research paper I’m citing proposes calling the moon of a moon a submoon, but that’s not an official scientific term.  Not yet.  It probably won’t be until an actual submoon is discovered somewhere out there.  Until then, other terms have been proposed, like meta-moon, nested moon, grandmoon, and moonmoon.  Moonmoon seems to be the most popular choice on the Internet, probably because of the Internet meme.  Which means when the time comes the I.A.U. will almost certainly not pick that one.  More likely, the I.A.U. will go with “dwarf moon” and insist that no further discussion of the matter shall be permitted.

For right now, I think submoon is the term with the most scientific legitimacy.  For the purposes of Sciency Words and other sciency writings, I think that’s the term to go with.  But what do you think?  What would you call the moon of a moon?

Sciency Words: Nominal Solar Radius

Sciency Words: (proper noun) a special series here on Planet Pailly focusing on the definitions and etymologies of science or science-related terms.  Today’s Sciency Word is:


Last week, I told you about the classification system in use for main sequence stars. Today we’re going to talk specifically about G-type stars.  Or rather, we’re going to talk about one G-type star in particular: the Sun.

I was recently clued in on a controversy about the Sun.  After reading up on the issue, though, I don’t think this is a real controversy.  It’s more like an Internet controversy.

If you’ve ever wondered how big the Sun is, a quick Google search will get you an answer.  But it won’t get you the correct answer.  That’s because we apparently do not know precisely how big the Sun is.  As this paper from 2018 states: “[…] measuring with high accuracy the diameter of the Sun is a challenge at the cutting edge of modern techniques.”

Part of the problem is that we’ve tried using multiple methods for either measuring the Sun’s radius by direct observation or by calculating the radius based on other kinds of measurements.  And we keep getting different answers.  I take it we’re not getting wildly different answers, but there’s enough variation there to create a problem for scientists who study the Sun.

So here’s where the alleged controversy comes in.  Our friends at the I.A.U.—the International Astronomy Union, the same organization that decided Pluto is not a planet—decided a few years ago what the Sun’s radius should be.  They said it equals 695,700 km.  No more, no less.  I mean, who are these people to decide what is or is not a planet?  Who are these people to decide now how big the Sun is?

Except that’s not actually what the I.A.U. did. Regardless of how I may feel about the whole Pluto thing, I do agree with the I.A.U. about their definition of the solar radius.  Or to speak more precisely, I agree with their definition of the nominal solar radius.  As explained in the I.A.U. resolution on this matter:

These nominal values should be understood as conversion factors only—chosen to be close to the current commonly accepted estimate […] not as the true solar properties.  Their consistent use in all relevant formulas and/or model calculations will guarantee a uniform conversion to SI units.

So I don’t think the controversy, such as it is, really exists.  If we’re going to use the nominal solar radius as a unit of measure, we all have to agree about what that unit of measure is equal to—especially because we still don’t know what the actual solar radius is.

Feel free to bash the I.A.U. about Pluto, if you want, but when it comes to their nominal solar radius definition, I think the way they handled it makes a lot of sense.