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:

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:

Trans-Neptunian objects: Stuck where the sun don't shine (very much).
“Trans-Neptunian objects: Stuck where the sun don’t shine (very much).”

In the beginning, there was the Earth.

Meaning, that’s the first solar system object humans knew about, mostly because we kept tripping and falling face-first onto it. Early humans weren’t particularly coordinated.

The sun was also pretty hard to miss, what with the light and heat and occasional scary eclipses. By the 2nd century B.C., eagle-eyed up-gazers had also spotted Mercury, Venus, Mars, Jupiter and Saturn. Not bad for people who didn’t have a LensCrafters at the local mall, probably.

It took a couple thousand years — and eyeglasses, binoculars and telescopes — to find the remaining (current) planets, Uranus (1781) and Neptune (1846). And then we had a problem. Based on calculations of the outer planets’ masses and shapes and favorite Hostess snack cakes, it appeared they were being influenced by some unseen astronomical force — other objects, further out, pulling the strings on Neptune’s orbit. (And pre-packaged dessert preference, apparently. Team Ho-Hos forever.)

So scientists went looking for these mystery bits of rock, called “trans-Neptunian objects”, because they spent (most of) their time chilling outside the orbit of Neptune, thirty times further from the sun as Earth. In 1930, they found the first trans-Neptunian object, and called it Pluto.

On the good side, Pluto was pretty much where astronomers thought it would be. On the bad, it wasn’t large enough to explain the discrepancy in Neptune’s behavior. Better measurements of Neptune determined its orbit actually made perfect sense, so they chalked it up to dumb luck, Pluto became the ninth planet, and nobody looked much for more trans-Neptunian objects for a while.

But Pluto seemed awfully lonely, way out there in a dusty corner of the solar system. So when a second trans-Neptunian object was spotted in 1992, the search was on again. Since then — because even our telescopes have LensCrafters now, probably — more than 1,500 trans-Neptunian objects have been found. So many, in fact, they get grouped into weird classifications like “twotinos” and “cubewanos” and “plutinos”.

(It sounds like the lineup for a Saturday night at the Mos Eisley cantina. But that’s really what they call them.)

All this family reunionizing was great for Pluto, presumably — until it wasn’t. In 2005, a trans-Neptunian object called Eris was found. It looked like Pluto. It had a moon, like Pluto. And it was bigger than Pluto — but no one was quite convinced it should be called a planet. So astronomers got together in 2006 and worked out criteria that said no, sorry, Eris is not technically a planet.

And oh, by the way, if you use the same criteria, neither is Pluto. Ouch. Finding Eris was like going on a date with someone who you don’t like very much, and instead of making you miss your previous relationship, you just realize you had bad taste in dating all along. Maybe you should try OKComet instead.

But there’s more. As astronomers discover even further-out hunks of rock — called extreme trans-Neptunian objects, because they drink Red Bull and get tattoos and stay out past curfew, I assume — an old problem reemerges: they don’t look quite right. In fact, a recent paper studying the orbits of some of these way-out objects says that apparently they are being influenced by something (or somethings), legitimately planet-sized and dark and mysterious even further out. So far, scientists haven’t seen them — or agree they exist — but some are now squinting their telescopes outward, just in case.

Here’s hoping they have a good LensCrafters nearby.

Image sources: NASA/JPL-Caltech (Sedna, the sexy TNO), and FreePik (‘Scopes heart LC), Princess Burlap (“I said, Team Ho-Hos!”), Electronic Cerebrectomy (Mos Eisley cantina band), FB-Troublemakers (sad Pluto)

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