I have a directory full of background information about the Ra universe, and I realised recently that some of this information is now wholly "declassified". That means you folks might want to see it. Here's the first one.
Technically, there are no spoilers here, even if you haven't started reading Ra yet. However, this is not the preferred entry point to the story! This is reference information. You should go and read from the beginning if you haven't already!
Magic is a type of energy and a set of methods for manipulating and transducing that energy into other, more useful forms. Magic energy is called mana to distinguish it from the practice of magic.
Mana is moved around and spent by people, using verbal commands known as magic words or spells. Spells form a sort of API for requesting magical services. Spells are localised and for the most part take effect at the point in space where they are spoken. Simply speaking the words is not sufficient. The words serve as a mantra for the person speaking them, and it is the process of mentally jumping through various "hoops" which actually causes the invocation to occur. Casting a spell is effectively like performing a very complicated piece of mental arithmetic in one's head.
Individual magical ability is therefore largely a function of ability to perform extremely fast mental logical deductions. This is loosely correlated with mathematical ability. Typically you have to be at least 15 years old before the simplest spell is in your grasp, although some will pick it up earlier, while the vast majority will never bother with it at all. Men and women are equally capable of magic, but the field, like many sciences, is male-dominated.
Clear speech is very important. A lisp or a bad "magic accent" (yes, magic words are a language unto themselves and have their own accent) will cause problems. A person unable to speak is unable to use magic. Machines can speak, but apparently they cannot do the "mental arithmetic", and so are also unable to use magic.
Physical objects can be used to channel, store, modulate, transduce and spend mana. Magical artifacts must be the correct shape and have the correct markings/engravings on them. These markings are long interleaving patterns.
Magical artifacts must also have a suitable chemical composition. Better manufacturing tolerance and more precise chemical ratios yield more reliable results. The best conductors of magic are magnesium, mercury and the noble gases; that is, soft metals and non-metals. Since these are clearly only workable at very low temperatures, and mercury in particular is poisonous, the preferred materials in practice are metals, usually steels or lighter alloys.
The most recognisable tool is the staff. This is canonically a tube two metres long, two centimetres in diameter, made of steel. It is usually made in three to six pieces which unscrew for portability. The staff's axis is always perfectly straight, but otherwise variations abound. Other tools take the form of specialised metallic magic rings of varying function, genus, composition and size: from tenths of millimetres to tens of metres in diameter.
Equipment accrues over a mage's professional life. Most mages end up with a toolbox and/or a car boot full of junk. Women sometimes wear magical equipment as jewellery. Men are more likely to carry a collection of smaller rings on a keychain or carabiner. Of course, it is all a matter of personal preference. Due to the necessary precision of construction and the unusual materials, even mass-produced magical tools are very expensive. Custom-manufactured tools cost ten times as much.
Mana is a natural byproduct of a working human body. Mana hangs around the person in a sort of cloud, constantly being replenished. From the cloud, mana either evaporates into waste mana (becoming unusable), or is spent by the mage on magic spells. When mana is spent or stored, the cloud will diminish, but it mostly replenishes after around 24 hours.
A person can only use his or her own mana.
Different people generate mana at different rates, depending on their health and age, and on other factors not yet fully determined. Replenishment happens faster while asleep. A person's mana output P can be measured (in watts) using appropriate magical machinery and a long and involved spell. Professional mages get "rated" every one or two years, much like an eye test, but the variation in wattage from person to person actually tends to be quite small.
A person's mana level E (the current "size" of the cloud, in joules) can be measured using a similar spell. But this is generally not worth the effort. Most mages develop routines to monitor their own usage and avoid running out before the end of the working day.
A magic spell takes mana (and usually some "regular" energy) as input. Its outputs are useful work, waste heat energy and waste mana.
The planet Earth itself is also a "mage" of sorts. Vast quantities of mana are generated directly from geothermal heat in certain poorly-understood geological processes. Again, these are generated in huge clouds above these geologically active locations, and again, these clouds evaporate into waste mana while being constantly replenished.
Geological mana, like biological mana, has an owner, and therefore cannot be used by any human. Waste mana has no owner (null owner).
At the beginning of the story, waste mana is undetectable and unusable, although theory predicts both that it exists and that it obeys the same laws as biological and geological mana. As far as anybody knows, waste mana sinks back down into the Earth where it is presumably unrecoverable. It is theoretically possible to capture escaping waste mana using a specialised mana battery known as a "bilge".
Principally, magic makes general energy transduction processes simpler and more efficient. For example, a small input of mana makes it easy to convert heat energy or light energy to electrical potential energy. This is mind-bogglingly useful in almost every existing heavy industry.
Magic also gives rise to force fields/shields. At the beginning of the story, force fields can only be generated using very bulky and inconvenient machines, and only very small, perfectly flat force fields can be generated. Even so they are extremely useful in chemical, electrical and mechanical systems. As a result, the state of the art is being driven ahead very quickly indeed.
Magic has some telecommunications applications, which aren't explored fully yet.
Directly converting mana itself into heat or electricity is not generally useful, because mana isn't available in sufficient quantities. While it is possible to store mana up in unlimited quantities,
Magic-based bombs are impractical for the same reason, although bombs with magical components are not. Converting mana itself into light is much more practical.
Most applications of magic occur in large-scale industry. Consumer applications are far more limited because, once a magical spell or artifact runs out of mana, it must be recharged in person by a human mage, which requires an expensive call-out. To keep this to a minimum, very low-drain spells are becoming popular.
Efforts are underway to investigate long-range charging methods and wide field-effect spells - e.g., cast a spell over the whole of London which powers every suitably attuned magical artifact within range. DIY/hobby magic is also possible, much like plumbing or electrical work, but very few people have any capability in this area.
Risks: Magic is not as immediately life-threatening as a highly toxic or radioactive substance is, and a few years of training might elapse before a student mage gets anywhere near the point of serious safety considerations. However, once the energy levels begin to ramp up, you have the same problems associated with all high-energy situations. A magic-specific danger is of slipping into a fatal trance and suffering brain damage.
Magic as a concept was discovered in India the middle of 1972. Most of the pioneers of magic are or were Indian and most of the key results in magic (standardised equipment, equations, spells) are named after these pioneers. During the late 1970s there was extreme scepticism and disbelief as to the nature of the new discoveries, with some cults and larger religions embracing magic as being holy, proof of God, and/or in line with their beliefs, but equally many decrying it as Satanic witchcraft, and scientists at the core of the argument repeatedly asserting that "magic" was merely a new and inexplicable, though robust, science. Magic was, and remains, banned in several less economically developed nations due to superstition and is frowned upon in some highly religious areas, even in the United States. Controversy resurfaces in cycles; although the utility of magic is unquestioned, the morality of it is not.
It took until the end of the 1970s to nail down some firm principles and the major limitation was computational power. During the 1980s, thanks to advancing numerical computation methods, superior/simpler modelling equations, better engineering and a wider acceptance of the topic as being factual and therefore fit for study, the science of magic progressed rapidly. By the end of the 1980s it had gone from an open question of theoretical physics to a field of post-graduate study and then to a degree subject for those with the (substantial) necessary raw talent. In addition, manufacturing processes had been standardised and components for magical machinery were far better understood, permitting magical machinery to be built at lower cost.
By 1990 magic was an inarguable fact of life and was rapidly becoming inextricably linked with other modern technologies. By the mid-1990s magic was added to lower education syllabuses and elementary concepts began to be demonstrated in schools using off-the-shelf equipment.
In the present day of the story (Ra mostly takes place in the early 2000s), magic is a mature branch of engineering alongside electrical engineering and chemical engineering. A practitioner of magic is a magical engineer or "mage". Terms like "witch", "wizard", "sorcerer" and "warlock" are frowned upon because of their superstitious connotations. "Magician" and "conjuror" are typically reserved for stage performers.
The ability to use magic is an advanced technical skill, not unlike being a qualified electrician, or being able to play a very difficult musical instrument. It is also about as useful as those skills. Magic is useless for "wizardry", although it does have great utility for self-defence. It is most useful in the maintenance of magic-based equipment. In theory almost anybody is capable of a very basic level of magical ability, but in practice very few people both possess the necessary mental discipline and can afford the training. Magical technology, however, is used all over the world in every conceivable application, complementing "conventional" electromechanical machines: aerospace, shipping, chemical engineering, electrical engineering, construction, refrigeration, particle physics. Demand for mages is high. Magical training usually begins at the age of 18 with either a university degree followed by possible academic study, or an apprenticeship followed by immediate work in the field.
Open carrying of dangerous magical equipment has been recently made illegal in the UK. Magical practitioners have to leave equipment in baggage when travelling by aeroplane.
Several enormously important unanswered questions exist in magic, some of which are so significant as to be numbered:
Magic is a new science. It is expensive, but the cost is coming down. It is poorly understood, but understanding is advancing rapidly. Its applications are presently limited to specialist fields, small components of larger, mainly electromechanical systems, and well-funded Big Science research and development (e.g. NASA, defence contractors)... but this is changing...