How far we have come from the Montgolfier balloon flights of 18th century France to today. How much farther will we go in the 21st century? In Part 7 of our look at transportation we will look at the evolution of flight technologies not including space. When we started talking about t

Renewable energy sources represent our best 21st century bet in replacing fossil fuels for generating electricity. Water, wind, waves and tides, solar and geothermal technologies have been in use in different forms for several centuries. Deriving new efficiencies through invention sho