Friday, February 28, 2003

Fowler, Fowler, Strunk, White, Turabian, et al.:

Call me a grammar Nazi, but wouldn't it worry you if your pilot said:

"...umm, ladies and gentlemen, we will be landing momentarily." ?

I can understand trains and subways stopping momentarily, but airplanes landing?

In my younger days I took up flying, and I distinctly remember my first flight as a licensed pilot, taking up my nervous parents. Now my father had been a fighter pilot in the RAF, so I was also somewhat nervous, knowing that I would never be able to equal his gracefulness in a Spitfire with my pitifully under-powered Cessna 152.

I came as close to a momentary landing as you can. It's called porpoising. Imagine a spastic, frantic, bucking airplane progressing down the landing strip in a series of violent crashes with the ground, followed by graceful arcs in the air.

That was me, momentarily seeing the end of my days.

 Thursday, February 27, 2003

Popol Vuh:

Today's date is 4: by the Mayan Long Count. Or maybe it's 4:, depending on whom you believe...

This also means that we have fewer than 4,000 days left before the count begins again. Some people are working themselves into a froth over the fact, but I don't see any reason for the Maya to have any better insight into the date for end of the world than, say, Douglas Adams.

The more interesting part of this is that the Maya had a concept of deep time that is totally lacking in Western culture. We occasionally talk of centuries, but rarely of millennia. The Mayan cycle is composed, at the highest level, of an aeon that is 5,125 years long. On top of this, they felt that they lived in the third of these aeons. Now, admittedly, a zero date somewhere in 15,000 BC is nothing compared to today's geologic or astronomical timescales, but it's a darn sight better than Bishop Ussher's guess for the Origin of the Earth on October 22, 4004 BC, and better even than Newton's guess based on the uniform cooling of a sphere (the Earth) from the temperature of molten lava to the temperature of 15th century England.

The fact that the Maya dealt in such immense lengths of time very probably gave them a very different perspective on things. Unfortunately, whatever of this perspective that they passed on to the Aztecs did not survive the arrival of Cortez and his busy e-caravelle full of cell-phones, fax machines, and smallpox.

BTW, for the Hindu world, each incarnation, or Day of Brahma lasts 4.32 billion years. And it's an endless cycle.

Today is day 14,587 for me...


 Wednesday, February 26, 2003

Arthur C. Clarke:

Many people are hard at work on perception and cognition in the AI field. Both government and industry are interested because having autonomous robots would solve the expensive and communications intensive problem we face when today's machines encounter a situation and simply say: "OK, now what do I do?" and wait for a human response. In a situation where time is precious, like in a bomb disposal, on a battlefield, or on the surface of a distant planet, it would be much better if the machine had some more autonomy.

The difficulty of the task has been underestimated. Even animals that can walk within hours of birth have had months of time to build up coordination in the womb, and have millions of years of genetic programming hard-wired into them. Watching your own child learn to move and react to their surroundings is an amazing thing -- but it takes a long time to reach "competence."

Admittedly, we are making the task simpler by redefining the tasks for which competence is necessary: 'grab and cut wires,' 'send pictures of boxy things with turrets,' or 'pick up small rocks.' But even these tasks take time to really figure out, and then to teach to a machine.

I remain a fan of AL vs. AI. Artificial Learning that is. Self-organizing systems are amazing things, and don't have to be that complicated in their individual parts -- it's the behaviour of the whole that is complex. Models of schooling fish are fairly easily built where very simple rules dictate the movement of the individual, but the complex swirls that so entrance us quickly emerge when a critical number of individuals exist. And I'm pretty sure this will be so for robots of the future too.

...and that was the scenario for the Terminator movies.

 Tuesday, February 25, 2003

Jane Goodall, continued...:

Well, in one of those moments that make one wonder if there truly are coincidences, my wife and were driving on I-95 and we came across Exit 20 for Jarratt, Virginia.

Seeing the Jarratt sign prompted me to exclaim that this was the site of the September 2000 monkey fruit attacks that I had blogged just days before.

My wife listened to the story and laughed, and then took the next obvious step, as she looked out the window at the passing farm fields and scrub pine forest of Southern Virginia. "I wonder where the monkeys got all that fruit? It's not like they have pockets or backpacks..."

The articles about the incident all seem to mention bananas and crab apples. Crab apples in Virginia are possible, but the nearest banana palms are several hundred miles to the South.

We pressed on, but luckily encountered no fruit-hurling capuchins.

 Thursday, February 20, 2003

Veenenbos & Cerf:

In an image credit in the last issue of Science on Mars, I caught the name of Kees Veenenbos. The work he has done in visualizing Mars as a wet planet is pretty grand. Well worth the price of my large computer monitor.

This kind of realistic animation was once sold by NASA as a reason for high resolution topography missions -- they were hoping to capitalize on the then-emergent video game phenomenon to get people to pay to simulate riding around on the Moon. Although I suspect that full sensory immersion is still a valid target for game development, we are a long way from it, and no sensible business plan could include it. But it will come. Orgasmatron and all.

Kees' views of Mars made me think of a conversation with Vint Cerf I had several years ago -- he was talking about communications between interplanetary craft, and specifically the set of missions slated for Martian exploration. NASA's mantra of 'faster, better, cheaper' led to the adoption of a lot of off-the-shelf hardware and the adoption of accepted communications standards (very unusual for NASA, since they had been a large enough gorilla to simply ignore most standards up to this point). The amazing thing is that these craft all have IP addresses. Yes, just like your little desktop, there are IP addresses for, say, Mars Odyssey, Mars Global Surveyor and the Mars Exploration Rover. And these addresses reach all the way out to Mars. So you thought .tv, .go, and .biz were cool? How about .mars?

But no, you can't ftp. Much less csh them. As you might guess, the real IPs are well protected. NASA has enough to worry about without having to deal with hackers inadvertently changing inches into centimeters...

 Tuesday, February 18, 2003

Snow, Nieve, Neige, Schnee, Snö, Neve:

This last weekend's snow storm led to a lot of watching weather forecasters on television.

It also brought home to me something that I picked up from, strangely enough, a show on botched plastic surgery. For such a supposedly liberated profession, tele-journalism is completely merciless when it comes to women's aging. You hit 30 and you are out. Only in cases where you can amass very large amounts of political clout within the company are you going to survive (Barbara Walters, and now Connie Chung).

I want a Barbara Bush to tell me gently, as I fall asleep watching the forecast, not to forget my galoshes and for goodness' sake, my hat, should I insist on going outside in tomorrow's frightful weather.

 Sunday, February 16, 2003

Lagrange, Euler, Poincaré, Lyapunov, Conley, McGehee & Simó:

That's a mouthful of mathematicians. What they have in common is a trail of discovery that was described in Caltech's latest magazine, Engineering & Science (LXV/4).

It makes sense that there is a minimum energy orbit between two planets that is simply tangent to the two ellipses -- the Hohmann transfer orbit. This is what we have used for most interplanetary missions. You fire your engine to give you a change of velocity at a precise time, and then you coast along in your new orbit, reaching your target later along the new orbit path.

However, there are some other very strange orbits possible that depend on the balance between competing gravitational pulls from two or more bodies. These orbits are not intuitive at all, and are not simple conic sections. The simplest of them describe shapes like the edge of a potato-chip, and they cycle around, well... nothing. These are the "halo orbits" that exist around the Lagrange points (a great animation of WMAP settling on an L2 halo orbit is the bottom one here.) We are already using these orbits for several research spacecraft (ISEE3, SOHO, COBE, WMAP, Genesis), and in fact we did a little early navigating of these tubes in the mad dancing of the Galileo probe between Jupiter's moons.

It turns out that each of these halo orbits has a family of possible insertion and exit orbits: think of them as on- and off-ramps, constrained by physics. If you drew all the possible orbits going in and out of a particular halo, they would describe a tube that passed through the halo. This tube is called a Lyapunov tube, or a 'manifold'.

The final leap of insight in this chain is that Lagrange points exist for any two bodies in the solar system. Therefore there are Lyapunov tubes between all the bodies of the solar system -- and therefore there are orbits between any two bodies that can be taken that require very little fuel. The thing they do require is a lot of time.

This is the rationale for some of the Martian meteorites reaching Earth - they travelled Lyapunov tubes completely at random, and some of those tubes led down to the Earth's surface. This also means that there must be asteroids in some really bizarre orbits - and indeed Oterma fits that bill very nicely.

My thinking of course is outside the solar system -- these Lyapunov tubes exist between stars too, but I suspect that the time involved in a Lyapunov transfer orbit between stars is geological in scale. OK, even astronomical.

I also wonder about those spokes, spiral waves, and braids in Saturn's rings that so puzzled us during the Voyager flyby - are these orbital resonances simply reflecting all the multilayered cross-sections of Lyapunov tubes between Saturn's large herd of moons and moonlets?

 Friday, February 14, 2003

Jane Goodall:

CNN reports...

Actually they were Iraqi operatives practicing traffic disruption. 'nuff said.

Wilfred Scawen Blunt:

St. Valentine's Day

To-day, all day, I rode upon the down,
With hounds and horsemen, a brave company
On this side in its glory lay the sea,
On that Sussex weald, a sea of brown.
The wind was light, and brightly the sun shone,
And still we gallop'd on from gorse to gorse:
An once, when check'd, a thrush sang, and my horse
Prick'd his quick ears as to a sound unknown.

I knew the Spring was come. I knew it even
Better than all by this, that through my chase
In bush and stone and hill and sea and heaven
I seem'd to see and follow still your face.
Your face my quarry was. For it I rode,
My horse a thing of wings, myself a god.

Not stunning poetry, but quite pleasing nonetheless.

Interesting that several places claim to have St. Valentine's remains:
1. Blessed St. John's Duns Scotus, Glasgow.
2. Whitefriar Street Church, Dublin.
3. Saint Praxedes, Rome.

This duplication is quite possible when one considers that the Catholic Encylopaedia contains references to three different Valentines who were canonized. There is not much chance that each of these corresponds to each of the separate Saints, given the amount of outright forgery surrounding historical remains, as well as the custom of dividing up legitimate ones between several sites. As to which sites have remains from the St. Valentine around which the celebration of love is centered, nobody knows, but ceremonies and pilgrimages are made to each of these places by those in love, and those in search of it.

"A rose is a cactus with a good education." -- Uncle Tim

 Tuesday, February 11, 2003

Eloy Rodriguez:

One of the consistently heard stories about the value of the jungles and the cultures that inhabit them is the potential for medicinal chemicals extracted from the inhabitants knowledge of the flora. We are hearing this story again, but this time it is focused on the sea, in coral reef communities and in benthic (deep sea) bacterial communities.

While I don't deny that those chemicals are there, and that local knowledge has discovered many of them, it's a sad fact that their discovery by Western science often dooms their use. Lost both to the locals, who begin to lose oral traditions with greater exposure to the outside, but also to us. And it is simply because of the way our market works. If a scientist goes in and discovers a potentially wonderful new drug, and publishes in the open literature, that very drug loses all its potential competitive advantage for a drug company, and is much less likely to be picked up for the necessary R&D to turn into a marketable product. Many medically active chemicals have already been lost this way -- yes, they are out there, but no company can find a way to make money from them, and so they do not produce them.

What is the alternative? To give the private sector free reign in forest preserves? Some governments have taken that approach, and some pharmaceuticals have taken the bait. But this business model has not worked out all its kinks, and the results are not promising. Neither the governments nor the pharmaceuticals have seen the revenue they expected.

So remember that this argument for forest and ecosystem value does not hold much water when viewed in the wider context of how the industry develops a new product. It simply costs too much to go through all the development, testing and certification to bother risking with a chemical that has been identified in the open literature.

And that is a great pity for how science works, but it is part of the bargain society makes for intellectual property. ...and that can of worms (intellectual property) can wait for another post.

 Monday, February 10, 2003

Dell and Jobs:

Remember the fuss about the young models who looked like they were doped out on heroin? Well it looks like computer geeks are catching up, sort of. The recent snafu about the Apple switch girl Ellen Feiss and her cough syrup use was capped off today by Ben Curtis' (the Dell computer surfer dude) arrest for posession at NYU, where he is obviously studying hard in drama school. Best of all, Dell is now selling Dude gear, clothing with Ben's witticisms printed on them.

Somehow, despite his T-shirt chic, I can't see Hamid Karzai in one of these...

 Sunday, February 09, 2003


Do you suppose there is a Burqa Barbie? And is there a Ken that has as stylish a green coat and as jaunty an Astrakhan lamb hat as President Hamid Karzai?

If I keep this up, I will merit my own fatwa.

 Thursday, February 06, 2003


I go underneath the Pentagon every day. Tens of thousands of people do. People who have nothing to do with the military. People who don't have any clearance. People from all over the world. People who are riding the Washington subway, or Metro.

Amazingly, the Metro has a stop directly under the Pentagon. It's where I get on the Metro after catching a ride in from home with strangers every day. It's where I get off the Metro at the end of the day to again catch a ride home with a stranger on the Washington area's unique commuting/hitchhiking system designed to deal effectively with High-Occupancy Vehicle lanes on local highways.

But all this commuting makes me wonder. I gaze shiftily around the brand new Breda railway cars, gleaming in their antiseptic gray-white that hasn't faded into comfortable computer beige yet, and I wonder who is carrying the anthrax today. Or the ricin. Or the smallpox. Or who is carrying the suitcase bomb deep into the heart of the military.

Damn it - this is exactly what al-Qaeda wanted, too. Terrorism works. Even on thinkin' folk. And I grew up with this crap, so you think I would be used to it - the FARC and M-19 guerrillas were blowing up truck-bombs, holding the supreme court hostage, and assassinating presidential candidates by bringing down fully loaded Boeings all the time. We used to change the times and routes we drove to school and work every day, depending on the traffic lights in order to avoid setting patterns that could be used by kidnappers. Going out to a friend's house was an exercise in perimeter security. So getting used to that tension again is difficult - but the best thing is that I know it's livable. Look at the familiar places that have adapted: not Bogota, since that might as well be Mars for most folks, but places like Londonderry, Paris, and Munich. They still live on. And so will we.

I somehow doubt that the public transportation systems in Baghdad stop inside the Republican Guard's headquarters. And certainly not inside the Presidential Palaces. I can hear Blix and Baradei now: "We'd like a transfer, please. Yes, from the aluminum pipe machining plant to the yogurt factory. Thank you. Eleikum-a."

 Wednesday, February 05, 2003

Echoes of 1861:

Yesterday a good friend told me that I live in the state that receives the most Federal dollars in contracts. I find it hard to believe that Virginia receives more than California or Texas, but given the military and government contractor headquarters here, it might just be possible.

This friend is a native son from Richmond, so when he also said that West Virginia receives the least, possibly as revenge for its secession, I listened.

The war of secession never really ended. Perhaps.

 Tuesday, February 04, 2003

Launch Abort Options:

On thinking about Columbia, and the focus on the impact of insulation/ice from the external tank on the left wing of the orbiter on launch, I realized that there were very few options.

If the damage could have been judged accurately during ascent (and the tracking scopes plus telemetry did not indicate this at the time) the only viable options I can see are two of several available intact abort modes: Return to Landing Site (RTLS) and the Trans-Atlantic Landing (TAL). The other ascent aborts are not viable - Abort to Orbit (ATO) and Abort Once Around (AOA) would both require re-entries like Saturday's, going through the atmospheric heating of a nominal re-entry. All of these abort modes require decisions by the mission control launch officer that have very small windows, and depend on the exact timing and nature of the problem. Both of these options require a decision before main engine cut-off.

Given the apparent damage to the left wing insulation, it is likely that the normal option of preferring TAL over RTLS would have been followed, with a trans-Atlantic ballistic trajectory ending in a glide to landing in Moron-Spain, Dakar-Senegal or in Ben Guerir-Morocco about 45 minutes later. There is still atmospheric heating associated with this option, and a risk that the reheating would cause the same failure.

RTLS mode would return the orbiter to Kennedy. This decision has to be take before the +04:20 mark, otherwise there is not enough propellant to undo the kinetic energy already invested in Eastbound flight. The main engines are used after SRB separation to turn and head back to KSC. Again, the stresses on the orbiter are not small, and heating will occur as the orbiter dissipates energy on its glide slope.

Having a hole in your armour is never a good thing.

 Saturday, February 01, 2003

Anderson, Brown, Chawla, Clark, Husband, McCool & Ramon:

...and now, Columbia is gone.

I landed at Dulles at 7:00 this morning, back from Argentina, went home and later turned on the TV.

We all knew this would happen someday - re-entry is only slightly less dangerous than lift-off.

I can only imagine the last moments of confusion as Husband and McCool watched F7 display the mad fight between the reaction control and aerosurface systems as they spiraled out of control. During this phase of re-entry, there is enough air pressure to use control surfaces, but the RCS can still contribute. Even if they had already switched to CSS flight control mode at this point, the navigational computers were surely quickly overloaded by mounting corrections.

I was angered to see the celebrations of the loss in Baghdad and on the West Bank, but I suppose it was somewhat understandable. There are sure to be many here who would celebrate Iraqi deaths if war comes.

So many children left without parents.