The Pillars of Eagle Castle

For your entertainment and edification, this recent image from Astronomy Picture of the Day: The Eagle Nebula star forming region. What a great sight this would be from the viewport! (Though, as with objects seen through a telescope eyepiece, the real thing is doubtless less vivid but more magical than this composite image.)

In the astronomy news, Sky and Telescope reports on possible evidence of 'midsized' black holes, one of which may be in globular cluster M54. Which, as it turns out, may be not just one more of our own galaxy's globular clusters, but perhaps the nucleus of a dwarf galaxy in the process of being torn apart by its overly close relationship with the Milky Way.

And don't forget this week's Star of the Week, Rho Aquilae.

Tough Guide: Singularity

Back by popular demand! I have not updated the Tough Guide to the Known Galaxy since I wrote it, but this begins a new sporadic series. I will add entries here, and (perhaps!) in due course as an addendum page to the original. So here we go!


The SINGULARITY has not happened anywhere in the Known Galaxy, at least not to Earth Humans. This is for two reasons: one plausible, the other decisive. The plausible reason, as with the decline of Robots and AI since the Golden Age, is niggling doubts about whether the thing could really happen. Computers are Really Fast, but not really all that bright, and it is not a bit clear how to make them brighter than we are when we haven't a clue how the human brain does our thinking for us.

Of course, plausibility problems alone would not stop SF. (See FTL.) The more serious problem, the decisive one in fact, is that the Singularity is an ultimate story killer. Its end result is a world as incomprehensible to us as, say, financial securities regulation would be to australopithecines. There's just enough room, barely, for some bittersweet awe, as Clarke managed in Childhood's End (a sort of proto-variation on the Singularity theme). But the Singularity provides little room for straightforward adventure and none at all for sequels, both of them the lifeblood of the Known Galaxy.

But a Singularity-like event may well have happened to some other race, in the Cosmic Background History. This provides a handy source of godlike beings who, being godlike, have the good sense to stay mostly offstage, turning up only when the author needs them to hustle the plot along.


Related links: My speculation about the nature of science fiction.

Garden Worlds, Park Worlds

In the old days, interstellar colonization was pretty simple and straightforward (once you had a starship handy). Heinlein, naturally, provided the real estate pitch:

"Imagine a place like Earth, but sweeter than Terra ever was … forests aching to be cut, game that practically jumps into the stew pot. If you don't like settlements, you move on until you've got no neighbors, poke a seed in the ground, then jump back before it sprouts. No obnoxious insects. Practically no terrestrial diseases and no native diseases that like the flavor of our breed." (Starman Jones, Ballantine pback, p. 68.)

Nova Terra, to be sure, was the pick of the lot. In the same book Heinlein alludes to harsh colony worlds – and later on, an Eden planet turns out to have non-prelapsarian locals already in possession, who intend to stay that way. But given a sky full of stars and a ship to get you there, why settle for the also-rans? Heinlein also supplied a host of secondary tropes, such as the utility of horses that can fuel themselves from a handy pasture and (given a stallion and a mare) manufacture their own replacements.

Unfortunately, as commenter Ian M. noted a couple of months back (in comments spinning off a post about the Moon), it is desperately unlikely to work out that way. Suppose a planet with complex life, and enough of it to have built up an oxygen-rich atmosphere. It may look like Paradise, or at any rate Earth. Convergent evolution might well produce para-forests and para-grasslands, just as dolphins have a similar configuration to fish. But dophins aren't fish, and alien life almost certainly will not be like us. Hydrocarbon life anywhere will be built out of the same basic building blocks, but with differing architectural details – and our digestive keys will not fit its nutritional locks.

The good news is that the local tigers and local germs won't find us tasty and nutritious. But by the same token we can't eat the local venison or berries, and chances are only slightly better that our cattle can graze on the grass. Plants have a far less demanding diet, and might well grow nicely in any soil that has nitrogen fixed in it. In fact they might grow too well, at least the ones that don't rely on bees or other terrestrial creatures as their dating service.

Terrestrial plants, devoid of natural enemies, might crowd the native stuff out of any remotely suitable environment – wrecking entire ecosystems. But this too could go both ways. To local para-algae we could be walking Petri dishes: warm, moist, and fertile. Our bodies' defenses, if any, are likely to take the form of allergic reactions, not terribly helpful to us.

In short, any garden worlds out there are probably not for us. Those valleys with forested slopes above babbling streams filled with flashing para-trout are the ultimate nature preserves, to be appreciated but not subdivided for housing tracts. Yes, theoretically we might simply wipe out the native life, then recolonize with a terrestrial ecosystem including ourselves. I don't think you have to be a Jain to find something repulsive about this.

Which leaves the option of terraforming. For every nature-park world we will probably find dozens that didn't quite make it. We do not yet know whether life arises wherever there is liquid water to be had – we may begin to find out on Mars and Europa. But if a planet has oceans but no life it is a candidate for terraforming, and only the ecopoetic or gardening stage is required – no need to sling comets from the outer system to provide water, or hoover up 90 bars of CO2 out of the atmosphere. Worlds with limited 'primitive' life may even allow a sort of biological nonaggression pact, the native forms going quietly on in their own local ecosystems. There are still ethical questions (we're precluding or at least greatly altering their evolutionary prospects), but not like the ethics of sterilizing a rich, living world.

Yet even interstellar colonization is not as simple as it used to be.


Related post: In the early days of this blog I commented on the largest-yet (still!) discovery report of extrasolar planets.

In the Course of Human Events ...

... And the broad perspective of history, Farmer George was rather a sad character than a wicked one. While the first two Hanoverians had nearly the sole virtue of not being Stuarts, George III seems to have been on the whole a rather decent man, if shall we say rather stubborn and pigheaded. And he suffered terribly from what passed for medical science in the 18th century.

But human events took their course, and so:

IN CONGRESS, July 4, 1776.

The unanimous Declaration of the thirteen united States of America,

When in the Course of human events, it becomes necessary for one people to dissolve the political bands which have connected them with another, and to assume among the powers of the earth, the separate and equal station to which the Laws of Nature and of Nature's God entitle them, a decent respect to the opinions of mankind requires that they should declare the causes which impel them to the separation.

We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness.--That to secure these rights, Governments are instituted among Men, deriving their just powers from the consent of the governed, --That whenever any Form of Government becomes destructive of these ends, it is the Right of the People to alter or to abolish it, and to institute new Government, laying its foundation on such principles and organizing its powers in such form, as to them shall seem most likely to effect their Safety and Happiness. Prudence, indeed, will dictate that Governments long established should not be changed for light and transient causes; and accordingly all experience hath shewn, that mankind are more disposed to suffer, while evils are sufferable, than to right themselves by abolishing the forms to which they are accustomed. But when a long train of abuses and usurpations, pursuing invariably the same Object evinces a design to reduce them under absolute Despotism, it is their right, it is their duty, to throw off such Government, and to provide new Guards for their future security.--Such has been the patient sufferance of these Colonies; and such is now the necessity which constrains them to alter their former Systems of Government. The history of the present King of Great Britain is a history of repeated injuries and usurpations, all having in direct object the establishment of an absolute Tyranny over these States. To prove this, let Facts be submitted to a candid world.

He has refused his Assent to Laws, the most wholesome and necessary for the public good.

He has forbidden his Governors to pass Laws of immediate and pressing importance, unless suspended in their operation till his Assent should be obtained; and when so suspended, he has utterly neglected to attend to them.

He has refused to pass other Laws for the accommodation of large districts of people, unless those people would relinquish the right of Representation in the Legislature, a right inestimable to them and formidable to tyrants only.

He has called together legislative bodies at places unusual, uncomfortable, and distant from the depository of their public Records, for the sole purpose of fatiguing them into compliance with his measures.

He has dissolved Representative Houses repeatedly, for opposing with manly firmness his invasions on the rights of the people.

He has refused for a long time, after such dissolutions, to cause others to be elected; whereby the Legislative powers, incapable of Annihilation, have returned to the People at large for their exercise; the State remaining in the mean time exposed to all the dangers of invasion from without, and convulsions within.

He has endeavoured to prevent the population of these States; for that purpose obstructing the Laws for Naturalization of Foreigners; refusing to pass others to encourage their migrations hither, and raising the conditions of new Appropriations of Lands.

He has obstructed the Administration of Justice, by refusing his Assent to Laws for establishing Judiciary powers.

He has made Judges dependent on his Will alone, for the tenure of their offices, and the amount and payment of their salaries.

He has erected a multitude of New Offices, and sent hither swarms of Officers to harrass our people, and eat out their substance.

He has kept among us, in times of peace, Standing Armies without the Consent of our legislatures.

He has affected to render the Military independent of and superior to the Civil power.

He has combined with others to subject us to a jurisdiction foreign to our constitution, and unacknowledged by our laws; giving his Assent to their Acts of pretended Legislation:

For Quartering large bodies of armed troops among us:

For protecting them, by a mock Trial, from punishment for any Murders which they should commit on the Inhabitants of these States:

For cutting off our Trade with all parts of the world:

For imposing Taxes on us without our Consent:

For depriving us in many cases, of the benefits of Trial by Jury:

For transporting us beyond Seas to be tried for pretended offences

For abolishing the free System of English Laws in a neighbouring Province, establishing therein an Arbitrary government, and enlarging its Boundaries so as to render it at once an example and fit instrument for introducing the same absolute rule into these Colonies:

For taking away our Charters, abolishing our most valuable Laws, and altering fundamentally the Forms of our Governments:

For suspending our own Legislatures, and declaring themselves invested with power to legislate for us in all cases whatsoever.

He has abdicated Government here, by declaring us out of his Protection and waging War against us.

He has plundered our seas, ravaged our Coasts, burnt our towns, and destroyed the
lives of our people.

He is at this time transporting large Armies of foreign Mercenaries to compleat the works of death, desolation and tyranny, already begun with circumstances of Cruelty & perfidy scarcely paralleled in the most barbarous ages, and totally unworthy the Head of a civilized nation.

He has constrained our fellow Citizens taken Captive on the high Seas to bear Arms against their Country, to become the executioners of their friends and Brethren, or to fall themselves by their Hands.

He has excited domestic insurrections amongst us, and has endeavoured to bring on the inhabitants of our frontiers, the merciless Indian Savages, whose known rule of warfare, is an undistinguished destruction of all ages, sexes and conditions.

In every stage of these Oppressions We have Petitioned for Redress in the most humble terms: Our repeated Petitions have been answered only by repeated injury. A Prince whose character is thus marked by every act which may define a Tyrant, is unfit to be the ruler of a free people.

Nor have We been wanting in attentions to our Brittish brethren. We have warned them from time to time of attempts by their legislature to extend an unwarrantable jurisdiction over us. We have reminded them of the circumstances of our emigration and settlement here. We have appealed to their native justice and magnanimity, and we have conjured them by the ties of our common kindred to disavow these usurpations, which, would inevitably interrupt our connections and correspondence. They too have been deaf to the voice of justice and of consanguinity. We must, therefore, acquiesce in the necessity, which denounces our Separation, and hold them, as we hold the rest of mankind, Enemies in War, in Peace Friends.

We, therefore, the Representatives of the united States of America, in General Congress, Assembled, appealing to the Supreme Judge of the world for the rectitude of our intentions, do, in the Name, and by Authority of the good People of these Colonies, solemnly publish and declare, That these United Colonies are, and of Right ought to be Free and Independent States; that they are Absolved from all Allegiance to the British Crown, and that all political connection between them and the State of Great Britain, is and ought to be totally dissolved; and that as Free and Independent States, they have full Power to levy War, conclude Peace, contract Alliances, establish Commerce, and to do all other Acts and Things which Independent States may of right do. And for the support of this Declaration, with a firm reliance on the protection of divine Providence, we mutually pledge to each other our Lives, our Fortunes and our sacred Honor.

Related link: In which I speculate on the future of the Glorious Fourth.

Space Warfare IV - Mobility

In space everything is moving, and all motion is relative. Hollywood naturally ignores this, with good reason from their perspective. With a handful of honorable exceptions, such as Babylon 5's Starfuries, media spacecraft move like airplanes or sea vessels, and when their drive engines fail they 'stop.' This Aristotelian physics, in fact, matches the universal human experience, with partial exception for the 499 people who have so far traveled into space.

Like the planet Mercury, real spacecraft do not move according to Newtonian physics. But unless you have an antimatter drive or some such, Einstein can be ignored (at least for navigation and maneuvering). This is fortunate, because dealing with Newton is complicated enough.

Whatever their drive (so long as it is non-magical), spacecraft move not like ships or airplanes, but rather like self-propelled artillery shells. Once they fire themselves into a particular orbit they can change that orbit only by another burst of power, expending more propellant in the process. (With the one exception of using a planetary atmosphere for 'aerobraking.') A task force headed, say, from Earth to Mars probably has reserve fuel for an abort option: an orbit returning to Earth, or to some friendly base. It probably does not have enough reserve to change orbit and attack Ceres instead - at least not without cutting dangerously into reserve margins, and likely not even then.

Fuel supplies and possible orbits will thus dominate every aspect of space warfare. In the familiar expression, amateurs study tactics while professionals study logistics. In space even amateurs ignore logistics at peril of finding themselves on orbit to nowhere. Assuming you avoid this and are on orbit to somewhere, if it is a hostile somewhere you will have a fight on your hands once you arrive. Unless you perform an abort maneuver, arrive there you most certainly will.

And you will arrive at impressive speed, relative to an enemy on a different orbit. Even economical (and sluggish) Hohmann transfer orbits imply typical encounter speeds of a few kilometers per second. If you take a fast, 'steep' interplanetary* orbit, encounter speeds can be dozens of km/s, on up to whatever your drive tech allows.

If you intend to stick around wherever you are attacking (as opposed to a 'drive by' raid), you may perform your orbit-matching maneuver before arriving in fighting range of the enemy, and encounter speed will be lower. But if you are fighting anywhere near a planet, its gravity well also has to be taken into account. Generally, unless the two sides tacitly agree to match orbits before the shooting starts, encounter speeds of at least a few km/s will be the rule. Which brings us to tactical maneuver.

The maneuver characteristics of spacecraft correspond roughly to the mathematical first derivatives of their terrestrial counterparts. Range, in the sense of cruising radius, hardly exists as a concept. Whatever your orbit, you will stay on it indefinitely until you change it or run into something. What a big fuel tank (or potent brand of fuel) gives you is not longer range but greater speed, the first derivative of motion. More precisely it gives you more delta v - the capacity to change your orbit. What a whomping powerful drive engine gives you is not speed but acceleration (the first derivative of speed): the ability to change orbit abruptly.

For a given power output there is a theoretical tradeoff between delta v and acceleration, in engineering terms specific impulse and thrust. For chemfuel this doesn't matter in practice, but for advanced drives it could be important. Some proposed drives, notably VASIMR, can operate in more than one mode, providing the equivalent of afterburning (though based on an entirely different principle). Such drives might have a fuel-efficient but low-acceleration cruise mode for deep space missions, and a combat mode providing short bursts of high acceleration for combat maneuvers.

Alas for Romance**, there is serious question whether dashing combat maneuvers are very useful in space. You can only hope to dodge a laser beam at very long ranges, probably a light-second (300,000 km) or more, and at that range a second or two of jinking will not affect the tactical geometry. If chemfuel missiles are in use they can be outdistanced; while their acceleration is very high their delta v is severely limited, a few km/s, and a missile that has run out of fuel is very easy to dodge. In contrast, missiles fitted with a scaled down version of ship drive - 'torch missiles' - are in Ken Burnside's vivid expression like police dogs. Needing fuel only for a one way trip they can outperform any practical ship. If one is sicced onto you it will hunt you down, and can be stopped only by shooting it. (Or throwing it a bone, perhaps!)

All of which suggests that - absent other complications - space tactics may have somewhat the flavor of 18th century formalism: Constellations of space warcraft approaching each other in well-defined formations, their engagements unfolding with the stately grandeur of a battle between mobile Vauban forts.

Combined with the inexorable quality of space motion - no calling a halt to think things over - this formalism could make space battles rare. If you are outgunned, clever shiphandling probably won't save your bacon. If you are the attacker, think long and hard about that abort orbit. If you are the defender, this might be a good time to seek mutual understanding through dialogue. Perhaps you can talk faster than the other side can shoot.

But what, you may ask, are those 'other complications' that could add a dash of dash to the mix? The most promising of these is a battle in orbital space, amid a clutter of civil spacecraft and stations that neither side is eager to destroy. Why the defender would prefer not to wreck their own infrastructure is obvious. Why the attacker might wish not to destroy these things will, for now, be left as an Exercise for the Reader. Suffice to say here that orbital combat near a planet has a multitude of complications that make it potentially both quite different from and more interesting than battles in deep space.

* For this discussion, enroute to or from a wormhole or other FTL jump point is just another interplanetary orbit.

** In the older, broader sense of Romance; the issue has no obvious bearing on love affairs.


Related links: A general discussion of interplanetary movement. And as always, Winch Chung's Atomic Rockets pages are a treasure trove of relevant information and commentary (plus a century of SF/space related eye candy).

Lord Of My Own Domains II

As the long, slow death of Compuserve reaches its final throes, the time has come at last to move my 'static' website, The Observatory, to a new domain: www.rocketpunk-observatory.com.

I cleared up much clutter from the old site (e.g. political stuff from the early 2000s) that no one will miss, but this is as good a time as any to highlight a couple of retained items of interest to readers of this blog. (You will also note that I've added a shameless little plug for myself, both at the website and on the sidebar of this blog. What can I say? We live in a capitalist system!)


Interstellar Trade: A Primer. For much of the decade my post was the top Google result for the search terms 'interstellar trade,' which was pretty cool. Even now it ranks third, after two links to economist and NYT columnist Paul Krugman. (He once wrote a paper on STL trade!) Alas, with the move it will lose old inbound links and drop down into the long tail somewhere. But you can still find it here.


The Tough Guide to the Known Galaxy. Obviously inspired by Diana Wynne Jones, encyclopedia-style thumbnail comments on space SF tropes. Winch of Atomic Rockets has done me the honor of citing quite a few of these - see his site for much, much more of interest.


The Observatory main page has a links to couple of other items, plus (scroll down) a few software toys I've written over the years.

And the comments thread for this post can serve for something I never had previously - a place to comment on Interstellar Trade and the Tough Guide to the Known Galaxy, or anything else on my static site.

Affordable Interstellar Tourism ...

Free, in fact. Okay, so it is only virtual, but still well worth the ticket price.

Scroll down about three screens at the Stars website for the Star of the Week. This weekend it is 3 Vulpeculae - click on the link to find out more about it. The site, run by University of Illinois astronomy professor emeritus Jim Kaler, features a new star most Saturdays, and the whole list is now up to 608, about a tenth of all naked eye stars. Scroll down his page for links to the other 607.

There is something very pleasing, at least to me, about reading this sort of travel-guide information about stars and other celestial objects. I get the same experience from Burnham's Celestial Handbook. In spite of my perhaps regrettable (but evidently popular) penchant for writing about how to blow stuff up, and the more respectable desire for knowledge, space travel is at bottom all about the tourist impulse.


Related links: I wrote about sky observing as a road trip, and two posts about extrasolar planets. The image of the Trifid Nebula (click on it for full size) is from NASA's Astronomy Picture of the Day.