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Is the Moon the Earth’s Shadow?

An alternate origin story for our celestial sidekick.

A couple weeks ago, I was awake at 4:30 AM with 6-month-old Stanley during the time of the “Blood Moon” eclipse. From the upstairs window, I was able to catch the last bit of the Earth’s shadow passing over the moon. Visually it wasn’t exactly stunning, but I appreciated the reminder that we’re here and we cast a shadow in the universe.

Probably because it was so ridiculously early, I started to wonder what other effects the Earth’s shadow might have on things out there. For instance, if you were some kind of particle floating near Earth, the shadow might be a nice spot to cool down and find shelter from the solar wind.

And maybe long ago, when the solar system was young and less dense, the stray gases and debris that managed to escape the Earth’s atmosphere, gathered together in the shadow to form a nice, comet-like tail. (Seems possible, since apparently the Earth has a vestigial tail even now.)

Maybe so many particles tried to squeeze into this shadow-tail over time, that they melded together and formed enough mass to assert some serious gravity, inviting more and more matter to join the party. Once things really got raging, this heated particle storm could’ve grown to the point that the charged breeze from the sun could no longer confine it to the shadow. Unable to resist the centripetal allure of the sun, but not wild enough to stray too far from mother Earth, it would’ve spun off into its own orbit. As this fiery attraction collided with more and more debris, it could’ve boiled over, then congealed and cooled to become the silver rock of inspiration we know and love today.

As I paced back and forth in the hall, trying find the exact patting rhythm that might possibly nudge Stan back to sleep, I tried to figure out if a moon could get ever started just by collecting a small amount of space debris in one place for a few billion years. I can get a pretty big dust-bunny under my dresser in only a week when the ceiling fan is on during the summer. If that dust-bunny managed to increase its diameter by only 1 mm every week, I could have a 1/2 cm dust bunny by the end of the year. But If it started accumulating at the same rate, back when the Earth started forming, some 4 billion years ago, it would now be 200,000 km wide or almost twice as big as Saturn!

But it’s really mass, not size that would have to increase to become a moon. To delve further into that question, I dimmed the brightness on my iPhone and began entering odd sentences into Wolfram/Alpha. “Mass of the Moon divided by Age of the Moon in kilograms” told me you’d need 16.2 trillion kg for every year of development or 514,600 kg/second – which, in our dust-bunny analogy would be like a dust-bunny volcano.


Well… according to pictures like this one, the Earth was crazy with volcanos back in the day. How much stuff could a volcano really produce?

I looked up the first volcano I could think of and discovered that Mt. Vesuvius spewed out 1.3 million kg of rock every second when it buried Pompeii back in 79 AD. That was a huge amount of stuff. Of course not much of that went into space. But then again, when the Earth was still forming, it wasn’t as massive, so it had less gravity so more volcanic debris could’ve escaped into space. Plus there was no atmosphere to hold it in.  And besides that, wasn’t there enough free-floating debris and gas to form the solar system? Why wasn’t the moon entitled to some of that? And even if the moon was formed by a giant collision with a Mars-sized object, as the current hypothesis suggests, wouldn’t the Earth’s shadow have been a nice place to get things started?

By the time I had this matter of mass and volcanos worked out to my satisfaction, Stan had drifted back to sleep, and the birds were beginning to chirp. I was now wide awake, stuck with a time-lapse animation running through my head showing the Moon materializing from a comet-like tail in the shadow of the Earth.

I pictured the sun acting as a sort of sand-blaster with the Earth as a stencil protecting the debris in it’s tail from annihilation. Something about this picture got me thinking about another eclipse-related question that has always bothered me: Why are the size of the sun and moon so closely matched when observed from Earth – to the point that they line up almost perfectly during a solar eclipse? It’s always felt like one of those coincidences that’s just too coincidental. With the sun’s rays implicated in the formation of the moon, could this origin story help to explain this peculiarity? Whether or not the trigonometry works out is a question for those who actually know how to do trigonometry.


I found myself facing the day, convinced, despite no serious evidence, that the significance of the Earth’s shadow has been overlooked. I don’t really know the particulars of the particles that were around during the early days of the solar system, or the ones that make up the Moon today (or the Earth, for that matter) and I’m no expert on the solar wind, but there’s a certain elegance to the story that feels compelling.

Having pushed the limits of “soft science” I decided the best course of action would be to create a quick visualization of the concept (see the video at the top of this post) and get it into the minds of people who think about this stuff on a regular basis.

So how ’bout it science? Can we get an accurate particle simulation that takes the Earth’s shadow and the solar wind into account? Can we give the particles some realistic gravitational properties, and plot some orbital trajectories? Can we speed it up over 4.5 billion years and see if we end up with a big rock ball that perfectly blocks out the sun during an eclipse? That would be cool. Please be so kind as to let me know if you pursue the question and be sure to spell my name right in all your papers and press-releases!

And if you don’t have the computing power, or academic credentials for such a thing, that’s ok too. Maybe just think about it at 4:30 in the morning and post your thoughts or relevant links in the comments.

FAQs: 1 Pixel Moon Map

Distance of the Voyager Spacecraft

I’ve received a lot of interesting questions from people who have taken a look at If the Moon Were Only 1 Pixel. Here I will try to quench your insatiable curiosity.

Are you some kind of expert astrophysicist who is qualified to answer questions about the scale of the universe?
Nope. I’m not even that good at math.

Where would the Voyager spacecraft be on the map?
After reaching Pluto, you’d need to scroll through about 1.6 more maps filled with emptiness before reaching Voyager 2 and then another half a map to reach Voyager 1. Pretty impressive distance for a couple of California bad boys shot out of the 70s. Visit the Jet Propulsion Lab website to really find out what they’re up to.

Why isn’t Titan on the map?
Except for the Titan-Centaur rockets (the kind that launched the aforementioned bad-ass spacecraft), I’ve determined that anything containing the word “titan” is doomed to mediocrity. The half-hearted Clash of the Titans (both the original and the remake), the forgettable Remember the Titans, Titan AE (the AE stands for animated ennui), and of course the disastrous Titanic. All were lacking some essential component that prevented them from being anything more than “not horrible.” At least that’s my rationale for omitting Saturn’s moon despite the fact that it’s actually larger than Callisto. (And also a section of code around Saturn had a bug in it so I took it out and never got around to fixing it.} Real astronomers will be happy to know that the map has now been updated to include Titan, despite its lackluster name.

If you included Pluto why didn’t you include insert name of favorite exoplanet here?
Do you ever hang a stocking out at Christmas for your cat, even though she’s not technically a human who celebrates Christmas? It’s like that.

If you combined the scrolling efforts of all the people who have scrolled through this map, how far would you get?
If all 3 million(!) visitors scrolled to Pluto (which they didn’t) and we combined all of their scrolling efforts in order to scroll through an inter-galactic mega-map drawn at the same scale, we wouldn’t even make it to the Canis Major Dwarf Galaxy, which is barely even a galaxy and is actually closer to us than the center of the Milky Way. If we really want to reach it, everyone will need to go back and scroll through the map 13 more times.

If everyone on Earth could somehow hold hands in a straight line across the map, how far would we reach?
7.125 billion people each with their arms outstretched 1.5 meters would get you about 10.7 million km, or roughly 1/5th of the distance between the Sun and Mercury. We tried Hands Across America, why not Hands Across the Solar System? Every participant gets a complimentary sun visor.

How big am I on the map?
1/46 millionth of a pixel. But you’re the most important 1/46th millionth of a pixel.

What kind of tools did you use for this project?
The folks at the Adobe CC blog asked me that same question. You can read what I told them in the lovely article they published a while back.

It says “You Are Here” under the Earth, but how do you know I’m on Earth?
The page is actually using an advanced geo-targeting algorithm to detect your location. By using the prefix “geo” it can tell you’re on Earth, because “geo” is Greek for “Earth.” Please don’t move to Ganymede or something, it’ll throw off the whole thing.

Can you make other maps where other things are only 1 pixel, like the whole solar system is 1 pixel or my whole life is one pixel?
How about If My Free Time Were 1 Pixel. Oh right. It already is.

To-Do List for When I’m Immortal

Mantis Paper

Longevity experts say death will eventually be a thing of the past. Once we’re able to manipulate our bodies with cellular precision or digitize our brain patterns so they can be backed-up and transferred to a fresh new body, we’ll be able to live on and on forever and ever. That’ll be great for me, since I’ve got a ton of projects that I just don’t have time for right now. I’ve started a to-do list so I don’t forget.

Stop and smell the roses.
All of them.
Rate their scents on a scale of 1-1000.

Catch up on all those past issues of National Geographic.

Proofread the internet.

Binge watch Days of our Lives

Get a new cat.
Film every moment of its life. When the cat dies, edit down the footage to one year’s-worth of highlights to create the greatest cat video ever.
Do a year-long screening of the film whenever I miss the cat.

Eat at every McDonalds.

Mess around with evolution.
Do some selective breeding to create:

      • Domesticated squirrels.
      • Bi-pedal wiener dogs.
      • Praying mantises to match my wallpaper.
      • A species of bird with a call that sounds like I’m Like a Bird by Nelly Furtado

Figure out once and for all how many blades of grass are on the front lawn by counting them individually.

Finally finish that Ken Burns Baseball documentary. Really take the time to study it. When it mentions a particular game, pause the documentary, track down a recording of that game and watch the whole thing.
When it mentions a particular player, do the same thing, but with every game in which that player appeared.

Open a museum for my socks.

Stage that one-man show I’ve always wanted to do: The Life and Times of Herbert Hoover. Reenact his whole life from birth to death. In real-time.
If it’s a hit, do all the other presidents.

Adopt a pet rock. Name it Roxy.
Leave it outside.
When it erodes down to almost nothing, change it’s name to Dusty.

Get into competitive tree racing.

Do one sit-up a year for 100 millennia. That’s 100,000 reps. I’ll have abs of steel!

Open a beach resort in Pittsburgh.

Start stockpiling sunscreen for when the Earth gets closer to the sun.

Write a series of books about a family. It will be a generation-spanning family saga. In each book, a different family member is the main character and you see the whole story from their perspective. Oh – and also the family is a family of bees.

Start planning my “End of the Holocene” party.
It’s going to be epoch.

Hey! What’s the Apple Watch Screen Resolution?

Apple unveiled the glamorous new Apple Watch on September 9, but they failed to mention what resolution the screen would have. For designers looking to start creating apps for this fancy little device, we’re left with the question: “What size do I make my comps?” Let’s see if we can put on our smarty-pants and solve this mystery right here.

Some might say resolution-dependent comps are a thing of the past in this multi-device era of liquid responsiveness, but I still like to use Photoshop to quickly set up an initial visual style. With that said, let us begin.

Firstly, how big is the screen? Already, we have a trick question. There are two sizes! A manly 42mm version as well and a dainty 38mm for the ladies. By performing a highly unscientific analysis of the screenshots from the Apple website, we can get a good idea of the aspect ratio and then the width.


Next question: Do the two sizes have a different resolution? Or, to rephrase it, would Apple really add hours of frustration to the lives of developers and designers, just for 4mm? Let’s hope not, and assume they both display the same pixel dimensions, and that the small one’s just a little crisper than the big one.

That still doesn’t tell us much about the actual pixel density. But neither did Apple. And that actually does tell us something. It means there was no major breakthrough in screen resolution to get a display to fit onto your wrist. If there was, we would have heard the disembodied voice of Jony Ive waxing poetically about it over semi-pornographic close-ups of polished aluminium chip-faces.

So if it wasn’t a big breakthrough, then surely they’d use the best they’ve got – especially if they’re concerned about maximizing the legibility of typefaces at such a small size. So the best they seem to have available was unveiled the same day for the iPhone6 plus.

401 pixels per inch seems like plenty.

So assuming the smallest size device (32.3mm x 38mm) is using the best possible resolution (401ppi), we can quickly run the numbers through Photoshop’s image size dialog.


Flipping the millimeters to pixels shows a resolution of 509 x 600. 600 is a remarkably elegant number, but I’ve never heard of an odd number of pixels on a screen, so I’ll assume my measurements were off by a bit and call it:

510 x 600

That’s my guess, at least. Feel free to post your alternate theories in the comments.

UPDATE: September 15, 2014
Something important that was brought to my attention in the comments is that the entire watch face is not used for the display. There’s actually a generous black border around the rendering area. Once we take that into account, using the same 401ppi resolution for the 38mm version, we get a height of 480px (another number that commonly occurs in display sizes). The final dimensions then come out to:

386 x 480


The Waterslide of Weirdness

waterslide photo by Charles Bodi
Photo courtesy of Charles Bodi

It wasn’t long ago that computing was solely the domain of nerd-boys like myself whose only hope of social redemption stemmed from Matthew Broderick’s romance with Ally Sheedy in War Games. Nowadays, if you’re not using a computer for your social interactions, you might as well be living in an Antarctic monastery.

And fifteen years ago, most of us would’ve been pretty shocked to see a waiting room full of people hopelessly enraptured by tiny glowing screens. But now we just shake our heads, post a snapshot to Instagram, and ask Siri to play The Times They Are A-Changin’.

Some pretty strange stuff is now more-or-less acceptable: Spending real money on a pair of shoes for your avatar, asking your phone if it’s raining in Denver, taking a photo of a taco, etc. There’s no question that technology is insinuating its way into our lives at an accelerating pace. But despite how adapted we’ve become to our shiny augmentations, it seems there are still a few lines we’re unwilling to cross.

The best example of where we’re at with this is Google Glass, which, in case you don’t know, is a pair of glasses that project a digital readout into your field of vision so you can always have important information when you need it. So, like, if you pass a Pizza Hut while you’re walking, you’ll always know they have 10% off all stuffed crust pizzas. It’s basically Google’s answer to the X-ray specs that were advertised in the back of comic books for so many years. The kids bought the x-Ray specs, put them on, looked at the cute girl in school, saw no underwear, and became angry at technology for being so limited. Now they are grown up and are enacting their sweet, sweet revenge.

Google Glass is a case where the technology is pretty much ready to go, but for most people, wearing crazy cyber-goggles in public is still just too weird. Adoption could probably be sped along with some better design, but even if the product was widely available, you wouldn’t be buying them for your mom for her birthday. At this point, the intrusion of such technology into our lives still feels kinda creepy.

Maybe it’s because we aren’t quite ready for the day when you put on a pair of glasses, and instead of seeing what’s in front of you, you’re seeing the view from your friend’s eyes as they walk through Shanghai, or you’re seeing the view from your own eyes when you visited Tomorrowland last year. While this may sound awesome to William Gibson fans, I’m guessing the average gadget buyer would prefer it if such mind-blowing possibilities remained in the realm of science fiction until further notice. Most of us have barely figured out how to do a video chat without at least one close-up of our nostrils.

Sometime soon, technological innovation will begin to outpace our ability to adapt to it. At which point, my monkey-level gut reactions will be all that’s preventing me from buying the style-o-matic closet that chooses my outfit based on the weather, my calendar events and my mood. And its inventors will be left wondering “why are some innovations easy to accept, and others just feel wrong?”

One place to start looking for an answer to this question is a place that robot-makers and other fans of digital biomorphism call the “uncanny valley.” The valley refers to a dip in the graph when you plot the human likeness of an object against its “familiarity” or how much you’d like to hang out with it.

The uncanny valley

If something doesn’t look remotely human, but still acts human, we love that – like Kermit the Frog. Most people would be fine having lunch with him. But as the object starts to look more and more human, we begin to get the willies. A ventriloquist’s dummy sits at the edge of the valley, the lady in this video sits at the bottom.

I suspect that somewhere close to the uncanny valley, is another form of creepiness that has more to do with how much technological immersion we can handle at any given time. This is a slightly different creepiness than the one found in the uncanny valley. The uncanny valley doesn’t seem to move with time. As far as we can tell, people have always been freaked out by dead-eyed clown puppets and they always will be. This other kind of weirdness fades over time as a technological concept percolates in the popular consciousness, until, quite suddenly, with the proper execution, it becomes something we should have had all along.

On a graph, this phenomenon would be the declining curve you get when you plot the time since a piece of technology was first mentioned in Star Trek against the likelihood of a user’s photo appearing on a single topic Tumblr page called Dorks with Newfangled Gadgets.

This curve would be less of a valley and more of an amusement park waterslide – a waterslide of weirdness. Time is the water rushing past our feet, scooting us ever closer to the possibilities offered by the new gadget. We’re up at the top where it’s dignified, trying to maintain some semblance of our former humanity, but the kids are rushing past us, diving in head-first, and our friends in line behind us are getting impatient. Finally, we say, “Why am I being such a fuddy-dud?”, put it in the Amazon cart and go sliding down into a new level of technological immersion. We hit the bottom and say, “This is great! I wonder if my mom would like one for her birthday?”

The Waterslide of Weirdness chart


This waterslide might explain why people are generally uncomfortable when futurists like Ray Kurzweil spout off about how, in fifty years, we’ll all be uploading our souls to the cloud, recording our every action with retinal-implant cameras, and upgrading our brains to genius-level intellect. Those things might be great when we get there, but we haven’t gone down those slides yet.

And what about the vat-grown hamburger? The design-your-own baby gene-splicer app? How far away, and how steep are the waterslides for those innovations? Even if such things were made available today, we’d need some time to adapt to them before they attain widespread acceptance.

On the other hand, I’ll take a USB enabled hearing implant if I’m going deaf, and I would gladly rearrange my kids’ chromosomes if it would keep them healthy. Nothing weird about that. Those slides I’ve already gone down.

As neuroscience and bioengineering begin to converge with digital technology, we may soon reach a point when the fear of plummeting down the waterslide of weirdness is the only thing separating us from a completely cybernetic future – or maybe those willies we get when installing the latest neuro-implant will be the last vestige of our old-fashioned humanity.

An Out of This World Exhibit


The Teylers Museum in the Netherlands is presenting Out of This World – The Search for Planets. It’s a fascinating exhibit that deals with the history of space exploration.

Besides the beautiful exhibit design (that makes exquisite use of vintage sci-fi art), one highlight for visitors is, of course, the chance to sit down at a computer and try out “If the Moon Were Only One Pixel.”

If you happen to be somewhere near Haarlem, be sure to stop by and contemplate your place in the universe. Click here for more info about the exhibit.