I'm sorry, my attempts to write civilopedia entries have largely stalled. A few more:
CHARTER
The earliest intercontinental explorers were part of government-funded expeditions, as with Zheng He, Christopher Columbus, and Bartholomew Diaz. Soon it became clear that there were vast riches to be had from trade in luxury goods with remote lands, and where long range seafaring continued to thrive, private enterprise soon followed.
For the people of the time, a trip from Europe to trade for spices, gems, silk and other precious goods in Asia was immensely time-consuming, requiring the most advanced ships and years of time and effort by a crew of skilled sailors. Quite a few ships that attempted the voyage never made it back, being destroyed by storms or hostile locals over the tens of thousands of kilometers of sea voyage.
The risks involved created a powerful incentive to limit the financial hazards of the trip- any one merchant who invested in such an expedition might be ruined if something went wrong. Groups of wealthy men began to organize 'companies-' bands that would pool their resources and share the costs of the long, immensely profitable trips.
Some of these companies were able to secure royal guarantees from their home nations of exclusive trading rights- early examples include the English, Dutch, and French East India Companies. Over time, these organizations became extremely powerful, as the first ancestors of the modern multinational corporation.
FIREARMS
In its first centuries, gunpowder was too unstable and metallurgy too crude for the new explosive mix to be used for applications other than demolitions, fireworks, and large, heavily overbuilt artillery pieces. But with advances in metalworking in the 15th and 16th centuries CE, it became possible to create man-portable gunpowder weapons, which began to supplement and then to replace earlier ranged weapons such as the bow, crossbow, and sling.
By the 17th century, the world's most modern armies relied in large part on blocks of musket-armed infantry, often supported by pike units to keep cavalry from running down the musketeers while they reloaded their clumsy weapons. The pike units were removed entirely with the development of the bayonet, and ever since that era infantry combat has been dominated by the role of the gun and advances in firearms technology.
Even though early firearms were little if any deadlier than a good bow on average, they triggered a revolution in warfare. Firearms were easy to learn to use, and incredibly easy to mass produce compared to the cost of a suit of "bullet proof" steel armor. This helped drive the last nails into the coffin of heavily armored shock cavalry in Europe, ended the dominance of nomadic horse-archer cultures in Asia, and triggered a shift towards mass armies recruited from among the populace, ultimately paving the way for the revolutionary leveé en masse of the Napoleonic French.
NUCLEAR POWER
The greatest peacetime use of the power of the atomic nucleus is in nuclear reactors. In the early days after the discovery of atomic fission, this was a subject of great hope and optimism- the ideal was expressed that nuclear power would make Early expectations that atomic energy would make electricity "too cheap to meter."
A nuclear reactor consists of a number of 'fuel rods' or 'fuel pellets' made up of fissile materials, kept at a concentration below that needed for a critical mass. Thus, the chain reaction cannot run away as in a nuclear bomb, and simply keeps the fuel running at a high temperature, steadily heated by rapid fission of the uranium. The heat is used to power turbines through a variety of media- pressurized water, steam, or liquid sodium, for instance; the turbines power electric generators.
Design of a nuclear reactor is extremely challenging. The radiation environment inside the reactor core is intense, and all substances used inside the reactor must be chosen with an eye to their resistance and behavior when faced with radioactive bombardment of neutrons. Beyond this, there are also safety concerns- a nuclear reactor contains enough radioactive materials to contaminate a large area, if those materials were spread across the landscape.
Early plant designs, dating to the 1950s, often had serious safety problems associated with the designs. Since then, the nuclear industry has learned much, but its tracks are dogged by anti-nuclear advocates opposed to the use of nuclear energy. This opposition points to nuclear accidents at Chernobyl and Fukushima and questions whether modern plants are truly safe from such disasters; they also object to the fact that nuclear reactors generate radioactive waste which remains dangerous to human life for thousands of years and must be stored under special conditions.
Supporters of nuclear power reply that there are viable ways to store the waste safely, but the controversy continues to rage. The dream of power "too cheap to meter" has foundered on this, along with a host of practical issues that come with designing the heavily reinforced, disaster-resistant facilities required for the reactor and its wastes.
