Why It Took So Long to Invent the Wheel?
At http://www.livescience.com/18808-invention-wheel.htmlWheels are the archetype of a primitive, caveman-level technology. But in fact, they're so ingenious that it took until 3500 B.C. for someone to invent them. By that time — it was the Bronze Age — humans were already casting metal alloys, constructing canals and sailboats, and even designing complex musical instruments such as harps.
The tricky thing about the wheel is not conceiving of a cylinder rolling on its edge. It's figuring out how to connect a stable, stationary platform to that cylinder.
"The stroke of brilliance was the wheel-and-axle concept," said David Anthony, a professor of anthropology at Hartwick College and author of "The Horse, the Wheel, and Language" (Princeton, 2007). "But then making it was also difficult."
To make a fixed axle with revolving wheels, Anthony explained, the ends of the axle had to be nearly perfectly smooth and round, as did the holes in the center of the wheels; otherwise, (...) ( more at http://www.livescience.com/18808-invention-wheel.html )'Twisted' waves could boost capacity of wi-fi and TV.
At http://www.bbc.co.uk/news/science-environment-17221490A striking demonstration of a means to boost the information-carrying capacity of radio waves has taken place across the lagoon in Venice, Italy.
The technique exploits what is called the "orbital angular momentum" of the waves - imparting them with a "twist".
Varying this twist permits many data streams to fit in the frequency spread currently used for just one.
The approach, described in the New Journal of Physics, could be applied to radio, wi-fi, and television.
The parts of the electromagnetic spectrum that are used for all three are split up in roughly the same way, with a spread of frequencies allotted to each channel. Each one contains a certain, limited amount of information-carrying capacity: its bandwidth.
As telecommunications have proliferated through the years, the spectrum has become incredibly crowded, with little room left for new means of signal transmission, or for existing means to expand their bandwidths.
But Bo Thide of Swedish Institute of Space Physics and a team of colleagues in Italy hope to change that by exploiting an entirely new physical mechanism to fit more capacity onto the same... ( more at http://www.bbc.co.uk/news/science-environment-17221490 )
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