Cometary Tales Blog Rain(man), Rain(man), Go Away

Rain(man), Rain(man), Go Away

This isn’t so much a blog post as a paper. There are footnotes and citations. Bear with me.

Have you had this experience? Someone in a group discussion notes that April is Autism Awareness Month. Then someone else says, “Oh, remember Rain Man? I watched it again recently! Isn’t that a great movie?” And then everyone has a lovely chat about movies. Unfortunately, this kind of response is what gamers call an Epic Fail. Let’s walk into April with some better awareness.[1]

So, what is autism? What isn’t it?


Photo Credit: Nina from Australia, Rain, Rain, Go Away (CC BY 2.0) via Wikimedia Commons

What it is

Autism is a set of neurological characteristics found in as many as 1 in 50 people [2,3] that can lead to difficulties with social interactions, repetitive behaviors, or intense engagement in special interests. Not necessarily all these things. (So, you know 100 people? Well, you likely know a couple of autistic people.)

Nobody knows what “causes” [4] autism, although probably there are combinations of genes that are more likely to yield autistic characteristics. (It may run in families, like other polygenic characteristics, such as height.) Autism presents on a spectrum, so its current designation is Autism Spectrum Disorder (ASD)…though many autistic people will counter, “there’s nothing disordered about me!”

What it isn’t

Autism has absolutely nothing to do with vaccines—that absurd idea was generated by publication of fraudulent research, a real-world hoax that has harmed untold numbers of people [5,6,7]

Autism is not Rain Man. Dustin Hoffman did his best, and the film made a positive difference at the time, but that was over thirty years ago. The movie is now woefully out of date, and most autistic people find it discomfiting, stereotyping autism, families of autistics, and the way the world perceives them.

Autism is not sociopathy/psychopathy/other-mispercepathy. The number of mysteries or thrillers or police procedurals in which the murderer/terrorist/stalker is a shifty-eyed, unempathetic, twitchy weirdo whose speech patterns and movements and sometimes specific labelling code them as “autistic” make my hair curl. No, the autistic people of the world are not spying on you, plotting the perfect murder, or designing weapons of terror. Instead, as a class, they are the kindest people you know.

Autism is not the strange child. The vast majority of autistics are adults. Autism doesn’t go away when you grow up. Why don’t you notice? Those whose difficulties with the world are great still live in relative isolation. As for the rest, they’re “masking.” This isn’t a lighthearted improv exercise. It is a progressive modification of behavior—often unconscious, in ways learned over many years—to appear more like you, because they’re pretty sure you won’t accept them otherwise. (So, maybe this should be Autism Acceptance Month.)

Masking isn’t perfect; you probably think of your autistic friends as ‘the little-bit odd one’ or the ‘cute, quirky one.’ You may not see them around as much as your other friends—because keeping up masking is hard work. The older an autistic person is, the better they can be at masking—but then, it’s harder for them to change that. Also, be aware that if you realize a friend is autistic, it doesn’t help to tell them to stop masking. It’s a difficult process, and they’ll let you know when they’re ready.

Photo Credit: Dietmar Rabbich (CC BY 4.0) via Wikimedia Commons

Unfortunately, old movies like Rain Man leave the impression that all autistic people are weird geniuses, can’t take care of themselves, and suffer extreme difficulties with life. Yes, some are in that boat (and a rare few are even geniuses). It’s important to be sure everyone’s properly supported in life—can we simply agree to support autistic people with needs just as we support neurotypical (NT) people with serious life issues?

A few thoughts to keep in mind, no matter what type of neurons you’re thinking with:

Autistic people are, as a group, extremely honest. This presents complications—because most autistic people don’t react in conversation in quite the exact way that neurotypicals expect. For instance, if someone doesn’t look you in the eye all the time—a favorite behavior of NT’s—they’re perceived as “dishonest”. That’s unfortunate…which is why ambitious autistic adults work hard to make eye contact, even though it may be enormously stressful to do so.

Autistic people are empathetic—and have all the same emotions you do. They may express their emotions a little differently, but that doesn’t mean they don’t have the exact same feelings you experience. Your autistic friends may even be more likely to notice how you’re feeling and to empathize with you, because they are observing you and working to figure you out, all the time. So they’re not just in possession of that deep, humanizing characteristic, they’re actively working at it, every day.

This doesn’t mean that autistic people are all perfect, wonderful, nice, diligent, hardworking, or what-have-you and are somehow better than neurotypical people. Everyone has shortcomings—and autistics don’t need to become the next perfectionist minority. It’s just that the stereotypes (weird, twitchy, untrustworthy) are contradictory.

If you’re reading this, you’re probably part of the reading/writing community. Here’s another thought for you.

Well. Ummmm. YOU might be autistic. Nobody wants to think of themselves as “different,” but writers—whether they’ve gone the publishing route or not—draw heavily from a well of “difference.” Lots of us grew up feeling like we were “on the fringe” or “the odd one out.” We dive deep into the special interests that drive our work. We can go on and on and on about a character or a situation or a plot point—whether in a story we wrote or in one of our favorites. Heck, some of us can sit down and hammer out 50,000, 100,000, a million words. That’s hardly what nonwriters would call “typical.”

If you’ve secretly, quietly wondered if there’s something you don’t know about yourself that maybe you should, here is one easily-accessible book to read: Cynthia Kim’s Nerdy, Shy, and Socially Inappropriate is a clever, affecting story of one woman’s journey of self-discovery. Some terminology it uses, unfortunately, became outdated the year after publication, with the elimination (for very good reasons) of the problematic term Asperger’s [8,9], but the self-realization content still holds up.

A cautionary note: take with gigantic doses of salt anything coming from the group Autism Speaks. They will be rather shouty during April and their old puzzle-piece logo will be cropping up all over, but this group is widely derided by autistic people as not speaking for them and, worse, actively spreading misperceptions about autism [10] and promoting [11] the application of abusive ‘therapy’ [12].  Many autistic people therefore consider Autism Speaks to be a hate group [13], but even without that label, their role in the politics of disability is subject to serious question [14].

Ready to raise awareness a little (or a lot) more?

Below are a couple of helpful, easy-to-access resources. You can find deeper reading by continuing to the Notes and Citations section.

Ask Autistic Adults is my current favorite website for quickly-accessed on-point information on what grown-up autistic people feel you should know:  labels, appropriate language, effective support, fake/abusive “therapies,” and more.

The Thinking Person’s Guide to Autism is a web-based organization that provides a broad array of resources and connections to useful information for autistic people and their allies.

To catch up on the current zeitgeist in the autistic community, try the hashtag #actuallyautistic. To some extent, outsiders have tried to co-opt it, but the hashtag has withstood that pretty well so far.

Now, have a very happy Autism Awareness Month, everybody!

Below the blue umbrella: Notes and Citations

A bright blue umbrella floats upside-down

Photo Credit: Tom Mrazek, An Umbrella In the Dark, (CC BY 2.0) via Wikimedia Commons

Yes, lots of notes and cites. Because a blog post needs to be brief, but the topic is complex!

  1. No one person speaks for all people in any marginalized group. I make no claims that my perspective, or those of the autistic individuals I’ve cited here, is more worthy than that of any other member of the broadly-defined autism community. This essay cannot be perfect, but I will update it as necessary, and I welcome honest, fact-based critique.
  2. “U.S. Autism Rates Up 10 Percent in New CDC Report” Bloomberg School of Health. Johns Hopkins. 26 March 2020. (Accessed 29 March 2022) https://publichealth.jhu.edu/2020/us-autism-rates-up-10-percent-in-new-cdc-report#:~:text=Researchers%20at%20the%20Johns%20Hopkins,2016%20(or%201.85%20percent).
  3. “Rising rates” of autism do not reflect changes in the incidence of autism; rather, reports like the Johns Hopkins article reflect how wider application of diagnosis reveals that more people are autistic than was thought previously. This article in particular highlights a progression over time, as researchers began attending to this data and improving their diagnostic techniques. I linked to this article because it is quite readable and provides links to the academic papers and data, for those who are interested. The choice of a headline in a public-facing news presentation can be misleading—remember to read more than headlines.
  4. Autistic people, by and large, dislike using “cause” to describe the mechanisms underlying autism. It makes it sound like a disease, something you can “cure,” and that detracts from attending to what can truly help autistic people thrive in a largely non-autistic society, understanding what “therapies” are harmful bunk, and listening to what autistics think. However, it’s the term that’s easiest for a casual reader follow in the context of a (supposedly) brief article like this one. As a reminder, this is a note to a sentence stating clearly that the mechanics are still unknown.
  5. “Wakefield’s article linking MMR vaccine and autism was fraudulent” British Medical Journal (BMJ). 6 January 2011. BMJ 2011;342:c7452. https://www.bmj.com/content/342/bmj.c7452
  6. Wakefield’s horrific piece of hoaxery was published in the Lancet in January of 1998, and its awful effects have flowed into every corner of our medical landscape—even influencing vaccine resistance during the current pandemic. By the time the journal retracted the piece, the damage was done and the evil thought-virus of ‘vaccines are scary’ had spread too far to eradicate it.
  7. Eggerston, Laura. “Lancet retracts 12-year-old article linking autism to MMR vaccines” Canadian Medical Association Journal (CMAJ). 9 March 2010. Accessed via National Institutes of Health, 29 March 2022. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2831678/
  8. Hans Asperger, the man after whom the so-called “high-functioning” side of the autism spectrum was (temporarily) named, is now known to have been a eugenicist, Nazi-assisting child-hurter, and all-around guy-you-wouldn’t-invite-round-to-dinner. The article below [9] is an accessible read and includes references.
  9. Juntti, Melaina. “It’s Time to Stop Calling Autism ‘Asperger’s’” Fatherly. 9 December 2021. https://www.fatherly.com/health-science/aspergers-vs-autism-and-hans-asperger/
  10. Lutterman, Sara. “The biggest autism advocacy group is still failing too many autistic people” Washington Post. 14 February 2020. https://www.washingtonpost.com/outlook/2020/02/14/biggest-autism-advocacy-group-is-still-failing-too-many-autistic-people/
  11. I’m not going to glorify this page with a detailed citation. This cite is here to prove that the organization supports this kind of treatment. https://www.autismspeaks.org/applied-behavior-analysis/
  12. Ira. “Why ABA Therapy Is Harmful to Autistic People” Autistic Science Person. Accessed 29 March 2022. https://autisticscienceperson.com/why-aba-therapy-is-harmful-to-autistic-people/
  13. Sequenzia, Amy. “Is Autism Speaks a Hate Group?” Autistic Women and Nonbinary Network. 19 August 2014. https://awnnetwork.org/is-autism-speaks-a-hate-group/
  14. Ne’eman, Ari. “Autism and the Disability Community: The Politics of Neurodiversity, Causation, and Cure” 1 February 2017 (Initially presented at Emory University in 2013). Autistic Self Advocacy Network (ASAN).  Accessed 29 March 2022. https://autisticadvocacy.org/2017/02/autism-and-the-disability-community-the-politics-of-neurodiversity-causation-and-cure/

You might also like to read:

A cylindrical spacecraft with long solar panels spreading out on both sides.

The names in “All That Was Asked”The names in “All That Was Asked”

In my previous post, I tried to explain how all those odd names ended up in my recently-published book and why I think it’s fun to play around with languages in the middle of a story.

So, what if you don’t really care about all that linquistic nonsense, but just want a guide to pronouncing stuff in this particular story?  In what follows, I’m going to share what I’ve prepared for the person doing our audio book.  On the surface, it may look daunting, but, really, it all hangs together with a few key elements:

Sensei, in Kanji
Source: japanesewithanime.com 
(CC BY-SA 4.0)
  • Lots of the names end in a shortened “ay” sound I’ve tagged here as ei. It sounds almost like a long ay, but is cut short like you were going to pronounce a “y” on the end, but stopped yourself just in time, “say” without that teensy “eeya” sound that wraps up that word. Sort of like “sensei” as pronounced in Japan, or at least in anime and Japanese TV shows.
  • In names ending in e, the final e is always sounded–usually as that shortened “ay” sound.
  • The exception is “ere”, which is ayr-ee, wherever it happens to fall, so some names end with ayr-ee, while some have that in the middle or at the beginning.
  • Children (or adults being teased as if they are children) or intimate friends get their names shortened with a bit of a stop in the middle, so Ansegwe becomes An-s-wei, and Kantalare becomes K-a-la-rei
  • As an example of the “translated words” system: the “aunts” are “awnts”, Brit/Northeast/Southern style, rather than Midwestern style “ants”.

Digression: How come I like weird names?  Well, jeepers, I’ve got one of my own, one that often gets pronounced weird, though I don’t care, really, I’ve heard ’em all.  The “correct” way is va-‘ness-uh ma-‘cla-ren-‘ray.  There are other pronunciations in use . . . but those are other Vanessas and other MacLarens. 

OK, here we go.  I’m not using really formal linguistic notation, but sound-shorthand that I think we all can follow. I put a single quote at the front of the stressed syllable in each word. 

  1. Our Main Characters

Varayla Ansegwe, Eskenyan Jemenga, Ensense Kantalare, Varaylas Ansele and Adeleke, and Haillyen.  These all appear frequently, though it takes a while for Kantalare to show up.  See how what we call “last names” (family names) come first, and “first names” (personal names) come second.

Wary, indeed.
Photo of sketch on wall, by Quinn Dombrowski, Berkeley, CA (CC BY-SA 2.0)

Varayla: Va-‘ray-la This one’s pretty phonetic, the tricky thing, from listening to auditions for our audio book, is that some people seem to read the “yla” as “lya”.  This reminds me of how people read the second half of my last name as “Wary” instead of “Wray”.  Don’t let it worry you, but if you prefer mispronouncing Varayla, just don’t go to Korlo. In the bad old days, you could earn a set of cement overshoes for mispronouncing that name to the wrong person.

Ansegwe: ‘ahn-seg-wei Our hero’s name is most likely to be mispronounced as on-‘seg-way, which is hilarious, as it makes me picture this enormous klutz trying to ride a Segway.  The first syllable should be said relatively slowly, so the second two click together fast, so that you almost lose the sound of the “e” in the middle: ahns’gwei. It has a kind of Japanese flavor to it.

Eskenyan: ess-‘ken-yan It sounds sort of like “a person from Kenya” (at least the way Americans say it) plus “Ess” in front of it.

Jemenga: ja-‘meng-uh When Jemenga is particularly pleased with himself, he really hits that middle syllable, so it’s like Ja-MENG-ah!

The Varayla Syndicate’s above-board operations include space-based solar power satellites.
(Not quite like this. This is NASA’s Solar-b satellite)

Ansele: ‘ahn-se-lei Tycoon aunt #1.

Adeleke: a-‘del-e-kei Tycoon aunt #2.

Haillyen: ‘hay-ul-lee-yen This is a “foreign” word to Ansegwe, so he’s basically phonetically “translated” it, the ‘y’ in the last syllable is a  bridge sound you get when putting ee and en together between the ee and the en.  Do ya get it? Yeah?  The reader should get it about 100 pages before Ansegwe catches on.

Ensense: en-‘sens-ei  You know, like, “sensei” with an “en” at the front.

Kantalare: kahn-tah-‘lahr-ei There’s a secondary stress on the first syllable.  Just make it sound pretty in your head.  Ansegwe is totally in love with her, so, whatever, hear her as beautiful

2. The people on the expedition

Some of these folks are only mentioned or quoted during the “expedition” chapters.

Tkonle: t-‘kawn-lei

Kulandere: koo-lahn-‘dayr-ee

Tekere: ta-‘kayr-ee

Tereinse: ‘tayr-ee-in-sei

Alekwa: ah-‘leek-wah

Nara: ‘nah-rah

Ensargen: en-‘sahr-gen It’s a hard g, as in “gun”, not a soft one as in “generation”. They don’t really use hard “g”

Korton: ‘kor-tun

Alawere: ah-la-‘wayr-ee

Tasegion: tah-‘seg-ee-on

Turame: too-‘rah-mei

3. People at home

Kateseo: ka-‘tay-see-oh

Kinshada: kin-‘shah-dah

Tumbal: ‘toom-bal

Erekulu: ayr-ee-‘koo-loo OK, this one isn’t a person, he’s a domesticated animal, so his name is a little goofy, meant to sound cute.

Tokal: toh-‘kahl

Ans’we: ‘ahn-se-wei This is a nickname for Ansegwe, used mostly by Kantalare, but also used by his expedition “friends” when they want to get on his case.

K’alare-: kah-‘lahr-ei This is a nickname for Kantalare, used by Ansegwe.

Az-dyel: ahz-dee-‘ell Note that this is another “foreign” word that Ansegwe has transcribed this way, so it’s pretty phonetic, the three syllables have almost equal stress, I hear just a little more on the last one, but you can feel more free to mess around with this one–it’s the ONLY word in this language that appears at all.

Eskewere: ess-ke-wayr-ee

Ensense Halense: en-‘sen-sei hah-‘len-sei This is a member of Kantalare’s extended family that they happen to run into at some point. 

4. List of authors. 

About two-thirds of the way through, someone gives Ansegwe a reading list, and the authors of the books are a mix of people from his world, one from outside his culture, and one (the last) he’s going to spend a lot of time with. I wouldn’t worry about these too much, but have fun with them.  Yeah, uh-huh, that’s intentional.

Asvelan Kulumbu: ‘ahs-veh-lahn  koo-‘loom-boo

Palawan Vejr: ‘pah-lah-wahn  vee-‘yay-zher

Trjia Qwijlian: ‘trr-zhee-ah  ‘kwizh-lee-ahn

Tsulander Tkonle: ‘Tzoo-lahn-der  T’kawn-lei

5. People in quotes.

Yeah, this is one of those books where each chapter opens with a quote from someone.  I picture these as remarks that people who know Ansegwe have made when interviewed about the events in the story.  Picture them sitting across the desk on their version of The Daily Show, chatting with their Trevor Noah.  Most of the quoted individuals made it into the final.  A few only get mentioned in these quotes.  These ones are mostly government officials.  Make them sound stuffy, self-important, and less-than-competent.

Insake Hailaware: ‘in-sah-kei  hai-uh-la-‘wahr-ei (For fussiness, there’s a secondary stress on first syllable in Hailaware. He will get all huffy if you miss that and maybe will find some minor infraction to write you up for.)

Elesennen Haileski: el-es-‘sen-en  hai-uh-‘les-kee

Kinsala Tkerelon: kin-‘sah-lah  T-‘kayr-ee-lon

6. Other words and place names.

The story takes place in a fairly limited set of “alien” geographic locations.  But I do have some place names included and there are a few other “thing” words that appear more than once.

The Kalinidor is something like this.
Alexander Fleming’s Nobel Prize (1945)
(Jemenga would discover penicillin if someone else hadn’t already.) Source: Science and Society Picture Library, London Museum of Science (CC BY-SA 2.0)

Korlo: ‘kor-low It simply sounds like “core” “low”.  This is Ansegwe’s country. 

Kalinidor: ka-‘lin-ee-dor This is a person’s name that’s become an object name–sort of like the Nobel Prize, well, actually, exactly like the Nobel prize.  Jemenga really really wants one of these.

Quazwallade: kwaz-‘wall-ah-dei  This is a place name, just a foreign country, one with some technological and cultural differences from Korlo.

Cignali: sig-‘nah-lee Let’s say that probably this was originally a person’s name, but now it’s the name of a famous university, think “Stanford”.

Utumwe: oo-‘tum-wei I told you there were academics in this story.  This is another university, a medical school actually, one that Jemenga lectures at, when they can get him.

Terende: ta-‘ren-dei  Another place name.

Tule: ‘too-lei Yep, place name. Doesn’t get much play, but even minor places count, says the writer who lives in a town that isn’t a proper town, just a collection of farms, houses, shops, and a gas station, that gets its own post office.

Nothing but a Day One Photo GalleryNothing but a Day One Photo Gallery

This is just a gallery of photos from the first day in the Grand Canyon.  Not in any particular order, either.

To see the photos in full format (and, in the case of vertical images, the full view), double-click on any one image, then use “previous” and “next” buttons to move around.

Yes, of course, the images are copyrighted.   Says so at the bottom of the page AND in the image IFTC’s.  Trip members–read the details, though.  You got  rights!  And if you can’t figure out the who’s-who, just email me, OK?

 

Chasing CometsChasing Comets

As a  re-entry activity, let’s fall right into the project which inspired the overarching theme for this so-called blog:  cometary tails.   That is, in this instance, we’ll be “studying” the behavior of the tails of actual comets falling along their orbits about a star.    But of course, this is a “Messy Monday” project, so it  involves running, arguing, and playing with scissors (not all at the same time).

So far, the only star whose comets we’ve observed have been those of our own Sun, but as our star is not particularly unusual, it’s likely that comets ply their trade throughout the cosmos.  We’ll not be delving too deeply into astrophysics, instead we’ll be building fun models of comets and playing games which illustrate the apparent motion of a typical comet’s tail.  If you’re running this project as part of a school science program, you can double-count the activity as a P.E. session, as the central game involves more than a bit of running, though not likely moving as fast as a comet.

Just as a reminder, what I want to give you in these “Messy Monday” project descriptions is 1) enough background on the science that you’ll be prepared for questions and have resources to draw on if your own curiosity is triggered, 2) a play-by-play description of running the project with a group, recognizing that your time and resources are limited and your participants will vary in both interest and prior knowledge, and 3) a shopping list detailed enough to help you minimize your costs as well the time you have to spend assembling supplies.

Shoemaker-Levy panoramic (courtesy NASA-NSSDC)

Fragments of Comet Shoemaker-Levy heading for Jupiter (courtesy NASA-NSSDC)

So, What Do You Want to Know?

For thousands of years, humans have wondered at the strange visitations of comets.

Natural philosophers of the middle ages studying comets.

Natural philosophers of the middle ages studying comets.

In our time, people now understand that comets are not harbingers of doom or annunciations of the births of kings but fellow travelers in our solar system, icy bodies wheeling in towards the sun and shedding a fraction of their substance as they approach the sun.  However, a key aspect of the comet’s tail remains counterintuitive to us earthbound air-dwelling creatures.  The tail of a running horse flows behind her as she gallops, so we naturally expect that the tail of comet simply flies behind it as it plunges along its course.  But a comet’s behavior plays tricks with such expectations.

Where do comets come from?  The Solar System is a big place, but for most of us, the territory ends with Pluto, the Object Formerly Known as The Ninth Planet.

Great_Comet_of_1577 by Georgium Jacobum von Datschitz public domain

The Great Comet of 1577

However, if you’re a fan of Cosmos (either Carl Sagan’s or Neil DeGrasse Tyson’s version) or if your school is lucky enough to have new textbooks, then you’ll know about the Oort Cloud , that sphere of orbiting material from which most comets emerge.  Do you realize how much farther out this region is? On a scale of one inch per 100,000 miles, in which the orbit of Pluto would be one mile across, the distance from the Sun to the Oort Cloud would be the length of the state of California.  It’s even been hypothesized that the Oort clouds of neighboring stars may physically interact, exchanging comets.

The Oort cloud is a long way out, but it’s still a part of the Solar System, because the objects there are still subject to the Sun’s gravity.  Occasionally, a piece of this clutter is jostled from its orbit and begins the long fall towards the sun.  Depending on the path it takes as it zooms around the sun, the comet may slingshot out of the solar system entirely or it may settle into a new orbit, returning to loop around the sun on a regular schedule.   For instance, Comet Halley returns every 86 years.  The last time round, it actually came in ’86–1986 that is.  I was lucky enough to visit New Zealand that year, so I can confirm that Comet Halley was extremely unspectacular that year–only just barely visible.  Fortunately, New Zealand itself is spectacular every single day of any given year.    NASA was more successful, having a noticeable advantage in telescope access.

Babylonian Astronomers Wrote Down Their Observations of Halley in BCE 164

Babylonian Astronomers Wrote Down Their Observations of Halley in BCE 164

Comet Halley's Appearance Dooms King Harold in 1066

Comet Halley’s Appearance Dooms King Harold in 1066

Comet Halley in 1910

Comet Halley in 1910

Comet Halley in 1986 (Courtesy of NASA)

Comet Halley in 1986 (Courtesy of NASA)

                                                                                                                                                                                        But why do comets even have tails?  We don’t see shiny tails glowing in the wakes of our planets.  Well, it all has to do with the change in environmental conditions as the comet moves towards the Sun.  Comets are composed of water ice, frozen gases, rocky matter, and even traces of organic compounds.  As this frozen jumble approaches the sun, it warms up enough that the various ices in the outer layers of the comet become gaseous—water vapor, ammonia, carbon dioxide.  These gases bubble and boil into a misty cloud, so the comet will have an atmosphere of sorts, called the coma, for the duration of its passage through the inner Solar System.  The gas expulsions may even shoot out of the comet’s rocky layers like jets, causing the comet itself to tumble as it falls along its inward path.  At the same time, very small-scale “dust” particles are swept from the cometary nucleus.  This is not the heavily-organic dust we find under our furniture here on Earth (if you really want to know what’s in household dust don’t use “Google images”;  stick to text searches or just ask your friendly neighborhood allergist).  What we mean is that the particle size—a few microns—is extremely fine, about the same size as the particles in cigarette smoke.

We get our fabulous cometary tail once these newly-ejected gases and dust of the coma approach the sun just a bit closer, enough that the various solar emissions can have their ways with the comet’s atmosphere.   First, there is sunlight itself, which acts in several ways to provide us with the visual spectacle of the comet’s tail.

The simplest role of sunlight is to shine on the cloud of dust ejected from the nucleus.  That’s the main tail we see.  But that still doesn’t explain why the dust forms a tail at all:  the secret is that light, as electromagnetic radiation, actually exerts pressure on objects, and with tiny objects like cometary dust this radiation pressure force is enough to fan that  material out from the core.  Plus, there is a cool bonus “secret”: that most comets actually have two tails—one formed by the gases and one formed by the dust.  The ultraviolet radiation in sunlight blasts the gas particles, stripping away electrons, and so creating a mass of ionized gas, which fluoresces (mostly blue) in sunlight. Then those glowing blue ions are blasted in a straight line away from the sun by the solar wind, a stream of high-energy particles hurtling at supersonic speeds through the solar system.  The solar wind is a wonderfully intricate system in its own right, but for our purposes here it is most important to convey that, like earthly winds, it consists of particles moving at high speeds and that its direction is away from the Sun.

The result of all these combined forces is that a complex, continuously shifting cloud of gases and dust streams out from a comet during its time in the inner solar system and that tail—or, rather, pair of tails—points away from the sun, even when the comet is on its way back out to its origin.  (If you’re a die-hard comet enthusiast, you’ll know that the dust tail does curve inward a bit, as the small particles of dust battle with the solar forces, striving to curl into their own individual orbits about the sun, but from our earthly perspective, the outward forces have the upper hand.)

In the next installment, we’ll get down to the nitty-gritty of building our own comet models and playing a game of As the Comet Tail Flies.

Oh, yeah, and I’m not making things up about radiation pressure.  Consider the prospects for spaceflight under the power of light!

The Japanese IKAROS spaceprobe in flight (artist's depiction by Andrzej Mirecki).

The Japanese IKAROS spaceprobe in flight (artist’s depiction by Andrzej Mirecki).

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