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 secondhandscience@gmail.com with comments, suggestions or wacky cold fusion ideas. Cheers!

Exosphere


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

Exosphere: It's where the innie space becomes an outie.
“Exosphere: It’s where the innie space becomes an outie.”

The earth’s atmosphere is sort of like a family. Everybody stays pretty close… but some stay closer than others. So the troposphere, the nearest layer, is like that aunt who comes over every weekend you can’t get rid of. The mesosphere, you maybe see at holidays, and it sends you stupid-looking sweaters for Christmas.

Or pictures of itself in stupid-looking sweaters. The mesosphere’s side of the family was always a little weird.

But the exosphere? No. The exosphere is the black sheep of the atmospheric family — and it likes it that way. You might get the exosphere to RSVP “NO!” to a family reunion, but that’s about it.

In planetary (as opposed to familial) terms, the exosphere is the outermost layer of influence, where individual molecules are still bound by gravity, but there’s nothing you could call an “atmosphere” to be found. Around Earth, the exosphere contains hydrogen, with a little bit of helium, carbon dioxide and oxygen flitting around. But not in a crowded way. It’s less “Times Square at rush hour”, and more “fans at a Miami Marlins baseball game”.

The spot where the exosphere begins is called the thermopause. That might sound like a fancy name for “hot flashes” — and if you happen to be a planet, that’s not too far from the truth. The thermopause marks the boundary of the Earth’s energy system, and the exosphere doesn’t have enough molecular oomph to be part of that.

Of course, the planet has good and bad days, just like the rest of us. So on a high-energy day — maybe it’s summer, or the sun is flaring, or Earth got its ass out of bed early for yoga — the exosphere might start six hundred miles or more above the surface. On days with less energy — Sundays, I’m assuming, and the day after Thanksgiving — the exosphere might start half that high, around three hundred miles up. Some days it’s just harder to push yourself up against outer space, you know?

Where the exosphere ends depends on how you feel about outer space. Or at least how you feel about defining it. If you prefer your outer space to start where the radiation from earth ends — light, heat, the glow from Ryan Seacrest’s front teeth, all of that — then your exosphere ends six thousand miles above the earth, give or take a few hundred miles.

If you want to be all technical about it, and consider where the gravitational pull of the earth on atoms of hydrogen gives way to radiation pressure from the sun, letting those atoms escape out into the ether, that’s a different story. That happens a wee bit further out — say, a hundred and twenty thousand miles up the chute. Or halfway to the moon, if we’re getting other celestial objects involved now.

Speaking of which, other globs of space rock — including our moon — have exospheres, though at lot of them don’t have much of anything else. So an exosphere is sort of the bare minimum possible, in lieu of something more substantial.

Kind of like Ryan Seacrest, apart from his teeth — or the stands at a Marlins game. Neat.

Actual Science:
Universe Today – Exosphere
University Cooperation for Atmospheric Research – Exosphere – overview
Science Daily – How the moon gets its exosphere
CBS News – NASA moon mission targets lunar dust, “exosphere”
University College London – Dione’s thin oxygen exosphere

Image sources: Surfline (atmospheric layers), (Christmas sweater), Buzzfeed (Marlins fans [both of them]), The Richest (Tom Cruise’s shiny, angry, shiny teeth)

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Pauli Exclusion Principle


· Categories: Physics
What I’ve Learned:

Pauli exclusion principle: If you're anything like me, then get the hell out.
“Pauli exclusion principle: If you’re anything like me, then get the hell out.”

The Pauli exclusion principle sounds like some rule a big Italian bouncer would use to keep you out of a swanky club, or maybe the reason Hollywood doesn’t let Pauly Shore make movies any more.

(That last one doesn’t really need a special name. The reason Pauly Shore isn’t allowed to make movies any more is all of them.)

But the Pauli exclusion principle is something else entirely. In the 1920s, physicists kinda-sorta understood something about the nature of atoms, and the electrons whizzing around them. They knew how many electrons the atoms of each element contained — one for hydrogen, two for helium, five for Milla Jovovich, et cetera — and they knew that some of those elements were more “stable” than others.

In physics terms, this stability meant that atoms of these elements didn’t share electrons with other atoms. They had no extras to give, and no empty electron-sized holes on their knickknack shelves to fill. These elements seemed to have atoms that were “full” of electrons — but no one knew exactly what that meant, or what kept the atoms in that “full” state.

A lot of people guessed it was those godawful Carl’s Jr. Thickburgers. But those didn’t exist yet — so it was probably something else.

Enter physicist Wolfgang Pauli, who simplified matters by making things more complicated. Because this is quantum physics, and that’s how it works most of the time.

At the time, electrons in an atom were characterized by three characteristics, or “quantum numbers”. Together, the values for these numbers described (roughly) the distance, shape and orientation of the electron’s orbit around the atom. And it took a hell of a lot of work to figure those three coordinates out.

Pauli decided that wasn’t enough, and added a fourth. He didn’t know what it was, exactly, but it was some characteristic with one of two possible values, like “on” or “off”. “Shirts” or “skins”. “Team Edward” or “Team Jacob”. Take your pick.

To make up for all the extra math, he then tacked on his Pauli exclusion principle: taking all four characteristics into account, no two electrons in an atom can have the same values. An electron orbital is “full” with two electrons in it — one with each possible value for Pauli’s fourth number. They can’t have the same number — and a third wheel can’t slip in, because both possible numbers are taken.

With that, it all came together. Atoms have different numbers and types and sizes of orbitals, but applying the Pauli exclusion principle explains which ones are “full”, and when the whole atom is “full”. The predictions lined up exactly with what scientists had already observed about atomic behavior. With one simple rule (well, relatively simple, for physics), Pauli gave physics a cornerstone of quantum mechanics and atomic physics. And in 1945, physics gave him back a Nobel Prize for it.

In the following years, Pauli’s fourth quantum number was identified as the “spin” of the electron, which for typically-complicated reasons has a value of either 1/2 or -1/2, but never anything else. All those physicists who bet on “boxers” versus “briefs” were apparently wrong.

But the impact of the Pauli exclusion principle didn’t end with electrons and atoms. The rule applies to all fermions (subatomic particles with half-integer spin), and also explains the characteristics of conductors and semiconductors, shows why matter is stable and takes up volume, and helps astrophysicists describe why white dwarf and neutron stars don’t collapse into black holes. Not bad for a scientific idea that basically started out with electrons picking “heads” or “tails”.

Actual Science:
The Physics Mill – Binary unity: the Pauli exclusion principle
The Physics of the Universe – Spin and the Pauli exclusion principle
David Yerle – A physics challenge: explain Pauli’s exclusion principle
NASA Astronomy Picture of the Day – Pauli exclusion principle: why you don’t implode
NanoWerk – New insights into the world of quantum materials

Image sources: StudyBlue (Pauli exclusion principle), Vevo (Pauly Shore, outside looking in), Kristy Lish (Leeloo / Fifth Element), Synotrip (Paris with a mouthful of Carl)

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Nucleation


· Categories: Physics
What I’ve Learned:

Nucleation: Once you start, you REALLY can't stop.
“Nucleation: Once you start, you REALLY can’t stop.”

Everybody has to start somewhere. If you’re a corporate lackey, you start at the bottom. If you’re a gravedigger, you start at the top. And if you’re a phase transition, you start with nucleation.

Phase transitions are the change of a substance from gas to liquid, or from liquid to solid. But transitions don’t magically happen everywhere at once; you never see a swimming pool full of water freeze in an instant.

Not outside of a Vegas Penn and Teller show, anyway. Preferably with David Blaine chained down in the deep end.

Instead, the process — in this case, the formation of ice crystals — starts in one or more places called nucleation sites. In pure substances, these sites may occur randomly; where materials are mixed or in an irregular container, the nucleation sites usually form where different surfaces meet. Like by a leaf floating in the swimming pool. Or the tip of David Blaine’s nose. Just for instance.

Once formed, the nucleation sites provide an anchor for the transition process. That process speeds up, piling onto the sites like tacklers on a running back, until the entire team is on the pig pile and the system comes back into equilibrium. In the example above, that would be when all the water on the surface that’s cold enough has frozen into solid ice. Or when they fish the David Blaine-cicle out with a pool noodle.

The magic-but-actually-science of nucleation is not limited to freezing water, however. It’s also a crucial part of other natural processes, like crystallization, cloud formation and elongation of biological polymers like actin filaments. Some quantum cosmologists have even hypothesized that our entire universe is the result of a sort of bubble nucleation in the vacuum of whatever it is that lies outside the universe we observe.

(My guess for what’s out there? That girl from the Wendy’s commercials. Because she seems to be every-fricking-where else these days.)

Speaking of bubbles, a lot of people have been having fun with nucleation, possibly without realizing it. The key to the explosive foaming mess you can make by dropping a Mentos candy into a bottle of diet soda is indeed nucleation. Small pores in the Mentos allow bubbles of gas from the soda to form, which attract more bubbles and more bubbles — and they tell two friends, and so on and so on until there’s foam all over your kitchen and mom’s asking why there’s half a dissolved mint embedded in the ceiling.

Of course, bubble nucleation doesn’t require all those theatrics to be useful. Microscopic irregularities in champagne glasses nucleate those nose-tickling bubbles in the bubbly everyone loves. Nucleation also explains why it’s harder to pour a beer into a used glass without foaming up the place; the remnants of the previous pint’s suds provide sites for bubble-making that a fresh clean glass would not.

So that’s nucleation in a nutshell. It’ll help you pour a good beer, it makes Mentos much more interesting, and it might help us get rid of David Blaine. Honestly, what more could you ask of science?

Actual Science:
WiseGEEK – What is nucleation?
Softpedia – How to make ice with lasers
New Scientist – Science of Mentos-Diet Coke explosions explained
Stanford Report – Chemistry professor explains the ‘fizzics’ of beer
Phys.org – Study shows calcium carbonate takes multiple, simultaneous roads to different minerals

Image sources: ASEPTEC (nucleation diagram), YouTube (cold, wet but sadly unfrozen David Blaine), Examiner.com (football pig pile), New York Times (science ‘n’ Mentos)

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Gravitational Lensing


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

Gravitational lensing: mirror, mirror in the sky; show me what's behind this guy
“Gravitational lensing: mirror, mirror in the sky; show me what’s behind this guy.”

If you’ve ever sat behind a really tall person at a movie, then you know the infuriating problem of not being able to see something on the other side of a solid object. At the theater, you probably deal with this in the usual ways — hoping the heighty person slouches in their seat, or spontaneously loses six inches of height, or their head explodes like in that Scanners movie.

But astronomy tells us there’s another viable option, known as gravitational lensing. All you have to do is push the movie a few million light years away, and make that big fat head in front of you as dense as a ten-billion star galaxy.

It’s a little complicated. I’ll explain.

One of the (now-famous) predictions of Albert Einstein’s general theory of relativity is that space (really spacetime, but who’s counting?) is curved, and that hugely massive objects with lots of gravitational force will further warp that curving. So if a celestial light source — like, say, a quasar — lies behind an enormous gravitational well such as a galaxy, the light from the quasar would get curved around the galaxy and slingshot out the other side.

It might appear that the light source lies beside the big heavy thing in the way, because the light doesn’t bend all the way back to the middle. And if the source is directly behind the obstacle, the light could take more multiple paths around it — left, right, up, down, south by southwest — and appear more than once on our side. It could even form a full ring of light all around the object in the middle, weirdly indicating that the thing producing the light isn’t anywhere around the obstacle at all, but directly behind it.

I know, right? It’s spooky. Real call is coming from inside the house stuff.

Because Einstein described relativity, and was a generally awesome dude, the light rings caused by gravitational lensing are called “Einstein rings”. There are very few complete rings — caused by a massive energy source directly behind a star or galaxy — but hundreds of partial rings, multiple-image systems and other gravitational lensing events have been observed. One of the most impressive, called Einstein’s Cross — because, again, cool smart guy — consists of four “bent” images of a way-distant quasar curved around a still-way-distant-but-not-as-way-distant galaxy in between.

It’s like having a head in the way, but still seeing the movie in double-stereo-vision. Because astronomy makes everything better.

So what do you need to make gravitational lensing work? First, a source of some kind of energy. Many of the known ones work in visible light, but any kind of electromagnetic energy will do in a pinch. The universe isn’t picky.

The energy source has to be ridiculously strong, though, because you’ll need to see the signal from way far away. Not just from down the block, or from that window in your attic, either. Instead, from billions of light years away. Which is kind of a big deal.

Why so far? Because you then need to find an incredibly massive object to plop between you and the energy source to produce the gravitational lensing. A bowling ball isn’t going to do it. A star might, if it’s in precisely the right orientation. A whole galaxy of stars would be better. Or you could try Nicki Minaj’s ass. It’s big enough to attract most of the pop culture paparazzi into a close orbit, apparently. Maybe it could work; I don’t know.

The point is, you’ll only see gravitational lensing by throwing that hypermassive whatever between you and and the signal. And then you can watch that gravity well bend electromagnetic waves like Beckham, off a straight line and down to your eyes.

So maybe it won’t help you the next time you’re blocked at the movies. But gravitational lensing could show you a star behind another star some day. And really, isn’t that how the movie industry works in the first place?

Actual Science:
NASA – Gravitational lensing
One-Minute Astronomer – Gravity’s lens
Hubble / ESA – Most distant gravitational lens helps weigh galaxies
Astronomy Magazine – Best view yet of merging galaxies in distant universe
Skyhound – Focus on Einstein’s Cross: a gravitational lens

Image sources: Cosmic Chatter (Einstein ring), Slate (big head at movie theater), Disease Prone (Scanners head), SlamXHype (rocket-powered Minaj)

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Heliosphere


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

Heliosphere: It's the sun's Twinkie. We're just along for the ride.
“Heliosphere: It’s the sun’s Twinkie. We’re just along for the ride.”

There are many complicated models of what our solar system looks like. Then there’s my model: the solar system is like a giant Twinkie, with a Red Hot candy jammed in one end.

Seriously, NASA. Why make things hard, when they could be so delicious?

So here’s how the Twinkie squishes:

The Red Hot, naturally, is the sun, radiating loose particles and waves of heat in all directions. With the candy, most of the particles are artificial cinnamon flavor and FD&C red #5, and they only make it as far as the nearest taste bud.

With the sun, the particles are solar wind — a plasmafied soup of protons and electrons — and they shoot outward at roughly 1.2 million miles per hour, give or take a speeding bullet or two.

The sun is therefore much more powerful than a Red Hot candy, but considerably less appetizing. And, so far as we know, non-fat. If you’re into that sort of thing.

Back to the model. The Twinkie represents the full spread of solar material, a region called the heliosphere. This bubble of sun-spewed plasma extends roughly 120 astronomical units — or A.U., the distance from the earth to the sun. That’s a very long way. Even wasabi pea particles don’t make it out that far.

The heliosphere doesn’t extend equally in all directions, though; hence the “Twinkie-shapedness” of the model. Remember that our sun is also constantly whirling around the galaxy at breakneck speed, which stretches the plasma bubble out behind it. Imagine the Twinkie as a speeding race car, with the Red Hot near the nose.

Or a Twinkie jet plane, if you like. Any method of theoretical Twinkie locomotion you prefer is fine. This is one of the main perks of stellar science, from what I understand.

The final bit of the heliosphere model is the outer part, where the delectable Twinkie cream turns into scrumptious Twinkie cake. In space, this interface is called the termination shock, and it’s where those plasma blasts from the sun finally slow down below the speed of sound. This happens when the solar wind interacts with the interstellar medium, a haze of gas and dust and cosmic rays flowing between the stars.

As the interstellar medium slows down the solar rays, the plasma stagnates and bubbles and clumps up — much like the spongecake cradling our Twinkie. This layer is called the heliosheath, and is immediately followed by the heliopause, where the solar wind finally disappears entirely. It’s the thin brown crust that marks the final boundary between Twinkie and not-Twinkie. When you pass the heliopause, you’re no longer in the solar system.

So how many man-made objects have made this journey out of the heliosphere, to boldly go where no Twinkie has gone before? One — or possibly none. Voyager 1, launched in 1977 to explore the outer planets, has been hurtling directly away from the sun at eleven miles per second since 1980. It’s believed that in August of 2012, Voyager 1 passed through the heliopause and out of the sun’s fiery clutches.

But because we don’t precisely know what the end of the solar system looks like, researchers are still proposing and conducting tests to determine exactly how “out” Voyager 1 is. If not yet, then it’s expected to pop through the heliopause within the next year or so, followed soon by Voyager 2.

(And if my petition to NASA goes through, next by Guy Fieri.)

Breaking an object out of the heliosphere will be quite an accomplishment, once confirmed. But why anyone would run away from a cinnamon-flavored Twinkie is beyond me.

Actual Science:
Universe Today –
NASA Science – Heliosphere
Time Magazine – Humanity leaves the solar system — or maybe not
RedOrbit – Has Voyager 1 actually reached interstellar space?
The Space Reporter – Scientists using new test to finally prove that Voyager 1 left heliosphere

Image sources: PlanetFacts (heliosphere diagram), Perfectly Crazy (Twinkie racer), DeviantArt / Jonnyetc (Winston’s big Twinkie), Rock ‘n Roll Ghost and GeekDad (Voyager Fieri)

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