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[ 20030131 ]

Because It Can Become Good (IV)

Via Glenn Reynolds, in Tech Central Station's Simple Goodness, Lee Harris writes:

If the whole of the United States were to disappear tomorrow in a catastrophic earthquake like a second Atlantis, it would not materially benefit a single suffering man, woman, or child anywhere on our planet.

... there is only one way that ... goal[s] can be achieved on [an] extraordinary scale ... and that is if the United States of America continues to be rich, powerful, and superbly organized.

(For the exceptionally masochistic diligent reader, earlier posts in this series are here, here, here, and here.)

Jay Manifold [8:00 AM]

[ 20030130 ]

Nanotechnology, Risk Management, and Institutions

Again via Glenn Reynolds, the magisterial Freeman Dyson reviews Michael Crichton's Prey, and it's all about risk management:

What is the appropriate response to dangers that are hypothetical and poorly understood? In this matter, as in other situations where public health hazards and environmental risks must be assessed and regulated, there are two strongly opposed points of view. One point of view is based on the "precautionary principle." The precautionary principle says that when there is any risk of a major disaster, no action should be permitted that increases the risk. If, as often happens, an action promises to bring substantial benefits together with some risk of a major disaster, no balancing of benefits against risks is to be allowed. Any action carrying a risk of major disaster must be prohibited, regardless of the costs of prohibition.

The opposing point of view holds that risks are unavoidable, that no possible course of action or inaction will eliminate risks, and that a prudent course of action must be based on a balancing of risks against benefits and costs. In particular, when any prohibition of dangerous science and technology is contemplated, one of the costs that must be considered is the cost to human freedom. I call the first point of view precautionary and the second point of view libertarian.

Notice, however, that at the extremes, these are merely risk avoidance and risk acceptance; other risk response strategies, transference ("seeking to shift the consequence of a risk to a third party together with ownership of the response") and mitigation ("seek[ing] to reduce the probability and/or consequences of an adverse risk event to an acceptable threshold") are not explored (definitions are drawn from the PMBOK). K. Eric Drexler, and undoubtedly others, have addressed these, as for example in the idea of "fact forums" and "science courts."

Then Dyson draws a characteristically masterful analogy:

Three hundred and fifty-nine years ago, the poet John Milton wrote a speech with the title Areopagitica, addressed to the Parliament of England. He was arguing for the liberty of unlicensed printing. I am suggesting that there is an analogy between the seventeenth-century fear of moral contagion by soul-corrupting books and the twenty-first-century fear of physical contagion by pathogenic microbes. In both cases, the fear was neither groundless nor unreasonable. In 1644, when Milton was writing, England had just emerged from a long and bloody civil war, and the Thirty Years' War, which devastated Germany, had four years still to run. These seventeenth- century wars were religious wars, in which differences of doctrine played a great part. In that century, books not only corrupted souls but also mangled bodies. The risks of letting books go free into the world were rightly regarded by the English Parliament as potentially lethal as well as irreversible. Milton argued that the risks must nevertheless be accepted. I believe his message may still have value for our own times, if the word "book" is replaced by the word "experiment."

Though Dyson does not mention it, Milton's argument -- "look how much we thus expel of sin, so much we expel of virtue" -- was undoubtedly based on Matthew 13:24-30.

This kind of hands-off approach, exemplified in the US by this Constitutional provision (see final sentence), would seem to be at odds with much popular opinion, as exemplified by this news item. But there is an important sense in which Alabama Chief Justice Roy Moore is right: a selection process is underway, at the level of the nation-state, favoring those who develop the most effective and enduring institutions. His prescription, to my mind, is superficial and perhaps even superstitious, and his perspective on events is bizarre: where he sees "... Americans running to get gas masks because (of) some bearded man in Afghanistan ... Fear struck this country ... You see, there are consequences when we turn away from our source of our strength" -- I see Americans risking, and not infrequently giving, their lives to save others.

And many of the individual memes Moore seeks, however inappropriately, to promote are, in fact, those most likely to yield competitive advantage. At a minimum, honest, nonviolent people with good impulse control are all but certain to prosper relative to people who don't consistently practice such things. Throw in a few things like this and they just might be unbeatable.

Jay Manifold [1:27 PM]

Idiotarianism, Economics, and Risk Management

Via Glenn Reynolds, Arnold Kling's Economic Idiotarianism, over on TCS, which makes a provocative diagnosis: "The idiotarian approach to debating economic policy is to frame an issue as a conflict between Authority Ranking (bad) and Communal Sharing (good)" -- ignoring the other two relational models of interpersonal transactions, Equality Matching and (especially) Market Pricing.

Of course, people who are hosting anticommercial memes are going to ignore or deny market mechanisms. Perhaps more tellingly, they may ignore Equality Matching because it is almost completely spontaneous and has no one in charge.

The analogy I'm going to draw here, however, is between the four relational models and the four basic strategies of project risk management. This earlier post, among others, discussed risk management; I noted elsewhere that "... where Medact/IPPNW goes astray is by, in a phrase, failing to acknowledge that there are any risk management strategies other than avoidance and acceptance."

Interpersonal Transaction Relational Model

Risk Management Strategy


Communal Sharing

risk avoidance

change plan to eliminate risk or condition

Authority Ranking

risk transference

shift consequence of risk to third party, together with ownership of response

Equality Matching

risk acceptance

deal with risks as they occur

Market Pricing

risk mitigation

reduce probability or consequences of risk event to acceptable threshold

Definitions are drawn from the PMBOK. Alert readers will notice that I have Medact/IPPNW inclining toward either family-of-nations communal sharing or nobody's-better-than-anybody-else equality matching. Is Medact/IPPNW idiotarian? Events will decide that one; if, as I believe, civilian casualties in Iraq turn out to be orders of magnitude below their prediction, then at the very least their model has some deficiencies.

As always, if you find these notions sufficiently intriguing or annoying, send feedback (if you haven't e-mailed me recently, you'll have to do a one-time confirmation).

Jay Manifold [10:15 AM]

Life Imitates The Onion (A Continuing Series)

You can't make this stuff up:

Iraq is in line to take over as chairman of the U.N. Conference on Disarmament in May ...

India now holds it and will be followed by Indonesia, Iran, Iraq, Ireland and Israel as countries take the job in alphabetical order.

In related news, the next President of the United States will be from Utah, followed by Vermont, Virginia, Washington, and West Virginia. Hey, that's actually a nice east-west balance -- let's try it!

Jay Manifold [7:55 AM]

[ 20030129 ]

The Definitive Analysis

-- of the rhetorical techniques employed in GWBush's 2003 SOTU address is here. Lotsa jargon, but it's explained. An immensely valuable lesson. I again suggest taking a quarter of an hour out to Read The Whole Thing.

Jay Manifold [7:07 PM]

SOTU: What I Liked and Didn't

Full text here. What I liked:

What's not so great:

In general, the two biggest problems were 1) the neo-Luddite, superstitious call for a ban on cloning (rant) and 2) numerous new spending initiatives which, however inspiring (especially the AIDS-in-Africa thing) are, with the exception of Project Bioshield, without Constitutional foundation.

Jay Manifold [6:15 PM]

Rand Study Establishes Costs/Benefits of Iraq War

... well, it's "just a couple-hour Rand study," actually, but still good enough for me to think that this is why blogging was invented.

Jay Manifold [12:05 PM]

[ 20030128 ]

What I Really, Really Didn't Like

About the SOTU address, that is. Can a Republican please crawl out of the woodwork and help me reconcile this

The American system of medicine is a model of skill and innovation, with a pace of discovery that is adding good years to our lives.

-- and this --

In this century, the greatest environmental progress will come about not through endless lawsuits or command-and-control regulations, but through technology and innovation.

-- and this --

This nation can lead the world in sparing innocent people from a plague of nature.

-- and this --

I ask you tonight to add to our future security with a major research and production effort to guard our people against bio-terrorism, called Project Bioshield.

-- yes, and this --

Intelligence sources indicate that Saddam Hussein has ordered that scientists who cooperate with U.N. inspectors in disarming Iraq will be killed, along with their families.

-- with this?

And because no human life should be started or ended as the object of an experiment, I ask you to set a high standard for humanity and pass a law against all human cloning.

A law, if it's anything like S.1899 in the last Congress, which would imprison scientists for ten years merely for working on somatic cell nuclear transfer.

Tomorrow: What I liked.

UPDATE: Senator Brownback is trying again -- and, incredibly, is in charge of helping to determine whether his own proposal is a good idea: "Brownback was scheduled to chair a hearing Wednesday examining the ethics of cloning." I am not making this up.

Jay Manifold [10:05 PM]

Strongly Recommended Reading

Others have linked to this, including Little Green Footballs, Meryl Yourish, and "N.Z. Bear," but I actually got to it from Blogdex: “The Shah Always Falls,” an interview with Ralph Peters. It'll take you maybe 15 minutes to read, a quarter of an hour well spent. My favorite line is the very Heinleinian "... the oppression of women anywhere is not only a human rights violation, it’s a suicide pact with the future."

Then there's this description of the American difference (which I have noted a couple of times before):

I believe that perhaps our greatest advantage is a tradition that grew up over centuries, that we inherited from England. This is our tradition of openness to new information, of respect for empirical data, and of resistance to theoretical constructs other than those generated within the scientific community. Theoretical constructs did fantastic damage to Europe in the twentieth century, and much of the rest of the world lives in a fantasy land.

Jay Manifold [7:51 PM]

The Pre-Game Show

... for SOTU is here; read & heed.

My own pre-speech commentary: The space geeks among us are all wondering whether GWBush is going to announce a Mars-or-bust initiative; I expressed doubts about a nuclear propulsion program back on the 17th, to the effect that if one is mounted, it will be nuclear-electric rather than nuclear-thermal. This is partly due to more easily handled propellant: liquid krypton at -153°C or liquid xenon at -108°C for nuclear-electric vs liquid hydrogen at -253°C for nuclear-thermal. In any case, nuclear-electric has much lower thrust -- and nonradioactive exhaust -- but much higher total impulse per unit weight of propellant; in fact, there is a > 3x difference in "specific impulse" (nuclear-electric has I > 3000; nuclear-thermal has I < 1000).

Applying mbo/m0 = 1/e
Dv/gI with Dv = 15.6 km sec-1 -- escape velocity from the Solar System, starting in low Earth orbit -- we find the following portions of spacecraft mass available for something other than fuel, that is, structural members, the propulsion system itself, and payload:


Specific Impulse

Non-Propellant Mass

chemical (hydrogen-oxygen)

475 sec



950 sec


nuclear-electric (existing)

3000 sec


nuclear-electric (proposed)

16000 sec


I got that "proposed" number from the synopsis of an interesting paper, Nuclear Electric Propulsion for the Exploration of the Outer Planets.

On an almost-but-not-quite separate topic, it will have escaped the notice of few people who remember the events of 17 years ago today that this anniversary is an obvious opportunity to announce some sort of space initiative or other. Rand Simberg has, as usual, commented ably on this:

A key difference between [the Apollo fire] and the Challenger catastrophe was that in Apollo, we had a goal and a schedule. Accordingly, we dusted ourselves off, analyzed the problem, addressed it, and kept to the schedule.

I have noted elsewhere that

The more disturbing question is whether an all-embracing national space program would result in recognizable achievements, even if lavishly funded over many decades. Manned exploration, in particular, is capable of swallowing almost any amount of money; Wendell Mendell of NASA-JSC recalled, in a speech to the first Commercial Lunar Base Development Symposium in Houston in July 1999, that the cost for developing a crane to assist in construction of a manned outpost on the Moon was quoted by NASA at $10 billion. Not the buildings, just the crane to help put them together. Present-day NASA spacesuits are custom-built at a cost of $10 million apiece, even though commercially available “hard suits” for deep-sea exploration, which cost $400,000 apiece, could be modified for space. There are undoubtedly innummerable other examples. At these prices, robotic exploration could be crowded out of budgets very quickly. The cost disparity between manned and unmanned space exploration is already at least two orders of magnitude, and may well be headed higher. The conflict between the two approaches, already acute, would likely worsen in a regime which attempted to combine them.

The lesson I would impart is: Beware of unlimited objectives being sought with unlimited means. The lack of any human (or active robotic) presence on the surface of the Moon, [over] 40 years ... after Yuri Gagarin’s orbital flight, is exasperating. But planetary science did not lapse in the wake of Apollo. Every planet except Pluto, scores of moons, and several asteroids and comet nuclei have been visited by spacecraft since the last Apollo mission. More are on the way. The project-based approach works; not always as well as we would like it to, but it gets things done.

So watch for whether the President proposes a specific project or an open-ended program.

UPDATE: So much for that idea. Nary a mention of space in the SOTU address, and a call to ban all human cloning to boot.

Jay Manifold [5:27 PM]

The Hiding Place?

Corrie ten Boom they're not.

Jay Manifold [9:21 AM]

Instructions for "Instalanchers"

Welcome, visitors from InstaPundit! After following the links in New to the Blogroll, below, you may wish to enhance your reading experience by grazing through the items under the heading "Important Stuff" in the left sidebar. Enjoy!

Jay Manifold [6:42 AM]

[ 20030127 ]

Bubbles and Meltdowns (II)

(Ref this earlier post.) Over on No Watermelons Allowed, J Bowen adds some info with The bubbles of Chernobyl. A commenter, David Gillies, states that

The explosion in the Chernobyl RBMK was actually a multi-stage process: the runaway core temperature was sufficiently high to start cat-cracking the water coolant on the zirconium sheaths of the fuel rods. The free oxygen then burnt with the graphite core, which then reacted with the hydrogen. Result: kablooie.

There were actually two explosions, and I'm not sure which one this was; possibly the second, after an initial steam explosion. This reads like something out of Blowups Happen, and this lists six "fatal errors" committed by operators and explains, in somewhat fractured English:

It took the shift manager thirty seconds to realize what was happening and shouted at another operators to press button AZ-5 which would driven all the control rods back into the core, but because the rods were melted from serious heat they didn't fit properly into the core.

The important point is that none of this can happen with modern reactor design. The risks to be managed are mainly those of nuclear proliferation.

Jay Manifold [7:28 PM]

New to the Blogroll

The pseudonymous "blaster," who has modified a historical document to produce the amusing, and perhaps instructive, If William T. Sherman was in Charge of CENTCOM. I note, however, that in an era of precision-guided munitions, plus American occupation forces adept at arranging humanitarian relief, Iraq will suffer far less than Georgia did.

In fact, Iraq will suffer far less than it's suffering right now.

Jay Manifold [4:45 PM]

One of a Plenitude ...

... of possible interpretations of my all-time favorite movie may be found here (thanks to Kevin Holtsberry for the link).

Jay Manifold [11:03 AM]

Fugitive In A White Van

Indulge me in a couple of day-in-the-life posts, then it's back to the usual mix of amateur astronomy, general science, and risk management.

Virginia Postrel imagines herself to be "the blogger with the oldest car: a 1986 Civic with about 85K miles on it ..."

Well, OK, maybe the oldest. But nowhere near the most disreputable.

In the category of "what does your car say about you?," my answer is something like: "that I'll end up on Death Row."

Picture a 1992 Chevrolet G20 cargo van, plain white, with swing-out side doors. A ding or two, but relatively little rust. An appearance which, in this case, is most deceiving.

Heard of a van, loaded with weapons,
packed up and ready to go ...

It's on its fourth transmission. It has been driven somewhat more than 170,000 miles. I don't know how much more because the odometer occasionally runs backward and, when running forward, seems to record about three miles for every mile I actually drive -- this is especially fun to watch on the freeway.

Packed up and loaded with ... junk, of course; I keep the telescope in there (a 13" reflector) and some camping stuff, and the van becomes the temporary home of everything being removed from our house for relocation to the 1) dump 2) recycling center 3) library. Thus the various chunks of paneling, sacks of cans, and plastic totes full of 15-year-old issues of Astronomy and Reason.

It goes through about a gallon of antifreeze a month. Not leaking out the bottom -- boiling off as the engine frequently comes perilously close to overheating. This has been checked by the local shop (Henry's Auto, in Raytown) three or four times. They think the engine's got a crack in the block. How long can it be driven like this? I don't know, but I'm going to find out.

I'm just waiting for the Amber Alert that mentions a white van.

Jay Manifold [10:03 AM]


Yesterday the two-legged members of the Manifold household continued our tradition of ignoring the Super Bowl and seizing the annual opportunity of eating at this joint (charming older webpage here) on the one day when there isn't a 1½-hour wait for a table.

Why am I bothering to blog this? Because it's important.

You see, there's an analogy I like to use.

Imagine that it is sometime late in the first millennium. You are an untutored barbarian, specifically a Viking, who has been recruited into the Varangian Guard of the Byzantine Emperor. For months, you have been traveling from your home in Scandinavia, through the forests of Russia and down the Dnepr to the Black Sea, then across it to the greatest city in the world, Constantinople. Your ship ties up along the Golden Horn; you disembark and march through the streets to the Hagia Sophia. You gaze up at the holy image of Christ Pantokrator, and you know that you have reached the very center of civilization, the pinnacle of all human culture and achievement.

... and that is what eating Kansas City barbeque is like.

Allow me to state for the record that I want their sauce smeared on the inside of my coffin. Bury a couple of bottles of it with me, too (this is admittedly inconsistent with my desire to have certain portions of my remains interred atop each of the Seven Summits, shot into solar orbit, etc). In fact, throw in a whole "Martin City Special" while you're at it (half a chicken, with turkey and barbecue Polish sausage, please, with the sides being hickory pit beans and cheesy corn bake).

Jay Manifold [10:02 AM]

[ 20030126 ]

Since It's Sunday ...

I see that several bloggers are at least temporarily severing their relationship with Martin Roth's blogs4God over this, which is a sort of Photoshop Phriday for the less subtle of our pro-life brethren.

While I enjoy this kind of guerilla theater as much as anyone, have no intention of dropping my permalink to blogs4God, and think the Margaret Sanger-as-eugenicist meme in particular deserves much wider circulation, the legalism lurking behind some pro-life sentiment is ludicrous. Just how ludicrous, we should be finding out soon, at least in one prominent jurisdiction; this document, for example, allows no exceptions, irrespective of the cause of pregnancy or the condition of the pregnant woman. The party whose actions it supposedly guides now controls both houses of the state legislature, as well as all statewide offices.

Meanwhile, back in reality, via looking back ... looking forward, via Jordon Cooper, we find ianua's quietly shattering reminder: "It's so easy to be loud and male and defiant."

Jay Manifold [10:15 AM]

[ 20030125 ]

Risk Management: Domestic

Great piece over on Winds of Change.NET about the police chief in Charleston (SC) advising local business owners to arm themselves.

I have a fantasy where GWBush 1) acquires a spine and 2) announces that the next major economic summit to be hosted by the US will take place in, say, Lubbock. Idiotarians everywhere make plans for the usual hi-jinks. Local authorities in Texas invite citizens to defend themselves from troublemakers by any means necessary. We all sit back and watch upper-middle class hooligans who've traveled thousands of miles to smash things get splattered all over the street by shopkeepers with shotguns.

Of course, in my fantasy world, homeowners would also be arming themselves against "no-knock" raids by law-enforcement personnel who have lost the plot, and young men would be arming themselves against conscription, should it be revived. A surprising number of political difficulties could be meliorated by greater individual willingness to defend one's life and property with lethal force.

Now for Celeste's questions, and my answers to them:

  • What will I do if there is a nuclear strike on DC?

    My naive pre-9/11 answer would have been "celebrate." And at this remove (1,100 miles or so), the answer is both vague and complex: assist in any way I can, while vigorously opposing authoritarian reflexes. Of course, living where I do, I should change the "D" to a "K," in which case the answer depends on the placement and yield of the device, and the wind direction at the time. Assuming something in the kiloton range, the random chance that I would become a prompt casualty is small; the challenge would be to deal with the effects of public panic and (perhaps) of evacuating a house full of animals.

  • What will I do if there is a smallpox outbreak?

    Nothing, because I'm vaccinated, and smallpox vaccinations are good for at least 50 years (my wife, however, would need to be inoculated).

  • What will I do the next time some nutjob is randomly targeting citizens in my area for assassination?

    Find the .380 and the 12-gauge, make sure they're loaded, and suggest that my wife put the .380 in the glove box of the car, while I conceal the 12-gauge in the van. Maybe spend some time at a shooting range.

  • What will I do if a terrorist attack takes out the communications and power infrastructure in my area?

    About what I'd do in an ice storm. Evacuate eventually if they couldn't get it fixed, though I expect we'd put up with it for a couple of weeks before leaving.

The lesson here is that managing the risk of domestic terrorism is a mix of individual and institutional responses. We need to be both prepared as individuals, up to and including willingness to sacrifice our lives to save others (obligatory link), and capable of creating and maintaining functional, autonomous institutions to operate on larger scales.

Jay Manifold [10:33 AM]

Risk Management: Memetic

Via Glenn Reynolds, the best 327-word sentence I've ever read (see final paragraph; language warning).

While we might not all be in perfect agreement about some of the items in the list (I hasten to add that I am in agreement with nearly all of it), anyone who is concerned with influencing the society in which they live -- in this case, to keep it from committing suicide -- should ponder what kinds of fears people find attractive, and craft their approach accordingly.

A while back I noted a striking correlation between one's occupation and the likelihood of signing the "Not In Our Name" petition. Now, suppose that there are enough such people to seriously influence public policy and thereby noticeably increase American vulnerability to terrorist attack. Those of us who feel otherwise should first be asking: what makes them tick?

Calling them all nitwits is no substitute for persuasion. And marshaling arguments of the sort one usually sees in the blogosphere is unlikely to be effective, by itself: ask yourself how many times your mind has been changed on a significant issue by a simple statement of fact, much less lengthy lists of facts interspersed with insults. (One person who did argue me around, many years ago, now has a blog; but I could count my number of purely rational changes of mind on one hand without running out of fingers.)

This event wasn't an essay in the pages of Foreign Affairs on the need to project American military power overseas, much less a Fisking on some blog read by a few dozen like-minded people. Encouraging our fellow citizens to respond appropriately to it will not be done by text alone. Warning: requires getting out from behind computer keyboard. And listening.

Jay Manifold [10:32 AM]

Risk Management: Foreign

I love charts (via Winds of Change.NET). An interesting risk-management tool, courtesy of Blaster's Blog. I'd have drawn it a bit differently, myself, like by moving Pakistan and Saudi Arabia nearer the top, but the idea of using quadrants is sound.

Jay Manifold [10:32 AM]

[ 20030124 ]

More Great Stuff on Rhetorica

Andy Cline's not paying me, really. But I just read a whole bunch of great stuff over there and recommend it highly. In particular, the idea of political spin points as evolving memes and the mathematical difficulties of reading and responding to citizens' comments on new regulations sound like, well, something I'd blog about if I actually knew anything about this stuff. ;)

Jay Manifold [4:32 PM]

Virginia Heinlein, 1916 - 2003

The real-life model for many of Robert Heinlein's fictional heroines -- surely among the strongest female characters ever depicted -- his wife Virginia, passed away on Saturday the 18th.

Thanks to The Truth Laid Bear, where I first saw the sad news. You may also wish to read this column by Spider Robinson, and this obituary at CalPundit.

Jay Manifold [4:06 PM]

Maybe Europe Won't Freeze After All

The recent suggestion that melting ice in the Arctic may be about to shut off the Gulf Stream and plunge western Europe into a temperature regime similar to Canada's might not be possible.

Via JunkScience.com, Columbia research reveals that Gulf Stream is not responsible for mild winters in Europe:

The Rocky Mountains play a major role. Analogous to an island in a stream, the Rockies set up a persistent wave in the winds downstream that brings cold winds from the north into eastern North America and warm winds from the south into western Europe. This pattern of movement of heat by the winds accounts for half of the total difference in winter temperatures between the two regions, with much of the other half attributable to the release of heat stored in the ocean.

Of course, this applies only if the Rocky Mountains aren't melted by global warming. ;)

Jay Manifold [11:39 AM]

Observing Opportunities

Sky & Telescope's This Week’s Sky at a Glance reports a double satellite transit on Jupiter tonight (and again next Friday evening the 31st), plus a striking alignment of the Moon, Mercury, Venus, Mars, and Antares ("anti-Ares," almost exactly the same color as Mars) in the predawn sky early next week.

Locals have numerous opportunities to spot the ISS in the evening sky over the next week, and the Shuttle in the morning sky. That long, narrow rectangle of blue and white squares at the top of this page (just under the flags) is a local dark-sky forecast; click on it for a full explanation.

Jay Manifold [10:51 AM]

[ 20030123 ]

The Brainerd Triangle (II)

(Ref this earlier post.) Got a couple of responses from people who actually know what they're talking about.

Previously encountered reader Chris Weitzel wrote:

What's that saying about the simplest solution usually being the correct one? Variations in the weather is likely the answer.

This winter has been slightly warmer in Minnesota than the 1990's average, as measured by the number of Heating Degree Days (HDD).

-- and pointed me to The Gull Lake Story:

Although one is tempted to interpret days of ice cover as a measure of the severity of winter, it is important to realize that ice cover is sensitive to several environmental factors other than air temperature. In particular, cloud cover, winds, and snow fall all affect freezing and thawing.

Chris concludes:

Someone interested in spending more time on this could check the cloud cover, winds, and snow fall this season compared to most. Perhaps this has been a cloudier year than most, or less windy.

Presumably the surrounding lakes do not experience the same effect or the news report would have covered them as well. This is probably due to a difference in depth, width, or volume of the lakes.

Previously unknown reader (the best kind) Troy Loney then wrote:

Well, I'm no expert in heat transfer -- just a physicist by degree and an engineer by practice, but I think there's a well-known analog of this phenomenon in the Antarctic Ocean: polynyas.

Quick overview here, but the better discussion is here, and especially check the link on formation -- there are two different formation methods, for near-shore and open-ocean polynyas, and either one might apply here.

In either case, the water under the ice will be warmer than the ice ... just as the measurements showed.

I'd never heard of these things. This is cool.

Jay Manifold [1:15 PM]

Food + Clothing + Shelter < Taxes

Via Glenn Reynolds, via Edward Boyd, a poll which shows that about 4 out of 5 Americans think that top tax rates are too high and that only 1 in 50 actually supports the current level of taxation. Zonitics.com also quotes this Tax Foundation finding that median two-income families paid 39% of their income in taxes in '98, which was actually lower than in '96 or '97.

This turns out to be more than their expenditures for food, clothing, and shelter combined!

Specifically, locals -- notoriously a good cross-section of the country as a whole -- spend:

22.4% on housing
10.3% on food
+3.4% on apparel and services

A majority of voters think the tax burden should be cut in half, to less than 20% of income. Who will campaign on such an idea? Not these guys, I'll bet. (The threats made by GWBush and Rangers management in general during the campaign for the tax, to the effect that they were talking to other suburbs about relocating the stadium, were later revealed to have been fabricated. Bush et al made tens of millions of dollars by stampeding the Arlington electorate in this manner.)

Jay Manifold [12:50 PM]


Several correspondents have noted that my set notation in Set Theory, Anti-Terrorism Initiatives, and ... is garbled. I expect they're right. I could say it was just a typo, but I expect it's not. If I'd done it graphically rather than textually, I probably wouldn't have screwed it up.

I could also have saved myself some trouble -- though probably without "earning" the couple of thousand extra hits of an Instalanche -- by saying something much shorter, like: any law-enforcement measure that potentially criminalizes millions of people, whether in the name of fighting terrorism, effecting gun control, enforcing chemical sobriety, or limiting abortion, is a bad idea. And you don't even have to rely on a strong belief in individual rights to prove it.

Jay Manifold [10:14 AM]

[ 20030122 ]

Yousefzadeh vs Manifold

I wrote Pejman to tell him I was slandering him, and he wrote back to offer an unsurprisingly able defense against my charges. Excerpts:

I wasn't trying to soft-pedal anything for a conservative audience, but rather to express my enthusiasm and fascination with the possibilities that nanotech could provide. Nor was I trying to "manage the risk of rejection" ...

... the lack of mention regarding government's role in mapping the human genome was an editing mistake on my part (likely caused by sending the wrongly saved article to the editors at TCS). Once I found out about the mistake, I sought immediately to have it corrected, and acknowledged the mistake in the comments section of the article. The language is now changed to indicate that the private sector played a "significant" role in mapping the human genome, rather than to imply that it played the only role.

... as you yourself mention, I discuss the ability of self-replicating systems to help and assist in oil spills. You mentioned that you would explain that matter "eventually," but since it does not appear that you have yet, I don't have anything to respond to.

Never tangle with a lawyer. Now I've gotta explain what I meant.

I ignored the oil-spills application because nanotech will practically eliminate the long-distance transport of raw materials (on Earth, that is). The inputs for molecular manufacturing are those of plant life: dirt, air, and sunlight. These are immediately available in the requisite quantities everywhere except certain urban areas of very high density. Molecular assemblers/disassemblers can furthermore recycle nearly any artifact or substance into any other (excepting, of course, transmutation of elements), so all organic waste and discarded items become raw materials for new food, clothing, shelter, and devices for personal transportation and communication.

In particular, the abundance of carbon in readily-available soil and organic waste matter will entirely obviate the need to pump hydrocarbons out of the Earth's crust and haul them halfway around the world. The diamondoid structural members of buildings, vehicles, etc, will similarly transcend the need for mining of metals. Resource extraction (on Earth) is not going to be a great business in another generation or so.

The radical degree of local autonomy all this will permit has interesting sociological implications, to say the least, but that's a post for another time.

(Please note that both Pejman and myself are members of the Secret Organization of People with Funny Last Names Planning to Take Over the World, so any appearance of conflict is nothing but a smokescreen in any case.)

Jay Manifold [5:55 PM]

And for Today's Anniversary ...

I encourage perusal of these polling data, which (to my mind) indicate an admirable ability on the part of the American public to draw distinctions in this area. See especially the graphic of "Abortion Attitudes: By Trimester." Roe v Wade respects the Tenth Amendment -- it allows states to ban 3rd-trimester abortions and regulate 2nd-trimester ones.

A ban on 1st-trimester abortions, however, would run into the same problems presented by gun control and Total Information Awareness, that is, defining an enormous (> 107 persons) criminal class into existence. See also Glenn Reynolds' comments on Congress' lack of Constitutional authority to legislate in this area.

Jay Manifold [5:07 PM]

For My Visitors from InstaPundit

The "Nuclear Rocket to Mars?" post is here; Glenn may have directed you to one about nanotech instead -- not that I mind you reading that one!

While you're here, you might browse through the seven (so far) posts listed under "Important Stuff" in the left sidebar. Enjoy, and don't hesitate to send feedback.

UPDATE: I've got Spam Arrest on, so if you do e-mail me, you'll get an e-mail asking for a one-time-only confirmation.

Jay Manifold [7:44 AM]

[ 20030121 ]

Set Theory, Anti-Terrorism Initiatives, and ...

This one's for Alphecca.

Over on Transterrestrial Musings, Rand Simberg points to Do the Math: Rooting Out Terrorists Is Tricky Business, by the invaluable John Allen Paulos.

(Before reading further, you may wish to brush up on Venn diagrams.)

In the scenario presented by Paulos, the universal set is the entire population of the US; set A is the set of future terrorists; and set B is the set of those apprehended, via some technology which is 99% accurate in anticipating their culpability. The conditional probability P(A|B) is quite high; nearly all future terrorists are apprehended.

Unfortunately, the 99%-accurate-technology operates on the universal set, not merely on set A -- and the universal set is several orders of magnitude larger than set A. As a result, while the conditional probability P(U|B) is relatively low, set B is overwhelmingly comprised of innocent members of the universal set.

Now to apply this to another public-policy problem ...

Once again, the universal set is the entire US. This time, set A is the set of owners of devices known as -- well, let's call them "kinetic projectors." Set B is the set of -- well, let's call them "impulsive redistributors." It is common knowledge that the conditional probability P(B|A) is fairly high; that is, many impulsive redistributors are owners of kinetic projectors. Law enforcement organizations make it a priority to apprehend members of set B. On this basis, it becomes public policy to restrict, and wherever possible to ban, the ownership of kinetic projectors, potentially subjecting all of set A to legal action, including criminal charges.

Ignoring for the moment any framework of individual rights that might be present, whether this public policy makes sense or not clearly depends on the relative sizes of sets A and B, to one another and to the universal set. If they are both small, we can hope to avoid the situation as presented by Paulos, where thousands of innocents are arrested for every guilty one; the conditional probabilities P(A|B) and P(B|A) may be roughly equal, and (taking set C as those apprehended for kinetic-projector possession) the conditional probability P(U|C) would be acceptable.

But if set A is much larger than set B, and is itself a large portion of the universal set, then the conditional probability P(A|B) is small and conditional probability P(U|C) is large -- in less fancy terms, we've just made criminals out of a big chunk of the population. I hope it's clear, from the Paulos scenario about botched anti-terror efforts, that this is not a good idea.

What are the actual numbers? The universal set is just over 290 million; set A is one-quarter of the entire population; set B (crudely assuming as many violent criminals outside of prisons as nonviolent criminals inside them) is 3% of the entire population; and the conditional probability P(B|A) -- the prevalence of gun use in violent crimes -- is approximately 8%.

But the conditional probability P(A|B) is less than 0.002 -- and for murder, it's only about 0.00003. So, just as in the Paulos scenario, thousands of innocents will be apprehended for each guilty member of set C.

I conclude that no one who is opposed to the Total Information Awareness initiative should support gun control.

Jay Manifold [8:31 PM]

[ 20030120 ]

Dr King and Dr Axelrod

Lest I appear unappreciative of this day's significance:

... stereotypes can be stable, even when they are not based on any objective differences. The Blues believe that the Greens are mean, and whenever they meet a Green, they have their beliefs confirmed. The Greens think that only other Greens will reciprocate cooperation, and they have their beliefs confirmed. If you try to break out of the system, you will find that your own payoff falls and your hopes will be dashed. So if you become a deviant, you are likely to return, sooner or later, to the role that is expected of you. If your label says you are Green, others will treat you as a Green, and since it pays for you to act like Greens act, you will be confirming everyone's expectations.

This kind of stereotyping has two unfortunate consequences: one obvious and one more subtle. The obvious consequence is that everyone is doing worse than necessary because mutual cooperation between the groups could have raised everyone's score. A more subtle consequence comes from any disparity in the numbers of Blues and Greens, creating a majority and a minority. In this case, while both groups suffer from the lack of mutual cooperation, the members of the minority group suffer more. No wonder minorities often seek defensive isolation.

-- Robert Axelrod, The Evolution of Cooperation (pp 147-8)

It gets even more depressing over the next couple of pages, enough to make any effort, to say nothing of a successful effort, to combat race prejudice seem virtually miraculous. Perhaps we should devote the MLK holiday to a celebration of game theory.

Jay Manifold [6:09 PM]

A Telescope Pointed Down Instead of Up

Over on The Kolkata Libertarian, Suman Palit points to Israel, India to launch shared satellite. Maybe they could share something like this, parked at about 60°E longitude ...

Jay Manifold [11:43 AM]

The Brainerd Triangle?

Over on ABCNews.com, we find a Great Void:

Smack in the middle of North Long Lake, surrounded by eight miles of ice thick enough to drive on, there is a gaping black hole nearly a half-mile long.

It is a lake within a frozen lake — a huge crescent of open water that, for some reason, refuses to freeze over.

(The lake is here.)

At the Sportland Cafe, a combination gas station, diner and convenience store, conversation centers on the mystery.

"It must be some kind of volcanic action," said a waitress topping off a cup of decaf.

"It could be aliens or someone's septic backing up," added a man in coveralls between bites of his waffle.

But Ed Peck, sitting on a swivel stool nearby, doesn't think any of his neighbors' theories hold water. "I think it's a bunch of hooey myself. It's no mystery. We live on an earthquake fault up here. People don't realize that."

I like the alien septic tank idea, or whatever that was, myself. Interestingly, Figure 2 in this document does indicate a fault line in the area (it's the one just beneath the "15" on the map), but the document itself says

Minnesota has one of the lowest occurrence levels of earthquakes in the United States .... Minnesota earthquakes, like those elsewhere in the Midwest, are attributed to minor reactivation of ancient faults in response to modern stresses.

... so I think we can forget about "volcanic action." Nonetheless, assuming the affected area to be 800 meters long, an average 100 meters wide, with an ordinary ice thickness of half a meter, something is elevating the temperature of about 40,000 tonnes of water by 30°C or more. At around 1 million calories per tonne per degree, this is not trivial.

Then there's the change of state: an 80-calorie difference for every cubic centimeter of water that freezes. That's another 80 million calories per tonne. So the total amount of heat energy looks to me like ~ 4 trillion calories.

That's ~ 4 million kWh. Suppose it would take a couple of weeks for the ice to freeze to its ordinary thickness. The power required to prevent this from occuring is upwards of ten megawatts, which is pretty near the entire electricity budget of Brainerd, population 13,000.

Anybody who actually knows something about heat transfer is invited to send me your comments.

Jay Manifold [11:14 AM]

Bubbles and Meltdowns

Over on No Watermelons Allowed, fellow Missourian blogger "J Bowen" imparts a fine engineering lesson, by way of explaining such things as the "pinging" noises in steam radiators and the "slamming" sound one sometimes hears when shutting a faucet off. Obscure hydrodynamics have consequences:

Bubbles are a really big deal with nuclear reactors ... pressurized water reactors (PWRs) (like ... Callaway in MO, Wolf Creek in KS ...) are not to have noticeable bubbles in them under any circumstances ...

This is what led to the worst nuclear accident of all; Chernobyl had a "positive void reactivity coefficient," a fancy way of saying that since steam absorbs fewer neutrons than water, overheating created a positive feedback loop -- more fission, more heat, more steam, more fission -- ending in disaster.

And while you're over there, don't miss this intriguing art project.

Jay Manifold [10:23 AM]

Klez Infection

I foolishly got my PC infected with the Klez virus yesterday. It's cleaned up now, but the virus may have e-mailed itself to a bunch of people through my machine. The fix is available here; my apologies if anyone else was inconvenienced.

Jay Manifold [10:23 AM]

[ 20030118 ]

Bias and Nanotechnology

David Appell points out, correctly, that Pejman Yousefzadeh's nanotech article on TCS is not a model of objective reporting. Not really surprising, since like all articles on TCS, it's an editorial.

David is somewhere to my left, and Pejman is somewhere to my right, so I can easily imagine writing things which would annoy either or both of them; but I find them both valuable, and I hope my readers do, too. I'm going to use this as a springboard to share some of my biases.

Pejman's portrayal of nanotech is far weaker than mine would have been; I'm something of a purist and would have likely gone straight to the source and stepped through the applications as presented therein. Indeed, I suspect that Pejman was soft-pedaling it for a conservative audience. Telling certain kinds of people that we're one generation away from, for example, indefinite life extension, may get a strong reaction of cognitive dissonance (at best). Feeding it to them slowly, and mentioning only those benefits with which they are sure to agree, is a strategy for managing the risk of rejection. -- Not a trivial risk, given that overwhelming majorities of Americans are terrified of reproductive cloning, which is, pardon the expression, child's play compared to nanotech (I note that the results of this search indicate that the TCSers do not share this fear).

Ironically -- given that David is criticizing him for downplaying the Federal role in sequencing the human genome -- Pejman retold the one we've all heard about how DARPA built the Internet. This isn't much more than an urban techno-government legend, like the one about how NASA invented the microchip. If one development can be singled out as having "created" the Internet, which is a highly debatable notion in any case, it was probably UC Berkeley's connection to BITNET in 1982, which prior to that time was a network of "elite East Coast institutions," not the US Department of Defense (source, p 316). But I digress.

The importance of nanotech as a means of providing us with truly long life in an open Universe is such that Spider Robinson has written that a future civilization may make our A.D. 1986 its year 1, because that's when Engines of Creation was published. Much of Drexler's book is not about the technology itself but about the institutions needed to manage its risks. Looking around the world today, one could easily be forgiven for believing that such institutions will not be successfully created on Earth, and the price of a decent existence, a few decades from now, will mean living someplace like this instead.

I would nonetheless emphasize the environmental benefits, which Pejman did not mention at all:

Consider the toxic waste problem. Whether in our air, soil, or water, wastes concern us because they can harm living systems. But any materials that come in contact with the molecular machinery of life can themselves be reached by other forms of molecular machinery. This means that we will be able to design cleaning machines to remove these poisons wherever they could harm life.

With replicating assemblers, we will even be able to remove the billions of tons of carbon dioxide that our fuel-burning civilization has dumped into the atmosphere. Climatologists project that climbing carbon dioxide levels, by trapping solar energy, will partially melt the polar caps, raising sea levels and flooding coasts sometime in the middle of the next century. Replicating assemblers, though, will make solar power cheap enough to eliminate the need for fossil fuels. Like trees, solar-powered nanomachines will be able to extract carbon dioxide from the air and split off the oxygen. Unlike trees, they will be able to grow deep storage roots and place carbon back in the coal seams and oil fields from which it came.

I believe that nanotech will play a crucial role in resolving the "Crisis of 2020" predicted by Strauss and Howe (terminology). But technology needs institutions, or at least memes, to manage it; so perhaps the Federal role should be to do these things rather than to develop the technology itself.

Jay Manifold [6:05 PM]

"For What It's Worth"

Forgive the implied antiwar-protest topic; I've moved on ... this is a tip o' the virtual hat to another blog, For What It's Worth, which just did a follow-up on my Satire Barely Stays Ahead of Actual News.

Jonathan Fox linked to this piece by Richard Hall of connexions, which provides some ammo to those of us who have never trusted the NIV.

Jay Manifold [2:37 PM]

Slow News Weekend Creates Anti-War "Movement"

This and many other stories (including this local one) are perfect examples of one of the main structural biases in news reporting, namely the impulse to create a narrative where there just isn't much of a story.

(My own support for the war is reluctant. Given that the Bush Administration will not directly confront the Pakistanis or [especially] the Saudis, this is as good a risk-management strategy as we're going to see for the next several years. I just want us to get it over with.)

But no amount of wishful thinking will turn Iraq in 2003 into Vietnam in 1968:

  • There is no draft to provide soldiers for the war, there is no income tax surtax to pay for the war, and neither is even remotely likely.

  • The war will last days, not years. The casualty ratio will be at least 1,000:1 in favor of the US. Thanks to precision-guided munitions, prompt civilian casualties will likely be in the hundreds, not the hundreds of thousands as widely predicted.

  • The "anti-war" demonstrations are being organized by Stalinists (source).

  • Support for a war with Iraq is greater than support for the war in Vietnam was in 1968.

  • And not to overlook the obvious: we will win, and the population of Iraq will celebrate.

UPDATE: Thanks to Damian Penny for pointing to this sickening account of American grovelling to the House of Saud.

Jay Manifold [2:04 PM]

More Archetypal Channels

This is my several-days-late follow-up to this earlier post; contributors to the following include, and may be limited to, Alan Henderson, Bob Hawkins, Leo Johns, and Bill Walker (whose only suggestion was that the Fox version of the Disaster Channel be called When Entropy Attacks). If I forgot anybody, send me a denunciatory e-mail.



Killer App

Typical Sponsors


The Elaborate Hoax Channel

deceptions and conspiracies, historical and contemporary

Rael: The New Eoanthropus dawsoni


World Wrestling Federation, Jerry Springer,Howard Stern

The Self-Referential Channel

people watching the SRC

people watching people watching the SRC

same as for Reality Television

Reality Television

The Channeling Channel


Raelian Reality: T or F?

the IRS

Sci Fi Channel, channelling-online.com

The English Channel

swimming, tides, the Gossamer Albatross

Chunnel Terrorism: Fire in the Hole

boat manufacturers; Speedo


The Archetypal Channel Channel (Channel 57)

What Makes Good Television?

The Lyrics of Bruce Springsteen

A Voyage To Arcturus

the entire blogosphere

The Funeral Channel

funerals of the rich and/or famous


funeral homes, life insurance

companies, florists

cable news channels


Theme Music and Logo (all suggestions from Alan Henderson)

Cuteness Channel

Either Symphony #6 (first movement) by Ludwig van Beethoven, or "Carnival of the Animals" by Camille Saint-Saens. Music accompanies scene of playful puppy, kitten, and toddler (maybe Gnat Lileks could get the gig) that, through the magic of CGI, morphs into the network's logo.

Disaster Channel I

Overture of Richard Wagner's opera "Die Valkure" (not to be confused with "Ride of the Valkyries"). When I heard the low rumbling of the cellos for the first time, I thought it should have been on the "Twister" soundtrack. Music would accompany a video clip of a tornado that morphs into the network's logo.

Disaster Channel II

"Burning Down the House" by the Talking Heads. Music would accompany video clip of burning building (make it FEMA headquarters for laughs) that morphs into the network's logo.

Wretched Excess Channel

"Money Money Money" by Abba. Music would accompany video clip of a 1940s Bentley pulling up in front of a mansion just as a Lear jet flies overhead - this morphs into the network's logo.

Lurid Channel

Carmina Burana ("O Fortuna") by Carl Orff. I'll let someone else suggest the visuals.

HP Lovecraft Channel

One of those reminiscent-of-a-slasher-movie-soundtrack Bela Bartok compositions. Music would accompany video clip of Antarctic explorers. They creep along as a giant shadow looms over them. As the violins screech at maximum volume, a blast of dense snowfall conceals the scene for a couple of seconds and then thins out, revealing that the expedition has disappeared. Antarctic scenery morphs into logo, which might be some creepy city ruins or simply a mountain range with a mysterious glow behind the horizon. No, it won't be a hundred CBS eyes :-)

Jay Manifold [12:58 PM]

[ 20030117 ]

Nuclear Rocket to Mars?

Not so fast, says NASA spokesman Don Savage in this Leonard David story on Space.com, which attempts to clear up some of the confusion; the Nuclear Systems Initiative is more about electric power generation for space probes than about propulsion, much less a manned mission to Mars (as I reported last March from LPSC).

The closest this comes to nuclear rockets is described in a news release as

Nuclear electric propulsion -- or the use of nuclear reactors to generate heat, which is converted into electrical power for high-performance electric thrusters -- has the potential to greatly improve the capability, sophistication and reach of future science missions. The development of high power thrusters and power conversion systems are critical components to enable future nuclear-electric propulsion systems.

"Electric propulsion systems," more familiarly known as ion rockets, are fantastically efficient (I = 3000 sec) but have very low thrust, and therefore cannot be launched from Earth but are excellent for moving spacecraft around the Solar System -- or even leaving it altogether. A spacecraft in low Earth orbit, as noted in the post below, needs an additional 3,300 m sec-1 or thereabouts to escape from Earth. It then needs another (Ö2 - 1), or .414, ´ Earth's orbital velocity of 29.8 km sec-1, to escape from the Sun. All this totals to Dv = 15.6 km sec-1.

Even a very efficient chemical rocket, burning liquid hydrogen and liquid oxygen and with I = 450 sec, must devote so much of its mass to propellant as to leave almost nothing left over for payload. This time, the relevant form of the rocket equation is

1 - (mbo/m0) = 1 - 1/eDv/gI

Plugging in the values for Dv and I and recalling that g = 9.81 m sec-2 and e = 2.718... shows that 97% of the entire mass of the spacecraft is propellant! Everything else -- rocket engines, propellant tanks, structural members, and payload -- must somehow fit in the other 3%.

This is why we have to use gravity-assist maneuvers so that our chemical-rocket-launched probes can make it to the outer Solar System. But change I to 3000 sec, and the propellant mass fraction drops to 41%, leaving nearly three-fifths of the spacecraft mass for engine, tank, structure, and payload.

The Deep Space 1 probe has already demonstrated this technology; of course, its electricity came from solar panels. Beyond Mars orbit (1.524 AU; by the inverse-square law, 43% the sunlight Earth gets) solar panels become impractical -- I've been told that they're ineffective even on the surface of Mars any farther than 30° from the equator. Thus the emphasis on nuclear generators of some kind to provide the electricity.

Wherever the word "nuclear" appears, there's sure to be a sideshow of protest, and in this case, it's being provided by this organization.

Jay Manifold [9:01 PM]

Fun with the Rocket Equation

-- but no fun with the Ariane 5-ESCA rocket, whose new 1.3 million-newton (290,000-lb) thrust Vulcain 2 engine blew up during a launch last month, thereby significantly delaying the launch of the Rosetta comet probe, even though "[i]t will go up on a standard version of the Ariane 5 - not the new configuration that was lost on 12 December."

The astonishing unreliability of launch vehicles is a topic for another time, though I could save some effort by simply referring my readers to Transterrestrial Musings, where Rand Simberg frequently discusses the economics (and politics) of the space industry. Let me put it this way: the first liquid-fueled rocket was launched 77 years ago; the first successful gasoline-powered internal-combustion four-cycle engine was produced in 1876; imagine it's 1953 and there's a 1% chance that a car will explode every time it's driven. That's how ridiculous this situation is.

But I blog to have fun, so upon reading in Mark Wade's incomparable Encyclopedia Astronautica that the Ariane 5 can put 6,800 kg in geosynchronous transfer orbit, and then grazing over to the Rosetta Spacecraft Design page and finding

... maximum 'wet' (spacecraft and fuel) mass is 2 900 kg, with a propellant portion of more than 50%. This mass limit is governed by the launch capability of Ariane-5 ...

A total amount of at least 1 578 kg propellant will be accommodated.

-- for a total Dv of 2200 m sec-1, I'm off to the races. You can read this for background if you want; I'll be working from the Manifold Condensed Version, as it were.

The information given about Rosetta is sufficient to calculate the efficiency of its propulsion system; the form of the equation to use for this is

I = Dv/(g ln (m0/mbo)), where

I is specific impulse in seconds
Dv is change in velocity in m sec-1
g is acceleration due to gravity at sea level on Earth, 9.81 m sec-2
ln is the natural logarithm (to the base e, 2.718...) of the following term
m0 is the initial mass of the spacecraft, that is, fully fueled, and
mbo is the mass of the spacecraft at "burnout," that is, after all propellant has been expended

We have:

I = 2200 m sec-1/(9.81 m sec-2 ln (2,900 kg/1,322 kg))

Result: 285 sec. So what the heck does that mean?

It means, first, that a given weight of propellant can yield the same amount of thrust for this number of seconds, ie 1 pound of fuel and oxidizer will produce 1 pound of thrust for 4 minutes and 45 seconds in the main rocket engine onboard Rosetta. Or 285 pounds of propellant could produce 285 pounds of thrust for 1 second. The higher this number, the more efficient a rocket engine is.

Secondly, this is typical of more or less room-temperature (non-cryogenic) propellants, such as N2O4/UDMH, which are often described as "earth-storable" or "space-storable" -- suitable for lengthy missions; Rosetta is to operate for over a decade.

Now let's look at the Ariane-5's capabilities. Its upper stage has I = 324 sec, m0 = 12,700 kg, and mbo = 2,500 kg; this is all to put 6,800 kg into GTO. In this application, we're putting 2,900 kg into an escape orbit. What's the highest possible velocity?

The form of the rocket equation now becomes

Dv = gI ln (m0/mbo)

With g and I as stated, m0 = 12,700 kg + 6,800 kg = 19,500 kg, and mbo = 2,500 kg + 6,800 kg = 9,300 kg. Result: 2,350 m sec-1.

Replacing the baseline 6,800 kg payload with the Rosetta 2,900 kg payload changes m0 to 15,600 kg, mbo to 5,400 kg, and the
Dv to 3,370 m sec-1, or 1,020 m sec-1 extra velocity.

But how fast is GTO? Better yet, what is GTO?

Geosynchronous transfer orbit is a highly elliptical orbit (with eccentricity e ~ 0.7-0.75) connecting two circular orbits: a lower one typically a few hundred kilometers above Earth's surface, and a higher one 35,786 km up, where one orbit takes exactly one day, thus keeping the satellite above the same point on the equator. It takes almost as much velocity to get from low Earth orbit (LEO) to GTO as it does to get from LEO into a completely independent orbit around the Sun.

Specifically -- and I built a spreadsheet to do this for me a while back, drawing heavily on Fundamentals of Astrodynamics, so there won't be any more equations in this post -- to go from a 200-km orbit to GTO requires 2,455 m sec-1 of additional speed. Since the actual
Dv rating of the Ariane-5 upper stage, as we have seen, is 2,350 m sec-1, we may infer that its starting point is somewhat higher than 200 km. It turns out to be about 560 km.

But to go from 560 km to solar orbit, that is, to escape from Earth entirely, requires only about 3,140 m sec-1, that is less than 800 m sec-1 more. So the Ariane-5/Rosetta combination, with 3,370 m sec-1, can do this and have 230 m sec-1 left over.

Jay Manifold [3:10 PM]