Note (12/2015): Hi there! I'm taking some time off here to focus on other projects for a bit. As of October 2016, those other projects include a science book series for kids titled Things That Make You Go Yuck! -- available at Barnes and Noble, Amazon and (hopefully) a bookstore near you!

Co-author Jenn Dlugos and I are also doing some extremely ridiculous things over at Drinkstorm Studios, including our award-winning webseries, Magicland.

There are also a full 100 posts right here in the archives, and feel free to drop me a line at with comments, suggestions or wacky cold fusion ideas. Cheers!

· Categories: Astronomy, Physics
What I’ve Learned:

Jeans instability: The fancy-pants stuff behind every star.
“Jeans instability: The fancy-pants stuff behind every star.”

Science is hard. Most of it is obviously complicated and full of tongue-twisty words that exist only so some eggbrain jerkass can school you at Words with Friends. But it’s sneaky, too. Whenever some small bit of science seems simple and straightforward, there’s always something way harder and full of Greek-letter math lurking underneath. That’s how science gets you.

Take Jeans instability, for example.

Everything physicists tell you up front about Jeans instability makes perfect sense. You’ve got this lumpy stuff called Jeans mass, and a size called a Jeans radius. If the Jeans mass exerts too much pressure for a given Jeans radius, the system flies apart and the mass spreads all over.

We’ve all been there. Like an hour after after Thanksgiving dinner.

On the other hand, if the Jeans mass has too little pressure, then Jeans instability occurs and the system collapses in on itself.

Presumably in a little pile around your ankles. I can’t say I’ve personally had experience with this phenomenon. It sounds like one of those tragic Euro supermodel problems. Oh, those poor twiggy bitches.

All of this is well and good, until the physicists then tell you that none of this has anything to do with distressed Calvin Kleins, Levis 501s or high-waist super skinny Jordache denim jeggings — and is that last one actually a thing? Merciful Darwin help us all.

To physicists — who mostly wear plain, practical polyester pants, it turns out — Jeans instability is a whole other thing entirely. It’s a phenomenon named after British physicist Sir James Jeans — personal legwear preferences unspecified — and describes the conditions under which interstellar gas clouds collapse to form stars.

On the bright side, most of the above reasoning still holds true. If the outward pressure of the gas in a cloud of a given size is too great — because the gas is especially hot, for instance — then the pressure will overcome gravitational force, and gas will spill out everywhere.

Like I said, usually an hour after Thanksgiving dinner. That happened to me twelve years ago, and Grandma still won’t invite me back for holidays.

But if the gas is sufficiently cool, or the mass of the cloud unusually high for the space it’s in, then gravity wins out and the gas will collapse in on itself, eventually forming a discrete object called a protostar, and later a star. It’s the Jeans instability that predicts under what conditions this collapse will begin to occur.

(Presumably, it includes declining seconds on pumpkin pie. Again, I wouldn’t know. That would require a stronger cloud of gas than I.)

That’s the good news, in terms of simplicity. The bad news is, the original equation for Jeans instability has been found by later researchers to not be completely accurate for real-world predictions. Which might explain why people try to fit into pants two sizes too small. Also, that equation for Jeans instability looks like this:

And to get the Jeans mass, you apparently solve this gibberish:

And the Jeans radius — more often called Jeans length — comes out the back end of this beast here:

I don’t know what any of that means. I have trouble enough figuring out the right inseam to put in the form on the Wrangler website. What if the gas cloud is wearing a belt? Is there more instability if you acid wash first? And how do I convert the units for the gravitational constant into boot-cut?

I’m telling you. Science is hard.

Image sources: Thinking Sci-Fi (baby protostar), Tenderfooting (gobbledy-Scrabbledy-gook), Denimology (serious jeans instability), LukeHamby (jeans + ankles = jankles), Wikipedia (scary equations)

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· Categories: Chemistry
What I’ve Learned:

Ytterbium, utterbium, we all terb for ytterbium!
“Ytterbium, utterbium, we all terb for ytterbium!”

You might see “ytterbium” and think it sprang from some Scrabble champ’s wet dream, or that it’s a young left winger drafted by the Winnipeg Jets. And it probably is. But also, it’s a little more.

Specifically, ytterbium is a chemical element — atomic number 70, if you’re scoring at home — and a member of the lanthanide series. And while “lanthanide” sounds like another puck-chucking hockey punk from East Brrritscoldistan, the series (plus a couple of kindred elements nearby on the periodic table) has another name, somewhat easier on the tongue: rare earth elements.

While easier to pronounce, it turns out “rare earth elements” isn’t really a great name. Granted, the “elements” part is accurate. And they do come from “earth”, or rather usually buried under quite a lot of it. But they’re not “rare”, for the most part, if you’re talking about the percentage of the planet’s crust they make up. The real issue with rare earth elements is they’re not often found in easily-mined ores. They tend to spread out in trace amounts, and clump up with similar elements so they’re difficult to separate. Many, including ytterbium, are fairly common; they’re just a pain in the ass to work with.

Still, it’s hard to blame scientists for the “rare” label. Nobody wants a “persnickety earth element” series on their periodic chart.

Speaking of persnickety, ytterbium certainly qualifies. At room temperature, it’s a shiny silvery metal that’s also also soft and squishable — like Play-Doh made from aluminum foil. This would be awesome, except that pure ytterbium will also irritate your eyes and skin, produce toxic fumes, violently explode and catch on fire in the way that water can’t put out. So it sits there, saying “play with me!“, all the while plotting your destruction in fourteen different ways. Like an evil sparkly porcupine, or a silver-plated Joker.

Which, I suppose, is coming. Super.

Because it’s difficult to extract — or because it’s dangerous as hell, maybe — only about fifty tons of ytterbium are produced worldwide each year. That’s not much, relatively speaking, but it makes sense because we haven’t found many things we can use ytterbium for.

(Contrast this with Adam Sandler movies, which are hauled in by the billions of tons every year, and no one’s found anything yet that those are good for. Chemists one, Hollywood zero.)

Still, ytterbium is good for a couple of things — and the very best we have at one. Certain ytterbium isotopes can produce gamma rays, which can be used in medical imaging, similar to X-rays. It can also be added to stainless steel to optimize certain properties, and to the materials used to generate solid state and other lasers.

But where ytterbium really shines is in telling time. According to the National Institute of Standards and Technology (NIST), ytterbium atomic clocks are the most stable in the world. NIST’s ytterbium clock is so accurate, it could keep “perfect timing for a period comparable to the age of the universe”. Tough titties, Timex. And suck it, cesium.

So that’s ytterbium’s claim to fame. It may never hoist the Stanley Cup or stretch across a Triple Word Score — although, could you imagine? — but it has one thing going for it: it’ll take a licking and keep on ticking.

But seriously, don’t lick ytterbium. That would hurt so bad. Ow.

Actual Science:
The Guardian / GrrlScientistYtterbium
Uncertain PrinciplesLaser-cooled atoms: ytterbium
NISTNIST ytterbium atomic clocks set record for stability
NatureChemistry: degrees of separation

Image sources: (ytterbium), CBC Sports (Y…y…y…ytterbium the Jet), MoviePilot (silver-toothed Joker), Memes of Doom (Adam and Adam)

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