Sciency Words: Moon

September 29, 2017

Today’s post is part of a special series here on Planet Pailly called Sciency Words. Each week, we take a closer look at an interesting science or science-related term to help us expand our scientific vocabularies together. Today’s term is:

MOON

There are three things I want to cover with today’s post. Firstly, for anyone who may not already know, Earth’s moon is officially called the Moon (with a capital M). Unless you don’t speak English, in which case it’s called whatever it’s called in your language, provided that you treat the word as a proper noun. This according to the International Astronomy Union (I.A.U.), the one and only organization with the authority to name and classify astronomical objects.

Phases of the Moon.

Of course the Moon is not the only moon out there, so I also want to talk a little about the official I.A.U. sanctioned definition of the word moon. Unfortunately there isn’t one, which seems odd given how the I.A.U. are such stickers about their official definition of the word planet.

A common unofficial definition is that a moon is any naturally occurring object orbiting a planet, dwarf planet, or other kind of minor planet (such as an asteroid or comet). Except this definition creates some problems:

Saturn has like a bazillion moons!

Since there’s no lower limit on size or mass, you could consider each and every fleck of ice in Saturn’s rings to be a moon.

The Moon isn’t a moon!

In a very technical sense, the Moon does not orbit the Earth. The Earth and Moon both orbit their combined center of mass, a point called a barycenter. In the case of the Earth-Moon system, the barycenter happens to lie deep inside the Earth, so this distinction may not seem important, but…

Pluto is Charon’s moon, and Charon is Pluto’s!

The barycenter of the Pluto-Charon system is a point in empty space between the two objects. Pluto is the larger of the pair, so we generally consider Charon to be Pluto’s moon; however, you could argue that Pluto and Charon are moons of each other. You could even write a love song about their relationship.

Of course I’m not seriously arguing that Saturn has billions upon billions of moons, nor am I arguing that our own Moon is not really a moon. There does seem to be some ambiguity about Charon’s status (is Charon a moon, or are Pluto and Charon binary dwarf planets?), but I’m not sure if this ambiguity has caused any real confusion in scientific discourse.

Still, as we learn more about moons in our own Solar System and also moons in other star systems, I think the I.A.U. will eventually have to come up with an official definition. And that brings me to the third and final thing I wanted to cover today: exomoons.

An exomoon would be defined as a moon (whatever that is) orbiting a planet or other planetary body outside our Solar System. Finding exoplanets is hard enough, so as you can imagine, searching for exomoons really stretches the limits of current telescope technology. But astronomers are trying, and next month (October, 2017) the Hubble Space Telescope will be making special observations of a planet named Kepler-1625b in an attempt to confirm a possible exomoon detection.


One Last Thing About the Eclipse

August 30, 2017

This hasn’t been much of a research week for me. I’m more focused on the fiction side of my writing at the moment, rather than the science stuff.

So today I’m just sharing some artwork, something I didn’t quite get done in time for the eclipse.

You know, we are kind of lucky that we have these total solar eclipses. By some amazing coincidence, our large Sun and small Moon appear to be the same size in Earth’s sky, allowing the Moon to perfectly cover up the Sun.

That doesn’t happen anywhere else in the Solar System. That perfect planet-moon-star alignment is likely rare, perhaps even unique in our galaxy. So whenever we make first contact with aliens, and they start bragging about their luminous forests or crystal waterfalls or whatever, we Earthlings will have a unique and beautiful thing to brag about to: we have total solar eclipses.


Eclipse Day 2017 and Hermione Granger

August 23, 2017

One of my favorite fictional characters—one of the characters I most strongly identify with—is Hermione Granger from the Harry Potter series. She’s depicted as extremely bookish, and at one point we’re told she’s nervous about flying because it’s “something you couldn’t learn by heart out of a book.”

Yup, that sounds like me. I’ve spent an enormous amount of time studying science, but almost everything I know comes out of books rather than from hands on experience.

And so as the Great American Eclipse of 2017 approached, I felt increasingly nervous, just like Hermione going out for her first flying lesson. I’d read a lot about the eclipse, done pretty thorough research about the kinds of glasses I’d need to buy, and yet… I still felt horribly unprepared.

To make matters worse, the eclipse glasses I’d ordered online seem to have gotten lost in the mail. On the day of the eclipse, they still hadn’t arrived. I had a backup plan, but I wasn’t sure if it was going to work. I’d read online that you can use a pair of binoculars to project an image of the Sun onto a piece of paper. Again, I’d read about this, but I’d never tried to do it, and I wasn’t 100% convinced this was going to work for me. Some of the instructions I’d read sounded kind of complicated.

And yet to me extraordinary delight, it worked! My hands were a bit shaky, but I was able to project the Sun onto a page of my sketchbook and watch as the Moon slowly moved across the image.

My hastily improvised eclipse observatory.

Watching the eclipse turned out to be a highly emotional experience for me. I’ve been going through some things in my personal life, and this was a powerful reminder that no matter what happens, the universe keeps turning. Also, I realized at one point that the binoculars I was using originally belonged to my Dad, so in a sense it was like I got to share the experience with him.

And lastly, for a Hermione Granger-type person like me, this was one of those rare moments when something I read about became real to me. Maybe it wasn’t as exhilarating as learning to fly on a broomstick, but still… Eclipse Day 2017 was a magical experience for me.


Sciency Words: Planet (An A to Z Challenge Post)

April 19, 2017

Today’s post is a special A to Z Challenge edition of Sciency Words, an ongoing series here on Planet Pailly where we take a look at some interesting science or science related term so we can all expand our scientific vocabularies together. In today’s post, P is for:

PLANET

In 2006, the International Astronomy Union approved a new, official definition of planet, and Pluto didn’t make the cut. Word has it Pluto took the news well.

The I.A.U.’s concern at the time was that more and more small, Pluto-like objects were being discovered, making Pluto seem less like the ninth planet and more like the first of some new class of thing.

To be fair, the I.A.U. did try to come up with a planet definition that would include Pluto while excluding the dozens or perhaps hundreds of other objects potentially out there. But it just didn’t work out.

So to meet the official, I.A.U. sanctioned definition, an astronomical body must meet three requirements:

  • It must orbit the Sun.
  • It must be spherical, due to the pull of its own gravity.
  • It must have cleared its orbital path of debris (this is the part of the planet test that Pluto failed).

Of course, if a definition can be changed once, it can be changed again. Recently, a group of six NASA scientists—specifically, six scientists from NASA’s New Horizons mission to Pluto—put forward a new proposal, which reads:

  • A planet is a sub-stellar mass body that has never undergone nuclear fusion and that has sufficient self-gravitation to assume a spheroidal shape adequately described by a triaxial ellipsoid regardless of its orbital parameters.

In other words, if it’s round, and it’s not a star or wasn’t a star at some point in the past, then it’s a planet. Under this new definition, Pluto’s back in the planet club! And so is the Moon, weirdly enough, along with many other moons elsewhere in the Solar System. In fact, the new definition would reclassify over one hundred Solar System objects as planets—possibly more than that.

The next I.A.U. general assembly meeting will be held in August, 2018. If they’re going to change the definition of planet again, that’s when they’ll do it. But I very much doubt it’ll happen.

Even though this is probably a lost cause, I want to say something in defense of the New Horizons team’s proposal. The strongest objection seems to be that moons should not be planets. I get that, but in my mind any world that I can picture myself standing on or walking on… I don’t know, that just feels planet-y to me.

I frequently catch myself calling Titan and Europa planets, even though they’re moons. Same for Pluto, Eris, Ceres, and all the other objects currently in the dwarf planet category. And I can’t help myself, but I keep calling Endor from Star Wars a planet, even though it’s specifically referred to multiple times in dialogue as a “forest moon.” All of these places—even fictional moons like Endor—feel planet-y to me.

And yes, even the Moon—the most quintessential moon of them all—has a certain planet-esque quality to it when I imagine myself living there, walking around, going about my daily business. I could get used to the Moon being a planet.

Next time on Sciency Words: A to Z, we’ll shrink from planet-scale to the scale of subatomic particles, and we’ll find out what’s so quantum about quantum mechanics.


Mars vs. the Moon: Where Do You Want to Go?

April 27, 2016

Okay, fellow humans. Where should we go next? Should we return to the Moon or push onward to Mars?

Ap12 Mars vs the Moon

It would be nice if we could do both, but space exploration is expensive. So at least in the near future, we as a species will probably have to choose.

If you pay any attention to NASA’s public relations, you know the United States is aimed for Mars. Almost every new piece of NASA tech is billed as Mars-ready or Mars-capable. Almost every experiment, including Scott Kelly’s Year in Space mission, is somehow Mars related. NASA has produced tons of videos, posters, and infographics, and they’ve made #JourneytoMars a thing on Twitter.

But an actual Mars landing is still at least twenty years away. A lot could happen in twenty years, politically and economically speaking. Regarding the politics of space exploration, international partnerships play a key role. Big, expensive projects become a lot more feasible when costs are divvied up among multiple countries.

Right now, the European Space Agency (ESA) is mulling over the idea of establishing a permanent outpost on the Moon. This moon base, or “moon village” as it’s sometimes called, would be the successor to the International Space Station.

If ESA does get their moon village started, no doubt the Russians and the Japanese will want to be part of it. And so will the U.S. But where will that leave NASA’s #JourneytoMars ambitions?

Personally, I’d really like human beings to finally set foot on Mars, preferably in my lifetime. But ESA’s moon base proposal seems more achievable in the near-term. In a way, it does feel like a logical next step after the International Space Station. But that’s just my opinion.

So what do you think? Were do you, fellow humans, want to go next: back to the Moon or onward to Mars?


Sciency Words: Dark Side of the Moon

April 1, 2016

Sciency Words PHYS copy

Today’s post is part of a special series here on Planet Pailly called Sciency Words. Each week, we take a closer look at an interesting science or science-related term to help us all expand our scientific vocabularies together. Today’s term is:

THE DARK SIDE OF THE MOON

As the Moon orbits the Earth, the same side of the Moon is always facing toward us. It’s like the Moon is staring at us, unblinking, perhaps with some awkward question it’s been meaning to ask.

My06 Stuff on the Moon

But what’s on the other side? What’s on the side facing away from us? Scientists call that the “dark side” of the Moon. Scientists love making Star Wars references, and this one really fits. The dark side of the Moon is cloaked in perpetual darkness, because it is not only turned away from Earth but also away from the Sun.

As a result, we don’t really know much about the dark side of the Moon. There have been rumors that the Apollo Missions, while in lunar orbit, observed secret alien bases in the Moon’s dark region. This is obvious nonsense. The dark side of the Moon is too dark to observe anything!

Maybe some day when humanity finally chooses to return to the Moon, we’ll get some answers. Just so long as we remember to bring a flashlight.

P.S.: Happy April 1st! No, there is no such thing as a “dark side of the Moon.” The side of the Moon facing away from Earth is properly called the “far side of the Moon,” and it gets just as much sunlight as the side facing us.