The National Cryptologic Museum

The only people who can get near the imposing, shiny-black National Security Agency in Fort Meade, MD are wearing suits and security clearances. But if you go beyond  National Vigilance Park and the Shell station, you can enter the Agency’s “principal gateway to the public” —  the National Cryptologic Museum.

The museum is housed in this converted motor hotel. When I first saw it, its 70s-era orange and brown accents reminded me of my old public school. Sure enough,  it also smelled like my old public school: that unmistakable musty government smell.  As it turns out, the National Cryptologic is less a gateway to the NSA than, well, perhaps a kiosk?

According to a recent article in Wired, NSA is  spending $2 billion on what the author of the article calls “The Country’s Biggest Spy Center” — a center that will have unprecedented abilities to do God-knows-what. Public education is not an Agency priority — its job is is not to broadcast, but to receive information. So the museum’s curator, Patrick Weadon, does what he can with donations and fund raising from events like the annual Eagle Alliance golf tournament.

Weadon is tall and  ingratiating.  He seems to love his job and the Museum. Some might prefer the National Spy Museum in DC, he says, with its Ripley’s-Believe-It-Or-Not glitz, $20 plus price tag, and interactive gimmicks. But compared with the Spy Museum, he says, the National Crypotologic Museum is “like NPR.” The museum has three goals, says Weadon: the first is to recognize the heroes of cryptology, who often by the nature of their work go unacknowledged. Another goal is to make the public appreciate government codemaking and codebreaking. The third —  this inspires Weadon’s personal passion and many sports metaphors — is to show how cleverness  can make or break a nation.  From a Jeffersonian cipher wheel to the first Cray supercomputer, the museum demonstrates how math, science and technology can defeat one’s adversaries and “win the game.”

To me, a large part of the appeal of the National Cryptologic Museum is that it is actually hiding something. When you walk into converted-motel lobby, the first image at eye-level is a bold sign warning NSA visitors and employees not to talk about anything CLASSIFIED. Only former NSA employees are allowed to work there, Weadon told me — not just because they are knowledgable, but because they know what they can and can’t say. The exhibits are arranged loosely by war: Civil War, WWI and WWII, Korean and Vietnam War, Cold War. The most current exhibit dates to 1993.  Most recent technologies are, you guessed it. Classified. He said he “couldn’t comment” on the spy center mentioned in Wired.

What counts as “code” in the museum is a loosely defined, including everything from symbolic patchwork quilts thought to have guided slaves to freedom along the Underground Railroad, to the signals hobos once used to mark welcoming homes.  There’s a soiled silk scarf, covered in minute writing, which ostensibly helped a soldier receive or send messages in enemy territory, and a deck of playing cards that’s been converted to a cipher. I liked the eclectic collection, because it helped me relate simple examples of encryption to the vastly more complicated computerized encryption they later inspired. As I walked through the maze of rooms, however, the amount of information and objects became dizzying.  The informational placards beside the displays, with their tiny font, were almost like encrypted messages themselves. The whole place felt outdated, particularly the lonely VCR machines running documentary films as a gesture toward something “interactive.” And although the one-sided presentation of controversial topics like biometrics and domestic spying wasn’t surprising, it was mind-numbing.

The saving grace of my visit was the museum docent. Proper in her silk blouse and pearls, her explanations tied the exhibits together conceptually. She introduced the concept of the “key” with the simplest kind of encryption, a cipher wheel, and slowly built on that  idea with more sophisticated ways of hiding messages in code.

The highlight of her tour was the original  Enigma encryption device that the Nazis used during WWII to communicate maneuvers and strategy. The museum has an assortment of them, two of which you can actually use. It looks like a typewriter, but its keys are wired to a series of discs arranged along a spindle.  When you press a key, a signal passes through the rotors and back. At every step, the rotors move, and the original letter is substituted for another letter, then another, and another…. In one of the Enigma’s advanced iterations, the number of ways that pairs of letters could be interchanged was 150 trillion.

Of all the displays, I thought the Enigma did the best job of accomplishing the Museum’s goals: celebrating heroes, generating enthusiasm (rather than, ahem, suspicion) about government spying, and inspiring young people to learn about math and science for national defense. A panel about Alan Turing, the British mathematician considered by many to be the father of the modern computer, explained how he helped break Enigma’s code and win the war. Not-so-subtly, it linked fighting Nazis to the U.S. government’s current quest to build omniscient supercomputers. And it was surely educational. As  my group approached the machines, a tow-headed little boy wearing camouflage pants was sitting on the floor and struggling to encode, then decode, his name using the machine. The docent stepped in to explain and help. Slowly, he worked it out, revealing MATTHEW. A spy enthusiast was born.


Calvin and Hobbes and Childhood Science

Imagination can be awfully addictive. I spent a lot of my childhood dreaming about made-up worlds, outer space and how the universe just doesn’t seem to make sense. I also ate up stories by other dreamers, from fantasy to science fiction. But there was one particular dreamer whose fantasies drew me in so long ago I can’t even remember when I got hooked.

Calvin and Hobbes was a story about an out-of-control dreamer. Not only that, but Calvin was a lover of the beauty of nature, so he tended to dream about the same things lovers of science dream about. Why is the universe the strange-seeming way it is? What happened millions of years ago? Is there intelligent life on other planets, and if so why haven’t we encountered it? All questions from a typical young mind trying to figure out the world.

I haven’t read the funny pages regularly since Calvin and Hobbes ended in 1995 — a wise decision by its creator, Bill Watterson, who didn’t want the strip to get stale. Fans of Calvin and Hobbes are also some of the most loyal, nostalgic comic fans out there. When the strip ended, it left a gap behind for a lot of us obsessive dreamers.

Now we live in an age of web comics. Many of these comics are far better than most of what you’ll find in newspapers today because these artists can lay their dreams and ideas out without worrying about the restrictions of syndication. Some of them wonderfully touch on the joys of science and explore the joy of childlike imagination much like Calvin and Hobbes did. But for me, Watterson’s strip will always be when I first saw science, beauty and imagination mix seamlessly.

The strip has been gone for longer than 15 years, but because its focus was on the timeless aspects of being human, Watterson’s humor and observations hold up today. Here’s a sampling of the most prominent science in Calvin and Hobbes:

Physics:  The duo decides to test special relativity by rolling down a hill in a wagon. Calvin famously renamed the Big Bang with the more sensationalist term “The Horrendous Space Kablooie” which even some cosmologists are fond of. Our protagonist even remarks on orbit trajectories as he flies off a swing.

Environmental and Planetary sciences: The strip had a heavy environmental message. A major setting was a vast plot of woods Calvin had access to and he hated to see it disrespected and damaged. At one point, Hobbes reminds Calvin that we need the Earth more than we need it. In one storyline, Calvin gets so frustrated with pollution that he and Hobbes go to Mars instead. This opened up a long storyline in which they have an encounter with the Viking spacecraft and even run into an alien. Calvin’s adventures visiting other worlds as the self-narrating Spaceman Spiff are also among his most dramatic and notorious.

Dinosaurs: But, for all his outer-space adventures, if Calvin was any kind of scientist, he’d probably be a paleontologist. He was obsessed with dinosaurs, and they were frequent guest stars in the comic. Oftentimes, Calvin imagined he was one. A lot of people who loved dinosaur science as a kid can probably identify with Calvin here. Though not everyone shared his wild imagination about the ancient reptiles.

Math: Contrary to his love of space and dinosaurs — and I’m guessing many biologists and my fellow writers will relate to this — Calvin struggled with math. He did everything he could to avoid it. Spaceman Spiff was not particularly helpful with Calvin’s math woes. Hobbes was full of smart-sounding but unhelpful advice. At one point Calvin, in my personal favorite of all the strips, even abused the abstract nature of mathematics to declare himself a math atheist.

Science Fiction: Calvin used his imagination to defy the laws of nature in a manner many kids do — with a simple cardboard box. That box became machines straight out of science fiction, using it for everything from shape-changing machine to a cloning machine to a time travel machine. Calvin predictably used his time travel machine to visit the dinosaurs, and narrowly escape being devoured by one.

Inquisitiveness: The 6-year-old protagonist didn’t spend the entire time in his head, though. He asked questions, and a lot of them. Calvin’s dad liked to play with his son’s curiosity, giving ridiculous answers to Calvin’s questions, such as what the wind is, what happens when the sun sets, and how load limits on bridges are determined. Calvin is largely remembered for testing his parents’ patience, but he tested a great many things. At Calvin’s best, he could be regarded a model for one of developmental psychologist Jean Piaget’s “little scientists,” intuitively testing and exploring how the world works.

What are some of your favorite strips?

GPS Demystified


Image courtesy of Digitalart,

Not long ago, a friend of mine told me she was planning on taking a long road trip to visit some national parks. I asked her if she had all her maps, and she laughed and said, “Oh I have my trusty GPS.”

“What if it doesn’t always work?” I responded.

She looked at me questioningly. “Why would it not work?”

I realized then how blindly we rely on technology today, and just how little many of us actually know about it. “Do you know how it works?” I asked.

“Um, I think it has something to do with a satellite, right?”

This is the conversation that inspired this blog post. Ancient travelers used to navigate based on the positions of the stars and constellations. Nowadays, many people use a different kind of constellation to find their ways, and most that I have spoken to don’t know that it even exists or how it really works. They view their GPS devices as pseudo-magical objects, and although I am by no means a total expert on the science, I do know the basics of how they work and hope to help explain it so that it is a little more understandable. This is the super-simplified answer.

Let’s start with a few definitions. “GPS” stands for the Global Positioning System, which is a combination of satellites and their ground stations that enable users to navigate if they have a receiver (for most people, it’s that piece you carry or put in your car). There is a network of 24 satellites with an additional 4-6 in reserve that act as ‘spares’ and form what is considered a ‘constellation’ that orbits the earth. These satellites are pretty far out—about 12,500 miles up. To put this in perspective, the International Space Station is only about 185 miles up, and the Hubble Space Telescope is about 365 miles up. Despite this distance, they move very quickly, and it takes each GPS satellite roughly 12 hours to circle the earth one time.

The GPS’s ground-based stations monitor where each satellite is at all times, how well each is working, as well as make corrections to the signals being transmitted from them and coordinate which ones are running at a given time. The master control station is at Schriever Air Force Base in Colorado, but the other stations are located in Hawaii and Kwajalein in the Pacific Ocean, Ascension Island in the Atlantic Ocean, Diego Garcia in the Indian Ocean, as well as Cape Canaveral and Colorado Springs.

This constellation of satellites also has a name: NAVSTAR. This stands for “Navigation System using Timing and Ranging.” This is a very important concept. Each NAVSTAR satellite is equipped with an atomic clock, and each emits its own unique radio signal that can be picked up and identified by a receiver on earth. The receivers have their own clocks too.

Your receiver’s clock is synched with the ones on the satellites as closely as possible. However, since atomic clocks are extremely expensive and super accurate, the average consumer receivers typically have to have the next best kinds. These clocks may not be quite as accurate, so there is usually a miniscule difference between the ones in the receivers and the satellites. Usually, the more expensive your device, the better the clock can keep time compared to the satellite and/or correct for any inconsistencies.

The receiver makes note of the time it was when a signal left a satellite compared to the time it receives it. Based on this information and the speed of the radio signal transmission itself, it can then calculate how far away each satellite is that it gets a signal from. If your receiver’s clock is not too accurate, the reading can sometimes be a little off. This typically doesn’t affect someone who is trying to get from one place to another, but it may if you are trying to get exact coordinates of a specific location.

Then, the receiver does some figuring. For example, if it is known that you are 10,000 miles away from a particular satellite, you can be anywhere on earth within a circle of that distance from it. But if you are also 11,000 miles from another nearby satellite, you would thus have to be at one of the two points where the two circles overlap on the ground, like a Venn Diagram. This narrows your location down significantly, but it is not precise. This is why if your GPS receiver says there are “only two satellites in range,” it won’t work well if it works at all. You need a third that would narrow it down even further and intersect one of the two points to confirm where you are, and the more satellites you have sending signals, the more accurate your receiver will determine your location. There usually is a minimum of 3 satellites needed at all times, which is why this is called trilateration.

In addition, the reading on the receiver may not be as accurate if the satellites happen to be clumped in the same general area of the sky, as opposed to being more spread out. Think of a bunch of circles being drawn on top of each other rather than being spread out enough to see where they actually overlap. This is called the Positional Dilution of Precision (PDOP), which can be another reason why your GPS receiver may not always work well.

But ultimately, once your receiver has figured out your location, it compares that to pre-loaded maps of roadways, etc. and displays them together. That is why you are supposed to periodically update your maps, though I don’t know anyone who actually does.

Finally, you may sometimes lose a radio signal in the event that a satellite moves behind a tall building or mountain that blocks it. If you have more than three satellites in range, this isn’t a problem, but I know my receiver gets confused when I drive in a city or through a tunnel. Some newer models can actually plan ahead—if they know based on the pre-loaded maps that a tunnel is coming up for instance, they can calculate your future trajectory and take that into account, so it never appears that the signal is lost in the first place.

Fun Fact:

Civilian GPS units weren’t always as accurate as they are today, but it was on purpose. Selective Availability was a term coined by the US military for their intentional degradation of the satellite signals accessible to the public for national security reasons, which would ensure a receiver’s reading would be at least 300 feet off. In the year 2000, President Bill Clinton ordered Selective Availability to be turned off because he and the government felt that it would be for the greater good. What do you think?

Mad Rant: Outer Space

Photo by Jay R. Thompson, taken Saturday, March 10, 2012, in Baltimore, Maryland.

Ask me to draw a diagram of a two-loop pressurized-water nuclear reactor and I can probably do it — I love to draw and it’s been a while since I tested myself on basic reactor layout. But understanding the fundamental design of nuclear reactors is simple compared to describing my enthusiasm for outer space.

I’m one of those who want our species to explore the emptiness, populate the solar system, and eventually wander the galaxy. But that’s not the enthusiasm I’m talking about. My adoration of the great beyond is simpler, and yet I can’t find a container in which to put that adoration so as to carry it around and show to others. I’m just geeked that outer space exists at all and that we’re a part of it, composed of its fused particles.

To me, the fascination seems obvious. I’ve tried more than once to put this feeling into words, and have achieved consistent and complete failure. The response is usually a raised eyebrow or something like it. Words fail me, or maybe I fail the words. Regardless, I’m going to take another shot at articulating my glee, or whatever it is. Hang on, let me put on my seatbelt and crash helmet. Right then, off we go.

So space is there, several dozen miles above your head, but so what? Humans have been there and back. No biggie. Space is nothing new. In fact, it’s the least new thing ever. Space has been out there (and here, for that matter) as long as time has existed, and I’m not trying to be hyperbolic or poetic about it. Time and space seemingly arrived on the scene at the same time. Maybe I should shrug and put on some fashionable air of “been there, done that.” But it would go against my very nature.

You may have noticed lately that two stars dominate the western sky shortly after sundown. They’re the planets Jupiter and Venus, the bright objects you saw in the photo at the top of this post. But which is which? Go ahead and guess. You might guess that the brighter one (bottom right) is Jupiter and the dimmer one is Venus.

Here, I’ll give you a clue. This is a close-up of the planet in the upper left of the photo:

Notice anything? Those little specks lined up near the planet are the four largest Jovian moons. From top to bottom they are Europa, Io, and Ganymede, with Callisto barely visible below Ganymede. That means this planet, the dimmer of the two, is Jupiter. If you want to double-check my interpretation of the image, see page 38 in the March issue of Astronomy.

Jupiter is more than twice the mass of all the other planets in our solar system combined, but its orbit is also 483 million miles from Earth’s orbit. That’s 18 times farther away from Earth than the orbit of our next-door neighbor, Venus. Hence, Jupiter is the dimmer of the two.

You can look up and see these things and so what? They’re just a couple of planets. What’s the big deal?

Jupiter, Venus and their brethren aren’t just points of blurry light. They’re three-dimensional worlds composed of the same stuff as our own. They’re planets, huge spheres of matter, entire worlds that no Earthling has ever visited. They just float there, out of reach, perpetual mysteries. Some have their own earthquakes, volcanoes, or lakes. Others have wind and storms, while others have no atmosphere whatsoever. The planets in our solar system have been there for billions of years, the only witnesses to the entire history of our solar system.

Even when the sun is up and the sky cloudless, the blue is only a veil, behind which the ultimate dynamo — the universe — continues to crank along as it has for all time. In a way, these worlds (and everything beyond) are reassuring. Being human if often frustrating and scary, but the worlds, the solar system and the universe don’t need anyone to mind the store. We can disappear, and everything will be fine. Our neighboring planets are just there, indifferent and presumably lifeless.

When I look up, I don’t really see the points of light that my eyes see. I see huge islands among emptiness. I see the forever-baking surface of Venus, Jupiter’s 60-plus moons whirring about, the Oort Cloud, the galaxies with solar systems of their own. Outer space is the place of mysteries, with room for the mind to ponder the strangest ideas imaginable.

Oh dear, I’ve failed again. Maybe I need a different medium. Poetry? Song? Modern interpretive dance? Maybe someday.

In the mean time, what do you think about when you look up at the stars? What is outer space, or the universe, to you?

Antidepressants soothe anxious minnows

If you were the most common bait fish, you would be anxious too.
You would hide in dark crannies, avoiding predators. That’s what fathead minnows normally do. But a new study from Baylor University, published 7 March in Environmental Science and Technology, shows that when the rosy-silver fish get a dose of Zoloft, they develop a false sense of security. Instead of ducking for cover when it’s light, they linger in the open, unconcerned.
Drugs like Zoloft and Prozac get into rivers, lakes and streams every time people who take them flush their toilets. The drugs can have bizarre effects on fish behavior. This is not big news: as my classmate Nina Bai reported in 2008, scientists have been documenting how antidepressants impact fish for a while. Other organisms, like shrimp and mussels, are also affected. But each new study is a step toward understanding how different species tolerate different chemicals, and in what concentrations.
For the minnows, it took 3 micrograms per liter of Zoloft to dim their evasive instincts.  The concentration of SSRIs in the wastewater described in the study was 3.2 micrograms per liter. Once the drugs have made it into the water, most wastewater treatment plants aren’t equipped to filter them out.
Image credit: Ohio Department of Natural Resources, BK

The Massive Log Jam That Was

It's hard to see, but there is a human being standing one of these logs in this 19th-century photo of The Great Raft.

It filled the river in both directions as far as the eye could see and continued on for many miles. It was called the Great Raft, and it lived in the Red River, which lines the Texas-Oklahoma border and ends at the Mississippi River in Louisiana. It was an unusual sight: an enormous log jam that, depending on the account, stretched anywhere from 100 to 210 miles long. It’s also the kind of thing you don’t see in the North American wilderness any more.

It’s unknown how old it was, but it was almost certainly caused by the natural migration of the river. Rivers are not the motionless, changeless squiggly lines that you see on maps. They shift across their floodplains, gradually, like a giant worm that takes millennia to squirm. Often, they even sever some of their curves and bends, leaving behind small lakes that look like a loop snipped off a length of ribbon. The Great Raft probably developed slowly as the river undercut its shoreline forestland, and the trees toppled in and accumulated.

In the 1830s, the federal government decided to open the Red River up for travel and commerce. It took them five years to remove the raft using steamboats and manual labor. But nature was stubborn — soon after they were done the raft began to regenerate, and within years it extended for miles all over again. The second removal attempt was interrupted by the Civil War and its surrounding political turmoil. The U.S. Army Corps of Engineers returned to the project in the 1870s using crane boats and explosives, until it was finally completely cleared away in 1873.

Though a log jam may look like just a messy obstruction — piles of rotting wood laying in dirty water — dead trees can have an impact on the environment just as living ones do. Robert Gastaldo, a geologist at Colby College in Maine, studies the evolution of terrestrial plants and the ecology of eras long passed. He has also used historical records about The Great Raft as a basis for comparison for his research on log jams from millions of years ago. His best guess is that the Great Raft would not have been an impediment to the flow of water in the same way it was an impediment to human travel. The raft’s removal would have slowed the river down because, without the squeeze from the logs, the water could move at a slower speed and still deposit its water at about the same rate.

The removal of the logs would likely have caused problems for fish that stay near the woody covering for protection. Records also show some small trees took root on the decaying wood. As the wood rotted it became like any other organic soil, Gastaldo says, and if a seed landed there it would have taken root, resulting in little trees growing on the floating remains of bigger trees. “It would’ve changed the ecology for sure,” says Gastaldo of the raft’s removal. “But who’s to say it was for the better or for the worse?”

Any sign of the raft is long gone now. To the 19th century Army Corps of Engineers, the raft was just a roadblock that had to be removed. The landscape was deforested for agriculture after the Civil War, and much of the earth that had gathered under the raft was moved downriver into the Mississippi. Though Gastaldo notes that modern-day engineers know that log jams would impact the river flow and would take the overall impact into account.

Some links if you want to read more: