Humanity's 15 most important milestones 11-15
001 Petroleum is a naturally occurring flammable liquid found beneath the Earth's surface and has been used in one form or another since ancient times. The Babylonians used tar in the building of walls and towers over 4,000 years ago, but it would not be until 1859 of the Common Era that the first modern oil well was drilled. Edwin Drake used a steam engine to drill the well near Titusville, Pennsylvania, USA. While petroleum is used mostly as fuel, it is also important in many other industries involved in pharmaceuticals, fertilizers, and plastics. Vital to many other activities and its importance in the maintenance of civilization itself, the discovery of petroleum has certainly changed the human landscape.
002 Prior to steam power, rail transport was marginally used, the earliest known of which dates to the 6th century BCE to transport ships across the Corinth isthmus in Greece. Most were powered by either slaves or animals. The development of steam power during the Industrial Revolution spurred ideas for mobile locomotives on tracks. In 1811 John Blenkinsop designed the first practical railway and built the locomotive the following year. It ran between Middleton Colliery and Leeds in Britain. Rail transport soon exploded across Europe and North America, altering both the range and magnitude of human expansion, connecting people who were previously separate, and allowing for the relatively cheap movement of goods and passengers. Today rail transport is widely used throughout the world, and is likely to increase in usage in the future.
003 The process of developing nuclear power began in earnest with James Chadwick who discovered the neutron in 1932. With its lack of an electric charge, it was deemed to be an excellent tool for experimentation. However, it would take an additional six years before German chemists Otto Hahn and Fritz Strassmann, and Austrian physicist Lise Meitner and her nephew Otto Robert Frisch discovered fission, or the splitting of uranium atoms with the bombardment of neutrons of barium. This news quickly spread and further research began in several countries, notably the United States, Germany and the Soviet Union.
004 On December 2nd, 1942, critical mass, or criticality, was achieved under the Manhattan Project in Chicago, Illinois, USA. Today, nuclear power provides 10 percent of the world's electricity with 439 reactors operating in 31 countries. But the most important aspect of nuclear power is in the near future for space propulsion applications, as nuclear power provides about 10 million times more energy than chemical reactions in rockets. As the Space Age dawns, nuclear power will demonstrate to be integral in the next Age of Discovery.