## Friday, December 31, 2010

### Reviving a computer

My sister's old computer - an IBM Thinkpad - was a few years old when she got it in 2004. By the time she got a new laptop in 2007, it was ancient and incredibly slow. It got put away for a while.

Fast-forward to today. Took it out, decided to see if we could make it work again. We tried turning in on, but nothing happened. Plugged the cord in real tight, tried again, it actually booted up. Verrrrry sloooowly. I immediately went to work. First I deleted all my sister's old documents (long since copied to a flash drive), then her music, then pictures. I had to restart once or twice when it froze, but eventually I cleaned everything out.

By this time the computer was getting pretty hot, so I figured it could use a cleaning inside as well. I got a few screwdrivers and started removing parts - very carefully, and keeping a neat order. Within half an hour, there were a CD/DVD drive, a 20 GB hard drive, keyboard, PC Card adapter, two RAM chips, a wireless card, CMOS supply battery, main laptop battery, and several dozen screws lying about on the floor. I wasn't able to clean the fan like I had hoped, but I did get some dust out and I cleaned the connections. Then I reassembled it, from memory.

Amazingly, it booted up on the first try. I uninstalled almost every program on the machine, leaving just Microsoft Office, Internet Explorer, and the system tools. Once I restarted to finish the uninstalls, it immediately started moving a bit faster. I ran the Disk Defragmenter and it cleared up lots of room. Et Voila, functioning laptop. It's not fast, but it works.

I plan to install some sort of basic antivirus so I can go online, then perhaps I can try my hand at installing Linux, or we might just use it to play Amazon Trail and other old games. We shall see.

### Twin Cities: Metro Transit rail map

I've made a pretty nifty map of a number of Metro Transit rail lines in the Twin Cities (St. Paul and Minneapolis, MN). It's on Google Maps, so it's zoomable and everything.

The map shows six lines - two heavy rail commuter lines and four light rail interurban lines. Only two of the lines are currently in operation - the light rail Hiawatha Line (shown in yellow) that serves downtown Minneapolis, the airport, and the Mall of America; and the Northstar commuter service (shown in blue) that serves the northern suburbs. (The proposed Northstar extension is, of course, in lighter blue.)

All six lines will eventually terminate at Target Field station in Minneapolis - light rail lines at street-level on a bridge, and commuter rail lines below. Currently open lines are bolded; the lighter a line is, the further it is from starting operation. Stations with currently open or visible station platforms have a dot in their marker; stations without do not.

The Central Corridor light rail, shown in red, is currently under construction and will open in 2014. Running on a few miles of the former 512-mile streetcar system, it will serve both downtown areas plus the University of Minnesota via University Avenue.

Southwest Corridor light rail has been approved for construction and is planned to open by 2016. The alignment is pretty much set, but the exact location of each station is not known.

The fourth light rail line is planned to be the Bottineau Boulevard Transitway serving the northwest suburbs. Two possible alignments are shown; the A alignment is more likely to be built.

The proposed commuter line is the Red Rock Corridor, to serve Minneapolis and Hastings via St. Paul. It is shown in pink and may start as soon as 2018.

View Twin Cities: Metro Transit Rail in a larger map

### Scary realization

There are now children, born after 9/11, who are older now than I was then.

That's a very strange thing to realize, and it makes me feel oddly...old. Like the assassination of JFK for the previous generation, you remember exactly where you were when you heard that the twin towers fell. I was sitting in my third grade classroom. When I went home that day, I watched the news, and I understood what was happening.

There are now kids - nine years old - who were born after the towers fell. They've lived their entire lives in the decade from hell.

(Relevant)

## Wednesday, December 29, 2010

### Animated GIF test

I just discovered that I can post animated GIFs in blogger. This makes me very happy, especially now that I have GIMP and can create them.

The above image is a short loop of Kaylee (Jewel Staite) from Serenity, the first episode of Firefly.

### Actual building!

I've finished the repairs on the Orbital Transport. The shock cord is reattached to the new extended forward section. I cut two new forward fins from the old pattern, coated and sanded them, and attached. The next time the weather warms up, I'll primer the forward section.

I've gotten a decent start on the MLAS. I decided not to use the motor hook and engine block, because I want to use D13W reloads at some point. (They weigh less than C6s, so that shouldn't be a problem.) I've got one of the two massive 3.5" diameter centering rings fully glued in place, and the other is currently drying.

I've also started on the nose cone. I glued the two-part cardboard base together, and drilled a quarter-inch hole for weights in the foam nose cone. Dick Stafford says about 0.3 oz added to the stock bolt should be sufficient; I'll use about an inch of quarter-inch steel rod from... something.

## Tuesday, December 28, 2010

### Danger

We humans, we tend to like danger, without actually being in danger. Danger gives us an adrenaline rush, but real danger just stinks. So, we as a species tend to find dangerous things, and then sit back and watch them unfold.

It's why we watch football. We get to watch twenty-two strong young men attempt to break each other, all while sitting back and enjoying a jumbo plate of nachos with that delicious not-quite-cheese sauce.

It's why we watch dangerous-situation reality shows like Deadliest Catch, because icy waters and ferocious storms can't harm you in your living room.

We love to ski and snowboard at high speeds down icy mountains - but only once we've strapped on a helmet, goggles, and plenty of layers of clothing.

We love action movies, because few things get the heart pounding like River Tam taking out a planetful of flesh-eating monsters. But not one of us would want to be there because, well, they're terrifying.

Danger, it seems, is only fun when you're not actually in danger. And that, my friends, is why there are few things better than sitting in a hot tub in below-freezing weather, watching the wind whip the powdery snow into a fury. While you are safe in your bubble of warm air. Absolutely magnificent.

## Monday, December 27, 2010

### Snow

Snow (n): a white, fluffy form of microcrystalline ice that only forms when there is no school for cancellation

About thirty-six hours ago, the weathermonkeys were predicting 11 to 16 inches of snow. We got maybe six inches, maybe not quite. I've learned to roughly halve the TV estimate if it's over six inches. It's usually pretty close to right, because we never live up to what they're saying. I wonder if they intentionally inflate the numbers so people will get inside and be safe.

In any case, it's not all bad. I get to have a snowball fight tomorrow with a couple of my friends. They have no idea what they're in for.

### MLAS

I got a Quest MLAS scale kit for my TRF Secret Santa gift last year. I'm finally starting to build it, mainly because I finally feel ready for the challenge. It's a very difficult kit - foam parts, not a huge amount of structural strength, and of course very finicky stability. Plus, I want to get a good paint job on it.

But, I've crossed that cardboard Rubicon. I started assembling the motor mount and the nose cone yesterday. So far, so good. I'll have more later; looks like we're going to be snowed in a bit.

## Sunday, December 26, 2010

### Nerdy Christmas Loot

Thanks to my family and friends, I had a wonderful Christmas, and I got some really awesome presents.

I got nine books, almost a whole linear foot:
• by Richard Feynman: The Pleasure of Finding Things Out, Six Easy Pieces and Perfectly Reasonable Deviations From the Beaten Path
• Transit Maps of the World - a collection of subway and metro maps, showing how they evolved over time to become the iconic works they are today
• Earth From Above: 365 days
• The Math Book - a collection of 250 milestones in mathematics, with really cool stuff
• 62 Projects to Make with a Dead Computer
• Historical Atlas of North American Railroads
• Finding Serenity: Anti-Heroes, Lost Shepherds, and Space Hookers in Joss Whedon's Firefly - a brilliant collection of critical essays about my favorite show.

I also got a bunch of really awesome stuff:

• Firefly and Sherlock Holmes on DVD
• Several pounds of twizzlers
• A really nice pocketknife, with a neat saw and a few other attachments
• A very weird alarm clock
• A Estes scale Patriot rocket kit - more about that later
• "Define interesting" t-shirt - a Firefly joke

My favorite, though, was my sister's present - this awesome Ada Lovelace shirt.

## Friday, December 24, 2010

### One Kilopost

That is, 1000 posts. It's taken me 30.5 months - since June 10, 2008.

1000 posts in 928 days is 1.077 posts a day - a post every 22 hours 15 min.

Figure half an hour per post, and that's 500 hours - just about three straight weeks of time, used for posting.

I took posts from all three Julys - 2008, 2009, and 2010 - and averaged out the wordcounts. I average about 185 words per post. That means I have written about 185,000 words. By comparison, Animal Farm is about 30,000; Ender's Game is just over 100,000.

(I'm still not up to the 560,000 of the English translation of War and Peace, though.)

It's just crazy to me to think that I've written this much. I'm not sure if it's a sign that I'm incredibly arrogant, or that I need a therapist, or that I need a life. But it's by far the biggest and longest-running project that I've ever undertaken. It's also really neat to see what comes out of my brain when Ive got a blank canvas to put it down on. I mean, this morning I just got thinking about zero while I was dragging my sorry carcass out of bed, and I ended up with 788 words about zero.

In any case, I'm pretty pleased.

It's almost midnight now. I'm listening to Trans-Siberian Orchestra play "Christmas Eve in Sarajevo", and there is no better music for the evening. Merry Christmas to all, and to all a good night!

### Proving Equality to Zero

Say you have several variables - in a computer program, for example - and you want to make sure that they all equal to zero. (For the sake of this example, let's assume that they are all real numbers, i.e, 5.5 rather than 5+8i). With one variable, it's easy; you just have to set up some form of the equation

x = 0
[1]

Of course, you'd have to actually implement that in code, but that depends on the programming language and isn't really relative to this. With one variable, you have a very nice, neat equation, and it works.

With two variables, you could still do something along the lines of

x = 0 AND y=0
[2]

But that becomes very unwieldy - and decidedly unelegant - when you want to use any more than two variables. Surely there's a simple equation that one can use. What about this:

$x\cdot y\cdot z = 0$
[3]

Unfortunately, this equation is a flop; it only requires at least one of the variables be zero*.
If x=0, then y and z can be any number, and so on for y=0 or z=0. What about addition, then?

x + y + z = 0
[4]

This is marginally better; it is slightly less likely to produce a false positive. However, it doesn't work. The set (x,y,z)=(2,4,-6) is a 'solution', yet none of the three variables equal zero.

A logical next step is to modify that linear equation to eliminate some false positives. for example:

x(y+n)(z+n) + y(x+n)(z+n) + z(x+n)(y+n) = 0
[5]

This eliminates most false positives, and it does in fact work if n is guaranteed to be of greater magnitude than x, y, and z, i.e, n is a sufficiently large positive or negative number that x+n, y+n, and z+n are all positive or all negative. Otherwise, however, there are still at least four solution sets: (-n,-n,-n), (0,-n,-n), (-n,0,-n), and (-n,-n,0). Additionally, if you try to generalize to complex numbers it doesn't work, and it's just plain ugly.

Eliminating those four trivial solutions is possible, if don't mind an even uglier equation:

x(y+a)(z+b) + y(x+c)(z+d) + z(x+e)(y+f) = 0
[6]

But, the problem with equations 5 and 6 is that they're not truly solving the problem. Unless variables a through f are picked very carefully, there might be a few values of x, y, and z that create a false positive, and with that many variables theres no general method to check that this is not the case. They don't generalize well to either lots of variables (to prove that ten variables all equal zero by this method, you'd need as many as 55 arbitrary variables a through j) or to complex numbers.

Now, let's think about the problem geometrically. What we are looking to prove is that the point (x,y,z) in 3D space is equal to (0,0,0). Or, if you prefer vectors, that <x,y,z> = <0,0,0> = $\vec{0}$

In other words, that our point (x,y,z) is within a radius of zero from (0,0,0). Now there's a handy equation for distance:

[7]

In this case, a=b=c=0 for the origin point (0,0,0). However, if the square root equals 0, then the equation inside also equals zero. Thus, we get a very neat equation:

$x^{2}+y^{2}+z^{2} = 0$
[8]

And equation 8 is pretty nifty. It generalizes to any number of real variables. It's elegant - it requires only a small amount of code that works on basically system, and it uses only squares and addition - operates that are much faster than square roots or division.

Additionally, if you have a system like Mathematica or a graphing calculator that can deal with vectors, it gets better. Most systems can't check the equality

<x,y,z> = <0,0,0>
[9]

or, where = vector u,

$\vec{u} = \vec{0}$

[10]

However, there's a nicely equivalent operation, taking the magnitude (length of the vector), that does work:

$\left |\vec{u} \right | = 0$
[11]

For vector-ready systems, equation 11 is elegant, though not as fast due to the square root involved in taking the magnitude of the vector.

Equation 8 can also be modified to make it even more powerful; this version allows determination of which single variable is nonzero. The exact constants do not matter; they simply must be primes greater than 3.

$5x^{2}+7y^{2}+11z^{2} = 0$
[12]

Thus, if the result of the left side is nonzero, it can be examined. If it is divisible by an odd power of 5, x is the non zero variable, and so forth. If it is not divisible by an odd power of either of the three constants, then two or three of the variables are nonzero.

All of the really nice-looking equations are made using Codecogs LaTeX Equation Editor; Detexify is spectacularly useful for finding LaTeX symbols.

* Incidentally, equation 3 actually generates the three coordinate planes when graphed.

## Thursday, December 23, 2010

### Elementary School Scientists

What sort of science did you do in elementary school? It was pretty basic stuff, right? Units covering the very basic bits of biology and chemistry and physics. Basic cell biology, weather, simple machines, stuff like that. Not much in the way of actual lab 'experiments'; they didn't trust us to work with beakers and balances until seventh grade, and such things as hot plates and acids were completely out of the question until high school.

Doing an actual controlled experiment - that's never been done before - with live animals, and getting published in a legitimate scientific journal? Utterly out of the question.

Yet, that's what exactly what 25 elementary school students between ages 8 and 10 did in Britain. (BBC News article)

The children designed the experiment, asked the question, hypothesized results, and wrote the majority of the paper. The only things done by the teacher and an assisting scientist, Beau Lotto, were to supply trained bees and to transcribe the student writings.

And they did indeed get results. Although they didn't refer to previous scientific literature - which would have been above their reading abilities - and they hadn't been trained in the use of statistical analysis, they were exploring a hole in scientific knowledge. They found that bumblebees "can use a combination of colour and spatial relationships in deciding which colour of flower to forage from."

They determined that it was possible to train bees to follow a logical pattern in determining where to seek found. In this case, they taught bees to go to the center of an opposing circular pattern of colors - i.e, to go to the blue center of a yellow flower, or the yellow center of a blue flower. This is different from normal circumstances, in which bees are attracted to flowers of a certain color.

The full paper, published in Biology Letters, a publication of the prestigious Royal Society, can be read in full online here. If you've got half an hour to read and understand, it's an excellent read, and more accessible than many scientific papers.

The paper was peer-reviewed by several other scientists, who determined that despite the lack of references or statistical analyses, the paper was "cleverly and correctly designed and carried out with proper controls" and "[the students} hold their own among experiments carried out by highly trained specialists". High praise indeed.

Just as impressive as the results is the repercussions of the experiment. They were denied public funding for the experiment because it was believed that children could not run an experiment that would generate results, so the experiment was funded by Lotto's LottoLab group. But they did indeed get results; this should show us all that the importance of research is not by who runs it or their ages, but what we can learn from it.

The students, I imagine, have also been impacted. They have been taught that they can do real science at a young age, that there is littler than they cannot do. That alone is incredibly empowering, and I imagine that those 25 children will be largely ambitious and successful as adults. But they have also been taught that science is interesting, it is alive, that it is everwhere. That science is about asking questions and finding a way to test them. ("Ideas are tested by experiment") How many scientists and engineers will there be in that group of twenty-five, how many whose abilities for scientific thinking were unmasked by this?

After all, their "principal finding" had a second part, just as important as the first part: "We also discovered that science is cool and fun because you get to do stuff that no one has ever done before."

## Tuesday, December 21, 2010

### On Finding stuff with Google Street View

So, I'm doing some research for a Wikipedia article, and I need to find the location of a former railway station in Montreal. It hasn't been used since 1912, so it's not easy to find. Not to mention, directions are given weirdly in Montreal. I'm not quite sure how you can give directions as being east or west of a street that runs east to west, but they do, somehow.

In any case, I was stuck. So I just went on Google Maps and turned on Street View, and started looking around. And then I found it:

Not only does the former station building still exist, but several tracks have been preserved as well, right down to the metal stops on the ends.

(In case you're interested, it's Dalhousie Square Station).

## Monday, December 20, 2010

### Final Went Well!

I'm not allowed to say anything else about it for the time being - because Conn College has a don't-talk-about the-test honor code which I respect - but my calc final went well today. All the studying paid off.

Now let's see if the same goes for my Marine Science test tomorrow. not so likely.

## Sunday, December 19, 2010

### It's Calculus Time

It's just about time for my calculus final. I have until Wednesday to take it, but I plan to take it tomorrow. It's only five chapters worth of material, but those are five dense chapters, covering vectors and 2D vector calculus; 3D functions, partial derivatives, min-max problems and Lagrange multipliers; double and triple integrals; and 3D vector calculus up to Green's Theorem.

I just spent from 3:40 to 11:30, minus two hours to visit my grandmother, studying - several times longer than any other final I've studied for before. I did 51 problems covering the last 9 sections and wrote up the essential formulae that I must know. The formulae cover front and back of two whole sheets of paper.

Eul me up, boys. It's Calculus Time.

### I don't usually talk about politics...

But it looks like Don't Ask Don't Tell is going to be repealed. Passed the House earlier this week and the Senate. Eight Republican senators had the balls (and ovaries) to vote for what's right, instead of the party line.

## Friday, December 17, 2010

### Llamapocalypse

I'm a pretty darned left brained person. I like logic and order, science and math. But, sometimes I branch out. I play the trumpet. I tried acting for the first time last year, and I (disastrously) tried writing a short story for NaNoWriMo.

So, now I've branched out. I started a second short story, and now I've written three short pieces for drama. Two are short plays; the third is a monologue. Here is the current draft, in full.

Llamapocalypse

They weren’t quite sure how it happened. Not that they had a lot of time to figure it out. It might have been a freak mutation, DNA gone wrong. Might have been some sort of sickness, a ruminantarian Mad Cow Disease. There was even speculation of malevolent action.
How it happened is beyond mattering now. Somehow, a small population escaped, and they multiplied like rabbits. They grow and breed at over ten times the natural rate. They eat everything organic, strip the soil bare.
They reached a critical point sometime in March, and the population exploded. Within a week, half of Nebraska was wasteland. Some folks managed to get out. Most didn’t. The military did their best, but they were ill-prepared to fight the massive herds. Three nuclear weapons barely dented the population. Biological weapons were useless. Somehow, the Joint Chiefs didn’t anticipate warfare against llamas.
It didn’t take long for the internet to dub it ‘Llamapocalypse”. Cute name, but no one was laughing. The rest of the world will survive; they quarantined the continent immediately. They finished dynamiting the Panama Canal bridges last week. But North America is reduced to a few defensive perimeters – New York, D.C., Denver. Some will hold. Life might return to the land someday.
As for me, well, it’s times like this that I really regret ever learning math. It’s the world’s worst word problem. If the tallest building in Cincinnati is one hundred meters high, and the llamas pile on an extra meter every single hour, will my meager food supplies run out before or after I become llama chow?

### I had a good day.

After the crapstorm that was yesterday (friend drama, lousy lab in Marine Science, long day, deferred from MIT) I needed a good day.

And, I got one. My physics quiz went excellently today, and then we spent most of Marine Science watching Blue Planet. If you haven't seen that show, you're seriously missing out.

Then, I had brownies, because I brought some in to reward the folks in my assigned homerooms who brought in money for the National Honor Society toy drive (bribery: it works, folks) and there were half a dozen extras.

Then, third block, I had study, so I played chess with some friends from band. They're much more interesting to play against than the computer. They haven't beat me yet, but one gal is getting quite tricky.

And then, I remembered that I had physics homework. So I did my entire problem set for the next chapter - three or four nights of homework - in one 80-minute block. Thank goodness for my ipod.

When I got home, I found an envelope from WPI. I'm accepted. So, I know I'm definitely going to college. Which is a nice feeling, even if WPI isn't my first choice.

## Wednesday, December 15, 2010

### Ice Cream

Protip: It's never too cold for ice cream. Anecdotal evidence from yours truly suggests it's just as delicious down to below-freezing temperatures.

### Voyager 1 has left the building

After thirty-three years, Voyager 1 has left the first layer of the Sun's domain - the first manmade object to cross the termination shock.

The sun puts out a huge volume of charged particles - protons and electrons, mostly - massing 6.7 billion tons every hour, the equivalent of five Empire State Buildings every second. This is known as the solar wind; it can bring a devastating amount of radiation, and Earth's magnetosphere shields us and makes life possible. The solar wind interacting with the upper atmosphere forms the auroras.

The solar wind eventually begins to peter out at around 90 AU (Astronomical Units, the earth averages 1 AU from the Sun. 1 AU is about 93 million miles), a boundary known as the termination shock. Phil Plait brings the awesome news that Voyager 1 has reached a point where the solar wind equals zero velocity. Within a few years, it will reach the heliopause, where it will feel the wind from other stars. At that point, it will be officially out of the sun's domain, and into interstellar space.

And, what's crazier: this was launched thirty-three years ago. There were no cell phones (only a few giant prototypes), no real personal computers. No internet. It's a marvel of technology. It is expected to have enough power to operate some instruments until 2025, 48 years after launch. Nothing that we have made will catch it - thanks to the gravity slingshots it received from Jupiter and Saturn, it is going faster than the Pioneer probes, faster than its twin Voyager 2, and faster than New Horizons which will visit Pluto in 2015.

This wasn't even its primary science mission. It was just supposed to last a few years, take pictures of Jupiter and Saturn. It discovered Jupiter's rings, volcanic activity on its moon Io, and took thousand of scientifically important images of the two planets.

Perhaps the most important image that it took, though, was the Pale Blue Dot image - which shows the Earth as exactly that, a pale blue dot. Seeing how all of human life ahs taken place on and around that tiny dot reinforces the need to protect it.

This is why I want to go into aerospace. To create things that go where nothing has explored before. To see what's out there. To create the rockets that show us what exists beyond that pale blue dot.

## Sunday, December 12, 2010

### More Nell Rebuilding

Believe it or not, rebuilding the Nell is going surprisingly well. Although many of the joints are broken, they retained their basic shape reasonably well. I just finished gluing and clamping (with masking tape) the last two joints than needed to be rejoined. It's actually a lot easier the second time around, because all the puzzle pieces do fit together.

I'm using entirely wood glue, and it seems to be absolutely strong enough. I'm still worried about twisting in the airframe, but hopefully that will fix itself when I reglue a few critical joints.

I also started repairs on the Orbital Transport, which crashed a few months back. I removed two inches of crushed tube from the front, and replaced it with a 24mm coupler and seven inches of tube. The extra length will make it significantly more stable, and look more like the original design.

### On the road to recovery

The Nell, that is.

I started the length rebuilding process today by fixing the broken side tubes. Both failed in the exact same mode - the joint halfway down the tube was not glued inside, so the outer cardboard tube snapped instead of the inner dowel.I put a layer of wood glue both between the two dowels and on the dowel-tube layer, thus ensuring a very strong joint. Once I re-enforce them with a layer of wood glue or epoxy clay, they will be two of the strongest parts of the rocket, instead of the weakest as before.

Unfortunately, I also discovered today that most of the angled side joints are broken. I may have to peel off the string, rewrap, and then finally refix them. I am not sure yet; it may vary joint-to-joint.

I will take more precautions on its return flight. An 18" plastic parachute, in warm weather, with plenty of wadding to protect it.

## Saturday, December 11, 2010

### Galaxy Zoo: Hubble

I've talked about Galaxy Zoo before a couple of times. It's a citizen science project to classify galaxies from automated sky surveys by type and shape. After not doing anything on the project in 18 months, I'm back. I've classified 135 'galaxies' today... including about actual galaxies, plus a few stars and a satellite trail.

The new project uses galaxies from the background of several Hubble Space Telescope images. Many are proto-galaxies from the beginning of the universe, too young to have formed into round spirals or ellipses. They just look like - like bluish lumps. Some 10 billion years old.

galaxyzoo.org

### Huh.

In just over 10 hours from now, the date in time (in American format) will be:

12/11/10 9:08:07

## Friday, December 10, 2010

### Brass Trio

What happens when your second trumpet and baritone player are late.

In retrospect, it's really fortunate than the first trumpet part had all the melodies. Otherwise, the dear folks at Mystic Aquarium would have been subjected to some rather strange harmonies.

## Thursday, December 9, 2010

### When I am the benevolent dictator of the world

99% of Christmas music will be banned, to be replaced with Trans-Siberian Orchestra music.

Headlights will be auto-on, making you actually work to turn them off.

White lab coats will be standard attire for all science classes, even the theoretical courses.

## Tuesday, December 7, 2010

### Middlesboro Impact Crater

Take a close look at the Appalachian Mountains in the southeast corner of Kentucky. Mile after mile of long, high ridges and narrow valleys carved by streams. And then, just at the junction of Kentucky, Virginia, and Tennessee, there's a very strange shape.

It resembles a giant smooth bowl:

View Larger Map

It's a very strange and out-of place shape. It's got nicely circular walls in a few spots. Yet, there's no volcanic activity for a few thousand miles. How do you get a crater in the middle of folded ridge-and-valley mountains?

From space.

No kidding.

It's a three-mile-wide impact crater, formed sometime in the last 300 million years. (Wikipedia article | Entry in Earth Impact Database) The crater size estimator at the University of Arizona's Lunar and Planetary Laboratory estimates an impactor diameter somewhere around 180 meters (600 feet). That's like getting hit with a ball of rock or iron the size of Fenway Park.

And that's a small crater. There are several confirmed craters on Earth with diameters greater than 100 km (60 miles), indicating an impactor over one mile in diameter. That's like getting smacked with the entire city of Boston instead.

But it gets crazier. Look carefully at that map again. The southeast corner of the crater rim touches one of the mountainous ridges. Right where it touches, there's a little gap in the ridge. You might vaguely recognize the name from your last American history course. It's Cumberland Gap. It's where Daniel Boone crossed the mountains to bring settlers through. It was where 250,000 settlers passed through on their way to the fertile Ohio Valley.

Now, that gap was, it seems, created by the impact. Which means that that anonymous space rock played an important role in American history.

## Sunday, December 5, 2010

### Ooh, pretty picture!

See this beautiful, sexy picture?

Yeah, I made that. Took a blank map, added the stations and the legend in GIMP. I'm rather proud of it.

(Click to take you to the file page, for embiggening.)

## Saturday, December 4, 2010

### Cold

So, I've been getting a cold, one symptom at a time.

Last weekend, I keep being hot and cold.

Then I couldn't stop sneezing.

Then I couldn't stop coughing.

Then my nose was runny.

And now I have a postnasal drip.

Plus, I may be on my way to an upset stomach. Happy funtimes.

### Gentlemen (and Ladies), we can rebuild her.

We can rebuild her. We have the technology. We can make her better than she was. Better... stronger... faster.

I am going to rebuild Nell. It's not going to be easy, but she will fly again.

Now, recall the result of her first flight. No parachute opening, ballistic recovery, crunch splat:

It's broken not-so-neatly into two parts. One contains the rear section plus one side brace; the other is the front section plus the second brace. Both braces are broken in the middle at the dowel joints.

The first order of business is fixing those dowel joints. They carry a whole lot of force, so I;m going to use JB Weld epoxy to fix them together, then epoxy clay to smooth the joint. Then I get to go about the arduous business of regluing all the old joints, then sanding, priming, sanding again.

Goal for the second flight is the first quarter of 2011.

## Wednesday, December 1, 2010

### Brian Marsden

I know this is old news by now, but I feel I owe him at least a few words. Brian Marsden passed away on the 18th of November.

His official title was director of the Minor Planet Center at the Harvard-Smithsonian Center for Astrophysics, but he was so much more than that. He was a walking encyclopedia of astronomy, an absolute genius. If you thought you'd found a new comet or asteroid, he was the guy you talked to. I was never involved in serious astronomy, but I sure had heard his name.

Sky and Telescope has a wonderful obituary and biography that says far more than I could possibly say.

### Eurydice

Back in November, I saw Ledyard Drama put on a performance of Sarah Ruhl's play Eurydice. It was absolutely fantastic - I saw it twice - and several of my friends played the leads, and a minor part, and mandachan was stage manager.

Near the end of the play, Eurydice's father dips himself in the river Lethe. Before he does, though, he states a series of memorized directions. I got a script from a friend; here is what he says:

"Take Tri-state South - 294 to Route 88 West. Take Route 88 West to Route 80. You'll go over a bridge. Go three miles and you'll come to the exit for Middle Road. Proceed 3 to 4 miles. Duck Creek Park will be on the right. Take a left on Fernwood Avenue. Continue straight on Fernwood past 2 intersections. Fernwood will curve to the right leading you to Forest road. Take a left on Forest Road. Go 2 blocks. Pass first entrance to the alley on the right. Take the second entrance. You'll go about 100 yards. A red brick house will be on the right. Look for Illinois license plates. Go inside the house."

It turns out, it's an actual set of directions. A few of the mileages are wrong, but it actually leads to an assuming brick house on an unnamed street in Davenport, IA.

Here's a road map of the route. It's not perfect - it actually takes the third entrance into the alley, not the second - but it provides a good idea of it.

View Larger Map

So, then, what does this route mean? Is it just a random journey?

Turns out, it is not. I found a very illuminating article in the New York Times. Apparently, Sarah Ruhl owns a large collection of her grandmother's clothes. She loves the memory of her grandmother that she finds contained within them. Memory, I should note, the remembering of love and family - is what Eurydice is all about.

The article goes on to discuss that Mrs. Ruhl grew up outside Chicago (Wikipedia says a town called Wilmette). Interstate 294 runs just a few miles from Wilmette, and is the best highway to jump on for journey to points west - like Iowa.

The kicker, though, is where her grandmother lived. Davenport, Iowa. I would, then, consider it reasonable to assume that that red brick house did belong to her grandmother. The journey from her home to there, the article says, was one she experienced many times during her childhood.

For her father, who is roughly analogous to Eurydice's father, the journey would be natural - from his own home to his mother's - the place where he grew up. It's ingrained in his memory, the last thing he gives up before his brain is wiped. And death is often likened to going home or joining one's relatives - and giving up all his memories is like dying again.

The directions end with the following, as he dips himself into the river:
"In the living room, look out the window. you'll see the lights on the Mississippi river. Take off your shoes. Walk down the hill. You'll pass a tree good for climbing on the right. Cross the road. Watch for traffic. Cross the train tracks. Catfish are sleeping in the mud on your left. Roll up your jeans. Count to ten. Put your feet in the river... and swim