Saturday, January 1, 2011
In a dangerous world people are often asked to trade some of their freedom
for increased security. In the face of increased terrorist threats, the
Transportation Safety Agency is investigating whole-body scanning devices
as an alternative to pat-down by agents searching for weapons or other
forbidden items. There are two scanning strategies for whole-body
searches: high sensitivity x-rays and sub-millimeter radio waves. The
public is clearly not happy with either alternative. The health community
properly objects to any additional x-ray burden, but if the added exposure
is small compared to the natural x-ray exposure at high-altitude it might
be acceptable. Sub-millimeter radio on the other hand is perfectly safe,
but many people have been led to believe its not by the terminally stupid
campaign against cell phone radiation. So where does that stand?
Maybe I missed it, but I have seen nothing from major media sources
refuting the preposterous claim that radiation from cell phones and other
wireless devices is linked to human health problems. We are bathed in
microwave radiation. Most of it is as natural as sunshine, but wireless
communication, including cell phone radiation, is not. What do we know
about the effect of this stuff on the human body, and how long ago did we
know it? The starting point is 1905, sometimes called "Albert Einstein's
miracle year." One of the four "miracle" papers he published that year
dealt with the photoelectric effect. He treated the light striking an
object as particles called quanta, having energy equal to the frequency
times the Planck constant. This predicted a photoelectron threshold at
the
extreme blue end of the visible spectrum, below which there would be no
photoemission. Almost nobody believed him, including Robert Millikan,
perhaps the world's greatest experimentalist. The photoelectric effect
had
already been explained with Maxwells wave theory, but experimental
confirmation was lacking. Einstein wasn't bothered; he had other great
things to do while waiting for confirmation. Millikan did the experiment
in 1917; it agreed perfectly with Einstein's theory. The 1921 Nobel Prize
in Physics was awarded to Einstein for his theory of the photoelectric
effect. Millikan won the Prize two years later. Their results show that
microwaves are great for warming pizza and they don't cause cancer.
Cell phones, along with electric cars, wind turbines, and a host of other
high-tech products rely on rare earths, 97% of which come from China. This
week, China announced plans to reduce exports of rare earths, which may be
a warning to potential competitors such as US Molycorp that China plays
hardball. China is also investing in rare earth mining sites in East
Africa
and is seeking to build a highway through the Serengeti. A friend who just
returned from a visit to Kenya describes the view from the air as looking
like Haiti. The forests have disappeared over vast regions to supply
firewood for the tiny, unproductive, shambas created by dividing the great
farms in the name of redistribution of wealth.
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