Thursday, February 11, 2010

Interstellar archaeology and surface engineering

The SETI League has published a short article describing my strategy for what some have dubbed "interstellar archaeology", namely the use of astronomical instruments to look for alien artifacts in other star systems or galaxies. In contrast to SETI, which listens for radio or optical transmissions, interstellar archaeology is looking for material structures. The connection between surface engineering and strategies that look for alien constructions seems quite obvious to me, now that I have thought of it, but I've done a literature and Internet search and haven't seen the connection made by others. The discussions seem to be all about the design of these hypothetical astrostructures themselves rather than about what astronomical instruments could give us a great deal of information about, if there are any to be seen, namely their surfaces.

My strategy emphasizes that, whatever the alien structure may be, we would be looking at its surface. Artificial surfaces tend to be highly engineered for useful thermal and optical properties. The spectra of artificial satellites, painted surfaces, skyscraper windows, and so on exhibit many features which are extremely improbable in nature. For example, skyscraper windows and spacecraft surfaces often have gold at concentrations millions of times higher than stellar dust clouds, because of gold's very good thermal and optical functions. There are also many artificial molecules used in paints, again with unique spectra that would stand out from natural galactic features. Advanced ETI may have moved on to more advanced surfaces, but whatever they use, it is very likely to have highly unnatural spectra in order to optimize its function.

My surface-engineering-based search strategy has the added benefit that it doesn't matter how large any individual structure is, so long as a collection of artifacts collectively present surfaces that look artificial enough to stand out from natural galactic spectra. It also doesn't matter whether or not ETI are operating any of a number of hypothesized high-energy nuclear technologies: natural sunlight reflected off artificial surfaces is sufficient. Thus "Fermi bubbles", hypothetical regions of other galaxies to which an ETI civilization has spread, may be most readily recognized not by features recognizable to the human eye (in any nearby large galaxy, astronomers would already have discovered them), nor by determining what kinds of structures the ETI have constructed, but analyzing, often by exhaustive computer search, spectra of different regions in galaxies for the tell-tale signatures of engineered surfaces.

Monday, February 01, 2010

The basics: procedural vs. substantive law

Several readers have expressed interest in learning some law. I highly encourage this. Knowledge of legal basics is not only of great practical use in modern society, it is essential for understanding politics and history, regardless of whether you have any interest in becoming a lawyer. I will thus be making a number of posts over the next few months discussing a variety of basic legal concepts. These may include subject matter jurisdiction, personal jurisdiction, the tort of trespass, contract formation, and a variety of other basic legal ideas. Today I write about the crucial distinction between procedural and substantive law.

Procedural law is about how the law gets passed and enforced: who has jurisdiction over whom, and what coercive processes they may use to bring suspected lawbreakers to justice. The famous Miranda lines "you have the right to remain silent...." generally uttered in the U.S. when you are arrested are a species of U.S. federal procedural law. Procedure usually starts in a given case with a great deal of uncertainty and tries to reduce that uncertainty by fairly gathering and evaluating evidence, interpreting the law, and applying those facts to the law to reach legal conclusions.

Substantive law involves every law that is not procedural: it is what we normally discuss when talking about law or politics, namely the laws defining and restricting rights and duties for their own sake, not primarily for the sake of enforcing other laws.

Thus for example modern property, contract, tort, family, and criminal law are substantive legal areas, as are environmental, workplace, traffic, and most other regulations. On the other hand, the laws defining who may sue whom and where, and what does and does not constitute proper arrest, interrogation, and search of criminal suspects, are procedural laws. Historically, just to confuse things a bit, property rights sometimes included rights of coercive procedure, for example the lord who had jurisdiction over his unfree tenants. This made property law in some cases part of the procedural law as well as a substantive law of economic property.

Computer protocols work in layers: wires carry bits of information, and bits of information carry text, pictures, and so on. The raw bits of information are a lower level protocol that carries the text and pictures in a higher level protocol. Language works like this too: at the lowest level, paper has letters written on it. Letters are a lower-level protocol that carries words in a higher level protocol. You can think of the distinction between substantive and procedural law in the same way: the procedural layer is a lower layer that "carries" the substantive law by specifying how it is to be enforced.

We can also think of government and government-like entities as lower levels of the legal protocol. Indeed, it is very useful to study political structures alongside procedural law. Think of coercive entities like police and courts as the paper and pencil, procedural law as the letters, and substantive law as the words and sentences we want to make out of these raw materials.