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!

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

Oort cloud: Go way, way Oort -- then Oort a little further.
“Oort cloud: Go way, way Oort — then Oort a little further.”

If you’ve ever played pinball — which you’ve probably only done ironically, if you’re under the age of thirty — then you’re familiar with the concept of “multiball”. You lock balls by making certain shots, and then there’s some way to unlock them, so a bunch of balls all come flying out at once. Sometimes there’s more than you locked. Often, they come from different places than you put them. They fly around higgledy-piggledy from all directions, until you lose them or you tilt the machine or you get bored and remember that video games and the internet and Netflix exist.

But maybe you’ve wondered, while the multiball madness ensues: where are all of these balls coming from? I always assumed there were some nifty mechanics inside the machine, pulling balls from a reservoir and gliding them around. Either that, or gnomes. Very small hippie gnomes. But then I learned something about astronomy, and found there’s another place those balls might be coming from: the Oort cloud.

Mind you, the Oort cloud is purely theoretical. But its existence has been predicted based on questions about our solar system’s own version of multiball — namely, comets. Some comets swing past the sun every few years. The orbits of these “short-period” comets aren’t so large, and most of them originate in either the Kuiper belt, around 30-50 AU (astronomical units; 1 AU is roughly the distance from the earth to the sun) or the overlapping “scattered disc”, which extends from around 30-100 AU.

These regions begin right around the distance of Neptune from the sun, and they’re not so mysterious. Definitely not “multiball mysterious”. Astronomers see Kuiper Belt objects all the time — probably with a decent pair of opera glasses. New Horizons, the space probe that buzzed Pluto a while back, is swooping through the Kuiper Belt right now. It’s practically down the block.

The Oort cloud is a leeeeetle cooler than that. First, it’s just slightly further away, occupying the space somewhere between around 2,000 – 100,000 AU, give or take a light year. (Which, as it happens, is about 50,000 AU. So it’s true!)

For perspective, that Voyager I probe launched back in 1977? You know, back when people actually played pinball (because it was either that or Pong, those poor primitive saps)? That craft has traveled further than any other we’ve made, it’s technically in interstellar space, and is traveling at around 38,000 miles per hour (a shade faster than New Horizons; don’t tell the Space Highway Patrol). Voyager is expected to enter the Oort cloud in roughly 300 years — or about 290 years after its radioisotope-powered generators are expected to fail, leaving it a silent hunk of space rubble.

So the Oort Cloud is a big ol’ faraway ball of space, is what I’m saying. Inside it are theorized to be trillions — that’s trillions, with a ‘truh-‘ — of objects at least one kilometer across. Most of these are icy bodies, but there are few (meaning few billion) rocky asteroids sprinkled in, just for fun. It’s thought that Oort cloud objects mostly come from debris left over from the formation of the solar system, when the original “protoplanetary disc” swirled into Saturn and Jupiter and Earth and the rest of the planetary gang. Some even theorize that part of the Oort cloud — up to 90%, at the upper end — comes from “sister stars” that were closer by during the sun’s early days, and spewing pre-planetary spittle all over the cosmos themselves.

But if we’ve never seen the Oort cloud, then why would we think it’s out there? Why don’t we just assume there’s nothing there, or space gnomes, and be done with it? Because of long-period comets, that’s why. When astronomers track the orbits of these comets, they see some that make a circuit in hundreds or even thousands of years. And unlike comets from the Kuiper belt or scattered disc, which lie flat in the same plane as the planets, these long-period take-your-time-grandpa comets come from everywhere.

So that’s the Oort cloud. Further out than we can see, surrounding our whole solar system and occasionally raining some of its trillions of balls of ice and rocks down on our pinball machines. Ding ding ding. Multiball, indeed.

Image sources: Universe Today (Oort cloud), Zazzle (MULTIBAAAAAAALL!), French Vocabulary Illustrated (opera-glassed stargazing), Drawception (space gnome [artist’s rendering])

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

Fast radio burst: and you thought Sex Pistols songs were short and confusing.
“Fast radio burst: and you thought Sex Pistols songs were short and confusing.”

If you’re like Fox Mulder, you believe the truth is out there.

That’s great and all, but what happens if you’re not fast enough to read it when “the truth” finally whizzes by?

That’s the sort of problem astronomers have faced since 2006, when the first “fast radio burst” (or FRB) was detected in radio telescope data recorded five years earlier. Poring over archived pulsar survey data, they found a brief spike in the signal across a range of wavelengths. It lasted less than five milliseconds, quick as a Ruby Rhod *bzzzzzz*. And then it was gone.

That may seem weird. But pulsar-hunting astronomers are used to this sort of now-you-see-it, now-you-don’t radio signal Whack-a-Mole. Pulsars are rapidly spinning neutron stars that emit radio signals, and their twirling makes the detectable signal come and go at regular intervals. Only with this particular fast radio burst, it came once… and it never came back.

Kind of like Jesus. Or Nelson Muntz’s dad.

Oh, no, wait. Nelson’s dad did come back eventually. Scratch him.

That was just the beginning of the mystery, though. The spread of the signal across wavelengths suggested that this fast radio burst had traveled across space and through interstellar gas, which can spread signal out, the way a prism does with light. Based on the spread, astronomers calculated that the signal had come from more than five billion light years away. Which meant whatever had created it must have been ginormously powerful, for the signal to make it so far through the cosmos.

That opened up a whole new can of WTFs. So far as we can tell — meaning as far as we can see with our various telescoping gadgets — there’s nothing in the region where the fast radio burst came from. No stars. No black holes. No outposts with Marvin the Martian plotting our destruction. Nada. If there’s something — or somethings — there, we’re not able to see it with our equipment. And we have no idea why it would scream at volume 11 for an instant, and then stop seemingly forever.

I mean, sure — Obi-Wan would tell you it was Alderaan. But what does he know? He doesn’t have an astrophysics degree.

The first fast radio burst was weird enough to make people skeptical. When we didn’t see another one for a few years — and when one team discovered they could make similar signals by opening a microwave door just right — astronomers wondered whether it was a technical glitch. Flying bird farts. Space voodoo. Something.

But in the past few years, ten more fast radio bursts have been detected. Now, there’s corroboration from a second radio telescope — and the last one, in 2014, was detected live as it happened. Now, scientists calculate that if we could point radio telescopes at the entire sky, full-time, we’d see hundreds — maybe even ten thousand — of these fast radio bursts per day.

That still doesn’t tell us what causes them — but there are some pretty cool theories. Each source is calculated to be no more than a few hundred kilometers wide, so these big (and quick) things are coming from some pretty celestially small packages. Some think it might be colliding black holes, or neutron stars collapsing together. Or black holes exploding, if that can even happen. Others blame them on blitzars — though why we have to bring Santa’s reindeer into this, I don’t know. We’re trying to do real science over here.

Whatever it is making fast radio bursts, astronomers are now agreed that they exist and are doggedly looking for more. Someday, with enough evidence, no doubt they’ll finally find “the truth” behind these weird astronomical aberrations.

Or they’ll find the Death Star. And I’m pretty sure Mulder wasn’t looking for that.

Image sources: PBS (fast radio burst [artist’s rendition, apparently]), QuickMeme (truthy Fox), Simpsons Wiki (Nelson and papa, haw haw!), Giant Bomb (Alderaan, we hardly knew ye)

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

Very Large Array: My, what a big telescoping instrument you have!
“Very Large Array: My, what a big telescoping instrument you have!”

Reasonable men and women can disagree — and lord, they often do — about what qualifies as “very large”. Reasonable astronomers, however, agree that the Karl G. Jansky Very Large Array of radiotelescopes in the plains of New Mexico is indeed “very large”.

It’s right there in the name. No debate or overcompensation or embarrassing pumping equipment necessary.

To be fair, 27 x 25 sounds pretty darned big, and the Very Large Array backs those numbers up: it’s comprised of 27 separate telescopes, each with a 25-meter diameter dish. The antennae are arranged in a Y-shaped formation, with a total collection area covering more than thirteen square miles. That’s some girthy science.

What’s more, the Very Large Array dishes sit on tracks, so they can be moved around into many different configurations. Given that the array is located in New Mexico, I assume several of those configurations spell out “BEAT ARIZONA” — but still. Moving the component parts around is pretty nifty. It’s like Puppetry of the Radio Antennae over there.

All of those dishes and formations give the Very Large Array remarkable telescoping power. The data from each dish is combined and calibrated to give the resolution of a single dish 22 miles across, and the sensitivity of a dish more than 400 feet in diameter. Some people say that “big things come in small packages”. Clearly, these people aren’t packing a Very Large Array in their arsenal. Because with these telescopes, a bunch of reasonably small packages add up to find some really big things.

How do they do that? By multiplying the radio wave signals captured by each antenna and studying the interference patterns that emerge from the combined data. This technique of interferometry relies on the Fourier transform — which sounds very French and very complicated — to accurately find and track radio sources throughout near and deep space.

And by “radio sources”, I don’t mean Bill and Marty on the KBBL morning show.

Rather, the Very Large Array has been used to study star formation at the center of our galaxy, explore galactic gas clouds, track electron beam bursts in the sun and investigate black holes, quasars, pulsars, gamma ray bursts and more. In 1989, the array was even tuned to listen to radio signals coming from the Voyager 2 space probe as it zoomed past Neptune. I wasn’t even aware NASA had imprisoned a ham radio buff on Voyager 2, but apparently so. Hey, good for them.

But being “very large” doesn’t help you do everything. Even though the Very Large Array featured prominently in the movie Contact, it’s not actually used on a regular basis in the search for extraterrestrial intelligence (SETI).

(That’s okay, though. I’m starting to suspect Jodie Foster isn’t a real astronomer, either. We know she’s not a poet, obviously. But past that, I have my doubts.)

Limitations aside, the Very Large Array’s radio-based interferometry has uncovered a number of fascinating scientific discoveries since coming online in 1980, from the presence of water ice on Mercury to the first detection of radio waves accompanying a gamma ray burst to the discovery of the first “Einstein ring” gravitational lens. A complete overhaul and digital upgrade in 2012 — when it also added the Jansky name to the official title — prompted the National Radio Astronomy Observatory (NRAO) overseers to declare the system significantly improved, and dub it the Expanded Very Large Array.

Me, I would have gone with “MAGNUM“. But what do I know? My array isn’t nearly as large, and can’t even pick up local FM stations.

I’m blaming shrinkage.

Image sources: Big History Project (Very Large Array), Portigal (“Giiiiiirthy!”), QuotesGram (Jodie, not a poet), The Ruddy Duck (shrinkage!)

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

Albedo: upon further reflection, it keeps getting better.
“Albedo: upon further reflection, it keeps getting better.”

I used to think “albedo” was a term for sex drive in people without skin pigmentation. This led to some very uncomfortable conversations. And, as someone who doesn’t tan very well, a lot of unsuccessful pickup lines.

As it turns out, albedo means something a little bit different. It’s another word for “reflection coefficient”, which is the ratio of light reflected off an object to the amount of light pumped in. For a highly shiny object — Gwyneth Paltrow’s forehead, say — then you have a high albedo, close to 1. On a much darker surface — where light rays check in, but they don’t check out — the albedo will be very close to zero.

A partial list of substances on the low end of the albedo scale:

A 7-11 asphalt parking lot: 0.12
Charcoal: 0.04
Vantablack carbon nanotube substance: 0.00035
C. Montgomery Burns’ shriveled heart: 0.002
Black hole: 0(-ish)
Spinal Tap’s Smell the Glove album (revised cover): 0.000000001

(How much more black could it be? The scientific answer is: negligibly more black, allowing for measurement variability and prevailing experimental conditions. Nigel Tufnel wasn’t so far off.)

The albedo of most objects is affected by two things: the angle and the wavelength of light streaming in. Light glancing past is easier to reflect, and some materials have a preference for absorbing or bouncing back light of various colors.

In fact, that’s how we perceive objects as having colors; we only see the wavelengths bouncing off them that they neglected to absorb. If every substance sucked up every wavelength of light like some kind of solar paper towel, then they’d all be completely black.

Unlike non-solar paper towels, which are white. Because the Brawny man will clean up your coffee spills. But he’ll never take away your sunshine.

In astronomy, albedo is an important characteristic of faraway objects, and can be used to determine what they’re made of. One of Saturn’s moons, Enceladus, has a surface of nearly pristine ice, and an albedo of 0.99. You could basically use Enceladus as a mirror to see if there’s spinach stuck between your teeth, except that its 750 million miles from your bathroom and your face would freeze if you got anywhere close to it.

This week’s flyby — or more accurately, screamingwhooooshby — of Pluto by the New Horizons spacecraft is providing details and answers to a question first raised by albedo measurements of Pluto and its largest moon, Charon. These bodies (as well as Pluto’s other moons) are thought to have formed from a collision of two large objects many millions of years ago. But looking at light reflected from them, Pluto has an albedo in the range of 0.49 – 0.66, while Charon is much darker, at 0.36 – 0.39.

Why the difference? Are the two made of different substances, after all? Did somebody polish Pluto up to try to get it reinstated as a planet? Or is Charon just going through a “goth” phase?

These are answers that albedo alone can only hint at, for objects at the edge of our solar system and for planets many, many light years away. It’s not a perfect tool for astronomical discovery — but for the places our probes (and horny albinos) can’t reach, it’s an awfully good start.

Image sources: University of Washington (albedo spectrum), ChaCha (Gwyneth aglow), Brass Collar (“none more black”), Got a Nerdy Mind? (the Brawny menagerie)

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· 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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