My new Sky Clock

Planets don’t look like stars. Their light is strong and steady, unlike the pale twinkling of their starry neighbors. Once you know what to look for, it’s easy enough to spot them. But since they wander around relative to the stars (“planet” literally means wanderer), it’s not always easy to tell one from another.

I often find myself looking at the evening sky and saying “I know that’s a planet, but which one is it?” To answer this question, I built the Sky Clock. It shows where the sun, moon, and five visible planets are situated relative to earth. The inner ring is occupied by the sun, the next is the moon, and third ring contains the planets. Outermost are the constellations of the zodiac, the backdrop against which the planets move. In a sense, this is view is a throwback to a pre-Copernican world: it shows the sun going around the earth. But at the same time, this is the true experience we have as humans standing on this planet. Stargazing is profoundly and inescapably geocentric. To a good first approximation, the sun goes around us, not the other way around.

The result is an accurate representation of where the planets can be found along the ecliptic, which is the great circle the sun traces through the sky on its yearly journey. For the accuracy, I am depending on the site sponsored by JPL. This tells you where in the sky to find each of the planets. Then I use my rudimentary PHP skills to draw the map. Everything in the brown part of the diagram (roughly speaking) is below your feet. The sun is directly beneath you at midnight. Everything in the blue upper part of the diagram is in the sky, though of course anything that shares the sky with sun can’t be seen. As for the letters in the triangles, E and W do stand for east and west respectively, but N stands not for north but for nadir, while Z is for zenith, these being the lowest and highest apparent parts of a stars daily travel.

UPDATE: Shame on me for not testing before shipping. I didn’t realize that the “transparent” backgrounds on my PNG files (the small planet images) were not in the least transparent on Internet Explorer. I developed it on Firefox, and it looked fine there. However I found a dandy JavaScript fix written by Bob Osola that, on my computer at least, makes it look presentable again on IE. Let me know if it still looks broken on your browser.

Amazon relationship game

Here’s an example of the fun that can be had with an open API:
Relate-a-zon is a game you play with the Amazon catalogue in which you hop from a starting product to a target product through as few as possible intervening stepwise related products. I found it difficult and frustrating (I kept ending up in self-referential cul-de-sacs), but I can see how you can develop a skill for it. As these game hints suggest, it’s more subtle than you might first think.

They supply all the missions right now. What they ought to do is let people create and share missions. For instance, how hard would it be to get from hobbit to Babbitt? Or from humbug to Humbert?

A visit to Uncanny Valley

John Singer Sargent once said, “A portrait is a picture with something wrong with the mouth.” You try to make a picture exactly like someone, but something smells “off.” A few days ago I read a nice piece by Clive Thompson about the related concept of Uncanny Valley and computer games.

The Uncanny Valley theory goes like this: suppose you want to render a human face, and you have a magic machine to help you. This machine has a knob on it that goes from “cartoon” to “photo-realistic.” As you turn the knob up toward realistic, the aesthetic effect on the viewer does something surprising. Instead of looking more and more familiar as it gets more photorealistic, at some point it starts to look downright disturbing. It almost looks like a person, but something’s gone wrong. In fact, it resembles a zombie-like abomination. This is the bottom of the Uncanny Valley.

The steep plunge from cute to creepy is something you’d think most game designers would like to avoid, but in fact there are some beautiful (as in awful) examples of it in action in recent games. Look at this, if you dare, and ask yourself how this got into a shipping product. Or maybe they actually want the Mary Smith character to look like a bucktoothed female impersonator doing Cher. If so, they could have had a lot more fun with it. At any rate, this video clip is the gold standard for the Uncanny Valley.

As the Italians say, make it realistic, ma non troppo.

Old school DNA purification

I often muse about the difference between the biology world and the software world. They’re ramming into each other more and more these days, and sometimes the result is more like a car accident than a gentle merger. Bioinformatics and systems biology are two rapidly growing fields where you are as likely to find a physics refugee bootstrapping a new career in biology as a biologist learning a few programming tricks in perl. The physicists and the biologists often betray their doubts about each other (as well as their own insecurities) to amusing effect.

One thing I know about software that works really well, though (you can see which side I come from), is how quickly well-written software tools can lower the barriers of entry to others that follow. For instance, I don’t need to write graphics primitives or web search engines, because someone else has written them for me. Even so, some people grumble… years ago a friend of mine complained that search engines were killing the joy he took in his skilled code hunting techniques using ancient tools like Gopher and Archie. I admire people who can chip their own flint spearpoints, but how nostalgic do you really want to be for a society of hunter-gatherers?

Given all this, I was entertained by this post on the Daily Transcript, a blog by cell biology postdoc Alex Palazzo. In a post about a product called Systems Biology Plasmid DNA Purification, he rips into those Johnny-Come-Lately’s who don’t know their protein assay from a hole in the ground. As he tartly puts it: “Now even a clueless Physicist can purify DNA without thinking about how this stuff actually works!” Ouch! Much better, though, was the comment posted by one of the blog’s readers.

Everyone is ripping on kits these days to prove how “old-school” they are. Look, you’re no Jacob Monod just because you make your own alkaline lysis buffers. You’re not a good scientist because you can isolate more DNA per cell than the other guy. You’re a good scientist because you can answer important questions quickly and definitively.

Well said. All those biology guys are just idiots who don’t get it.

Ooooh, I wish I hadn’t said that.

Meta-popularity list

Witness the hive mind in action at It’s the next logical step after popularity aggregation websites like,, and take all of the popularity aggregation websites and aggregate them into a one giant meta-popularity conglomeration. Obviously we’re not out of meta’s yet… one can imagine this process continuing for a few more generations. What I worry about, though, is what happens when we have a meta-meta-meta-meta-popularity list that’s been winnowed down to one single URL so irresistably popular that it amounts to an informational black hole. There’s a chance that everyone on the planet could click on it at exactly the same moment, thereby imploding the metaverse and taking down this sector of space-time. It makes me shudder to think that the apocalyptic singularity may result from a bad video of teenagers lip-synching to an old Backstreet Boys song.

Potential catastrophes aside, is a pretty entertaining place to graze. It feels to me like a slice through the Great Brain. Or maybe an MRI snapshot of the hive at work.

Gasoline heat map

How much are you paying for gas? The people at will tell you, and they’ll also tell you where to find the cheapest gas in your area. They’ve got a good social network/web application thing going where people around the US regularly report what gas costs near them. So, for instance, here are the prices in Watertown, Massachusetts. They’ve also got historical trend charting available, which turns up some intertesting stuff. I compared Boston to New Orleans for the past year, and I was amazed to see that Boston prices jumped 60 cents in less than a week after Katrina last August, while at the same time gas prices in Louisiana were constant. But it turns out this was more of a legal mandate than anything else… Atlanta and Houston both had the same post-hurricane spike as Boston.

The pièce de resistance for the site, however, is the gas temperature map. Here you can see in one place, county-by-county, what the average price is for a gallon of gas anywhere in the country. It’s very entertaining to make up theories to account for the disparities. California is always most expensive because of its more demanding (and expensive) refining requirements. But what explains the difference between Wisconsin and Minnesota?

Muybridge animations

When a horse is running, is there ever at point at which all four feet are off the ground? That was the question that vexed Leland Stanford, the California governor, robber baron, and eponymous university benefactor. Today high quality photography and video makes it difficult to believe that this could actually be a controversial question. But in 1872, Stanford retained the magnificently named Eadweard Muybridge to determine the definitive answer. Muybridge’s photographic work anticipated the movie; by using multiple cameras he was the first to capture a sequence of images that show exactly how a horse gallops. Muybridge was like a 19th century version of MIT’s “Doc” Edgerton who used strobe photography to stop time as, for example, a bullet exploded through an apple.

Using multiple still cameras to suggest motion has come back in vogue lately, most notably with the so-called “bullet time” effect seen in The Matrix. This effect, known more generally as time slicing, extends the Muybridge idea: the camera seems to move infinitely fast, viewing the subject from multiple directions at the same instant. The technique can also be used for less purely cinematic purposes. Here’s a nifty timeslice video of a cheetah running through an African encampment.

Seeing all this stop motion photography made me think of fun little video I saw over at Google: The Art of Motion by Russell Wyner. It has several Matrix-like homage shots. And finally, when it comes to goofing on the Matrix, you can’t top the magical ping pong video. Turn the volume up and watch it all the way through.

And for the record, galloping horses do have all four feet off the ground at one time or another.

Paperback book notifications

Ben Hammersley has shut down the Lazyweb, but the key insight that it embodied still endures:

…if you wait long enough, someone will implement that wacky idea you had… (or already has!) Alternatively, that if your blog has enough readers, a reader will know and provide the answer to a question you are too lazy to research yourself.

I make no claims to a vast readership, but I am certainly lazy. So when I imagine a web service that must exist somewhere, I ask clever people like you where to find it. The service I’m thinking of this week is paperback release schedules. I love books, but I don’t often buy hardback books. I don’t like them. They are less pleasing than paperbacks in several dimensions: bigger, heavier, harder to handle, more expensive, harder to flip through (if it has those silly ragged pages), and you’re always having to worry with that stupid paper cover thing that wants to fall off. But since they are more profitable, publishers are clearly motivated to sell them exclusively for as long as possible, and so I’m often in the position of seeing a new hardback book for which I want to buy the paperback edition. I want a web service that lets me register my interest in, say, Philip Ball’s new biography The Devil’s Doctor: Paracelsus and the World of Renaissance Magic and Science, and then emails me when the paperback edition gets released. Does such a service exist? It seems like it should, but my Google scrying glass was cloudy and my searches came to naught.

On a related note, since I consume a good many books by audio these days, I want a similar service that will notify me when a given book is released in audio form (unabridged editions only, naturally).